Biochem Class 2

Question 1

animals are ______ aerobic _____-trophs

Answer 1

obligate heterotrophs

Question 2

the lipid/fat soluble vitamins are

Answer 2

ADEK

the rest are water soluble

Question 3

most water soluble vitamins are converted into

Answer 3

coenzymes

*except for Vitamin K, which is fat soluble yet is converted into coenzyme

Question 4

reactants, intermediates, and products of metabolic pathways are all referred to as

Answer 4

metabolites

Question 5

acetyl-CoA is a common _________ in metabolic pathways

Answer 5

intermediate

Question 6

enzymatic reactions in metabolic pathways fall into which 4 major classes?

Answer 6

1. oxidations and reductions (catalyzed by oxidoreductases),
2. group-transfer reactions (catalyzed by transferases and hydrolases),
3. eliminations, isomerizations, and rearrangements (catalyzed by isomerases and mutases),
4. reactions that make or break carbon–carbon bonds (catalyzed by hydrolases, lyases, and ligases).

Question 7

the end products of aerobic glycolysis are

Answer 7

2pyruvate + 2NADH + 2ATP

^this is the net end products. the total ATP output is 4 but since 2 ATP are initially used, the net ATP produced is 2

Question 8

equation for aerobic glycolysis

Answer 8

Glucose+2NAD⁺+2ADP+2P_i → 2pyruvate+2NADH + 2ATP + 2H₂O +4H⁺

Question 9

the step in glycolysis responsible for reducing NAD+ into NADH does so by oxidizing a _________ into a _________

Answer 9

aldehyde into a carboxilic acid

Question 10

T/F: glycolisis does not require or use oxygen

Answer 10

true

Question 11

Glyceraldehyde 3 phosphate in glycolysis represents

Answer 11

abbreviated GAP.. it is the first product of glucose in which it is split into 2 and is no longer cyclic

Question 12

the step immediately following the cleavage of cyclic fructose (F-1,6-bP) into 2 Glyceraldehydes is significant how?

Answer 12

it is the one step in which 2 NAD+ are converted into 2 NADH

Question 13

T/F: hexokinase is inhibited by it’s product

Answer 13

true

Question 14

phosphofructokinase is inhibited by _____

Answer 14

ATP

Question 15

what type of enzymatic reactions do both phosphofructokinase and hexokinase accomplish

Answer 15

phosophorylation (adding a phosphate)

Question 16

how would you characterize the reversibility of the reaction from fructose-6-phosphate to fructose 1, 6 biphosphate?

Answer 16

nearly irreversible because it has a delta G much less than zero

Question 17

the activity of _______________is the key regulatory step in glycolysis due to its thermodynamic favorability and from it’s strong mechanism of regulation: it is allosterically regulated by ATP

What enzyme is described?

Answer 17

PFK (phosphofructokinase)

Question 18

what would be the effect of increased ATP concentration in glycolysis

Answer 18

cell will slow glycolysis (d/t the allosteric inhibition by ATP on PFK)

Question 19

product of PDC (Pyruvate dehydrogenase complex)

Answer 19

Acetyl-CoA

Question 20

1 NADH inputted into the electron transport chain produces # ____

Answer 20

3 ATPs

Question 21

the citric acid cycle is the entry point for what molecules:

Answer 21

fats and proteins that are converted into Acetyl CoA

Question 22

Is any Co2 produced during the stage 1 reaction of the Krebs cycle

*Stage 1 is the reaction of oxaloacetate and acetyl-CoA to make citric acid

Answer 22

no

Question 23

what are the stages of the Krebs Cycle

Answer 23

1. Acetyl CoA + Oxaloacetate→ Citric Acid _{(6 Carbons)}
2. Citric acid → → succinyl CoA _{(5 carbons)} 2NADH + 2CO₂
3. Succinyl CoA _{(4 carbons*)} → succinate + GTP→→→oxaloacetate +NADH +FADH₂

*not including the CoA part

Question 24

enzymes of the electron transport train/oxidative phosphorylation are bound to what structure?

Answer 24

the inner mitochondrial membrane

Question 25

T/F: Succinate dehydrogenase (Complex 2 in electron transport chain) is the only membrane-bound enzyme in the Citric acid cycle

Answer 25

True

Question 26

\_\_\_\_\_\_ is the final electron acceptor in the electron transport chain

Answer 26

Oxygen (to form water)

Question 27

how many hydrogens moving throught ATP synthase can create 1 ATP

Answer 27

4

Question 28

How many NADH are produced from the citric acid cycle per glucose

Answer 28

6 Products of the first turn of the cycle are one GTP (or ATP), three NADH, one QH2, and two CO2. Because two acetyl-CoA molecules are produced from each glucose molecule, two cycles are required per glucose molecule. Therefore, at the end of two cycles, the products are:two GTP, six NADH, two QH2, and four CO2

Question 29

eukaryotes make 30 ATP from glucose, prokaryotes make

Answer 29

32

Question 30

enzyme activity normally increases with increasing temperature, extreme high temperature does what?

Answer 30

denatures the enzyme and renders it inactive.

Question 31

at what concentrations are the equivalence points?

Answer 31

1 and 2

Question 33

pH + pOH = ?

Answer 33

14 sample calculation: given: pH of 7.6. Since pH + pOH = 14, that means the pOH of the solution should be 7.6 + pOH = 14, or 6.4

Question 34

Based on the Figure, which of the following is least supported? A. The OCA2 proteins in the eight species studies would be considered homologous. B. The OCA2 protein is conserved across eukaryotes. C. Zebrafish and Japanese killifish have a OCA2 common ancestor protein which is more related that that between horse and human. D. Humans and chimpanzees are more closely related than fission yeast and the wild boar. **topic: interpreting phylogenetic trees**

Answer 34

D. Humans and chimpanzees are more closely related than fission yeast and the wild boar. Explanation: OCA2 in zebrafish and Japanese killifish share a common ancestor which is not far away in evolutionary terms **(i.e., is not very far down the diagram).** In contrast, the common ancestor protein between human and horse OCA2 protein is the point at the bottom of the diagram; this is farther away in evolutionary terms (choice C is supported and can be eliminated).

Question 35

what does the process of PDC use and produce?

Answer 35

Question 36

T/F: the citric acid cycle oxidizes acetyl groups from many sources, not just pyruvate.

Answer 36

True

Question 37

During fermentation, pyruvate is reduced/oxidized to lactate

Answer 37

reduced

Question 38

What is the best description for the energetics of glycolysis?

Answer 38

Overall under typical cellular conditions, glycolysis has a negative free-energy change, though there are steps of both positive and negative free-energy change

Question 39

Which glycolytic reaction cannot be directly reversed in gluconeogenesis? Glucose → glucose-6-phosphate Glyceraldehyde 3-phosphate → 1,3-bisphosphoglycerate 1,3-bisphosphoglycerate → 3-phosphoglycerate Glucose-6-phosphate → fructose-6-phosphate

Answer 39

The three most favorable steps (and therefore most difficult to reverse) of glycolysis are: glucose→ G-6-P, fructose-6-phosphate→ fructose 1,6-bisphosphate, and phosphoenolpyruvate (PEP)→ pyruvate. So the answer is Glucose → glucose-6-phosphate

Question 40

What carbohydrates are reactants in glycolysis? Neither glucose or sucrose directly participate in glycolysis Glucose and sucrose Sucrose only Glucose only

Answer 40

Glucose only

Question 41

Will an agent that acts as an inhibitor of the electron transport chain kill a mammalian cell?

Answer 41

Yes

Question 42

fermentation has evolved to regenerate \_\_\_\_\_in anaerobic conditions, thereby allowing glycolysis to continue in the absence of oxygen

Answer 42

NAD⁺

Question 43

What is the role of fructose-2,6-bisphosphate

Answer 43

Fructose 2,6-bisphosphate allosterically affects the activity of the enzymes phosphofructokinase 1 (PFK-1) and fructose 1,6-bisphosphatase (FBPase-1) to regulate glycolysis and gluconeogenesis. [1]Fru-2,6-P2 itself is synthesized and broken down by the bifunctional enzyme phosphofructokinase 2/fructose-2,6-bisphosphatase. \*don't confuse with fructose-1,6-bisphosphate, which is an intermediate in glycolysis

Question 44

which intermediate product in glycolysis can be shuttled to the pentose phosphate pathway?

Answer 44

only Glucose-6-phosphate (product #2) is shuttled from glycolysis to the pentose phosphate pathway Order of products: 0-1-1-2-1-2-1-1-1-0 (numbers indicate number of phosphate present)