AP Bio (Cellular Respiration)

22) Overall formula for cellular respiration

C6H12O6 + O2 ------> CO2 + H2O + ATP

23) Three stages of cellular respiration

Glycolysis

Krebs Cycle (Citric Acid Cycle)

Electron Transport Chain (ETC)

Glycolysis

a. Where does it occur?

b. What are the substrates/reactants? c, What are the end products?

d. How many of each end product?

e. Where do the end products go? (waste/another part of CR)?

f. What are waste products? (We don't use/see again. Cells get rid of these.)

B. Where is the energy? (Trace the flow of electrons.)

h. Does it require oxygen?

i. What kinds of living organisms can complete each stage?

a) Where? Cytoplasm

b) Substrates/reactants → Glucose, 2 ATP, and NAD+

c) End products → Pyruvate (or pyruvic acid), ATP, and NADH.

d) Quantity → 2 pyruvate, 2 NADH, 2 ATP net

e) Where products go? Pyruvate → Krebs cycle (Mitochondrial Matrix); ATP→Cellular Work; NADH → ETC

f) Waste → None

g) Energy location → Electrons stored in NADH and chemical bonds in pyruvate

h) Oxygen required? → No (Anaerobic Process)

i) Which organisms? → All living organisms (aerobic and anaerobic)

Krebs Cycle

a. Where does it occur?

b. What are the substrates/reactants? c, What are the end products?

d. How many of each end product?

e. Where do the end products go? (waste/another part of CR)?

f. What are waste products? (We don't use/see again. Cells get rid of these.)

B. Where is the energy? (Trace the flow of electrons.)

h. Does it require oxygen?

i. What kinds of living organisms can complete each stage?

a) Where? Mitochondrial matrix

b) Substrates/reactants → Acetyl-CoA, NAD+, FAD, and ADP

c) End products → Carbon dioxide, ATP (or GTP), NADH, and FADH2

d) Quantity → Per glucose molecule (two turns of the cycle): 4 molecules of CO2; 2 molecules of ATP (or GTP); 6 molecules of NADH; 2 molecules of FADH2

e) Where products go? ATP —> cellular work; NADH and FADH —> electron transport chain.

f) Waste → CO₂

g) Energy location → Most of the energy is held in the high-energy electron carriers NADH and FADH2. A small amount is in the ATP produced via substrate-level phosphorylation.

h) Oxygen required? → Indirectly (Used in ETC) (Mainly No)

i) Organisms? → Eukaryotes (aerobic only)

Electron Transport Chain (ETC)

a. Where does it occur?

b. What are the substrates/reactants? c, What are the end products?

d. How many of each end product?

e. Where do the end products go? (waste/another part of CR)?

f. What are waste products? (We don't use/see again. Cells get rid of these.)

B. Where is the energy? (Trace the flow of electrons.)

h. Does it require oxygen?

i. What kinds of living organisms can complete each stage?

a) Where? Inner mitochondrial membrane

b) Substrates/reactants → NADH, FADH₂, O₂, ADP + Pi

c) End products → ATP, water, NAD, and FAD

d) Quantity → ~32 ATP per glucose, 6 H₂O

e) Where products go? ATP → used by cell; NAD+ and FAD—>Recycled back to Glycolysis

f) Waste → H₂O

g) Energy location → Electrons from NADH/FADH₂ pass through ETC; energy stored in proton gradient

h) Oxygen required? → Yes

i) Organisms? → Aerobic eukaryotes

25) Main electron carriers

NAD+ (which becomes NADH)

FAD (which becomes FADH2)

26) At the end of glycolysis, most energy is in

Pyruvate molecules (and some in NADH)

27) Endosymbiotic theory

Mitochondria and chloroplasts were once free-living bacteria engulfed by early eukaryotic cells.

28) Final electron acceptor

Oxygen (forms water)

29) How is a proton gradient formed in mitochondria?

Electrons pass through the ETC, pumping H⁺ ions from the matrix into the intermembrane space.

30) What does the proton gradient drive?

ATP synthase, which produces ATP from ADP + Pi.

31) CR takes place in plants (T/F)

True

CR (Cellular Respiration) takes place in bacteria (T/F)

True

CR takes place in animals (T/F)

True

Glycolysis takes place in plants (T/F)

True

Glycolysis takes place in bacteria (T/F)

True

Glycolysis takes place in animals (T/F)

True

37) When oxygen is not present organisms undergo?

Fermentation (anaerobic respiration)

38) Two main types of fermentation and products

Lactic acid fermentation → Lactic acid

Alcoholic fermentation → Ethanol + CO₂