Chapters 6-7

Question 1

Aerobic Respiration

Answer 1

• main energy-releasing pathway leading to ATP formation
• requires oxygen; in cytoplasm and mitochondria

Question 2

Glycolysis

Answer 2

• splits 1 glucose to 2 pyruvates, +2 ATP
• ATP donate P to glucose, which splits to 2 PGAL
• Enzymes add P to each PGAL
• 2e and 1H from PGAL to NAD+ (is reduced)–> NADH (2 PGA form)
• each PGA has 2 phosphates, which are transferred to ADP –> ATP (substrate-level phosphorylation)
• NET: 2 Pyruvate, 2(+2) ATP, 2 NADH

Question 3

Acetyl-CoA formation

Answer 3

• 2nd stage, step 1
• inner membrane of mitochondria
• pyruvate enters via facilitated passive transport
• pyruvate binds to coenzyme A
• 1 C removed as CO2
• transfer from NAD+ to reduced NADH
• 2C acetyl-CoA joins oxaloacetate (4C)

Question 4

Krebs cycle

Answer 4

• 2nd stage, step 2
• release of 2CO₂ from citrate
• forms reduced 3NADH and 1 FADH2
• 1 P transferred to ADP (form ATP)
• net stage 2: 8NADH, 2 FADH2, 6CO2, 2ATP

Question 5

Electron transfer phosphorylation

Answer 5

• 3rd stage, outer mitochondrial compartment
• NADH and FADH₂ give up H+ and e- giving up energy
• active transport of H+ from inner to outer compartment by enzymes
• 36 ATP

Question 6

Fermentation Pathways

Answer 6

• glycolysis yields 2 pyruvate, 2 NADH, and 2 ATP
• acetyl CoA can’t donate e-
• fermentation generates more NAD+

Question 7

Lactate fermentation

Answer 7

2 pyruvate (no intermediates)→ 2 lactate + regenerates NAD+

Question 8

Alcohol fermentation

Answer 8

2 pyruvate release 2CO2→ 2 acetaldehyde; accept e- from NADH to form 2EtOH + NAD+

Question 9

Energy from triglycerides

Answer 9

• bonds between glycerol and fatty acids broken
• liver: glycerol → PGAL
• fragments become Acetyl CoA for Kreb’s cycle

Question 10

Thylakoid membrane

Answer 10

loci of light dependent rxns; released energy moves H+ across membrane

Question 11

Loci of light independent reactions

Answer 11

stroma

Question 12

Thylakoid compartments

Answer 12

3rd membrane in stroma; chloroplast build-up of H+, which flow via ATP Synthase as they follow their concentration gradient (from high to low)

Question 13

Photosynthesis input vs. output

Answer 13

Input: CO2, H2O, NADH, ATP; output: NAD+, ADP, glucose; NAD+ reacts with H+ from photolysis of H2O

Question 14

chlorophyll a

Answer 14

main photosynthetic pigment; absorbs all UV-vis light, but only a little yellow-green and green

Question 15

noncyclic. light-dependent reactions

Answer 15

• forms ATP and NADPH; H₂O splits into ions H, e^-, and O
• e^- enter photosystem II, transport, photosystem I, another transport
• NADP⁺ forms NADPH

Question 16

cyclic, light-dependent reactions

Answer 16

forms ATP only; photosystem I gives excited e- to a transport system; spent ones go back to the photosystem

Question 17

Calvin-Benson Cycle (light-independent)

Answer 17

requires ATP, H+ & e- from NADPH, & CO2 - starts when rubisco (enzyme) fixes CO2 to 5C- RuBP - unstable 6C splits to 2 PGA, which undergoes carbon fixation - PGA accepts P, H, e- to form 2 PGAL - 1 glucose requires 6CO2, 18ATP, 12NADPH

Question 18

Carbon fixation

Answer 18

incorporating a C from CO2 into a stable organic cpd; requires rubisco

Question 19

Rubisco

Answer 19

enzyme that helps remove CO2 from atmosphere

Question 20

12H2O+6CO2 –> 6O2 + C6H12O6 + 6H2O

Answer 20

photosynthesis equation