Chapter 13 : Energetics and Catabolism

Question 1

what is the yielding of energy from e- transfer between chemicals?

Answer 1

chemotrophy

Question 2

what is the yielding of energy from light absorption?

Answer 2

phototrophy

Question 3

what does NADH consist of?

Answer 3

ADP molecule attached to a nicotinamide ring

Question 4

how does FADH2 compare to NADH?

Answer 4

it is weaker but similar in that they both donate 2e- to acceptor

Question 5

what is the catalytic site of an enzyme?

Answer 5

part of the protein that binds with the substrate and catalyzes the reaction

Question 6

what are carbohydrates broken down into in the catabolism process?

Answer 6

short chains(oligosaccharides), then to disaccharides, then monosaccharides

Question 7

what are lipids broken down into during catabolism?

Answer 7

microbes catalyze lipids by hydrolysis to glycerol and fatty acids

Question 8

what are peptides broken down into during catabolism?

Answer 8

broken down protein that are hydrolyzed to amino acids

Question 9

what types of products are made in fermentation?

Answer 9

all e- are put back onto organic products

Question 10

what types of products are made in respiration?

Answer 10

e- are transferred to inorganic acceptors, products are H2O and CO2

Question 11

what are the three routes to pyruvate used by bacteria and archaea?

Answer 11

glycolysis, entner-doudoroff(ED) pathway, and the pentose-phosphate pathway(PPP)

Question 12

what happens during glycolysis to G6P?

Answer 12

G6P isomerizes to F6P, which becomes 2 pyruvate molecules

Question 13

what are the products of glycolysis?

Answer 13

2 pyruvate, 2 ATP, and 2 NADH

Question 14

what happens to G6P in the PPP pathway?

Answer 14

it is oxidized to G6-phosphoglucanate, then decarbonxylated to a 5-carbon sugar(pentose) called ribulose 5-phosphate

Question 15

what is the purpose of the sugars that the PPP pathway creates?

Answer 15

they are used as precursors to biosynthesis or are converted to pyruvate if necessary

Question 16

what are the products of the ED pathway?

Answer 16

2 pyruvate, 1 ATP, 1 NADH, 1 NADPH

Question 17

what are the products of the PPP pathway?

Answer 17

biosynthesis, 1 ATP, 2 NADPH

Question 18

what happens to G6P in the ED pathway?

Answer 18

G6P is oxidized to G6-phosphoglucanate, making 2 pyruvate

Question 19

what does it mean that ATP formation is substrate-level phosphorylation in lactic acid fermentation?

Answer 19

it only involves substrate ions, no proton pumping across membranes

Question 20

how many ATP does lactic acid fermentation create?

Answer 20

2 ATP

Question 21

how is pyruvate converted to lactic acid?

Answer 21

adding 2e-, so one glucose molecule becomes 2 lactic acid molcules(C3H6O3)

Question 22

how many ATP are created in ethanolic fermentation?

Answer 22

2 ATP

Question 23

what are the byproducts of ethanolic fermentation?

Answer 23

2 ethanol molecules and 2 CO2 molecules

Question 24

how many ATP are created in heterolactic fermentation?

Answer 24

2 ATP

Question 25

what are the byproducts of heterolactic fermentation?

Answer 25

one lactic acid, one ethanol, one CO2

Question 26

what are the products of mixed-acid fermentation?

Answer 26

acetate, formate, succinate, ethanol, lactate, H2, CO2

Question 27

in what process are the products of sugar breakdown catabolized into CO2 and H2O?

Answer 27

tricarboxylic acid cycle(TCA) cycle, a.k.a Krebs cycle

Question 28

what molecules does the Krebs cycle generate that donates e- to ETS?

Answer 28

NADH and FADH2

Question 29

where does the Krebs cycle occur in plant and animal cells?

Answer 29

in the mitochondria

Question 30

what is the first step of the Krebs cycle, one that occurs before the loops starts?

Answer 30

pyruvate must be converted to acetyl CoA

Question 31

what does the acetyl group condense with to form citrate?

Answer 31

oxaloacetate

Question 32

what is citrate rearranged to become?

Answer 32

isocitrate

Question 33

when isocitrate is decarboxylazed oxidatively, it transfers energy from 2H+ and 2e- to form NADH + H+. what does it become?

Answer 33

2-oxoglutarate

Question 34

what does 2-oxoglutarate become once it is decarboxylzed, releasing CO2 and making NADH and H+?

Answer 34

succinyl-CoA

Question 35

once succinyl-CoA releases CoA, it yields energy to phosphorylate ADP to ATP. what does it become?

Answer 35

succinate

Question 36

why is FAD used instead of NAD in the succinyl-CoA step?

Answer 36

e- donation from succinyl-CoA does not yield enough energy to reduce NAD

Question 37

what does fumarate incorporate in its double bond to form malate?

Answer 37

H2O, forming final NADH and H+

Question 38

what does each acetate form in the Krebs cycle?

Answer 38

3 NADH, 1 FADH2, and 1 ATP

Question 39

what is the process of e- transport and ATP generation known as?

Answer 39

oxidative phosphorylation

Question 40

what happens to the Krebs cycle when glucose is scarce?

Answer 40

cells switch to the glyoxylate bypass which avoids losing carbons as CO2 to the atmosphere