CHAPTER 9.1 Outline: The Need for EnergyI. Cell Energy 1. Work and the need for energy:

- Energy - the ability to do work

- Living Organisms depend on energy.

- Living things get energy from food.

- The ultimate source of energy is the sun.

a) Autotrophs and Heterotrophs 1. Autotrophs - Organisms that make their own food; Example: plants use sunlight to make food

2. Heterotrophs - Organisms that need to consume food for energy; Example: herbivores - eat plants, carnivores - eat animals that have stored energy from plants they eat, and detritovores - eat decomposing organisms

b) Chemical Energy and ATP- Forms of energy: light, heat, electricity and chemical energy (stored in bonds)- ATP (Adenosine Triphosphate) - the basic energy source, the chemical energy, of all cells

II. Forming and Breaking Down ATP

1. How cells tap into the energy stored in ATP

a) Storing Energy- ADP (Adenosine Diphospate) contains 2 phosphates instead of 3.

- If a cell has extra energy, small amounts can be stored by adding a phosphate group to ADP molecules to produce ATP.

b) Releasing Energy- to release energy stored in ATP, the cell can break the high energy bond between the 2nd and 3rd phosphate group

III. Uses of Cell Energy1. Using Biochemical Energy

a) Uses- Carry out active transport

- aids in moving organelles throughout the cell

- Protein synthesis

- Producing light

b) Cells contain small amount of ATP. Only enough to provide a few seconds of activity

c) ATP is great at transferring energy but not good at storying large amounts of energy

d. Glucose stores 90 times more energy than ATP

e. The energy stored in Glucose can be used to regenerate ATP when the cell needs it.

CHAPTER 9.2 Outline: Photosynthesis: Trapping the Suns Energy

I. Trapping Energy from Sunlight1. Photosynthesis - puts together sugar molecules using water, carbon dioxide, and energy from light

a) Photosynthesis happens in two phases:1. The light-dependent reactions2. The light-independent reactionsthat produce simple sugars.

c) 6CO2 + 6H2O f0 C6H12O6 + 6O2

2. The Chloroplast and Pigments a) Chloroplast is the cell organelle where photosynthesis occurs.

Example: It is in the membranes of the thylakoid discs in chloroplasts that the light-dependent reactions take place.

b) To trap the energy in the suns light, the thylakoid membranes contain pigments, molecules that absorb specific wavelengths of sunlight.

Example: Chlorophyll absorbs most wavelengths of light except green. Because chlorophyll cannot absorb this wavelength, it is reflected, giving leaves a green appearance.

II. Light-Dependent Reactions

1. The light-dependent reactions - convert light energy into

chemical energy.

a) Process - Chlorophyll molecules absorb light energy and energize electrons for producing ATP and NADPH.

1. Light energy from the sun transfers to chlorophyll.

2. Chlorophyll passes energy down through the electron transport chain.

3. Energized electrons provide energy that

- splits H2O --> releases oxygen --> H+ + NADP+ = NADPH - bonds P to ADP forming ATP

4. For use in the light-independent reactions.

2. Restoring Electrons

a) Photolysis - a molecule of water is split to replace electrons lost from chlorophyll, H+ for chemiosmosis, and oxygen.

b) H2O ----> 2H+ + O2 + 2e

III. Light-Independent Reactions

1. Light-Independent Reactions - The molecules of ATP produced

in the light-dependent reactions are then used to fuel the light-independent reactionsthat produce simple sugars. The second phase of photosynthesis does not require light.

a) The Calvin Cycle - (dark reaction; light independent) A series of reactions that use carbon dioxide to form sugars; Occurs in the Stroma with or without light.

1. CO2 enters the system: 6 CO2 combines with 6 5-C compounds; product= 12 3-C compounds

2. Energy input: The ATP & NADPH (from the light reaction) are used to convert the 12 3-C compounds into a higher energy form.

3. 6-Carbon Sugar is produced: 2 of the 12 3-C are used to make glucose and other compounds.

4. 5-Carbon Molecules Regenerated: 10 remaining 3-C are converted into 6 5-C molecules

b) Products of Calvin Cycle: 2, 3 C Compound PGAL --> 1 C6H12O6 (glucose) --> other high energy sugars, starches and lipids

CHAPTER 9.3 Outline: Getting Energy to Make ATPI. Cellular Respiration

1. Cellular Respiration - the process that releases energy by breaking down glucose and other food molecules in the presence of oxygen.

a) he mitochondria is the organelle known as the powerhouse- the site where energy is produced: Cellular respiration takes place in the mitochondria.

b) The equation for cellular respiration: 6CO2 + 6H20 + Energy 6O2 + C6H12O6 c) 3 main stages of cellular respiration:

2. Glycolysis - the process in which one molecule of glucose is broken in half, producing two molecules of pyruvic acid, a 3-carbon compound.

a) his pathway does not require oxygen b) Prokaryotes depend on this process alone for ATP. c) Produces:- 2 ATP Net: energy molecules - 2 NADH: electron carriers- 2 Pyruvic Acid: 3-C sugars

2. Krebs Cycle - process where pyruvic acid is broken down into carbon dioxide in a series of energy-extracting reactions.

a) Occurs in the Mitochondria, only in Eukaryotes, when pyruvic acid enters mitochondria.

b) Pyruvate (pyruvic acid) Oxidation Produces for glucose: - 2 acetyl-CoA (2-C sugar) - 2 NADH (electron carriers) - 2 Carbon dioxide (waste product) c) Energy Extraction- Acetyl CoA (2-C) binds with a Oxaloacetic acid (4-C) molecule to form Citric Acid (6-C)- Citric Acid is oxidized (by NAD+ and FAD) through a series of reactions that finally produces Oxaloacetic Acid again.

d) The Krebs Cycle runs 2 times per Glucose molecule. Once per pyruvic acid.

e) Produces per glucose molecule: - 6 NADH (electron carriers-go to ETC) - 2 FADH2 (electron carriers-go to ETC) - 2 ATP (energy-used by cell to do work) - 4 CO2 (waste product- gets exhaled) 3. Electron Transport Chain (ETC) - process that uses the high-energy electrons from the Krebs cycle to convert ADP into ATP.

a) Process: 1. Glycolysis and the Krebs Cycle deliver their NADH and FADH2 to the matrix of the mitochondria.

2. NADH and FADH2 donate their high energy electrons to the ETC.

b) Electrons are passed from carrier to carrier in the inner membrane. In prokaryotes the ETC is in the cell membrane.

c) At the end of the chain, Oxygen is the final electron acceptor. d) Oxygen uses the electron to covalently bond with hydrogen forming water. Oxygen is reduced.

e) Produces:- 34 ATP (energy-used by cell to do work) - H2O

II. Fermentation 1. Fermentation - release of energy from food molecules by producing ATP in the absence of oxygen.

a) Glycolysis still occurs in the cytoplasm producing pyruvic acid. b) The pyruvic acid can go through one of two types of fermentation:

2. Alcoholic Fermentation: - occurs in yeast cells and other microorganisms

- Pyruvic acid + NADH alcohol + CO + NAD+

- CO2 that is released is what makes bread rise

3. Lactic Fermentation:- made in the muscle cells when oxygen levels are too low

- Build up of Lactic Acid causes the burning feeling

- NAD+ is regenerated to keep running glycolysis.

- Prokaryotes are used to make food because they do produce lactic acid. Some examples: cheese, kimchi, sour cream, yogurt, sauerkraut, buttermilk, pickles

III. Comparing Photosynthesis and Cellular Respiration

- Photosynthesis: Food synthesized- Cellular Respiration: Food broken down

- Photosynthesis: Energy from sun stored in glucose - Cellular Respiration: Energy of glucose released

- Photosynthesis: Carbon dioxide taken in - Cellular Respiration:Carbon dioxide given off

- Photosynthesis: Oxygen given off- Cellular Respiration: Oxygen taken in

- Photosynthesis: Produces sugars from PGAL - Cellular Respiration: Produces CO2 and H2O

- Photosynthesis: Requires light - Cellular Respiration: Does not require light

- Photosynthesis: Occurs only in presence of chlorophyll - Cellular Respiration: Occurs in all living cells