Ch. 8 Cellular Respiration

Question 1

the evolution of metabolic pathways of cellular respiration

Answer 1

when life originated, there was little oxygen in the atmosphere
- anaerobic respiration was used by earliest organisms
later, non-cyclic pathway of photosynthesis increased atmospheric O2
-cells arose that used oxygen as the final acceptor in the ETC

Question 2

ATP

Answer 2

universal energy source for all cells
-photosynthesizers get energy from the sun
-animals get energy second- or third- hand
regardless, energy is converted to the chemical bonds of ATP before it’s used

Question 3

cellular respiration equation

Answer 3

C6H12O6 + 6O2—> 6O2 + 6H2O + 36ATP

Question 4

main type of energy releasing pathways

Answer 4

• anaerobic

- aerobic

Question 5

anaerobic respiration

Answer 5

• evolved first
• doesn’t require oxygen
• produces less ATP
• starts with glycolysis in cytoplasm
• completed in cytoplasm

Question 6

aerobic respiration

Answer 6

• evolved later
• needs oxygen
• starts with glycolysis in cytoplasm
• completed in mitochondria

Question 7

types of anaerobic respiration

Answer 7

• alcoholic fermentation

- lactic acid fermentation

Question 8

alcoholic fermentation

Answer 8

occurs in yeast of beer, wine, and bread

produces: ethyl alcohol, CO2

Question 9

lactic acid fermentation

Answer 9

occurs in bacteria, and muscles

produces lactic acid = sore muscles, cheese

Question 10

fermentation pathways

Answer 10

begins with glycolysis
does not break glucose down completely to CO2 and H2O
- only a yield of 2 ATP
steps that follow just regenerate NAD+

Question 11

3 steps of the aerobic respiration

Answer 11

1. glycolysis
2. Krebs cycle (citric acid cycle)
3. electron transport chain/ phosphorylation

Question 12

glycolysis

Answer 12

net yield of 2 ATP and 2 NADH

Question 13

glycolysis equation

Answer 13

C6H12O6—> C3H4O3

Question 14

Prep steps

Answer 14

yields 2 NADH, 2 CO2

Question 15

krebs cycle

Answer 15

1. takes 2 pyruvates and converts it into 2 acetyl co-a
2. oxaloacetate, a 4-carbon molecule, is produced at the end of the cycle
3. cycle repeats for a second time

Question 16

results of the krebs cycle

Answer 16

-all of carbon molecules in pyruvate end up in CO2
-coenzymes are reduced (they pick up hydrogen and electrons
yields 4 CO2, 2 ATP, 6 NADH, 2 FADH

Question 17

role of coenzymes/ electron carriers

Answer 17

-NAD+ and FAD accept hydrogen and electrons
- becomes NADH and FADH2
delivers hydrogens to ETC
- provides energy for ADP+P to convert to ATP

Question 18

electron transport chain/ phosphorylation

Answer 18

-occurs in mitochondria
-coenzymes deliver electrons to electron transport chains
-electron transport sets up a H+ gradient
-H+ flows down concentration gradient and powers ATP formation
after ATP, O2 is the final acceptor of H+ forming H2O

Question 19

importance of oxygen

Answer 19

electron transport phosphorylation requires presence of oxygen because the final electron acceptor at the end of cellular respiration is O2

Question 20

what happens if there are no carbs?

Answer 20

• body will use carbs first
• need 500-600 carbs a day to fuel the brain
• body will next use fatty acids and glycerol in fats
• body will use amino acids and carbon backbones of proteins as a final resort