honors biology 1st semester exam study guide
Post on 29-Nov-2014
5.632 Views
Preview:
DESCRIPTION
TRANSCRIPT
End Show
3–2 Energy Flow
Slide 1 of 41
Honors Biology
1st Semester Exam Study Guide
PowerPointCopyright Pearson Prentice Hall
End Show
3–2 Energy Flow
Slide 2 of 41
Copyright Pearson Prentice Hall
Feeding Relationships
Trophic Levels
Each step in a food chain or food web is called a trophic level.
Sun < Primary Producer < Primary Consumer < Secondary Consumer < Tertiary Consumer < Quatenary Consumer
Each consumer depends on the trophic level below it for energy.
End Show
3–2 Energy Flow
Slide 3 of 41
Copyright Pearson Prentice Hall
Ecological Pyramids
How efficient is the transfer of energy among organisms in an ecosystem?
Only about 10 percent of the energy available within one trophic level is transferred to organisms at the next trophic level.
End Show
3–2 Energy Flow
Slide 4 of 41
Copyright Pearson Prentice Hall
Ecological Pyramids
0.1% Third-level consumers
1% Second-level consumers
10% First-level consumers
100% Producers
Energy Pyramid:
Shows the relative amount of energy available at each trophic level.
Only part of the energy that is stored in one trophic level is passed on to the next level.
End Show
3–2 Energy Flow
Slide 5 of 41
Copyright Pearson Prentice Hall
Ecological Pyramids
50 grams of human tissue
500 grams of chicken
5000 grams of grass
Biomass Pyramid: Represents the amount of living organic matter at each trophic level. Typically, the greatest biomass is at the base of the pyramid.
End Show
3–2 Energy Flow
Slide 6 of 41
Copyright Pearson Prentice Hall
Ecological Pyramids
Pyramid of Numbers:Shows the relative number of individual organisms at each trophic level.
End Show
3–2 Energy Flow
Slide 7 of 41
Copyright Pearson Prentice Hall
Feeding Relationships
Food Chains
A food chain is a series of steps in which organisms transfer energy by eating and being eaten.
End Show
3–2 Energy Flow
Slide 8 of 41
Copyright Pearson Prentice Hall
Feeding Relationships
In some marine food chains, the producers are microscopic algae and the top carnivore is four steps removed from the producer.
Algae
ZooplanktonSmall Fish
SquidShark
End Show
3–2 Energy Flow
Slide 9 of 41
Copyright Pearson Prentice Hall
Feeding Relationships
Food Webs
Ecologists describe a feeding relationship in an ecosystem that forms a network of complex interactions as a food web.
A food web links all the food chains in an ecosystem together.
End Show
3–2 Energy Flow
Slide 10 of 41
Copyright Pearson Prentice Hall
Feeding Relationships
This food web shows some of the feeding relationships in a salt-marsh community.
End Show
3–2 Energy Flow
Slide 11 of 41
Copyright Pearson Prentice Hall
Producers
Autotrophs
Only plants, some algae, and certain bacteria can capture energy from sunlight or chemicals and use that energy to produce food.
These organisms are called autotrophs.
They harness energy through:
photosynthesis and chemosynthesis
Because they make their own food, autotrophs are called producers.
End Show
3–2 Energy Flow
Slide 12 of 41
Copyright Pearson Prentice Hall
Consumers
Heterotrophs
Many organisms cannot harness energy directly from the physical environment.
Organisms that rely on other organisms for their energy and food supply are called heterotrophs.
Heterotrophs are also called consumers.
End Show
3–2 Energy Flow
Slide 13 of 41
Copyright Pearson Prentice Hall
Consumers
There are many different types of heterotrophs.
•Herbivores eat plants. (cows, rabbits)
•Carnivores eat animals. (snakes, dogs, owls)
•Omnivores eat both plants and animals. (humans)
•Detritivores feed on plant and animal remains and other dead matter. (snails, crabs, earthworms)
•Decomposers break down organic matter. (bacteria, fungi)
End Show
3–2 Energy Flow
Slide 14 of 41
Copyright Pearson Prentice Hall
Nutrient Cycles
Nutrient Cycles
All the chemical substances that an organism needs to sustain life are its nutrients.
Every living organism needs nutrients to build tissues and carry out essential life functions.
Similar to water, nutrients are passed between organisms and the environment through biogeochemical cycles.
End Show
3–2 Energy Flow
Slide 15 of 41
Copyright Pearson Prentice Hall
Nutrient Cycles
The Carbon Cycle
Carbon is a key ingredient of living tissue.
Biological processes, such as photosynthesis, respiration, and decomposition, take up and release carbon and oxygen.
Geochemical processes, such as erosion and volcanic activity, release carbon dioxide to the atmosphere and oceans.
End Show
3–2 Energy Flow
Slide 16 of 41
Copyright Pearson Prentice Hall
Nutrient Cycles
CO2 in Atmosphere
Photosynthesis
feeding
feeding
Respiration
Deposition
Carbonate Rocks
Deposition
Decomposition
Fossil fuel
Volcanic activity
Uplift
Erosion
Respiration
Human activity
CO2 in Ocean
Photosynthesis
End Show
3–2 Energy Flow
Slide 17 of 41
Copyright Pearson Prentice Hall
Nutrient Cycles
The Nitrogen Cycle
All organisms require nitrogen to make proteins.
Although nitrogen gas is the most abundant form of nitrogen on Earth, only certain types of bacteria can use this form directly.
Such bacteria live in the soil and on the roots of plants called legumes. They convert nitrogen gas into ammonia in a process known as nitrogen fixation.
End Show
3–2 Energy Flow
Slide 18 of 41
Copyright Pearson Prentice Hall
Nutrient Cycles
Bacterial nitrogen fixation
N2 in Atmosphere
NH3
Synthetic fertilizer manufacturer
Uptake by producers
Reuse by consumers
Decomposition excretion
Atmospheric nitrogen fixation
Uptake by producers
Reuse by consumers
Decomposition
Decomposition excretion
NO3 and NO2
End Show
3–2 Energy Flow
Slide 19 of 41
Copyright Pearson Prentice Hall
Other soil bacteria convert nitrates into nitrogen gas in a process called denitrification.
This process releases nitrogen into the atmosphere once again.
Nutrient Cycles
End Show
3–2 Energy Flow
Slide 20 of 41
Copyright Pearson Prentice Hall
Nutrient Cycles
The Phosphorus Cycle
Phosphorus is essential to organisms because it helps forms important molecules like DNA and RNA.
Most phosphorus exists in the form of inorganic phosphate. Inorganic phosphate is released into the soil and water as sediments wear down.
End Show
3–2 Energy Flow
Slide 21 of 41
Copyright Pearson Prentice Hall
Organic phosphate moves through the food web and to the rest of the ecosystem.
Nutrient Cycles
Ocean
Land
Organisms
Sediments
End Show
3–2 Energy Flow
Slide 22 of 41
Copyright Pearson Prentice Hall
The Major Biomes
Biomes are defined by a unique set of abiotic factors—particularly climate—and a characteristic assemblage of plants and animals.
End Show
3–2 Energy Flow
Slide 23 of 41
Copyright Pearson Prentice Hall
Tropical rain forest
Tropical dry forest
Tropical savanna
Tundra
Temperate grassland
Desert
Temperate woodlandand shrublandMountains and ice caps
Boreal forest(Taiga)
Northwesternconiferous forest
Temperate forest
60°N
30°S
0° Equator
60°S
30°N
The Major Biomes
End Show
3–2 Energy Flow
Slide 24 of 41
Copyright Pearson Prentice Hall
The Major Biomes
Tropical Rain Forest
Tropical rain forests are home to more species than all other biomes combined.
The tops of tall trees, extending from 50 to 80 meters above the forest floor, form a dense covering called a canopy.
End Show
3–2 Energy Flow
Slide 25 of 41
Copyright Pearson Prentice Hall
The Major Biomes
In the shade below the canopy, a second layer of shorter trees and vines forms an understory.
Organic matter that falls to the forest floor quickly decomposes, and the nutrients are recycled.
End Show
3–2 Energy Flow
Slide 26 of 41
Copyright Pearson Prentice Hall
The Major Biomes
Abiotic factors: hot and wet year-round; thin, nutrient-poor soils
Dominant plants: broad-leaved evergreen trees; ferns; large woody vines and climbing plants
End Show
3–2 Energy Flow
Slide 27 of 41
Copyright Pearson Prentice Hall
The Major Biomes
Dominant wildlife: sloths, capybaras, jaguars, anteaters, monkeys, toucans, parrots, butterflies, beetles, piranhas, caymans, boa constrictors, and anacondas.
Geographic distribution: parts of South and Central America, Southeast Asia, parts of Africa, southern India, and northeastern Australia
End Show
3–2 Energy Flow
Slide 28 of 41
Copyright Pearson Prentice Hall
The Major Biomes
Tropical Dry Forest
Tropical dry forests grow in places where rainfall is highly seasonal rather than year-round.
During the dry season, nearly all the trees drop their leaves to conserve water.
A tree that sheds its leaves during a particular season each year is called deciduous.
End Show
3–2 Energy Flow
Slide 29 of 41
Copyright Pearson Prentice Hall
The Major Biomes
Abiotic factors: generally warm year-round; alternating wet and dry seasons; rich soils subject to erosion
Dominant plants: tall, deciduous trees; drought-tolerant plants; aloes and other succulents
End Show
3–2 Energy Flow
Slide 30 of 41
Copyright Pearson Prentice Hall
The Major Biomes
Dominant wildlife: tigers, monkeys, elephants, Indian rhinoceroses, hog deer, great pied hornbills, pied harriers, spot-billed pelicans, termites, snakes and monitor lizards
Geographic distribution: parts of Africa, South and Central America, Mexico, India, Australia, and tropical islands
End Show
3–2 Energy Flow
Slide 31 of 41
Copyright Pearson Prentice Hall
The Major Biomes
Tropical Savanna
Tropical savannas, or grasslands, receive more rainfall than deserts but less than tropical dry forests.
They are covered with grasses.
Compact soils, fairly frequent fires, and the action of large animals prevent them from becoming dry forest.
End Show
3–2 Energy Flow
Slide 32 of 41
Copyright Pearson Prentice Hall
The Major Biomes
Abiotic factors: warm temperatures; seasonal rainfall; compact soil; frequent fires set by lightning
Dominant plants: tall, perennial grasses; drought-tolerant and fire-resistant trees or shrubs
End Show
3–2 Energy Flow
Slide 33 of 41
Copyright Pearson Prentice Hall
The Major Biomes
Dominant wildlife: lions, leopards, cheetahs, hyenas, jackals, aardvarks, elephants, giraffes, antelopes, zebras, baboons, eagles, ostriches, weaver birds, and storks
Geographic distribution: large parts of eastern Africa, southern Brazil, and northern Australia
End Show
3–2 Energy Flow
Slide 34 of 41
Copyright Pearson Prentice Hall
The Major Biomes
Desert
All deserts are dry, defined as having annual precipitation of less than 25 centimeters.
Deserts vary greatly, some undergoing extreme temperature changes during the course of a day.
The organisms in this biome can tolerate extreme conditions.
End Show
3–2 Energy Flow
Slide 35 of 41
Copyright Pearson Prentice Hall
The Major Biomes
Abiotic factors: low precipitation; variable temperatures; soils rich in minerals but poor in organic material
Dominant plants: cacti and other succulents; plants with short growth cycles
End Show
3–2 Energy Flow
Slide 36 of 41
Copyright Pearson Prentice Hall
The Major Biomes
Dominant wildlife: mountain lions, gray foxes, bobcats, mule deer, pronghorn antelopes, desert bighorn sheep, kangaroo rats, bats, owls, hawks, roadrunners, ants, beetles, butterflies, flies, wasps, tortoises, rattlesnakes, and lizards
Geographic distribution: Africa, Asia, the Middle East, United States, Mexico, South America, and Australia
End Show
3–2 Energy Flow
Slide 37 of 41
Copyright Pearson Prentice Hall
The Major Biomes
Temperate Grassland
Temperate grasslands are characterized by a rich mix of grasses and underlaid by fertile soils.
Periodic fires and heavy grazing by large herbivores maintain the characteristic plant community.
End Show
3–2 Energy Flow
Slide 38 of 41
Copyright Pearson Prentice Hall
The Major Biomes
Abiotic factors: warm to hot summers; cold winters; moderate, seasonal precipitation; fertile soils; occasional fires
Dominant plants: lush, perennial grasses and herbs; most are resistant to drought, fire, and cold
End Show
3–2 Energy Flow
Slide 39 of 41
Copyright Pearson Prentice Hall
The Major Biomes
Dominant wildlife: coyotes, badgers, pronghorn antelopes, rabbits, prairie dogs, introduced cattle, hawks, owls, bobwhites, prairie chickens, mountain plovers, snakes, ants and grasshoppers
Geographic distribution: central Asia, North America, Australia, central Europe, and upland plateaus of South America
End Show
3–2 Energy Flow
Slide 40 of 41
Copyright Pearson Prentice Hall
The Major Biomes
Temperate Woodland and Shrubland
This biome is characterized by a semiarid climate and mix of shrub communities and open woodlands.
Large areas of grasses and wildflowers are interspersed with oak trees.
End Show
3–2 Energy Flow
Slide 41 of 41
Copyright Pearson Prentice Hall
The Major Biomes
Communities that are dominated by shrubs are also known as chaparral.
The growth of dense, low plants that contain flammable oils makes fires a constant threat.
End Show
3–2 Energy Flow
Slide 42 of 41
Copyright Pearson Prentice Hall
The Major Biomes
Abiotic factors: hot, dry summers; cool, moist winters; thin, nutrient-poor soils; periodic fires
Dominant plants: woody evergreen shrubs; herbs that grow during winter and die in summer
End Show
3–2 Energy Flow
Slide 43 of 41
Copyright Pearson Prentice Hall
The Major Biomes
Dominant wildlife: coyotes, foxes, bobcats, mountain lions, black-tailed deer, rabbits, squirrels, hawks, California quails, warblers, lizards, snakes, and butterflies
Geographic distribution: western coasts of North and South America, areas around the Mediterranean Sea, South Africa, and Australia
End Show
3–2 Energy Flow
Slide 44 of 41
Copyright Pearson Prentice Hall
The Major Biomes
Temperate Forest
Temperate forests contain a mixture of deciduous and coniferous trees.
Coniferous trees, or conifers, produce seed-bearing cones and most have leaves shaped like needles.
These forests have cold winters that halt plant growth for several months.
End Show
3–2 Energy Flow
Slide 45 of 41
Copyright Pearson Prentice Hall
The Major Biomes
In autumn, the deciduous trees shed their leaves.
Soils of temperate forests are often rich in humus, a material formed from decaying leaves and other organic matter that makes soil fertile.
End Show
3–2 Energy Flow
Slide 46 of 41
Copyright Pearson Prentice Hall
The Major Biomes
Abiotic factors: cold to moderate winters; warm summers; year-round precipitation; fertile soils
Dominant plants: broadleaf deciduous trees; some conifers; flowering shrubs; herbs; a ground layer of mosses and ferns
End Show
3–2 Energy Flow
Slide 47 of 41
Copyright Pearson Prentice Hall
The Major Biomes
Dominant wildlife: Deer, black bears, bobcats, squirrels, raccoons, skunks, numerous songbirds, turkeys
Geographic distribution: eastern United States; southeastern Canada; most of Europe; and parts of Japan, China, and Australia
End Show
3–2 Energy Flow
Slide 48 of 41
Copyright Pearson Prentice Hall
The Major Biomes
Northwestern Coniferous Forest
Mild, moist air from the Pacific Ocean provides abundant rainfall to this biome.
The forest is made up of a variety of trees, including giant redwoods, spruce, fir, hemlock, and dogwood.
Because of its lush vegetation, the northwestern coniferous forest is sometimes called a “temperate rain forest.”
End Show
3–2 Energy Flow
Slide 49 of 41
Copyright Pearson Prentice Hall
The Major Biomes
Abiotic factors: mild temperatures; abundant precipitation during fall, winter, and spring; relatively cool, dry summer; rocky, acidic soils
Dominant plants: Douglas fir, Sitka spruce, western hemlock, redwood
End Show
3–2 Energy Flow
Slide 50 of 41
Copyright Pearson Prentice Hall
The Major Biomes
Dominant wildlife: bears, elk, deer, beavers, owls, bobcats, and members of the weasel family
Geographic distribution: Pacific coast of northwestern United States and Canada, from northern California to Alaska
End Show
3–2 Energy Flow
Slide 51 of 41
Copyright Pearson Prentice Hall
The Major Biomes
Boreal Forest
Dense evergreen forests of coniferous trees are found along the northern edge of the temperate zone.
These forests are called boreal forests, or taiga.
End Show
3–2 Energy Flow
Slide 52 of 41
Copyright Pearson Prentice Hall
The Major Biomes
Winters are bitterly cold.
Summers are mild and long enough to allow the ground to thaw.
Boreal forests occur mostly in the Northern Hemisphere.
End Show
3–2 Energy Flow
Slide 53 of 41
Copyright Pearson Prentice Hall
The Major Biomes
Abiotic factors: long, cold winters; short, mild summers; moderate precipitation; high humidity; acidic, nutrient-poor soils
Dominant plants: needleleaf coniferous trees; some broadleaf deciduous trees; small, berry-bearing shrubs
End Show
3–2 Energy Flow
Slide 54 of 41
Copyright Pearson Prentice Hall
The Major Biomes
Dominant wildlife: lynxes, timber wolves, members of the weasel family, small herbivorous mammals, moose, beavers, songbirds, and migratory birds
Geographic distribution: North America, Asia, and northern Europe
End Show
3–2 Energy Flow
Slide 55 of 41
Copyright Pearson Prentice Hall
The Major Biomes
Tundra
The tundra is characterized by permafrost, a layer of permanently frozen subsoil.
During the short, cool summer, the ground thaws to a depth of a few centimeters and becomes soggy and wet. In winter, the topsoil freezes again.
Cold temperaturs, high winds, the short growing season, and humus-poor soils also limit plant height.
End Show
3–2 Energy Flow
Slide 56 of 41
Copyright Pearson Prentice Hall
The Major Biomes
Abiotic factors: strong winds; low precipitation; short and soggy summers; long, cold, and dark winters; poorly developed soils; permafrost
Dominant plants: ground-hugging plants such as mosses, lichens, sedges, and short grasses
End Show
3–2 Energy Flow
Slide 57 of 41
Copyright Pearson Prentice Hall
The Major Biomes
Dominant wildlife: birds, mammals that can withstand the harsh conditions, migratory waterfowl, shore birds, musk ox, Arctic foxes, caribou, lemmings and other small rodents
Geographic distribution: northern North America, Asia, and Europe
End Show
3–2 Energy Flow
Slide 58 of 41
Copyright Pearson Prentice Hall
Levels of Organization
Ecosystem
Community
Population
Individual
Biome
Biosphere
End Show
3–2 Energy Flow
Slide 59 of 41
Copyright Pearson Prentice Hall
Levels of Organization
A species is a group of organisms so similar to one another that they can breed and produce fertile offspring.
Populations are groups of individuals that belong to the same species and live in the same area.
Communities are assemblages of different populations that live together in a defined area.
End Show
3–2 Energy Flow
Slide 60 of 41
Copyright Pearson Prentice Hall
Levels of Organization
An ecosystem is a collection of all the organisms that live in a particular place, together with their nonliving, or physical, environment.
A biome is a group of ecosystems that have the same climate and similar dominant communities.
The highest level of organization that ecologists study is the entire biosphere itself.
End Show
3–2 Energy Flow
Slide 61 of 41
Copyright Pearson Prentice Hall
Community Interactions
Competition
Competition occurs when organisms of the same or different species attempt to use an ecological resource in the same place at the same time.
A resource is any necessity of life, such as water, nutrients, light, food, or space.
End Show
3–2 Energy Flow
Slide 62 of 41
Copyright Pearson Prentice Hall
Community Interactions
Direct competition in nature often results in a winner and a loser—with the losing organism failing to survive.
The competitive exclusion principle states that no two species can occupy the same niche in the same habitat at the same time.
End Show
3–2 Energy Flow
Slide 63 of 41
Copyright Pearson Prentice Hall
Community Interactions
The distribution of these warblers avoids direct competition, because each species feeds in a different part of the tree.
Yellow-Rumped Warbler
Bay-Breasted Warbler
Fee
ding
hei
ght
(m)
0
6
12
18
Cape May Warbler
End Show
3–2 Energy Flow
Slide 64 of 41
Copyright Pearson Prentice Hall
Community Interactions
Predation
An interaction in which one organism captures and feeds on another organism is called predation.
The organism that does the killing and eating is called the predator, and the food organism is the prey.
End Show
3–2 Energy Flow
Slide 65 of 41
Copyright Pearson Prentice Hall
Community Interactions
Symbiosis
Any relationship in which two species live closely together is called symbiosis.
Symbiotic relationships include:
• mutualism
• commensalism
• parasitism
End Show
3–2 Energy Flow
Slide 66 of 41
Copyright Pearson Prentice Hall
Community Interactions
Mutualism: both species benefit from the relationship.
Commensalism: one member of the association benefits and the other is neither helped nor harmed.
Parasitism: one organism lives on or inside another organism and harms it.
End Show
3–2 Energy Flow
Slide 67 of 41
Copyright Pearson Prentice Hall
Exponential Growth
Exponential Growth
Under ideal conditions with unlimited resources, a population will grow exponentially.
Exponential growth occurs when the individuals in a population reproduce at a constant rate.
The population becomes larger and larger until it approaches an infinitely large size.
End Show
3–2 Energy Flow
Slide 68 of 41
Exponential Growth
Copyright Pearson Prentice Hall
Exponential Growth
End Show
3–2 Energy Flow
Slide 69 of 41
Copyright Pearson Prentice Hall
Logistic Growth
Logistic Growth
As resources become less available, the growth of a population slows or stops.
Logistic growth occurs when a population's growth slows or stops following a period of exponential growth.
End Show
3–2 Energy Flow
Slide 70 of 41
Logistic Growth
Logistic growth is characterized by an S-shaped curve.
Copyright Pearson Prentice Hall
End Show
3–2 Energy Flow
Slide 71 of 41
Copyright Pearson Prentice Hall
Density-Dependent Factors
Density-Dependent Factors
A limiting factor that depends on population size is called a density-dependent limiting factor.
End Show
3–2 Energy Flow
Slide 72 of 41
Copyright Pearson Prentice Hall
Density-Dependent Factors
Density-dependent limiting factors include:
• competition
• predation
• parasitism
• disease
End Show
3–2 Energy Flow
Slide 73 of 41
Copyright Pearson Prentice Hall
Density-Dependent Factors
Density-dependent factors operate only when the population density reaches a certain level. These factors operate most strongly when a population is large and dense.
They do not affect small, scattered populations as greatly.
End Show
3–2 Energy Flow
Slide 74 of 41
Copyright Pearson Prentice Hall
Density-Independent Factors
Density-Independent Factors
Density-independent limiting factors affect all populations in similar ways, regardless of the population size.
End Show
3–2 Energy Flow
Slide 75 of 41
Copyright Pearson Prentice Hall
Density-Independent Factors
Examples of density-independent limiting factors include:
• unusual weather
• natural disasters
• seasonal cycles
• certain human activities—such as damming rivers and clear-cutting forests
End Show
3–2 Energy Flow
Slide 76 of 41
Copyright Pearson Prentice Hall
Designing an Experiment
Designing an Experiment
The process of testing a hypothesis includes:
• Asking a question
• Forming a hypothesis
• Setting up a controlled experiment
• Recording and analyzing results
• Drawing a conclusion
End Show
3–2 Energy Flow
Slide 77 of 41
Copyright Pearson Prentice Hall
Designing an Experiment
Asking a Question
Many years ago, people wanted to know how living things came into existence. They asked:
How do organisms come into being?
End Show
3–2 Energy Flow
Slide 78 of 41
Copyright Pearson Prentice Hall
Designing an Experiment
Forming a Hypothesis
One early hypothesis was spontaneous generation.
For example, most people thought that maggots spontaneously appeared on meat.
In 1668, Redi proposed a different hypothesis: that maggots came from eggs that flies laid on meat.
End Show
3–2 Energy Flow
Slide 79 of 41
Copyright Pearson Prentice Hall
Designing an Experiment
Setting Up a Controlled Experiment
manipulated variable
responding variable
End Show
3–2 Energy Flow
Slide 80 of 41
Copyright Pearson Prentice Hall
Designing an Experiment
Redi’s Experiment
Controlled Variables:jars, type of meat,Location, temperature,time
Covered jarsUncovered jars
End Show
3–2 Energy Flow
Slide 81 of 41
Copyright Pearson Prentice Hall
Designing an Experiment
Redi’s Experiment
Manipulated Variable:Gauze covering that keeps flies away from meat
Responding Variable:whether maggots appear Maggots appear.
Severaldays pass.
No maggots appear.
End Show
3–2 Energy Flow
Slide 82 of 41
Copyright Pearson Prentice Hall
Designing an Experiment
Drawing a Conclusion
Scientists use the data from an experiment to evaluate a hypothesis and draw a valid conclusion.
End Show
3–2 Energy Flow
Slide 83 of 41
Copyright Pearson Prentice Hall
Designing an Experiment
Experimental Design
Quantitative vs. Qualitative
Quantitative: measured by appearance, by observations; cannot be measured by numbers
Qualitative: measured by numbers
Independent vs. Dependent
Independent: variable you get to manipulate (usually graphed on x-axis)
Dependent: variable you don’t get to manipulate that changes based on the independent variable (usually graphed on y-axis)
End Show
3–2 Energy Flow
Slide 84 of 41
Copyright Pearson Prentice Hall
Designing an Experiment
Hypothesis vs. Theory vs. Law
Hypothesis: possible explanation for a set of observations or possible answer to a scientific question
Theory: well-tested explanation that unifies a broad range of observations
Law: concise verbal or mathematical statement of a relation that expresses a fundamental principle of science
End Show
3–2 Energy Flow
Slide 85 of 41
Copyright Pearson Prentice Hall
Atoms
Atoms
The study of chemistry begins with the basic unit of matter, the atom.
End Show
3–2 Energy Flow
Slide 86 of 41
Copyright Pearson Prentice Hall
Atoms
Placed side by side, 100 million atoms would make a row only about 1 centimeter long.
Atoms contain subatomic particles that are even smaller.
End Show
3–2 Energy Flow
Slide 87 of 41
Copyright Pearson Prentice Hall
Atoms
The subatomic particles that make up atoms are
•Nucleus
Neutron: neutral (mass: 1)
Proton: positive (mass: 1)
•Outer Shell
Electron: negative (mass: 1/1800)
# protons = # electrons
# protons = atomic #
# protons + # neutrons = mass #
End Show
3–2 Energy Flow
Slide 88 of 41
Copyright Pearson Prentice Hall
Atoms
The subatomic particles in a helium atom.
End Show
3–2 Energy Flow
Slide 89 of 41
Copyright Pearson Prentice Hall
Elements and Isotopes
Elements and Isotopes
A chemical element is a pure substance that consists entirely of one type of atom.
• C stands for carbon.
• Na stands for sodium.
End Show
3–2 Energy Flow
Slide 90 of 41
Copyright Pearson Prentice Hall
Elements and Isotopes
The number of protons in an atom of an element is the element's atomic number.
Commonly found in living organisms:
End Show
3–2 Energy Flow
Slide 91 of 41
Copyright Pearson Prentice Hall
Elements and Isotopes
Isotopes
Atoms of the same element that differ in the number of neutrons they contain are known as isotopes.
End Show
3–2 Energy Flow
Slide 92 of 41
Copyright Pearson Prentice Hall
Elements and Isotopes
Because they have the same number of electrons, all isotopes of an element have the same chemical properties.
End Show
3–2 Energy Flow
Slide 93 of 41
Copyright Pearson Prentice Hall
Elements and Isotopes
Isotopes of Carbon
6 electrons6 protons8 neutrons
End Show
3–2 Energy Flow
Slide 94 of 41
Copyright Pearson Prentice Hall
Elements and Isotopes
Radioactive Isotopes
Some isotopes are radioactive, meaning that their nuclei are unstable and break down at a constant rate over time
End Show
3–2 Energy Flow
Slide 95 of 41
Copyright Pearson Prentice Hall
Elements and Isotopes
Radioactive isotopes can be used:•to determine the ages of rocks and fossils.
•to treat cancer.
•to kill bacteria that cause food to spoil.
•as labels or “tracers” to follow the movement of substances within an organism.
End Show
3–2 Energy Flow
Slide 96 of 41
Copyright Pearson Prentice Hall
The Water Molecule
A water molecule is polar because there is an uneven distribution of electrons between the oxygen and hydrogen atoms.
End Show
3–2 Energy Flow
Slide 97 of 41
Copyright Pearson Prentice Hall
The Water Molecule
Water Molecule
End Show
3–2 Energy Flow
Slide 98 of 41
Copyright Pearson Prentice Hall
The Water Molecule
Hydrogen Bonds
Because of their partial positive and negative charges, polar molecules can attract each other.
End Show
3–2 Energy Flow
Slide 99 of 41
Copyright Pearson Prentice Hall
The Water Molecule
Cohesion is an attraction between molecules of the same substance.
Because of hydrogen bonding, water is extremely cohesive.
End Show
3–2 Energy Flow
Slide 100 of 41
Copyright Pearson Prentice Hall
The Water Molecule
Adhesion is an attraction between molecules of different substances.
End Show
3–2 Energy Flow
Slide 101 of 41
Copyright Pearson Prentice Hall
Acids, Bases, and pH
Acids, Bases, and pH
A water molecule is neutral, but can react to form hydrogen and hydroxide ions.
H2O H+ + OH-
End Show
3–2 Energy Flow
Slide 102 of 41
Copyright Pearson Prentice Hall
Acids, Bases, and pH
The pH scale
Chemists devised a measurement system called the pH scale to indicate the concentration of H+ ions in solution.
The pH scale ranges from 0 to 14.
End Show
3–2 Energy Flow
Slide 103 of 41
Copyright Pearson Prentice Hall
Acids, Bases, and pH
At a pH of 7, the concentration of H+
ions and OH- ions is equal.
The pH Scale
Human blood
Milk
Sea water
Normal rainfall
Pure water
End Show
3–2 Energy Flow
Slide 104 of 41
Copyright Pearson Prentice Hall
Acids, Bases, and pH
AcidsAn acid is any compound that forms H+ ions in solution.
End Show
3–2 Energy Flow
Slide 105 of 41
Copyright Pearson Prentice Hall
Acids, Bases, and pH
Bases
A base is a compound that produces hydroxide ions (OH- ions) in solution.
End Show
3–2 Energy Flow
Slide 106 of 41
Copyright Pearson Prentice Hall
Acids, Bases, and pH
Buffers
The pH of the fluids within most cells in the human body must generally be kept between 6.5 and 7.5.
Controlling pH is important for maintaining homeostasis.
End Show
3–2 Energy Flow
Slide 107 of 41
Copyright Pearson Prentice Hall
Macromolecules
Four groups of organic compounds found in living things are:
•carbohydrates
•lipids
•nucleic acids
•proteins
End Show
3–2 Energy Flow
Slide 108 of 41
Copyright Pearson Prentice Hall
Carbohydrates
What is the function of carbohydrates?
Source of Energy
Structure
End Show
3–2 Energy Flow
Slide 109 of 41
Copyright Pearson Prentice Hall
Carbohydrates
Carbohydrates
Carbohydrates are compounds made up of carbon, hydrogen, and oxygen atoms, usually in a ratio of 1 : 2 : 1.
End Show
3–2 Energy Flow
Slide 110 of 41
Copyright Pearson Prentice Hall
Carbohydrates
Different sizes of carbohydrates:
Monosaccharides
Disaccharides
Polysaccharides
End Show
3–2 Energy Flow
Slide 111 of 41
Copyright Pearson Prentice Hall
Carbohydrates
Starches and sugars are examples of carbohydrates that are used by living things as a source of energy.
Glucose
Starch Examples:CelluloseStarchGlycogen
End Show
3–2 Energy Flow
Slide 112 of 41
Copyright Pearson Prentice Hall
Lipids
Lipids
Lipids are generally not soluble in water.
The common categories of lipids are:
fats
oils
waxes
steroids
End Show
3–2 Energy Flow
Slide 113 of 41
Copyright Pearson Prentice Hall
Lipids
Lipids can be used to store energy. Some lipids are important parts of biological membranes and waterproof coverings.
End Show
3–2 Energy Flow
Slide 114 of 41
Copyright Pearson Prentice Hall
Lipids
End Show
3–2 Energy Flow
Slide 115 of 41
Copyright Pearson Prentice Hall
Nucleic Acids
Nucleic Acids
Nucleic acids are polymers assembled from individual monomers known as nucleotides.
End Show
3–2 Energy Flow
Slide 116 of 41
Copyright Pearson Prentice Hall
Nucleic Acids
Nucleotides consist of three parts:
•a 5-carbon sugar
•a phosphate group
•a nitrogenous base
End Show
3–2 Energy Flow
Slide 117 of 41
Copyright Pearson Prentice Hall
Nucleic Acids
Nucleic acids store and transmit hereditary, or genetic, information.
ribonucleic acid (RNA)
deoxyribonucleic acid (DNA)
End Show
3–2 Energy Flow
Slide 118 of 41
Copyright Pearson Prentice Hall
Proteins
Proteins
Proteins are macromolecules that contain nitrogen, carbon, hydrogen, and oxygen.
• polymers of molecules called amino acids.
End Show
3–2 Energy Flow
Slide 119 of 41
Copyright Pearson Prentice Hall
Proteins
Amino acids
End Show
3–2 Energy Flow
Slide 120 of 41
Copyright Pearson Prentice Hall
Proteins
The portion of each amino acid that is different is a side chain called an R-group.
End Show
3–2 Energy Flow
Slide 121 of 41
Copyright Pearson Prentice Hall
Proteins
The instructions for arranging amino acids into many different proteins are stored in DNA.
AminoAcids
Protein Molecule
End Show
3–2 Energy Flow
Slide 122 of 41
Copyright Pearson Prentice Hall
Proteins
Some functions of proteins:–Control rate of reactions – Enzymes–Used to form bones and muscles–Transport substances into or out of cells –Help to fight disease - antibodies
End Show
3–2 Energy Flow
Slide 123 of 41
Copyright Pearson Prentice Hall
Energy in Reactions
Activation Energy
Chemists call the energy that is needed to get a reaction started the activation energy.
End Show
3–2 Energy Flow
Slide 124 of 41
Copyright Pearson Prentice Hall
Enzymes
Enzymes
Some chemical reactions that make life possible are too slow or have activation energies.
These chemical reactions are made possible by catalysts.
End Show
3–2 Energy Flow
Slide 125 of 41
Copyright Pearson Prentice Hall
Enzymes
Enzymes speed up chemical reactions that take place in cells.
End Show
3–2 Energy Flow
Slide 126 of 41
Copyright Pearson Prentice Hall
Enzyme Action
The Enzyme-Substrate Complex
Enzymes provide a site where reactants can be brought together to react, reducing the energy needed for reaction.
The reactants of enzyme-catalyzed reactions are known as substrates.
End Show
3–2 Energy Flow
Slide 127 of 41
Copyright Pearson Prentice Hall
Enzyme Action
An Enzyme-Catalyzed Reaction
End Show
3–2 Energy Flow
Slide 128 of 41
Copyright Pearson Prentice Hall
Enzyme Action
Regulation of Enzyme Activity
Enzymes can be affected by any variable that influences a chemical reaction.
• pH values
• Changes in temperature
• Enzyme or substrate concentrations
End Show
3–2 Energy Flow
Slide 129 of 41
Copyright Pearson Prentice Hall
The Discovery of the Cell
Scientists
Robert Hooke: looked @ slices of plant tissue and coined name “cells”
Anton van Leeuwenhoek: observed single-celled living organisms in pond water and called them Animacules. Also observed some bacteria.
Mattheis Schleiden: looked @ plant material an concluded all plants are made of cells
Theodor Schwann: looked @ various animal cells an concluded all animals are made of cells
Rudolf Virchow: studied cellular reproduction an concluded that “all cells must come from pre-existing cells”
End Show
3–2 Energy Flow
Slide 130 of 41
Copyright Pearson Prentice Hall
The Discovery of the Cell
The cell theory states:
•All living things are composed of cells.
•Cells are the basic units of structure and function in living things.
•New cells are produced from existing cells.
End Show
3–2 Energy Flow
Slide 131 of 41
Copyright Pearson Prentice Hall
Exploring the Cell
Electron Microscopes
Electron microscopes reveal details 1000 times smaller than those visible in light microscopes.
Electron microscopy can be used to visualize only nonliving, preserved cells and tissues.
End Show
3–2 Energy Flow
Slide 132 of 41
Copyright Pearson Prentice Hall
Exploring the Cell
Transmission electron microscopes (TEMs)
•Used to study cell structures and large protein molecules
•Specimens must be cut into ultra-thin slices
End Show
3–2 Energy Flow
Slide 133 of 41
Copyright Pearson Prentice Hall
Exploring the Cell
Scanning electron microscopes (SEMs)
•Produce three-dimensional images of cells
•Specimens do not have to be cut into thin slices
End Show
3–2 Energy Flow
Slide 134 of 41
Copyright Pearson Prentice Hall
Exploring the Cell
Scanning Electron Micrograph of Neurons
End Show
3–2 Energy Flow
Slide 135 of 41
Copyright Pearson Prentice Hall
Prokaryotes and Eukaryotes
Prokaryotes
Prokaryotic cells have genetic material that is not contained in a nucleus.
•Prokaryotes do not have membrane-bound organelles
•Prokaryotic cells are generally smaller and simpler than eukaryotic cells.
•Bacteria are prokaryotes.
•They are the same size as mitochondrion.
End Show
3–2 Energy Flow
Slide 136 of 41
Copyright Pearson Prentice Hall
Prokaryotes and Eukaryotes
Eukaryotes
Eukaryotic cells contain a nucleus in which their genetic material is separated from the rest of the cell.
End Show
3–2 Energy Flow
Slide 137 of 41
Copyright Pearson Prentice Hall
Prokaryotes and Eukaryotes
•Eukaryotic cells are generally larger and more complex than prokaryotic cells.
•Eukaryotic cells contain organelles and have a cell membrane.
•Many eukaryotic cells are highly specialized.
•DNA is in the chromosomes.
•Plants, animals, fungi, and protists are eukaryotes.
End Show
3–2 Energy Flow
Slide 138 of 41
Copyright Pearson Prentice Hall
Eukaryotic Cell Structures
Animal Cell vs. Plant Cell
•Have centrioles•Gain energy through eating
•Have cell walls•Have chloroplasts•Use photosynthesis for energy
•Similar organelles
End Show
3–2 Energy Flow
Slide 139 of 41
Copyright Pearson Prentice Hall
Eukaryotic Cell Structures
Plant Cell
Nuclear envelope
Ribosome (free)
Ribosome (attached)
Mitochondrion
Golgi apparatus
Vacuole
Nucleolus
NucleusSmooth endoplasmic reticulum
Rough endoplasmic reticulum
Cell wall
Cell membrane
Chloroplast
End Show
3–2 Energy Flow
Slide 140 of 41
Copyright Pearson Prentice Hall
Eukaryotic Cell Structures
Smooth endoplasmic reticulum
Ribosome (free)
Ribosome (attached)
Golgi apparatus
Mitochondrion
Rough endoplasmic reticulum
Cell membrane
Nucleus
Nuclear envelope
Nucleolus
Centrioles
Animal Cell
End Show
3–2 Energy Flow
Slide 141 of 41
Copyright Pearson Prentice Hall
Nucleus
Nucleus
The nucleus is the control center of the cell.
The nucleus contains nearly all the cell's DNA and with it the coded instructions for making proteins and other important molecules.
Nucleolus: makes ribosomes
Nuclear Pores/Envelope: allow things in/out of nucleus
End Show
3–2 Energy Flow
Slide 142 of 41
Copyright Pearson Prentice Hall
Nucleus
The Nucleus
Nucleolus Nuclear envelope
Nuclear pores
Chromatin
End Show
3–2 Energy Flow
Slide 143 of 41
Copyright Pearson Prentice Hall
Ribosomes
Ribosomes
One of the most important jobs carried out in the cell is making proteins.
Proteins are assembled on ribosomes.
Ribosomes are small particles of RNA and protein found throughout the cytoplasm.
End Show
3–2 Energy Flow
Slide 144 of 41
Copyright Pearson Prentice Hall
Endoplasmic Reticulum
Ribosomes
Endoplasmic Reticulum
There are two types of ER—rough and smooth.
Assembles components of cell membrane & some proteins
End Show
3–2 Energy Flow
Slide 145 of 41
Copyright Pearson Prentice Hall
Golgi Apparatus
Golgi Apparatus
Proteins are activated & transported in vesicles to their destination
End Show
3–2 Energy Flow
Slide 146 of 41
Copyright Pearson Prentice Hall
Vacuoles
Vacuole
Storage area of cells
Animal cells have smaller ones than plant cells
Vacuole
End Show
3–2 Energy Flow
Slide 147 of 41
Copyright Pearson Prentice Hall
Mitochondria and Chloroplasts
Mitochondrion
Mitochondria
Produce energy through cellular respiration
Powerhouse of the cell
End Show
3–2 Energy Flow
Slide 148 of 41
Copyright Pearson Prentice Hall
Mitochondria and Chloroplasts
ChloroplastChloroplasts
Plants and some other organisms contain chloroplasts.
Chloroplasts capture energy from sunlight and convert it into chemical energy in a process called photosynthesis.
End Show
3–2 Energy Flow
Slide 149 of 41
Copyright Pearson Prentice Hall
Cytoskeleton
Centrioles
Located near the nucleus and help to organize cell division
Only in animal cells
Centrioles
End Show
3–2 Energy Flow
Slide 150 of 41
Cell Walls
Copyright Pearson Prentice Hall
Cell Wall
Cell walls are found in plants, algae, fungi, and many prokaryotes. The protect and support and are located outside of the membrane.
End Show
3–2 Energy Flow
Slide 151 of 41
Copyright Pearson Prentice Hall
Cytoskeleton
Cytoskeleton
The cytoskeleton is a network of protein filaments that helps the cell to maintain its shape. The cytoskeleton is also involved in movement.
The cytoskeleton is made up of:
•Microfilaments: movement and support of cell
•Microtubules: tracks to move organelles/vesicles
End Show
3–2 Energy Flow
Slide 152 of 41
Copyright Pearson Prentice Hall
Cytoskeleton
Cytoskeleton
Ribosomes Mitochondrion
Endoplasmic reticulum
Cell membrane
Microtubule
Microfilament
End Show
3–2 Energy Flow
Slide 153 of 41
Copyright Pearson Prentice Hall
Cell Membrane
Cell Membrane
The cell membrane regulates what enters & leaves the cell and also provides protection/support; is also selectively permeable
A.k.a. plasma membrane, fluid mosaic model, phospholipid bilayer
Made up of phospholipids:
End Show
3–2 Energy Flow
Slide 154 of 41
Copyright Pearson Prentice Hall
Cell Membrane
Cell Membrane
Outside of cell
Phospho-lipid Bilayer
Inside of cell (cytoplasm)
Integral Protein
<Peripheral Protein
Glycoprotein>
Phosphate Heads & Fatty
Acid Tails
Glycolipids
End Show
3–2 Energy Flow
Slide 155 of 41
Copyright Pearson Prentice Hall
Diffusion Through Cell Boundaries
Diffusion
Particles in a solution tend to move from an area where they are more concentrated to an area where they are less concentrated.
This process is called diffusion.
When the concentration of the solute is the same throughout a system, the system has reached equilibrium.
End Show
3–2 Energy Flow
Slide 156 of 41
Copyright Pearson Prentice Hall
Diffusion Through Cell Boundaries
End Show
3–2 Energy Flow
Slide 157 of 41
Copyright Pearson Prentice Hall
Osmosis
Osmosis
Osmosis is the diffusion of water through a selectively permeable membrane.
End Show
3–2 Energy Flow
Slide 158 of 41
Copyright Pearson Prentice Hall
Osmosis
How Osmosis Works
Movement of water
Dilute sugar solution (Water more concentrated)
Concentrated sugar solution (Water less concentrated)
Sugar molecules
Selectively permeable membrane
End Show
3–2 Energy Flow
Slide 159 of 41
Copyright Pearson Prentice Hall
Osmosis
Water tends to diffuse from a highly concentrated region to a less concentrated region.
If you compare two solutions, three terms can be used to describe the concentrations:
hypertonic (“above strength”).
hypotonic (“below strength”).
isotonic (”same strength”)
End Show
3–2 Energy Flow
Slide 160 of 41
Copyright Pearson Prentice Hall
Osmosis
Osmotic Pressure
Osmosis exerts a pressure known as osmotic pressure on the hypertonic side of a selectively permeable membrane.
End Show
3–2 Energy Flow
Slide 161 of 41
Copyright Pearson Prentice Hall
Osmosis
Osmotic Pressure
Hypertonic: solution has higher solute concentration than cell
Isotonic: concentration of solutes same inside & outside of cell
Hypotonic: Solution has lower solute concentration than cell
Examples:
Blood in isotonic water = nothing
Celery in salt water = hypotonic
End Show
3–2 Energy Flow
Slide 162 of 41
Copyright Pearson Prentice Hall
Facilitated Diffusion
Facilitated Diffusion
Protein channel
Glucose molecules
•Diffusion of molecules thru protein channel•Requires energy•Requires concentration gradient
End Show
3–2 Energy Flow
Slide 163 of 41
Copyright Pearson Prentice Hall
Active Transport
Active Transport
Sometimes cells move materials in the opposite direction from which the materials would normally move—that is against a concentration difference. This process is known as active transport.
Active transport requires energy.
End Show
3–2 Energy Flow
Slide 164 of 41
Copyright Pearson Prentice Hall
Active Transport
Molecular Transport
In active transport, small molecules and ions are carried across membranes by proteins in the membrane.
Energy use in these systems enables cells to concentrate substances in a particular location, even when diffusion might move them in the opposite direction.
End Show
3–2 Energy Flow
Slide 165 of 41
Copyright Pearson Prentice Hall
Active Transport
Molecule to be carried
Active Transport
Molecular Transport
End Show
3–2 Energy Flow
Slide 166 of 41
Copyright Pearson Prentice Hall
Active Transport
Endocytosis and Exocytosis
Endocytosis is the process of taking material into the cell.
Two examples of endocytosis are:
• phagocytosis
• pinocytosis
During exocytosis, materials are forced out of the cell.
End Show
3–2 Energy Flow
Slide 167 of 41
Copyright Pearson Prentice Hall
Events of the Cell Cycle
Reasons for Cell to Divide
•Larger a cell becomes, more demands cell places on its DNA
•Cell has more trouble moving enough nutrients & wastes across cell membrane
End Show
3–2 Energy Flow
Slide 168 of 41
Copyright Pearson Prentice Hall
Cell Cycle
Events of the Cell Cycle
End Show
3–2 Energy Flow
Slide 169 of 41
Copyright Pearson Prentice Hall
The Cell Cycle
The cell cycle consists of four phases:
• G1 (First Gap Phase)
• S Phase
• G2 (Second Gap Phase)
• M Phase
End Show
3–2 Energy Flow
Slide 170 of 41
Copyright Pearson Prentice Hall
Events of the Cell Cycle
Events of the Cell Cycle
During G1, the cell
• increases in size
• synthesizes new proteins and organelles
End Show
3–2 Energy Flow
Slide 171 of 41
Copyright Pearson Prentice Hall
Events of the Cell Cycle
During the S phase,
•chromosomes are replicated
•DNA synthesis takes placeOnce a cell enters the S phase, it usually completes the rest of the cell cycle.
End Show
3–2 Energy Flow
Slide 172 of 41
Copyright Pearson Prentice Hall
Events of the Cell Cycle
The G2 Phase (Second Gap Phase)
•organelles and molecules required for cell division are produced
•Once G2 is complete, the cell is ready to start the M phase—Mitosis
End Show
3–2 Energy Flow
Slide 173 of 41
Copyright Pearson Prentice Hall
Mitosis
Mitosis
Biologists divide the events of mitosis into four phases: (PMAT)
•Prophase
•Metaphase
•Anaphase
•Telophase
End Show
3–2 Energy Flow
Slide 174 of 41
Copyright Pearson Prentice Hall
Mitosis
Mitosis
End Show
3–2 Energy Flow
Slide 175 of 41
Copyright Pearson Prentice Hall
Mitosis
Prophase
Prophase is the first and longest phase of mitosis.
The centrioles separate and take up positions on opposite sides of the nucleus.
Spindle forming
CentromereChromosomes(paired chromatids)
End Show
3–2 Energy Flow
Slide 176 of 41
Copyright Pearson Prentice Hall
Mitosis
The centrioles lie in a region called the centrosome.
The centrosome helps to organize the spindle, a fanlike microtubule structure that helps separate the chromosomes.
Spindle forming
CentromereChromosomes(paired chromatids)
End Show
3–2 Energy Flow
Slide 177 of 41
Copyright Pearson Prentice Hall
Mitosis
Chromatin condenses into chromosomes.
The centrioles separate and a spindle begins to form.
The nuclear envelope breaks down.
Spindle forming
CentromereChromosomes(paired chromatids)
End Show
3–2 Energy Flow
Slide 178 of 41
Copyright Pearson Prentice Hall
Mitosis
Metaphase
The second phase of mitosis is metaphase.
The chromosomes line up across the center of the cell.
Microtubules connect the centromere of each chromosome to the poles of the spindle.
Centriole
Spindle
End Show
3–2 Energy Flow
Slide 179 of 41
Copyright Pearson Prentice Hall
Mitosis
Anaphase
Anaphase is the third phase of mitosis.
The sister chromatids separate into individual chromosomes.
The chromosomes continue to move until they have separated into two groups.
Individualchromosomes
End Show
3–2 Energy Flow
Slide 180 of 41
Copyright Pearson Prentice Hall
Mitosis
Telophase
Telophase is the fourth and final phase of mitosis.
Chromosomes gather at opposite ends of the cell and lose their distinct shape.
End Show
3–2 Energy Flow
Slide 181 of 41
Copyright Pearson Prentice Hall
Mitosis
A new nuclear envelope forms around each cluster of chromosomes.
End Show
3–2 Energy Flow
Slide 182 of 41
Copyright Pearson Prentice Hall
Cytokinesis
During cytokinesis, the cytoplasm pinches in half.
Each daughter cell has an identical set of duplicate chromosomes
End Show
3–2 Energy Flow
Slide 183 of 41
Copyright Pearson Prentice Hall
Cytokinesis in Plants
In plants, a structure known as the cell plate forms midway between the divided nuclei.
Cell wallCell plate
End Show
3–2 Energy Flow
Slide 184 of 41
Copyright Pearson Prentice Hall
Cell Cycle Regulators
Cell Cycle Regulators
The cell cycle is regulated by a specific protein.
The amount of this protein in the cell rises and falls in time with the cell cycle.
Scientists called this protein cyclin because it seemed to regulate the cell cycle.
Cyclins regulate the timing of the cell cycle in eukaryotic cells.
End Show
3–2 Energy Flow
Slide 185 of 41
Copyright Pearson Prentice Hall
A sample of cytoplasmis removed from a cellin mitosis.
The sample is injectedinto a second cell inG2 of interphase.
As result, the secondcell enters mitosis.
Cyclins were discovered during a similar experiment to this one.
Cell Cycle Regulators
End Show
3–2 Energy Flow
Slide 186 of 41
Copyright Pearson Prentice Hall
Internal Regulators
Internal regulators allow the cell cycle to proceed only when certain processes have happened inside the cell.
Example: p53 Gene that regulates the passage into mitosis
Cell Cycle Regulators
End Show
3–2 Energy Flow
Slide 187 of 41
Copyright Pearson Prentice Hall
Cell Cycle Regulators
External Regulators
Proteins that respond to events outside the cell are called external regulators.
External regulators direct cells to speed up or slow down the cell cycle.
End Show
3–2 Energy Flow
Slide 188 of 41
Copyright Pearson Prentice Hall
Metabolism
Metabolism
Metabolism: the chemical changes in living cells by which energy is provided for vital processes and activities and new material is assimilated
Catabolism: breakdown in living organisms of more complex substances into simpler ones together with release of energy
e.g. Cellular Respiration
Anabolism: the synthesis in living organisms of more complex substances (e.g., living tissue) from simpler ones together with the storage of energy
e.g. Photosynthesis
End Show
3–2 Energy Flow
Slide 189 of 41
Copyright Pearson Prentice Hall
Exergonic vs. Endergonic
Exergonic vs. Endergonic
Exergonic: releases energy
e.g. Cellular Respiration
Endergonic: absorbs energy
e.g. Photosynthesis
End Show
3–2 Energy Flow
Slide 190 of 41
Copyright Pearson Prentice Hall
Chemical Energy and ATP
An important chemical compound that cells use to store and release energy is adenosine triphosphate, abbreviated ATP.
ATP is used by all types of cells as their basic energy source.
End Show
3–2 Energy Flow
Slide 191 of 41
Copyright Pearson Prentice Hall
Chemical Energy and ATP
ATP consists of:
• adenine
• ribose (a 5-carbon sugar)
• 3 phosphate groups
Adenine
ATP
Ribose 3 Phosphate groups
End Show
3–2 Energy Flow
Slide 192 of 41
Copyright Pearson Prentice Hall
Chemical Energy and ATP
Storing Energy
ADP has two phosphate groups instead of three.
A cell can store small amounts of energy by adding a phosphate group to ADP.
ADPATP
Energy
Energy
Partiallycharged battery
Fullycharged battery
+
Adenosine Diphosphate (ADP) + Phosphate
Adenosine Triphosphate (ATP)
End Show
3–2 Energy Flow
Slide 193 of 41
Copyright Pearson Prentice Hall
Chemical Energy and ATP
Releasing Energy
Energy stored in ATP is released by breaking the chemical bond between the second and third phosphates.
P
ADP
2 Phosphate groups
End Show
3–2 Energy Flow
Slide 194 of 41
Copyright Pearson Prentice Hall
Chemical Energy and ATP
Breaking ATP
Last phosphate bond in ATP broken by adding H20 during hydrolysis process.
ATPase = enzyme used to help weaken/break bond
Forming ATP
When phosphate bond broken, ADP & free phosphate form
ATP Synthetase = enzyme used to rejoin ADP & free phosphate
Using ATP’s energy & then remaking it called ADP-ATP cycle
End Show
3–2 Energy Flow
Slide 195 of 41
Copyright Pearson Prentice Hall
Chemical Energy and ATP
The energy from ATP is needed for many cellular activities, including active transport across cell membranes, protein synthesis and muscle contraction.
ATP’s characteristics make it exceptionally useful as the basic energy source of all cells.
End Show
3–2 Energy Flow
Slide 196 of 41
Copyright Pearson Prentice Hall
Overview of Cellular Respiration
The equation for cellular respiration is:
6O2 + C6H12O6 → 6CO2 + 6H2O + Energy
oxygen + glucose → carbon dioxide + water + Energy
End Show
3–2 Energy Flow
Slide 197 of 41
Copyright Pearson Prentice Hall
Overview of Cellular Respiration
Glycolysis takes place in the cytoplasm. The Krebs cycle and electron transport take place in the mitochondria.
CytoplasmMitochondrion
Glycolysis
End Show
3–2 Energy Flow
Slide 198 of 41
Copyright Pearson Prentice Hall
Glycolysis
ATP Production
At the beginning of glycolysis, the cell uses up 2 molecules of ATP to start the reaction.
2 ADP 4 ADP 4 ATP
2 Pyruvicacid
2 ATP
Glucose
End Show
3–2 Energy Flow
Slide 199 of 41
Copyright Pearson Prentice Hall
Glycolysis
When glycolysis is complete, 4 ATP molecules have been produced.
2 ADP 4 ADP 4 ATP2 ATP
Glucose2 Pyruvicacid
End Show
3–2 Energy Flow
Slide 200 of 41
Copyright Pearson Prentice Hall
Glycolysis
This gives the cell a net gain of 2 ATP molecules.
4 ADP 4 ATP
Glucose
2 ADP2 ATP
2 Pyruvicacid
End Show
3–2 Energy Flow
Slide 201 of 41
Copyright Pearson Prentice Hall
Glycolysis
NADH Production
One reaction of glycolysis removes 4 high-energy electrons, passing them to an electron carrier called NAD+.
Glucose2 Pyruvicacid
4 ADP 4 ATP2 ADP2 ATP
2NAD+
End Show
3–2 Energy Flow
Slide 202 of 41
Copyright Pearson Prentice Hall
Glycolysis
Each NAD+ accepts a pair of high-energy electrons and becomes an NADH molecule.
Glucose2 Pyruvicacid
4 ADP 4 ATP2 ADP2 ATP
2NAD+2
End Show
3–2 Energy Flow
Slide 203 of 41
Copyright Pearson Prentice Hall
Glycolysis
The NADH molecule holds the electrons until they can be transferred to other molecules.
To the electrontransport chain
2NAD+ 2 Pyruvicacid
4 ADP 4 ATP2 ADP2 ATP
2
End Show
3–2 Energy Flow
Slide 204 of 41
Copyright Pearson Prentice Hall
Glycolysis
The Advantages of Glycolysis
The process of glycolysis is so fast that cells can produce thousands of ATP molecules in a few milliseconds.
Glycolysis does not require oxygen.
End Show
3–2 Energy Flow
Slide 205 of 41
Copyright Pearson Prentice Hall
Anaerobic vs. Aerobic
Anaerobic vs. Aerobic
Anaerobic: does not require oxygen
e.g. Glycolysis, Fermentation
Aerobic: requires oxygen
e.g. Krebs Cycle & ETC
End Show
3–2 Energy Flow
Slide 206 of 41
Copyright Pearson Prentice Hall
The Krebs Cycle
During the Krebs cycle, pyruvic acid is broken down into carbon dioxide in a series of energy-extracting reactions.
End Show
3–2 Energy Flow
Slide 207 of 41
Copyright Pearson Prentice Hall
The Krebs Cycle
The Krebs cycle begins when pyruvic acid produced by glycolysis enters the mitochondrion.
End Show
3–2 Energy Flow
Slide 208 of 41
Copyright Pearson Prentice Hall
The Krebs Cycle
One carbon molecule is removed, forming CO2, and electrons are removed, changing NAD+ to NADH.
End Show
3–2 Energy Flow
Slide 209 of 41
Copyright Pearson Prentice Hall
The Krebs Cycle
Coenzyme A joins the 2-carbon molecule, forming acetyl-CoA.
End Show
3–2 Energy Flow
Slide 210 of 41
Copyright Pearson Prentice Hall
The Krebs Cycle
Citric acid
Acetyl-CoA then adds the 2-carbon acetyl group to a 4-carbon compound, forming citric acid.
End Show
3–2 Energy Flow
Slide 211 of 41
Copyright Pearson Prentice Hall
The Krebs Cycle
Citric acid is broken down into a 5-carbon compound, then into a 4-carbon compound.
End Show
3–2 Energy Flow
Slide 212 of 41
Copyright Pearson Prentice Hall
The Krebs Cycle
Two more molecules of CO2 are released and electrons join NAD+ and FAD, forming NADH and FADH2
End Show
3–2 Energy Flow
Slide 213 of 41
Copyright Pearson Prentice Hall
The Krebs Cycle
In addition, one molecule of ATP is generated.
End Show
3–2 Energy Flow
Slide 214 of 41
Copyright Pearson Prentice Hall
The Krebs Cycle
The energy tally from 1 molecule of pyruvic acid is
• 4 NADH• 1 FADH2
• 1 ATP
End Show
3–2 Energy Flow
Slide 215 of 41
Copyright Pearson Prentice Hall
Electron Transport
Electron Transport
The electron transport chain uses the high-energy electrons from the Krebs cycle to convert ADP into ATP.
End Show
3–2 Energy Flow
Slide 216 of 41
Copyright Pearson Prentice Hall
Electron Transport
High-energy electrons from NADH and FADH2 are passed along the electron transport chain from one carrier protein to the next.
End Show
3–2 Energy Flow
Slide 217 of 41
Copyright Pearson Prentice Hall
Electron Transport
At the end of the chain, an enzyme combines these electrons with hydrogen ions and oxygen to form water.
End Show
3–2 Energy Flow
Slide 218 of 41
Copyright Pearson Prentice Hall
Electron Transport
As the final electron acceptor of the electron transport chain, oxygen gets rid of the low-energy electrons and hydrogen ions.
End Show
3–2 Energy Flow
Slide 219 of 41
Copyright Pearson Prentice Hall
Electron Transport
When 2 high-energy electrons move down the electron transport chain, their energy is used to move hydrogen ions (H+) across the membrane.
End Show
3–2 Energy Flow
Slide 220 of 41
Copyright Pearson Prentice Hall
Electron Transport
During electron transport, H+ ions build up in the intermembrane space, so it is positively charged.
End Show
3–2 Energy Flow
Slide 221 of 41
Copyright Pearson Prentice Hall
Electron Transport
The other side of the membrane, from which those H+ ions are taken, is now negatively charged.
End Show
3–2 Energy Flow
Slide 222 of 41
Copyright Pearson Prentice Hall
Electron Transport
ATP synthase
The inner membranes of the mitochondria contain protein spheres called ATP synthases.
End Show
3–2 Energy Flow
Slide 223 of 41
Copyright Pearson Prentice Hall
Electron Transport
As H+ ions escape through channels into these proteins, the ATP synthase spins.
ATP synthase
Channel
End Show
3–2 Energy Flow
Slide 224 of 41
Copyright Pearson Prentice Hall
Electron Transport
As it rotates, the enzyme grabs a low-energy ADP, attaching a phosphate, forming high-energy ATP.
ATP
ATP synthase
Channel
End Show
3–2 Energy Flow
Slide 225 of 41
Copyright Pearson Prentice Hall
The Photosynthesis Equation
The Photosynthesis Equation
The equation for photosynthesis is:
6CO2 + 6H2O C6H12O6 + 6O2
carbon dioxide + water sugars + oxygen
Light
Light
End Show
3–2 Energy Flow
Slide 226 of 41
Copyright Pearson Prentice Hall
Light and Pigments
Light and Pigments
How do plants capture the energy of sunlight?
In addition to water and carbon dioxide, photosynthesis requires light and chlorophyll.
End Show
3–2 Energy Flow
Slide 227 of 41
Copyright Pearson Prentice Hall
Light and Pigments
Plants gather the sun's energy with light-absorbing molecules called pigments.
The main pigment in plants is chlorophyll.
There are two main types of chlorophyll:
• chlorophyll a
• chlorophyll b
End Show
3–2 Energy Flow
Slide 228 of 41
Chlorophyll absorbs light well in the blue-violet and red regions of the visible spectrum.
Copyright Pearson Prentice Hall
Light and Pigments
Wavelength (nm)
Est
imat
ed A
bsor
ptio
n (%
)
100
80
60
40
20
0400 450 500 550 600 650 700 750
Chlorophyll b
Chlorophyll a
Wavelength (nm)
End Show
3–2 Energy Flow
Slide 229 of 41
Copyright Pearson Prentice Hall
Light and Pigments
Chlorophyll does not absorb light will in the green region of the spectrum. Green light is reflected by leaves, which is why plants look green.
Est
imat
ed A
bsor
ptio
n (%
)
100
80
60
40
20
0400 450 500 550 600 650 700 750
Chlorophyll b
Chlorophyll a
Wavelength (nm)
End Show
3–2 Energy Flow
Slide 230 of 41
Copyright Pearson Prentice Hall
Light and Pigments
Light is a form of energy, so any compound that absorbs light also absorbs energy from that light.
When chlorophyll absorbs light, much of the energy is transferred directly to electrons in the chlorophyll molecule, raising the energy levels of these electrons.
These high-energy electrons are what make photosynthesis work.
End Show
3–2 Energy Flow
Slide 231 of 41
Copyright Pearson Prentice Hall
Light and Pigments
Carotenoids
Plant pigments that include red and orange colors
The plants absorb low-level energy from the sun w/ carotenoids
This, and b/c green pigments are greatly reduced during fall, is why plants change colors during this time
End Show
3–2 Energy Flow
Slide 232 of 41
Copyright Pearson Prentice Hall
Inside a Chloroplast
Mesophyll Cell
In plants, photosynthesis takes place in the mesophyll cells.
Cell Wall
CentralVacuole
Nucleus
Chloroplast
End Show
3–2 Energy Flow
Slide 233 of 41
Copyright Pearson Prentice Hall
Inside a Chloroplast
Inside a Chloroplast
In plants, photosynthesis takes place inside chloroplasts.
Plant
Plant cells
Chloroplast
End Show
3–2 Energy Flow
Slide 234 of 41
Copyright Pearson Prentice Hall
Inside a Chloroplast
Chloroplasts contain thylakoids—saclike photosynthetic membranes. Stroma is the space outside the thylakoid membranes.
Chloroplast
Singlethylakoid
Stroma
End Show
3–2 Energy Flow
Slide 235 of 41
Copyright Pearson Prentice Hall
Inside a Chloroplast
Thylakoids are arranged in stacks known as grana. A singular stack is called a granum.
Granum
Chloroplast
End Show
3–2 Energy Flow
Slide 236 of 41
Copyright Pearson Prentice Hall
Inside a Chloroplast
Proteins in the thylakoid membrane organize chlorophyll and other pigments into clusters called photosystems, which are the light-collecting units of the chloroplast.
Chloroplast
Photosystems
End Show
3–2 Energy Flow
Slide 237 of 41
Copyright Pearson Prentice Hall
Inside a Chloroplast
Chloroplast
Light
H2O
O2
CO2
Sugars
NADP+
ADP + P
Calvin Cycle
Light- dependent reactions
Calvin cycle
End Show
3–2 Energy Flow
Slide 238 of 41
Copyright Pearson Prentice Hall
Light-Dependent Reactions
Light-Dependent Reactions
The light-dependent reactions require light.
The light-dependent reactions produce oxygen gas and convert ADP and NADP+ into the energy carriers ATP and NADPH.
End Show
3–2 Energy Flow
Slide 239 of 41
Copyright Pearson Prentice Hall
Light-Dependent Reactions
End Show
3–2 Energy Flow
Slide 240 of 41
Copyright Pearson Prentice Hall
Photosystem II
Light-Dependent Reactions
Photosynthesis begins when pigments in photosystem II absorb light, increasing their energy level.
End Show
3–2 Energy Flow
Slide 241 of 41
Copyright Pearson Prentice Hall
Light-Dependent Reactions
Photosystem II
These high-energy electrons are passed on to the electron transport chain.
Electroncarriers
High-energy electron
End Show
3–2 Energy Flow
Slide 242 of 41
Copyright Pearson Prentice Hall
Light-Dependent Reactions
Photosystem II
2H2O
Enzymes on the thylakoid membrane break water molecules into:
Electroncarriers
High-energy electron
End Show
3–2 Energy Flow
Slide 243 of 41
Copyright Pearson Prentice Hall
Light-Dependent Reactions
Photosystem II
2H2O
• hydrogen ions• oxygen atoms• energized electrons
+ O2
Electroncarriers
High-energy electron
End Show
3–2 Energy Flow
Slide 244 of 41
Copyright Pearson Prentice Hall
Light-Dependent Reactions
Photosystem II
2H2O
+ O2
The energized electrons from water replace the high-energy electrons that chlorophyll lost to the electron transport chain.
High-energy electron
End Show
3–2 Energy Flow
Slide 245 of 41
Copyright Pearson Prentice Hall
Light-Dependent Reactions
Photosystem II
2H2O
As plants remove electrons from water, oxygen is left behind and is released into the air.
+ O2
High-energy electron
End Show
3–2 Energy Flow
Slide 246 of 41
Copyright Pearson Prentice Hall
Light-Dependent Reactions
Photosystem II
2H2O
The hydrogen ions left behind when water is broken apart are released inside the thylakoid membrane.
+ O2
High-energy electron
End Show
3–2 Energy Flow
Slide 247 of 41
Copyright Pearson Prentice Hall
Light-Dependent Reactions
Photosystem II
2H2O
Energy from the electrons is used to transport H+ ions from the stroma into the inner thylakoid space.
+ O2
End Show
3–2 Energy Flow
Slide 248 of 41
Copyright Pearson Prentice Hall
Light-Dependent Reactions
Photosystem II
2H2O
High-energy electrons move through the electron transport chain from photosystem II to photosystem I.
+ O2
Photosystem I
End Show
3–2 Energy Flow
Slide 249 of 41
Copyright Pearson Prentice Hall
Light-Dependent Reactions
2H2O
Pigments in photosystem I use energy from light to re-energize the electrons.
+ O2
Photosystem I
End Show
3–2 Energy Flow
Slide 250 of 41
Copyright Pearson Prentice Hall
Light-Dependent Reactions
2H2O
NADP+ then picks up these high-energy electrons, along with H+ ions, and becomes NADPH.
+ O2
2 NADP+
2 NADPH2
End Show
3–2 Energy Flow
Slide 251 of 41
Copyright Pearson Prentice Hall
Light-Dependent Reactions
2H2O
As electrons are passed from chlorophyll to NADP+, more H+ ions are pumped across the membrane.
+ O2
2 NADP+
2 NADPH2
End Show
3–2 Energy Flow
Slide 252 of 41
Copyright Pearson Prentice Hall
Light-Dependent Reactions
2H2O
Soon, the inside of the membrane fills up with positively charged hydrogen ions, which makes the outside of the membrane negatively charged.
+ O2
2 NADP+
2 NADPH2
End Show
3–2 Energy Flow
Slide 253 of 41
Copyright Pearson Prentice Hall
Light-Dependent Reactions
2H2O
The difference in charges across the membrane provides the energy to make ATP
+ O2
2 NADP+
2 NADPH2
End Show
3–2 Energy Flow
Slide 254 of 41
Copyright Pearson Prentice Hall
Light-Dependent Reactions
2H2O
H+ ions cannot cross the membrane directly.
+ O2
ATP synthase
2 NADP+
2 NADPH2
End Show
3–2 Energy Flow
Slide 255 of 41
Copyright Pearson Prentice Hall
Light-Dependent Reactions
2H2O
The cell membrane contains a protein called ATP synthase that allows H+ ions to pass through it
+ O2
ATP synthase
2 NADP+
2 NADPH2
End Show
3–2 Energy Flow
Slide 256 of 41
Copyright Pearson Prentice Hall
Light-Dependent Reactions
2H2O
As H+ ions pass through ATP synthase, the protein rotates.
+ O2
ATP synthase
2 NADP+
2 NADPH2
End Show
3–2 Energy Flow
Slide 257 of 41
Copyright Pearson Prentice Hall
Light-Dependent Reactions
2H2O
As it rotates, ATP synthase binds ADP and a phosphate group together to produce ATP.
+ O2
2 NADP+
2 NADPH2
ATP synthase
ADP
End Show
3–2 Energy Flow
Slide 258 of 41
Copyright Pearson Prentice Hall
Light-Dependent Reactions
2H2O
Because of this system, light-dependent electron transport produces not only high-energy electrons but ATP as well.
+ O2
ATP synthase
ADP2 NADP+
2 NADPH2
End Show
3–2 Energy Flow
Slide 259 of 41259
Chemiosmosis
Chemiosmosis
• Powers ATP synthesis
• Takes place across the thylakoid membrane
• Uses ETC and ATP synthase (enzyme)
• H+ move down their concentration gradient through channels of ATP synthase forming ATP from ADP
End Show
3–2 Energy Flow
Slide 260 of 41260
Chemiosmosis
H+ H+
ATP Synthase
H+ H+ H+ H+
H+ H+high H+
concentration
H+ADP + P ATP
PS II PS IE
TC
low H+
concentration
H+ThylakoidSpace
Thylakoid
SUN (Proton Pumping)
End Show
3–2 Energy Flow
Slide 261 of 41
Copyright Pearson Prentice Hall
The Calvin Cycle
The Calvin cycle uses ATP and NADPH from the light-dependent reactions to produce high-energy sugars.
Because the Calvin cycle does not require light, these reactions are also called the light-independent reactions.
End Show
3–2 Energy Flow
Slide 262 of 41
Copyright Pearson Prentice Hall
The Calvin Cycle
Six carbon dioxide molecules enter the cycle from the atmosphere and combine with six 5-carbon molecules.
CO2 Enters the Cycle
End Show
3–2 Energy Flow
Slide 263 of 41
Copyright Pearson Prentice Hall
The Calvin Cycle
The result is twelve 3-carbon molecules, which are then converted into higher-energy forms.
End Show
3–2 Energy Flow
Slide 264 of 41
Copyright Pearson Prentice Hall
The Calvin Cycle
The energy for this conversion comes from ATP and high-energy electrons from NADPH.
12 NADPH
12
12 ADP
12 NADP+
Energy Input
End Show
3–2 Energy Flow
Slide 265 of 41
Copyright Pearson Prentice Hall
The Calvin Cycle
Two of twelve 3-carbon molecules are removed from the cycle.
Energy Input
12 NADPH
12
12 ADP
12 NADP+
End Show
3–2 Energy Flow
Slide 266 of 41
Copyright Pearson Prentice Hall
The Calvin Cycle
The molecules are used to produce sugars, lipids, amino acids and other compounds.
12 NADPH
12
12 ADP
12 NADP+
6-Carbon sugar produced
Sugars and other compounds
End Show
3–2 Energy Flow
Slide 267 of 41
Copyright Pearson Prentice Hall
The Calvin Cycle
The 10 remaining 3-carbon molecules are converted back into six 5-carbon molecules, which are used to begin the next cycle.
12 NADPH
12
12 ADP
12 NADP+
5-Carbon MoleculesRegenerated
Sugars and other compounds
6
6 ADP
End Show
3–2 Energy Flow
Slide 268 of 41
Copyright Pearson Prentice Hall
The Calvin Cycle
The two sets of photosynthetic reactions work together.
• The light-dependent reactions trap sunlight energy in chemical form.
• The light-independent reactions use that chemical energy to produce stable, high-energy sugars from carbon dioxide and water.
End Show
3–2 Energy Flow
Slide 269 of 41269
Photorespiration
Photorespiration
• Occurs on hot, dry, bright days
• Stomates close
• Fixation of O2 instead of CO2
• Produces 2-C molecules instead of 3-C sugar molecules
• Produces no sugar molecules or no ATP
End Show
3–2 Energy Flow
Slide 270 of 41270
Photorespiration
Because of photorespiration, plants have special adaptations to limit the effect of photorespiration:
1. C4 plants
2. CAM plants
End Show
3–2 Energy Flow
Slide 271 of 41271
C4 Plants
C4 Plants• Hot, moist environments
• 15% of plants (grasses, corn, sugarcane)
• Photosynthesis occurs in 2 places
• Light reaction - mesophyll cells
• Calvin cycle - bundle sheath cells
End Show
3–2 Energy Flow
Slide 272 of 41272
C4 Plants
Mesophyll Cell
CO2
C-C-C
PEP
C-C-C-CMalate-4C sugar
ATP
Bundle Sheath Cell
C-C-C
Pyruvic Acid
C-C-C-C
CO2
C3
Malate
Transported
glucoseVascular Tissue
End Show
3–2 Energy Flow
Slide 273 of 41273
CAM Plants
• Hot, dry environments
• 5% of plants (cactus and ice plants)
• Stomates closed during day
• Stomates open during the night
• Light reaction - occurs during the day
• Calvin Cycle - occurs when CO2 is present
End Show
3–2 Energy Flow
Slide 274 of 41274
CAM Plants
Night (Stomates Open) Day (Stomates Closed)
Vacuole
C-C-C-CMalate
C-C-C-CMalate Malate
C-C-C-CCO2
CO2
C3
C-C-CPyruvic acid
ATPC-C-CPEP glucose
End Show
3–2 Energy Flow
Slide 275 of 41275
CAM Plants
Why do CAM plants close their stomata during the day?
Cam plants close their stomata in the hottest part of the day to conserve water
End Show
3–2 Energy Flow
Slide 276 of 41276
Mendel’s Experiment
Why peas, Pisum sativum?Can be grown in a small area
Produce lots of offspring
Produce pure plants when allowed to self-pollinate several generations
Can be artificially cross-pollinated
End Show
3–2 Energy Flow
Slide 277 of 41
Mendel’s Experiment
Reproduction in Flowering Plants•Pollen contains sperm
–Produced by the stamen
•Ovary contains eggs
–Found inside the flower
Pollen carries sperm to the eggs for fertilization
Self-fertilization can occur in the same flower
Cross-fertilization can occur between flowers
End Show
3–2 Energy Flow
Slide 278 of 41
Mendel’s Experiment
Mendel’s Experimental Methods
Mendel hand-pollinated flowers using a paintbrushHe could snip the stamens to prevent self-pollinationCovered each flower with a cloth bag
He traced traits through the several generations
End Show
3–2 Energy Flow
Slide 279 of 41
Mendel’s Experiment
How Mendel BeganMendel produced pure strains by allowing the plants to self-pollinate for several generations
End Show
3–2 Energy Flow
Slide 280 of 41
Mendel’s Experiment
Eight Pea Plant TraitsSeed shape --- Round (R) or Wrinkled (r)Seed Color ---- Yellow (Y) or Green (y)Pod Shape --- Smooth (S) or wrinkled (s)Pod Color --- Green (G) or Yellow (g)Seed Coat Color ---Gray (G) or White (g)Flower position---Axial (A) or Terminal (a)Plant Height --- Tall (T) or Short (t)Flower color --- Purple (P) or white (p)
End Show
3–2 Energy Flow
Slide 281 of 41
Mendel’s Experiment
End Show
3–2 Energy Flow
Slide 282 of 41
Mendel’s Experiment
End Show
3–2 Energy Flow
Slide 283 of 41
Mendel’s Experiment
Mendel’s Experimental Results
End Show
3–2 Energy Flow
Slide 284 of 41284
Punnett Square
Used to help solve genetics problems
End Show
3–2 Energy Flow
Slide 285 of 41285
Punnett Square
End Show
3–2 Energy Flow
Slide 286 of 41286
Alleles
Alleles - two forms of a gene (dominant & recessive)
Dominant - stronger of two genes expressed in the hybrid; represented by a capital letter (R)
Recessive - gene that shows up less often in a cross; represented by a lowercase letter (r)
End Show
3–2 Energy Flow
Slide 287 of 41287
Genotype & Phenotype
Genotype - gene combination for a trait (e.g. RR, Rr, rr)
Phenotype - the physical feature resulting from a genotype (e.g. red, white)
End Show
3–2 Energy Flow
Slide 288 of 41288
Genotype & Phenotype
Genotype of alleles:R = red flowerr = yellow flower
All genes occur in pairs, so 2 alleles affect a characteristic
Possible combinations are:
Genotypes RR Rr rr
Phenotypes RED RED YELLOW
End Show
3–2 Energy Flow
Slide 289 of 41289
Genotype & Phenotype
Genotypes
• Homozygous genotype - gene combination involving 2 dominant or 2 recessive genes (e.g. RR or rr); also called pure
• Heterozygous genotype - gene combination of one dominant & one recessive allele (e.g. Rr); also called hybrid
top related