A. Autotrophs

1. make their own food (e.g. glucose)
2. are often called producers
3. photoautotrophs - plants, some protists, some bacteria
4. chemoautotrophs - some bacteria

B. Heterotrophs

1. can not make their own food
2. are oftem called consumers
3. rely on other organisms, dead or alive, a a source of organic molecules
4. animals, fungi, many protists, many bacteria
5. decomposers (detriovores) - feed on organisms that are already dead
6. predators - kill organisms for food
7. grazers - eat living plant material
8. carnivores - eat animal material
9. herbivores - eat plant material
10. omnivores - eat plant and animal material
11. parasites - feed on living organisms without killing them (at least not immediately)

C. Movement of (most) energy in biosphere:

1. source - sun
2. converted to usable form (food) by photoautotrophs
3. photoautotrophs are eaten
4. many heterotrophs eat other heterotrophs
5. detritovores recycle matter but not energy
6. detritovores feed on the remains of autotrophs and heterotrophs
7. energy captured by organisms to do work eventually leaves as heat
8. the biosphere is an open system

D. ADP + Pi -> ATP (endergonic)

E. ATP -> ADP + Pi

F. NAD⁺ + 2H -> NADH + H⁺ (endergonic)

G. NADH + H⁺ + 1/2O₂ -> NAD⁺ + H₂ (exergonic)

H. NADH is nicotinamide adenine dinucleotide

I. Oxidation - reduction reactions (redox reactions)

1. electrons are transferred
2. energy is transferred
3. reduced - electrons added
4. oxidized - electrons taken away
5. reducing agent - the substance that is oxidized
6. oxidizing agent - the substance that is being used

J. Overview of cellular respiration

1. O₂ is needed for entire process to occur
2. glycolysis
a. 1 glucose -> 2 pyruvate
b. some ATP and NADH are produced
c. occurs are cytosol
3. Kreb's Cycle (citric acid cycle)
a. pyruvate -> CO₂
b. in mitochondrion, in matrix
c. some ATP, NADH, and FADH₂ are produced
4. electron transport chain
a. uses products of first 2 stages
b. in mitochondrion's inner membrane
c. lots of ATP produced

K. Glycolysis

1. occurs in cytoplasm
2. glucose broken down into 2 pyruvate molecules
3. 2 ATP required
4. 4 ATP generated
5. net gain of 2 ATP
6. 2 NADH generated
7. numbers given above are per 1 molecule of glucose
8. no CO₂ is released by glycolysis
9. no O₂ is used in glycolysis
10. if no O₂ available, products of glycolysis can be broken down further to extract more energy

I. Pyruvate oxidation

1. occurs in inner membrane of mitochondrion
2. pyruvate converted into Acetyl CoA
3. 1 NADH generated per pyruvate
4. 4 NADH generated per glucose
5. 1 CO₂ generated per pyruvate
6. 6 CO₂ generated per glucose
7. How many C in 1 Acytyl CoA?

M. Krebs Cycle (citric acid cycle)

1. occurs in mitochondrial matrix
2. Acetyl CoA enters Krebs cycle
3. energy-storing molecules produced
a. per 1 Acytyl CoA
- 3 NADH
- 1 FADH₂
- 1 ATP
b. per 1 glucose
- 6 NADH
- 2 FADH₂
- 2 ATP
4. NADH and FADH₂ go to electron transport chain
5. All C from glucose now in CO₂

N. Electron Transport Chain (Respiratory Chain)

1. occus in inner membrane of mitochondrion
2. receives
a. NADH from glycolysis
b. NADH from pyruvate oxidation
c. NADH and FADH₂ from Krebs cycle
3. generates ca. 34 ATP

O. Overall yield of cellular respiration is ca. 36 ATP

P. More glycolysis details

1. consists of 10 different chemical reactions
2. energy investment phase
a. ATP used
b. glucose broken down
3. energy-yielding phase
a. ATP, NADH formed

Q. More pyruvate oxidation details

1. Acetyl CoA is an acetate molecule bound to coenzyme A
2. CoA is derived from a B vitamin

R. More Krebs cycle details

1. consists of 8 chemical reactions
2. oxaloacetate is the first compound use in the cycle
3. the last step of the Krebs cycle reforms oxaloacetate

S. Substrate-level phosphorylation

1. an enzyme transfers a phosphate group from a substrate to ATP
2. glycolysis, Krebs cycle

T. Oxidative phosphorylation

1. The transfer of a phosphate group to redox reactions. The final reduced molecule is O₂
2. electron transport chain

U. More electron transport chain details

1. series of molecules embedded in inner membrane of mitochondrion
2. most of these molecules are proteins
3. redox reactions
4. at end of chain is O₂
5. O₂ + 4H⁺ + 4e^- -> 2H₂O
6. components of the chain
a. NADH-Q reducatase
- 26 subunits
- integral
b. ubiquinone
- lipid
- within phospholipid bilayer
c. cytochrome reductase
- 10 subunits
- integral
d. cytochrome c
- small
- peripheral
e. cytochrome oxidase
- 8 subunits
- integral
7. NADH enters the chain at NADH-Q reductase
8. FADH₂ enters the chain at succinate-Q reducatase (another protein complex). Electrons are then transferred to uniquinone.
9. Each NADH yields ca. 3 ATP.
a. 10 NADH x 3 ATP = 30 ATP
10. Each FADH₂ yields ca. 2 ATP
a. 2 FADH₂ x 2 ATP = 4 ATP
11. How is the energy released in the electron transport chain used to synthesize ATP?
a. Energy is used to actively transport protons (H⁺) across the inner membrane to the inner membrane space.
b. This establishes a H⁺ concentration gradient
c. An integral channel protein called ATP synthase allows the H⁺ to diffuse down the concentration gradient
d. The difference in charge between the intermediate space and the matrix proton-motive force
e. The energy released during this chemiosmosis is used to form ATP from ADP and Pi.

V. Summary of ATP production

1. glycolysis = +2 ATP
2. Krebs cycle = +2 ATP
3. moving NADH = -2 ATP
4. electron transport chain = + 34 ATP
5. total = +36 ATP

W. Glucose metabolism is ca. 38% efficient. 62% of the energy in glucose is dissipated as heat.

X. Do we eat a lot of plain glucose molecules?

Y. What is the source of glucose in our diet?

Z. Food is a source of energy and raw materials for growth, development, etc.