Biology Characteristics of Life:
1. Living things are composed of cells. 2. Living things have different levels of organization. 3. Living things use energy. 4. Living things respond to their environment. 5. Living things adapt, grow and reproduce. 6. Living things reproduce. 7. Living things adapt to their environment.
Organic Compounds:
A compound is a combination of 2 or more atoms.
An organic compound is a compound that contains carbon atoms that have combined with each other.
An inorganic compound is a compound with no combination of carbon atoms.
The Four Types of Organic Compounds The Molecules of Life:
1. Carbohydrates:
Sugars (saccharides)
used for short term
energy.
2. Lipids: Fats and oils
used for long term
energy & insulation.
3. Proteins: Made up of amino
acids; used for construction
materials and chemical
reactions in the body. DNA
holds the message for
making all proteins.
o Enzymes:
Special types of proteins that speed up (catalyze) chemical reactions in the body but are not changed by the reactions.
4. Nucleic acids: DNA and RNA; contains genetic
information and instructions for making proteins.
Cell Types and Organelles
Cell - is the smallest unit that is alive and can carry on all the
processes of life.
Prokaryotic: cell that does not have a nucleus or
other membrane-bound organelles. Unicellular.
Eukaryotic: cell that has a nucleus and other
membrane-bound organelles. Uni/Multicellular.
Organelles: specialized structures that carry out a
specific function (job).
Organelle
Function
Plant
Animal
Bacteria
Nucleus
Controls center; contains chromosomes made of DNA
Mitochondria
Cell respiration; provides energy, power and heat (ATP)
Endoplasmic
Reticulum
Transports substances through the cell
Golgi body
Sorts, modifies, cell products/proteins
Ribosome
Protein synthesis/Makes proteins
Lysosome
Contains digestive enzymes to break down and digest waste and old organelles
Cell
Membrane
Maintains homeostasis by controlling what enters and leaves the cell. Protection.
Cell Wall
Support and Protection
Chloroplast
Traps sunlight to make food for the plant through Photosynthesis
Vacuole
Stores water.
Cytoplasm
Suspends organelles in a cell; enclosed within the cell membrane
Organic Compounds
Cell Membrane
-Made up of biomolecules called phospholipids (fats that don’t like water). -Phospholipid bilayer is the 2 layers of phospholipids that make up the cell membrane. -Selectively permeability, which means that it allows some, but not all materials to cross.
Cellular Transport
Homeostasis: ability of cell, system, organism to maintain stable
internal equilibrium. (temperature, pH, water content). Cell Transport: movement of molecules across the cell
membrane.
Transport through the Cell Membrane
Transport
Movement of molecules
Requires Energy from
Cell?
Passive High to low concentration No
Active Low to high concentration Yes
Passive transport: requires no energy, moves with concentration
gradient (high to low).
Diffusion: movement of molecules from high to low
concentration.
Osmosis: diffusion of water across a selectively
permeable membrane, from high to low, until equilibrium is reached.
Facilitated diffusion: the movement of molecules from
high to low concentration, but requires a channel protein to help the molecule across.
Active transport: requires energy, moves against the
concentration gradient (low to high).
Types of solutions:
Hypotonic solutions cause water to move into the cell causing the cell to swell.
Hypertonic solutions cause water to move out of the cell causing the cell shrivel or die.
Isotonic solutions cause water molecules to move into and out of the cell at an equal rate; cell size does not change.
MEASUREMENT
Cellular Energy
Photosynthesis: radiant energy from the sun is used by
producers to join carbon dioxide and water to make food (glucose); process takes place in the chloroplast. Photosynthesis: 6CO2 + 6H2O C6H12O6 + 6O2
Cellular Respiration: mitochondria break down food molecules
(glucose) to produce cell energy (ATP).
Cellular Respiration: C6H12O6 + 6O2 6CO2 + 6H2O + ATP (energy)
Reactant(s) Product(s) Organelle Involved
Photosynthesis -Carbon dioxide (CO2) -Water (H2O)
-Glucose (C6H12O6) -Oxygen (O2)
Chloroplast
Cellular Respiration
Glucose (C6H12O6) -Oxygen (O2)
-Carbon dioxide (CO2) -Water (H2O) -ATP
Mitochondria
ATP: made of adenosine molecule, ribose sugar, and three
phosphate groups; all held together by chemical bonds. ATP Cycle:
Remember that when bonds are made = ENERGY STORED
When bonds are broken = ENERGY RELEASED
So the way energy is stored and released with ATP is to add or remove a phosphate.
.
The cell cycle is the phases in the life of a cell consisting of cell growth and division:
Process starts with diploid cells and ends with diploid cells.
- Diploid – two sets of chromosomes – 2n
Before mitosis: Chromosomes have copied themselves.
Sister chromatids: original chromosome and its exact
copy are attached to each other. Phases of mitosis
Cell Specialization: DNA holds the genetic information that
controls what a cell can do and what molecules it can make. Example: White blood cells in animals are specialized to attack pathogens like viruses or bacteria.
Cell Differentiation: process by which a cell becomes specialized
for a specific structure or function during multicellular development.
DNA and Replication
Nucleotides: structures that make up nucleic acids (DNA/RNA)
DNA
Sugar Deoxyribose
Bases Adenine, Thymine, Guanine, Cytosine
Base Pairs A T
C G
Shape Double Helix
Function Codes for proteins/RNA
Replication: the process used by cells to copy DNA; takes place
during the S phase of the cell cycle.
The enzyme, Helicase, unzips DNA and each side of the ladder acts as a template for the building of the new half.
The enzyme, DNA Polymerase, bond the new nucleotides together.
EX) TACGGAC (old strand) ATGCCTG (new strand
DNA RNA
Sugar Deoxyribose Ribose
Bases Adenine, Thymine,
Guanine, Cytosine
Adenine, Uracil,
Guanine, Cytosine
Base
Pairs
A T
C G
A U
C G
Shape Double Helix Single Strand
Function Codes for proteins/RNA
Copy of DNA
information for
transcription
Cell Cycle
Phase Steps in Phase
Interphase
G1: intense growth and enzyme production S: DNA synthesis/replication G2: growth and preparation for cell division.
Mitosis
M: Division of a cell into 2 identical daughter
cells (PMAT)
Transcription: process that copies DNA’s genetic information into
messenger RNA: 1. DNA strands temporarily unwind. 2. Complementary RNA nucleotides pair up with one strand
of DNA nucleotides. 3. Messenger RNA (mRNA) carries specific protein
synthesis instructions to ribosomes. EX) TACGGAC (template DNA strand) AUGCCUG (RNA built) Codon: formed from a sequence of three nucleotides (like AAA or
GAC); different codons specify one of twenty different amino acids. Translation: process by which a protein is made from mRNA;
occurs within a cell’s ribosomes; tRNA (transfer RNA) matches codons to amino acids which then join together to form a protein chain.
Protein: molecule made of amino acids that performs a specific
task.
Codon Chart
Mutation: genetic change in DNA.
There are many kinds of mutations that occur at different levels, but they all change DNA.
At the DNA level during Replication.
At the Chromosome level during Meiosis and Mitosis. Point mutations effect single bases
Substitution Frameshift mutations shift the “reading frame” of the DNA.
Insertion
Deletion
Mutations can be harmful, beneficial or have no effect on the organism.
A mutation that changes codon AAA to codon AAG (substitute G for the last A) likely has no effect because AAA and AAG both code for Lysine.
A mutation that results in codon UAA would likely result in an observable change because UAA is a stop codon.
Meiosis: Cell division that produces gametes (sex cells), such as
sperm and egg cells.
Haploid – cell with half the number of chromosomes - n Steps in meiosis 1. Before meiosis:
2 chromosomes of the same type come together to make a chromosome pair.
Each chromosome doubles (DNA replication during S phase of Interphase).
This gives 4 chromosomes stuck together.
2. Meiosis I: Chromosome pairs separate into two new cells-
PMAT 3. Meiosis II: Each chromosome separates from its copy into 4
new cells- PMAT
In meiosis, one cell becomes four non-identical daughter cells. BUT in mitosis, one cell becomes two daughter cells.
Chromosomes: DNA strands in the nucleus that contain the
directions on how to make and keep an organism alive. Copied and passed from parent to offspring. Crossing over occurs during Meiosis, pieces of chromosomes are
exchanged.
Protein Synthesis Mutations and Genetic Variations
Translation
Transcription
Fertilization: Process of an egg and a sperm cell combining to
produce a zygote, both haploid cells.
Zygote: Baby that is only 1 cell big
Human egg cell (23 chromosomes) + Human sperm cell
(23 chromosomes) = baby (46 chromosomes)
Autosomes: Chromosomes that do not determine gender
(chromosomes 1 through 22) Sex chromosomes:
Chromosomes that determine gender (chromosome 23)
Females are XX, Males are XY
GENETICS
Genetics: the study of heredity.
Gregor Mendel is an Austrian monk credited with beginning the study of genetics.
Gene: segment of DNA; controls specific traits.
Humans have 2 genes for every trait. Heredity: passing on of characteristics from parents to offspring.
Alleles: Different forms of a single trait, like blue and brown are
two eye color alleles.
Dominant gene: Allele that is expressed when two different
alleles are present in an organism’s genotype.
Represented by a capital letter.
Recessive gene: Allele that is expressed only when two copies
are present.
Represented by a lowercase letter.
Homozygous (purebred): When 2 genes are alike for a trait.
BB is homozygous dominant; bb is homozygous
recessive.
Heterozygous (hybrid): When 2 genes are different for a trait.
Bb is heterozygous.
Phenotype: The physical appearance of an organism (Brown
eyes), like a picture - what it looks like on the outside. Genotype: Includes both of the genes that code for a trait;
represented by the letters. Example: BB, Tt, Rr
Mendelian Genetics: Laws regarding the inheritance of genetic
traits: 1. Law of Segregation: alleles segregate and recombine;
one allele is inherited from each parent. 2. Law of Dominance: one trait may mask (dominant) the
effect of another trait. 3. Law of Independent Assortment: allele for a trait
segregate and recombine independently of other traits; example: height and eye color do not influence each other.
Monohybrid Cross: One trait
G = dominant allele for yellow g = recessive allele for green
Dihybrid Cross: two traits
G and R = dominant allele for yellow and round g and r = recessive allele for green and wrinkled.
Non-Mendelian Inheritance: inheritance pattern that does not
follow Mendelian genetics law. Incomplete Dominance: One allele is NOT completely dominant
over the other. R = dominant (incomplete) allele for red flower r = recessive allele white flower
Co-Dominance: Both alleles are dominant; both alleles are
expressed. R = dominant allele for red coat W = dominant allele for white coat
Sex-Linked Inheritance: Allele for a trait is carried on only one of
the sex chromosomes.
The gene for male-pattern baldness is linked to the x chromosome. XB = female sex chromosome with dominant baldness allele Xb = female sex chromosome with recessive baldness allele (carrier) Y = male sex chromosome does not carry baldness allele
Biotechnology DNA Fingerprinting: process of identifying the location of base
pairs at certain locations on the DNA for comparison to a known sample. Gel Electrophoresis: is a process of passing DNA fragments
through agar gel to separate the fragments by size.
Karyotypes: pictures of chromosomes that can be counted and
sorted. Chromosomes from a single cell are isolated in a solution and used to create the Karyotype, which can determine if a person
has an abnormal number of chromosomes and the location of the abnormality
Nondisjunction mutations: (monosomy and trisomy) can result in Down Syndrome, Kleinfelter’s Syndrome and Turner’s Syndrome
Genetic Recombination: At times, either biologically or artificially,
it is useful to combine certain segments of DNA from other organisms.
Evolution and Natural Selection
Evolution: Genetic change in a species over time. Changing of a
species’ (not an individual’s) traits over many, many years; natural selection is a mechanism for evolution. Natural Selection: process by which organisms with certain
favorable traits survive and reproduce more successfully than others; causes change in populations (NOT individuals) and affects the diversity of a species.
Example: insects that are resistant to insecticide are
more likely to survive and reproduce.
Adaptation: inherited trait that gives and advantage to individual
organisms and is passed on to future generations. Traits: Characteristic that is inherited.
Behavior: the way an organism moves, functions or reacts.
Behavior Description Example
Inherited Born with it; not learned Breathing
Learned Not born with it; must learn Reading
Evidences of Evolution
1. Fossil Record: preserved remains or traces of
organisms.
2. Homologous Structures: same basic structure formed
from same embryonic tissue.
3. Analogous Structures: same basic functions due to
same environmental pressures.
4. Embryology: embryos of various species appear
identical.
5. Molecular Homology: DNA and protein amino acid
sequence comparisons. Strongest evidence for Evolution. EX: the human genome and the chimpanzee genome are approximately 99% identical.
6. Biogeography: geographic distribution of organisms;
species that live in the same area are more closely related, but related species can also be found living far apart.
Evolutionary Mechanism
Description Effect on Genetic
Variation
Genetic Drift
Change in green pool caused by chance. EX: catastrophic event; flood, volcano, mass isolation of groups, hunting.
Gene Flow
Change in gene pool caused by organisms’ gradual movement into or out of the population.
INTO population
OUT of population
Mutation
Change in gene pool caused by insertion, deletion, or substitution of DNA sequence of gamete cell.
Recombination
Change in gene pool caused by exchange of genetic sequence during gene crossover events during Prophase I of meiosis.
Taxonomy: the study of the methods of man-made classification
systems. Classification: way of organizing information by putting objects or
ideas into groups based on similarity.
Enables us to study relationships and differences Example: Man’s best friend, the dog.
General Specific
Kingdom Characteristics
Archaebacteria Ex: halophiles, methanogens
prokaryotic, cell wall, no nucleus; lives in extreme environments
Eubacteria Ex: bacteria, algae
prokaryotic, cell wall, no nucleus; autotrophs or heterotrophs
Protists Ex: amoebas, paramecium
eukaryotic, nucleus and cell membrane; autotrophs or heterotrophs
Fungi Ex: yeasts, mushrooms
eukaryotic, cell wall, nucleus, cell membrane; no chloroplasts, heterotrophs
Plantae Ex: mosses, ferns, trees
eukaryotic, cell wall, nucleus, cell membrane, chloroplasts, autotrophs
Animalia Ex: worms, fish, insects, bird, dog
eukaryotic, nucleus, cell membrane, heterotrophs
Binomial Nomenclature: modern classification system using a
two-word (genus and species) naming system; written in italics. Genus species Ex: Homo sapien human Phylogenetic Tree: diagram taxonomist use to show evolutionary
relationships among species Cladogram: diagram based on patterns of shared, derived traits
that shows the evolutionary relationship between groups of organisms.
Dichotomous Key: Guide used to identify organisms. Uses pairs
of observable traits as a checklist to pinpoint the organism’s identity.
Taxonomy & Classification
Kingdom Animalia
Phylum Chordata
Class Mammalia
Order Carnivora
Family Canidae
Genus Canus
Species lupus
Virus: microscopic (smaller than bacteria) nonliving particle that
can only reproduce in host cell and causes diseases/conditions like smallpox, colds, influenza (flu), HIV, warts Is made up of a capsid head/protein coat (containing DNA or RNA) and a tail that attaches to the host cells. Host: a living cell in which a virus reproduces.
Comparison Virus Cell
Classification Nonliving Living
Structure Head has nucleic acids surrounded by protein coat
Has nucleic acids, ribosomes, cytoplasm, etc.
Metabolism None; depends on host cell
Makes own proteins
Reproduction Needs host cell; does not grow
Divides into two similar cells after growth
Interactions Among Systems in Animals
Function Examples of Interactions
Regulation
The endocrine system makes hormones. Blood in the circulatory system carries the hormones to the skeletal system to control the amount of calcium released from bones.
Nutrient Absorption
Food is broken down in the stomach mechanically by the muscular system and chemically by water, acid, and enzymes in the digestive system. Nutrients are then absorbed by blood in the circulatory system.
Reproduction Certain hormones produced in the endocrine system control ovulation in the female’s reproductive system.
Defense
Mucus in the lungs traps a virus in the respiratory system. T-cells in the immune system destroy virus-infected cells. Nerves in the nervous system sense the need to cough.
Interactions Among Systems in Plants
Function Examples of Interactions
Transport The roots uptake water. Xylem tissues transport water to the leaves. Phloem tissue transport sugar and nutrients throughout the plant.
Reproduction
The reproductive organs in a flower are the pistil (female) and the stamen (male). A seed is a mature, pollinated ovule (fertilized egg). Hormones in a plant’s roots help trigger the growth of a seed.
Response
If light hits on one side of a stem, auxins (hormone) will build up in the cells on the shaded side of the stem. These cells then elongate and grow longer, causing the stem to bend toward the light.
Homeostasis: the regulation and maintenance of constant internal
conditions in and organism. Internal Feedback Mechanisms: self-regulating process, like a
chemical reaction, that can help maintain homeostasis. Positive Feedback: increases the effect in response to a stimuli.
EX: blood clotting after a cut. Blood clotting happens once the sensory for it has been triggered and the brain sends information to start blood clotting. Once blood clotting starts it sends information for more clotting factors.
Negative Feedback: decreases the effect in response to a
stimuli. EX: maintenance of normal body temperature.
Living things are affected by biotic and abiotic things in the
environment
Abiotic factor: the nonliving parts of an organism’s environment.
EX: air currents, temperature, light, and moisture
Have effects on living things and often determine which species can survive in an area.
Biotic factor: the living things that inhabit an environment.
EX: plants, animals, fungus, bacteria
all organisms depend on others directly or indirectly for food, shelter, reproduction, or protection
Levels of Organization
Species Population Community Ecosystem Biosphere Species: a group of similar organisms that can interbreed and
produce fertile offspring. Population: a group of the same species, that lives in one area.
Members of the same population may compete with each other for resources.
Some may have adaptations to reduce competition.
VIRUSES AND BACTERIA
Interactions Among Systems in Plants and Animals
Ecology
Community: a group of different species that live together in one
area. EX: a group of alligators, birds, fish, and plants that live together in Armand Bayou. A change in one population in a community may cause changes in the other populations. Ecosystem: includes all of the organisms as well as the climate,
soil, water, rocks and other nonliving things (abiotic factor) in a given area. Types of ecosystems:
Terrestrial ecosystems – located on land (forest, meadow)
Aquatic ecosystem – freshwater (ponds, lakes, river) and saltwater (ocean, marine)
Ecosystem Stability: changes in the environment, caused by
nature or humans, can affect the stability of an ecosystem in positive or negative ways. Environmental changes can help sustain diverse and abundant populations over a long period of time, or they can diminish or destroy populations.
EX: Human Impacts including air/water pollution or conservation
Limiting Factors: conditions
that control a population’s size (food, water, living space, disease, predators, etc.). Carrying Capacity: maximum
population that can live in area over given period of time; controlled by limiting factors.
Nutrition and Energy Flow
The ultimate source of energy for life is the sun! Autotroph/Producers: an organism that uses the suns energy to
make food energy in a process called photosynthesis. EX: grass, trees, green algae
Heterotroph/Consumer: an organism that must obtain nutrients
by eating others.
Herbivores – Only feed on autotrophs; eats plants.
Carnivores – Only feed on other heterotrophs (meat).
Scavengers – Eat animals that have already died.
Omnivores – Eat autotrophs and other heterotrophs.
Decomposers – Break down the complex compounds of
decaying plant and animals.
Community Interactions
Mutualism – a relationship in which both species benefit.
+/+ A bee pollinating a flower.
Commensalism – a relationship in which one species
benefits and the other species is unaffected. +/≠ Barnacles on a whale.
Parasitism – a relationship in which a member of one
species benefits at the expense of another species (the host). +/- Heartworms in a dog.
Matter, in the form of carbon, nitrogen, and other elements, flow through the levels of an ecosystem from producers to consumers. Food Chain: shows how energy and matter move from one
organism to another; energy originates from Sun; arrows show the direction of energy flow. Food Web: shows many food chains in an ecosystem; size limited
by amount of energy that can be transferred. Trophic Levels: classification of organisms by feeding
relationships; organisms (like omnivores) may appear in multiple levels.
Level Description Example Energy
First Producer Plants Most
Second Primary consumer Herbivores
Third Secondary consumer
Carnivores that eat herbivores
Fourth Tertiary consumer Carnivores that eat carnivores Least
Energy Pyramid: shows how energy is lost from one trophic level
to the next (energy for metabolism etc.); only about 10% of energy transfers to next level; therefore approximately 90% is lost as heat. Max of 4 to 5 trophic levels per pyramid; energy moves in one direction only (not recycled).
Biological magnification: The increasing concentration of a
substance, such as a toxic chemical, in the tissues of organisms at higher levels in a food chain.
As a result of biomagnification, organisms at the top of the food chain generally suffer greater harm from a persistent toxin or pollutant than those at lower levels.
Role of Microorganisms
Beneficial Bacteria: helpful bacteria are used to make
yogurt, cheese, and drugs like insulin; decompose and recycle nutrients (nitrogen cycle); help absorb nutrients during digestive process; used to tan leather; etc.
Harmful Bacteria: harmful bacteria can spoil food or
cause diseases like streptococcus (strep throat).
Roles of Organisms
Energy in an Ecosystem
Cycles in Nature
Carbon Cycle: the movement of carbon through the environment.
Plants use CO2 to make sugars and starches via photosynthesis.
Animals eat plants and use this carbon for cellular respiration.
Ecological Succession:
Nitrogen Cycle: constant movement of nitrogen through the
environment.
Bacteria change the atmosphere’s nitrogen gas (N2) into a usable form, like nitrates.
Plants uptake nitrates from the soil; plants are then eaten by animals.
Decomposers return nitrogen to the soil by breaking down dead organisms and/or waste.
Denitrifying bacteria change nitrogenous compounds back to N2