May-Lissa Faustin

Big Idea Two: Biological systems utilize free energy and molecular bindings to grow, to reproduce, and to maintain dynamic homeostasis.

Living systems require free energy and matter to maintain order, grow, and reproduce. Organisms use many strategies to capture, use, and store energy and other important resources.

There are autotrophs and heterotrophs. Autotrophs synthesize their foods from inorganic substances using chemical energy or solar energy. While heterotrophs on the other side, synthesize their foods from organic substances. They use organic carbon for growth, while autotrophs are different.

There are different types of autotrophs and heterotrophs. There are photo autotrophs which require sunlight energy, fixes CO2 into organic compounds. There are chemo autotrophs which require energy from inorganic compounds, and fixes CO2 into organic compounds. Photoheterotrophs require sunlight energy, and organic compounds from other organisms. Chemohetertrophs, require energy from inorganic compounds, and organic compounds from other organisms.

Autotrophic cells get free energy by the process of photosynthesis and chemosynthesis. Photosynthesis, are processes used by plants and other autotrophic organisms to convert light energy from the sun into chemical energy that can be used for those organisms activities.

Important structures that are involved in photosynthesis are, the stomata, stroma, chloroplasts, chlorophyll, and the thylakoids. The thylakoid membrane is concerned with the initial conversion of light energy into chemical energy that's stored in ATP and NADH. The stroma on the other hand, takes place in the substance surrounding the thylakoids.

Chloroplasts take in sunlight and convert it into energy. The chloroplasts contain chlorophyll which gives the plants the green color that plants usually have.

In photosynthesis, Organisms split water as a source of electrons, and then they release O2. Electrons also reduce CO2 to sugars.

There are two stages of photosynthesis, which are the light reactions, and the Calvin cycle. In the light reactions, the light that's absorbed creates NADPH, water splits, ATP is produced, phosphorylation occurs, and the Thylakoids are involved. Phosphorylation is, the addition of a phosphate group to an organic molecule, or protein. It can either activate or deactivate an enzyme. In the Calvin Cycle on the other hand, there's carbon fixation, it uses NADPH and ATP, lastly. The stroma is involved.

There are three different types of variables that affect the rate of photosynthesis. Those are environmental variables, plant or leaf variables, and method variables. Environmental variables include light intensity, light color, temperature, and the pH of the solution. The plant or leaf variables that affect the rate of photosynthesis are the leaf color, the leaf size, leaves kept in bright light, the type of plant, and leaf age. The method variables that affect the rate of photosynthesis are the sizes of the leaf disk, the leaf disk overlap, and the soap amount.

Chemosynthesis captures the energy that's present in inorganic molecules. These things include cellular respiration and fermentation, which harvests free energy from sugars to produce free energy carriers, including ATP. The free energy that's available in the sugars drives metabolic pathways into the cells.

In Cellular Respiration, there are three separate steps that happen. These steps are glycolysis, the Krebbs cycle, and oxidative phosphorylation.

In glycolysis, the six carbon sugar glucose is broken down into two molecules of a three carbon molecule which is called pyruvate. That change is accompanied by a net gain of 2ATP molecules and 2NADH molecules. Fact! Glycolysis occurs in the cytosol.

The Krebbs cycle on the other hand occurs in the mitochondria, and generates a pool of chemical energy which is ATP, NADH, and FADH2, from the oxidation of pyruvate, and the end product of glycolysis. Pyruvate is transported into the mitochondria and loses carbon dioxide so that it can

form acetyl-CoA which is a two carbon molecule. When acetyl-CoA is oxidized to Carbon Dioxide in the Krebbs cycle, chemical energy is released and captured in the form of ATP, NADH, and FADH2.

In Oxidative phosphorylation, the electron transport chain allows the release of large amounts of chemical energy stored in reduced NADH+, and reduced FADH2. The energy is then released into the captured form of ATP. The electron transport chain consists of a series of molecules, mostly proteins, embedded in the inner mitochondrial membrane.

In fermentation, all cells are able to synthesize ATP via the process of glycolysis. In many cells, if oxygen isn't present pyruvate is metabolized, which is what's called fermentation.

Fermentation compliments glycolysis and makes it possible for ATP to be continually produced in the absence of oxygen. By oxidizing the NADH that's produced in glycolysis, fermentation regenerates NAD+, which can take a part in glycolysis again, to produce more ATP.

The chemical energy that's stored in glucose generates more ATP in aerobic respiration than in respiration without oxygen. Each of the molecules of glucose can generate 36-38 molecules of ATP in aerobic respiration but only 2ATP molecules in respiration without oxygen.

OPEN RESPONSE TIME!:

#1:

Cells transport substances across their membranes. Choose THREE of the following four types of cellular transport.

Osmosis

Active transport

Facilitated diffusion

Endocytosis/ Exocytosis

For each of the three types of transport you choose,

a. describe the transport process and explain how the organization of cell membranes functions in the movement of specific molecules across membranes, and

b. explain the significance of each type of transport to a specific cell (you may use different cell types as examples)

#8 (1993) (also photo and resp)

Membranes are important structural features of cells.

a. Describe how membrane structure is related to the transport of materials across a membrane.

b. Describe the roles of membranes in the synthesis of ATP in either cellular respiration or photosynthesis.

#12

Photosynthesis and cellular respiration recycle oxygen in ecosystems. Respond to TWO (and only two) of the following:

a. Explain how the metabolic processes of cellular respiration and photosynthesis recycle oxygen.

b. Discuss the structural adaptations that function in oxygen exchange between each of the following organisms and its environment : a plant, an insect, a fish.

c. Trace a molecule of O2 from the environment to a muscle cell in a vertebrate of your choice.

#13 (1995)

Energy transfer occurs in all cellular activities. For 3 of the following 5 processes involving energy transfer, explain how each functions in the cell and give an example. Explain how ATP is involved in each example you choose.

- cellular movement- active transport- synthesis of molecules- chemiosmosis- fermentation

#14

The rate of photosynthesis may vary with change that occur in environmental temperature, wavelength of light, and light intensity. Using a photosynthetic organism of your choice, choose only ONE of the three variables (temperature, wavelength, , or light intensity) and for this variable

- design a scientific experiment to determine the effect of the variable on the rate of photosynthesis for the organism

- explain how you would measure the rate of photosynthesis in your experiment

- Describe the results you would expect. Explain why you would expect these results.

#15

Energy is neither created nor destroyed, but it is changed from one form to another. Energy transfer is an important concept in cellular biology. In most eukaryotic cells, chemical bond energy in glucose is eventually converted to the chemical bond energy in ATP molecules in the process of aerobic cellular respiration.

a. The majority of ATP molecules are produced in the process of oxidative phosphorylation. Describe this process including the names and locations of the structures involved and the formation of the electrochemical gradient.

b. For 3 of the following situations, discuss the role of ATP in completing these examples of cellular work.

- active transport

-Glucose production in the dark reaction

- Cytokinesis in an animal cell

- Movement of a flagellum

- Contraction of a muscle

- Control of the stages in mitosis

In case you didn’t know what any of the questions up there were asking?

What is Osmosis?:

Osmosis is the process where fluids pass through a semi permeable membrane, moving from an area where solute (such as salt) is present in areas of

low concentration, to an area where solute is present in areas of high concentration. The end result of this would be that there will be equal amounts of fluid on either side of the barrier, creating an isotonic. (Isotonic is, of equal tension. What’s on the inside would be equal to what’s on the outside).

Key terms associated with osmosis are as follows:

Solvent this is the fluid that passes through the membrane.

Then there is solute which is, the dissolved substance in the fluid.

Together the solvent and the solute make up a solution.

Fact:

When the solution has low levels of a solute, it’s considered to be hypotonic. While solutions with high solute levels are known as hypertonic.

Plants use osmosis to absorb water and nutrients from the soil. The solutions in the roots are hypertonic, drawing in water from the soil. Roots are like selective permeable membranes, taking in not only water, but useful solutes, such as minerals, that the plant will need for survival. Osmosis plays a critical role in plants in animals with fluids coming in and out of the cell wall to bring in nutrients and carry out waste.

The fluid passes both in and out of the selective permeable membrane in osmosis, but usually there’s a net flow in one direction or the other, depending on which side of the membrane has the higher concentration of solutes.

What is selectively permeable?:

Selective permeability is the property of a living cell membrane that allows the cell to control which molecules can pass through the membrane, moving into or out of the cell.

What is active transport?:

Active transport is the pumping of solutes across a biological membrane against their concentration. The ability of cells to be able to maintain small solutes with the cytoplasm, within the cytoplasm at concentrations higher than the surrounding fluid of the cell is essential when it comes to cell survival.

To really understand active transport, you have to understand passive transport, which is the transport of a substance across a cell membrane by diffusion; energy is not required. Active transport on the other hand, does require energy. You also have to understand the second law of Thermodynamics, which states that, the entropy of an isolated system never decreases.

Passive transport is the natural movement of solutes across a membrane, down the concentration gradient.

An example of this type of active transport protein is the sodium-potassium pump. Most animal cells hold a higher concentration of potassium, and a lower concentration of sodium, than what is found in the extracellular environment. Since sodium ions carry a positive charge and potassium ions carry a negative charge, this imbalance represents not only a concentration gradient, but also an electrochemical gradient. Sodium-potassium pumps move three sodium ions out of the cell for every two potassium ions they bring into it, resulting in a net negative charge on the cell as a whole. The

difference of charges on each side of the cellular membrane creates a voltage — the membrane potential — that allows the cell to act as a battery, and power cellular work. <http://www.wisegeek.com/what-is-active-transport.htm>

What is facilitated diffusion?:

Facilitated diffusion is a type of passive transport that allows substances to cross membranes with the assistance of special transport proteins.

What is endocytosis, and exocytosis? What’s the difference?:

Endocytosis is the taking in of matter by a living cell by invagination of its membrane to form a vacuole.

While exocytosis is the process by which the contents of a cell vacuole are released to the exterior through fusion of the vacuole membrane with the cell.

Through exocytosis, the membrane used to form a vesicle is restored to the surface of the cell.

What is chemiosmosis?:

Chemiosmosis is, the diffusion of ions across a selectively permeable membrane.

Labs:

Plant Pigments and Photosynthesisby Theresa Knapp HoltzclawIntroduction

In photosynthesis, plant cells convert light energy into chemical energy that is stored in sugars and other organic compounds. Critical to the process is chlorophyll, the primary photosynthetic pigment in chloroplasts.

This laboratory has two separate activities: I. Plant Pigment Chromatography, and II. Measuring the Rate of Photosynthesis. Select the one you want to study, beginning with Key Concepts for that section.

Key Concepts I: Plant Pigment Chromatography

Paper chromatography is a technique used to separate a mixture into its component molecules. The molecules migrate, or move up the paper, at different rates because of differences in solubility, molecular mass, and hydrogen bonding with the paper.

For a simple, beautiful example of this technique, draw a large circle in the center of a piece of filter paper with a black water-soluble, felt-tip pen. Fold the paper into a cone and place the tip in a container of water. In just a few minutes you will have tie-dyed filter paper!

The green, blue, red, and lavender colors that came from the black ink should help you to understand that what appears to be a single color may in fact be a material composed of many different pigments —and such is the case with chloroplasts.

Design of the Experiment I

In paper chromatography the pigments are dissolved in a solvent that carries them up the paper. In the ink example, the solvent is water. To separate the pigments of the chloroplasts, you must use an organic solvent.

 In the following activity, you will separate plant pigments using an organic solvent such as a mixture of ether and acetone. Be sure to keep the bottle tightly closed except when you are using it because the solvent is very volatile and produces fumes you should not breathe.

The next screen shows you the separation of plant pigments.

Depositing the Pigment

Pigment Separation (time-lapse view)

Lab analysis: Analysis of Results I

If you did a number of chromatographic separations, each for a different length of time, the pigments would migrate a different distance on each run. However, the migration of each pigment relative to the migration of the solvent would not change. This migration of pigment relative to migration of solvent is expressed as a constant, Rf (Reference front). It can be calculated by using the formula:

Look back at the black ink chromatogram, and then calculate the Rf value for green.

Diffusion and Osmosis lab:

Diffusion and Osmosisby Theresa Knapp HoltzclawIntroduction

The processes of diffusion and osmosis account for much of the passive movement of molecules at the cellular level.

In this laboratory, you will study some of the basic principles of molecular movement in solution and perform a series of activities to investigate these processes.

Key Concepts

DiffusionMolecules are in constant motion and tend to move from regions where they are in higher concentration to regions where they are less concentrated. Diffusion is the net movement of molecules down their concentration gradient. Diffusion can occur in gases, in liquids, or through solids. An example of diffusion in gases occurs when a bottle of perfume is opened at the front of a room. Within minutes people further and further from the source can smell the perfume.

Osmosis is a specialized case of diffusion that involves the passive transport of water. Inosmosis water moves through a selectively permeable membrane from a region of its higher concentration to a region of its lower

concentration. The membrane selectively allows passage of certain types of molecules while restricting the movement of others.

Closer Look: Osmosis

 

The solute concentration in the beaker is higher than that in the bag, and thus the water concentration is lower in the beaker than in the bag. This causes water to move from the bag (left) into the beaker (right).

Movement of Molecules in Solution

There are often several different types of molecules in a solution. The motion of each type of molecule is random and independent of other molecules in the solution. Each molecule moves down its own concentration gradient, from a region of its high concentration to a region of its low concentration.

Though the net movement of molecules is down their concentration gradient, at any time molecules can move in both directions as long as the membrane is permeable to the molecule. Keep this in mind while you take a closer look at the beaker below.

Closer Look: Concentration Gradient

 

Notice that the starch molecules are too large to pass through the pores in the membrane. The iodine molecules move across the membrane in both directions, but their net movement is from the bag, where their concentration is higher, into the beaker, where their concentration is lower. The iodine combines with starch to form a purplish-colored compound.

The net movement of water is into the beaker.

Movement of Molecules in Cells

Like dialysis bags, cell membranes are selectively permeable. As you view the next animation, watch for the selective property of the cell membrane and the two-way diffusion of molecules. Finally, notice the net movement of the molecules.

 The movement of water is influenced by the solute concentrations of the solutions. Let's review the different types of solutions.

Types of Solutions Based on Solute Concentration

The terms hypotonic, hypertonic, and isotonic are used to compare solutions relative to their solute concentrations.

In the illustration, the solution in the bag contains less solute than the solution in the beaker. The solution in the bag is hypotonic(lower solute concentration) to the solution in the beaker. The solution in the beaker ishypertonic (higher solute concentration) to the one in the

bag. Water will move from the hypotonic solution into the hypertonic solution.

In this illustration the two solutions are equal in their solute concentrations. We say that they are isotonic to each other.

Will there be a net movement of water between two isotonic solutions?

 Yes   No

Water Potential

The water potential of pure water in an open container is zero because there is no solute and the pressure in the container is zero. Adding solute lowers the water potential. When a solution is enclosed by a rigid cell wall,

the movement of water into the cell will exert pressure on the cell wall. This increase in pressure within the cell will raise the water potential.

Look again at the equation for water potential:

Water potential ( ) = pressure potential ( ) + solute potential ( )

http://www.phschool.com/science/biology_place/labbench/lab1/intro.html

http://www.phschool.com/science/biology_place/labbench/lab4/intro.html

Cell Respiration

There are two components to water potential: solute concentration and pressure. How do you think this fact affects the movement of water into and out of cells? For example, can two solutions that differ in their solute concentration be at equilibrium in terms of water movement? Can a solution with a molarity of 0.2 be in equilibrium with a solution with a molarity of 0.4?

 Yes 

 No

by Theresa Knapp HoltzclawIntroduction

Cellular respiration occurs in most cells of both plants and animals. It takes place in the mitochondria, where energy from nutrients convertsADP to ATP. ATP is used for all cellular activities that require energy.

In this laboratory, you will observe evidence for respiration in pea seeds and investigate the effect of temperature on the rate of respiration.

Design of the Experiment

How can the rate of cellular respiration be measured? When you study the equation for cellular respiration, you will see that there are at least three ways:

1. Measure the amount of glucose consumed.2. Measure the amount of oxygen consumed.3. Measure the amount of carbon dioxide produced.

In this experiment, we are going to measure the amount of oxygen consumed.

Features and Functions of a Respirometer

This illustration shows you the basic features of a respirometer. It will measure changes in gas volume related to the consumption of oxygen.

You can construct a respirometer by putting any small organism in a vial with a pipette attached. This example uses a cricket; in the laboratory experiment, you will use peas. Remember, cellular respiration occurs in the cells of both animals and plants!

How the Respirometer Works

When the tip of the respirometer is submerged, no additional air will enter.

As O2 is used up, the pressure of gases inside the respirometer decreases. This causes water to enter the pipette.

The CO2 that is produced combines with KOH to form a solid precipitate, K2CO3.

Notice that as the gas volume inside the vial decreases, the pressure of water outside the vial forces water into the pipette. Because the amount of water that enters the pipette is directly proportional to the amount of oxygen consumed by the cricket, measuring the water volume in the pipette allows you to measure the rate of respiration.

Assembling the Respirometer

In this experiment you will compare the rate of respiration in peas that are germinating to the rate in peas that are dormant (dry peas). You will make the comparison at two different temperatures: 10°C and 25°C. In addition, you will compare these rates to a nonmetabolizing control.

Why is it important to have a control?

The following illustration shows you how to assemble a respirometer.

It is important that the three vials contain an equal volume of contents. You do this by adding glass beads to the vial with the dormant peas, since the dry peas take up less space than an equal quantity of germinating peas.

Note: Because you are measuring the rate of respiration at two different temperatures, prepare two sets of three vials.

Lab Hints

1. You will need to use a layer of nonabsorbent cotton between the KOH and the peas.

2. The stopper must be firmly inserted for an air-tight seal. Check that no peas or beads block the opening to the pipette.

3. Let the respirometers equilibrate for several minutes in their respective waterbaths. This will minimize volume changes due to change in air temperature.

More Information on Germinating PeasSeeds contain a plant embryo and its initial food supply protected by a seed coat. When warmth and moisture conditions are favorable, germination, or sprouting, will begin. When you soak pea seeds for this laboratory, germination begins. Enzymes begin using the stored food supply to generate ATP, and the rate of cellular respiration accelerates.

It is important to know that nongerminating seeds are not dead; they are dormant. Do they respire?

Measuring the Rate of Respiration

Gas volume is related to the temperature of the gas. According to the gas law (V=nRT/P) , a change in temperature will cause a direct change in volume. Because the temperature in the respirometers may vary during the course of the experiment, you must correct for differences in volume that are due to temperature fluctuation rather than rate of respiration. To do this, subtract any difference in the movement of water into the vial with glass beads from the experimental vials held at the same temperature. Record the result as the corrected difference.

http://www.phschool.com/science/biology_place/labbench/lab5/intro.html

Membranes allow cells to create and maintain internal environments that are different from the external environments. The structure of the cell membrane results in selective permeability. The movement of molecules which can occur either through diffusion or osmosis.

Organisms also have feedback mechanisms that maintain dynamic homeostasis by allowing them to respond to changes in their internal and external environments.

Negative feedback loops maintain internal environments, and positive feedback amplifies responses. A good example of negative feedback would be your blood sugar levels. When your blood sugar level is too high, insulin is released so that it can lower the amount of sugar in your blood, and when your blood sugar level is too low, glucagon is made so that it can increase the amount of sugar in your blood. An example of positive feedback on the other hand, would be a woman who is pregnant with a baby. When a woman is pregnant she has constant pains that are called

contractions, and when she gives birth, those contractions increase instead of decreasing.

Cells and organisms have to exchange matter with their environment. Water and nutrients for example are used in the synthesis of new molecules. The carbon moves from the environment to organisms where it's incorporated into carbohydrates, proteins, nucleic acid, or fats.

Major points of Big Idea Two:

Growth, reproduction, and maintaining organization of living systems require energy and matter.

Growth, reproduction,and homeostasis require that cells create and maintain internal environments that are different from their external environments.

Organisms use feedback mechanisms to regulate growth, and maintain homeostasis.

Growth and homeostasis of a biological system are influenced by changes in the systems environment.

Many biological processes involved in growth, reproduction, and homeostasis include temporal aspects.

Energy is the ability to do something. There are two general types of energy, and that is kinetic and potential energy. Potential energy is the ability to store something. Potential energy is the result of gravity pulling downwards. An example would be the heavy ball of demolition machine, storing energy when it’s held at an elevated position. Types of potential energy are, nuclear, electrical, chemical, nuclear, and gravitational. Chemical energy is potential energy that’s available for release in a chemical reaction. To find the potential energy of a product, you use this equation:

Potential Energy Formula: Potential Energy: PE = m x g x hMass:

Acceleration of Gravity:

Height:

where,PE = Potential Energy, m = Mass of object,

g = Acceleration of Gravity, h = Height of object,

<http://easycalculation.com/physics/classical-physics/learn-potential.php>

A Potential energy problem from the link I put up there:

Potential Energy Example:Case 1: A cat had climbed at the top of the tree. The Tree is 20 meters high and the cat weighs 6kg. How much potential energy does the cat have? m = 6 kg, h = 20 m, g = 9.8 m/s2(Gravitational Acceleration of the earth) Step 1: Substitute the values in the below potential energy formula: Potential Energy: PE = m x g x h = 6 x 9.8 x 20 Potential Energy: PE = 1176 Joules

While Kinetic energy is, the energy that a body possesses by virtue of being in motion. Types of kinetic energy are moving objects, radiation, thermal, and electrical. Heat or thermal energy is kinetic energy associated with random movement of atoms or molecules. Kinetic energy is a property of a moving object or particle and depends not only on its motion but also on its mass. An example of kinetic energy would be, a man running. This is kinetic because the man is moving. To find the kinetic energy of a product, you have to use a formula:

Where m = mass of objectv = speed of object

A kinetic energy problem:

Determine the kinetic energy of a 625-kg roller coaster car that is moving with a speed of 18.3 m/s.Use the formula that I put up there!:The way to solve it:

So the formula is:

M being the mass of the object, and V being the velocity, so you just plug in the numbers to find the answer. :

 KE = 0.5*m*v2

KE = (0.5) * (625 kg) * (18.3 m/s)2

KE = 1.05 x105 Joules

Then there are the laws of thermodynamics:

The first law states that, energy is never created or destroyed, energy is transformed from one form to another, and winds motion is converted to electricity, which is then converted to heat, and light bulb energy in a light bulb.

The second law states that the entropy of an isolated system is always increasing (entropy is an amount of energy in a form that’s unusable. Usually this form can be heat.), and that systems are always losing forms of energy that are useable.

This means that in every conversion of energy, a lot of the energy is lost as heat. Energy spreads from areas of high energy to low energy. An example of this would include, heat being transferred from a hot pan to the air around it.

Exergonic and Endergonic reactions:

An exergonic reaction is a chemical reaction where the change in the Gibbs free energy is negative, meaning that this is a spontaneous reaction. In an exergonic reaction, energy is being lost during the process of the reaction. Activation energy catalyzes the reaction to make it occur in a spontaneous manner. The change in the Gibbs free energy in an exergonic reaction has a negative value, because energy is lost.

The Gibbs free energy of a system is defined as the enthalpy of the system, minus the product of the temperature, times the entropy of the system. <http://chemed.chem.purdue.edu/genchem/topicreview/bp/ch21/gibbs.php>

Free energy is used to maintain body temperature for some organisms, reproduction, growth, and development.

To find it, you use this formula:

An endergonic reaction on the other hand is a chemical reaction in which the standard change in free energy is positive, and energy is absorbed. <http://en.wikipedia.org/wiki/Endergonic_reaction>

An endergonic reaction is a reaction that requires energy to drive the reaction. The activation of that energy is larger than the requirement for the

exergonic reaction because energy is consumed in the process of the reaction. Unlike exergonic reactions, endergonic reactions are not spontaneous.

Cellular respiration for example is an endergonic reaction, because it has this amount of energy that’s required, in making ATP.

Just a couple of random things that you should know, involving big idea two:

Ninety nine percent of all living matter is made up of, Nitrogen, Carbon, Hydrogen, and Oxygen. Cells that are damaged or infected have what’s called a programmed cell death which is apoptosis. Apoptosis protects neighboring cells from damage that they would suffer and allows molecules to be reused. It also helps maintain homeostasis.

For body temperature regulation, there are endothermic and exothermic. Endothermics use heat released by metabolic reactions to keep a stable temperature. Endothermics include humans.

While exothermics use external sources to try and maintain body temperature. These include snakes and reptiles.

Reproduction on the other hand requires a lot of energy. Fact: Most species only reproduce when energy is available. Example: plants. Most plants flower in the spring when there is a lot of sunlight energy.

When energy deprivation occurs, mass is broken down to provide energy. If there for some reason, isn’t any energy input, then death will occur eventually.

Smaller organisms have more surface area relative to their volume, so they lose more heat. To replenish that energy loss they tend to eat more than larger animals.

In trophic levels:

Energy works its way up the food chain.

At every energy level though, energy is being lost due to entropy, which means that there’s less energy available for the higher levels in the food chain.

The reason that most animals become endangered is because, there’s very energy left for them.

Apoptosis during paw development: apoptosis eliminates the cells in the interdigital regions forming the digits.

Now onto bonds:

Hydrogen bonds facts:

The partial negative charges on oxygen attracts partial positive charge on hydrogen atoms.

Impacts most of waters properties.

In cohesion, water molecules stick to each other. The water can be pulled as each molecule pulls on the molecule next to it.

Adhesion is when water can also stick to other charged surfaces. This is important when it comes to plants being able to take in water.

In surface tension, hydrogen bonds cause water to have a high surface tension or a surface that’s hard to break. It’s measured as the energy required to increase the surface area of a liquid by a unit of area. The surface tension of a liquid can result from an imbalance of intermolecular attractive forces, also known as the cohesive forces, between molecules.

Capillary action is the ability of a liquid to flow in narrow spaces without the resistance and the opposition of external forces such as gravity. It results in the elevation or depression of liquids in the capillaries.

Specific heat is a measure that’s used in Thermodynamics that states the amount of energy that’s necessary to raise the temperature of a given mass of a particular substance by some amount. <http://www.wisegeek.org/what-is-specific-heat.htm>

“ While different scales of measurement are sometimes used, this term usually specifically refers to the amount required to raise 1 gram of some substance by 1.8°F (1° Celsius) or by 1 Kelvin — 1 Kelvin is the same as 1°C. It follows that if twice as much energy is added to a substance, its temperature should increase by twice as much. Specific heat is usually expressed in joules, the unit typically used in chemistry and physics to describe energy.” <http://www.wisegeek.org/what-is-specific-heat.htm>

Evaporative cooling facts:

Water has a high heat of evaporation.

Evaporating water takes up a lot of energy.

The reason that sweat cools us off is because the hottest molecules evaporate first.

Evaporative cooling is the reduction in temperature resulting from the evaporation of a liquid. As a result, this removes heat from the surface.

The Big question! Ice Float facts:

Most solids are most dense than liquids. When ice floats, the H bonds become locked, keeps the rest of the lakes and rivers from freezing, and it warms the rest of the water. A substance floats if it’s less dense, or has less mass per unit volume, than other components in a mixture. Water reaches its maximum density at 4 degrees Celsius, which is 40 degrees Fahrenheit. As it cools more and more, and turns into ice, it becomes less dense, while most substances are denser in their solid state, instead of their liquid states.

A water molecule is made from one oxygen atom and 2 hydrogen atoms, joined together by a covalent bond. Water molecules can also be attracted to each other by weaker hydrogen bonds between the positively charged hydrogen atoms, and negatively charged oxygen atoms of neighboring water molecules. As the water cools below 4 degrees Celsius, the

hydrogen bonds adjust to hold the negatively charged oxygen atoms away from each other. This then produces ice. The ice floats because it’s 9% less dense then the liquid water. The heavier water displaces the lighter ice, which causes the lakes and rivers to freeze from top to bottom, allowing the fish to survive even when the surface of the lake is completely frozen. If the ice sank, then the water would be on moved to the top, and exposed to the colder temperatures, forcing rivers and lakes to fill with ice, and become frozen solid. This would end up killing many animals who’s habitats are in that water, because they would not be used to that kind of temperature.

Functional groups:

Functional groups, are specific groups of atoms or bonds within molecules that are responsible for the chemical reactions of those molecules.

Some functional groups to remember:

A hydroxyl group is oxygen containing group based on an alcohol or OH group. They are known as the alcohols, and are polar.

A polar molecule is a molecule that has a mostly positive charge on one side, and a mostly negative charge on the other side. The difference in this charge allows the positive end to attract the negative end, to one another.

A carboxyl group is a functional group that consists of a carbon atom joined to an oxygen atom, by a double bond, and to a hydroxyl group by a single bond.

“Carboxyl groups frequently ionize, releasing the H from the hydroxyl group as a free proton (H+), with the remaining O carrying a negative charge. This charge "flip-flops" back and forth between the two oxygen atoms, which make this ionized state relatively stable. (Hydroxyl groups sometimes ionize momentarily, but the resulting ionic forms are not stable and the ions immediately rejoin.) 

Molecules containing carboxyl groups are called carboxylic acids and dissociate partially into H+ and COO–. “ <http://www.phschool.com/science/biology_place/biocoach/biokit/carboxyl.html>

Amino groups are known as amines, and act as a base accepting protons. They are an essential part of amino acids. It consists of a nitrogen atom attached by single bonds to a hydrogen atom, alkyl groups, aryl groups, or a combination of the three. An aryl group is a group of atoms derived from benzene or from a benzene derivative, by removing one hydrogen that is bonded to a benzene ring. Benzene is a colorless, flammable toxic liquid. It’s a hydrocarbon with formula C6H6. Alkyl groups on the other hand are a group of carbon and hydrogen atoms derived from an alkane molecule by removing one hydrogen atom.

Amino acids are organic compounds that consist of both a carboxyl group and an amino group.

Sulfhydryl Group:

Like oxygen, sulfur typically has a valence of 2, although it can also have a valence of 6, as in sulfuric acid. 

Sulfur is found in certain amino acids and proteins in the form of sulfhydryl groups (symbolized as -SH). Two sulfhydryl groups can interact to form a disulfide group (symbolized as -S-S-).

Sulfhydryl groups are involved in stabilizing proteins.

Phosphate group:

Phosphate groups are strongly negatively charged, they are hydrophilic, and are found in DNA and RNA.

“Phosphate groups can be joined together to form phosphodiester bonds. Phosphate groups can also be joined to other molecules, such as sugar.

When phosphate is added to a nucleoside, the molecule is called a nucleotide.” <http://www.phschool.com/science/biology_place/biocoach/bioprop/phosphat.html>

Macromolecules:

Polymers:

1. Long chain of monomers2. Takes energy and involves removal of water

Hydrolysis:

Macromolecules are split apart by water. It releases new energy. A macromolecule is a molecule containing a very large number of atoms.

Carbohydrates:

They are simple sugars, disaccharides, and polysaccharides. These include starch, glycogen, cellulose, and chitin. Disaccharides are carbohydrates created by two monosaccharides.

Polysaccharides are a carbohydrate whose molecules consist of a number of sugar molecules bonded together.

Monosaccharides are any class of the sugars that cannot be hydrolyzed to give a simpler sugar.

Starch: An odorless tasteless white substance occurring widely in plant tissue and obtained chiefly from cereals and potatoes. It is a polysaccharide.

Glycogen: A substance deposited in bodily tissues as a store of carbohydrates; a polysaccharide that yields glucose on hydrolysis.

Cellulose: An insoluble substance that is the main constituent of plant cell walls and of vegetable fibers such as cotton. It is a polysaccharide.

Fact: You can’t digest cellulose

Carbs facts:

It’s the way that organisms store sugars

They are made of simple sugars by dehydration reactions.

They are important in plant cell walls.

Saturated V. Non Saturated:

Saturated = all single bonds in the hydrocarbon tail

Straight chain

Solid at room temperature

Most animal fats

(lard, butter)

Unsaturated = at least one double bond

Kink in chain

Liquid at room temp

Called oils

Found in fish and plants

They are both used for energy storage and insulation.

Amino acids:

All proteins are made of amino acids

Amino acids contain an amino group, a carboxyl group, an H atom and a “variable group”

The R group is the only thing that changes

Proteins:

Structural support, storage, transport, signaling, movement, defense, enzymes etc.

There are tens of thousands of different proteins in the body

Proteins make up amino acids.

In the Carbon cycle:

• Taken in during photosynthesis

• Center of almost all molecules made in plant

• Animals obtain by eating carbon-based foods

Other things to know: