Chapter 8:

Question 1

Which glut transporter is associated with the uptake of glucose into to the tissue of the brain?

Answer 1

GLUT 1

Question 2

Which GLUT transporter is associated with uptake of glucose into the liver?

Answer 2

GLUT - 2

Question 3

Which GLUT is responsible for uptake of glucose into neurons and placental cells?

Answer 3

GLUT-3

Question 4

Whichh GLUT is responsible for glucose uptake into the muscles, adipose tissue, and heart?

Answer 4

GLUT-4

Question 5

A child is found to have a genetic condition that impairs the bodies ability to create a sufficient amount of insulin. Which receptors will be predominantly effected by this?

a. GLUT 1
b. GLUT 2
c. GLUT 3
d. GLUT 4

Answer 5

GLUT 4 - because GLUT 4 is the only indulin dependant transporter in this family.

Question 6

Entry of glucose into the cells is powered by?

a. Active transport.
b. Diffusion.
c. Concentration gradient.
d. The dephosphorylation of ATP to ADP

Answer 6

C - concentration gradient.

Question 7

As a cell digests 3 molecules of glucose, it will go through 3 cycles of glycolysis - producing a net gain of 2 ATP. How many carbon atoms will be lost during this process?

a. 0.
b. 1.
c. 2.
d. 4.

Answer 7

a - 0 - no carbons are lost. From glycolysis we will get 2 pyruvate (3c), 2 ATP, and 2 NADH.

Question 8

The conversion of glucose to pyruvate will occur through glycolysis, in both anaerobic and aerobic conditions to produce energy. In the energy payout phase, how many ATP and NADH will be produced/used respectively?

a. 2 ATP produced, 2 NADH produced.
b. 0 ATP produced, 0 NADH produced.
c. 2 ATP used, 0 NADH produced.
d. 2 ATP used, 2 NADH used.

Answer 8

c. 2 ATP used, 0 NADH produced.

energy investment phase will use 2 ATP in the process of creating 2 G3P out of glucose.

Question 9

During glycolysis, which enzyme will function to transform fructose-6-phosphate into fructose-1,6-biphosphate, ultimately using up 1 ATP in the process?

1. Aldolase.
2. Phosphofructokinase-1.
3. Phosphoglycerate kinase.
4. Glyceraldehyde-3-phosphate dehydrogenase.

Answer 9

2 - Phosphofructokinase will act during the energy investment stage of glycolysis to convert fructose-6-phosphate to fructose -1,6-biphosphate - using 1 ATP.

Question 10

Which enzyme is responsible for splitting fructose-1,6-biphosphate into G3P (3 carbon) and DHAP (3 carbon)?

Answer 10

Aldolase.

Question 11

Describe the 1st step of glycolysis:

Answer 11

Hexokinase will use 1 ATP to add a phosphate group to glucose, creating glucose-6-phosphate.

Question 12

A new drug is targeting the dephosphorylation of ATP in glycolysis as a way to slow excess metabolism of glucose. This has shown great results at maintaining regular blood sugar and improving quality of life for patients. This drug would NOT be targeting:

a. GLUT transporters.
b. Hexokinase.
c. Phosphofructokinase-1.
d. Pyruvate kinase.

Answer 12

a. GLUT transporters and d. pyruvate kinase.

Hexokinase and phosphofructokinase are both used in the energy investment phase of glycolysis to add Pi to the glucose molecule from dephosphorylating ATP. Pyruvate will phosphorylate ADP to ATP and actually produce ATP, and GLUT transporters do not directly do substrate level phosphorylation.

Question 13

Glyceraldehyde-3-phosphate dehydrogenase:

Answer 13

An enzymes that performs a REDOX rxn on G3P to transform it into 1,3-biphosphoglycerate. This redox reaction will generate 2 NADH.

Question 14

Which of the following enzymes is used to generate NADH in glycolysis:

a. hexokinase.
b. pyruvate kinase.
c. phosphoglycerate kinase.
d. Glyceraldehyde-3-phosphate dehydrogenase.

Answer 14

d - glyceraldehyde-3-phosphate dehydrogenase will convert G3P to 1,3-biphosphoglycerate and will generate 2 NADH through that.

Question 15

Phosphoglycerate kinase:

Answer 15

An enzyme used in the energy payout stage of glycolysis, which will convert 1,3-biphosphoglycerate into 3-phosphoglycerate. In this process it will do two subtrate level phosphorylations of ADP to ATP (produces 2 ATP)

Question 16

We want to target ATP production in glycolysis as a means to control blood sugar in new diabetes medication research. We discovered that these 2 enzymes must be targeted:

1. aldolase, hexokinase.
2. pyruvate kinase, and phosphoglycerate kinase.
3. Pyruvate kinase and aldolase.
4. Phosphofructokinase-1, and hexokinase.

Answer 16

2 - Pyruvate kinase and phosphoglycerate kinase - both of these will be used in the energy payout phase to alter glucose derivatives and produce ATP.

Question 17

_________ _________: The metabolism of a derivative of lactose.

Answer 17

Galactose metabolism.

Question 18

What enzymes are involved in galactose metabolism?

Answer 18

1. Galactose kinase - traps galactose into the cell.
2. Galactose-1-phosphate-uridyl transferase.
3. Ultimately galactose will get transformed into glucose-1-phosphate and be shuttled into glycolysis.

Question 19

Which enzymes will be used during fructose metabolism?

Answer 19

1. Fructokinase - will trap fructose in the cell.
2. Aldolase B - cleaves fructose into glyceraldehyde and DHAP, to get shuttled into glycolysis.

Question 20

When blood sugar levels are high, insulin will have a ________ effect on the GLUT 4 transporter?

a. Stimulatory.
b. Inhibitory.
c. Degrading.
d. Primary.

Answer 20

a - stimulatory - insulin responds to high blood sugar and stimualtes process that would cause more uptake and usage of glucose by the cells.

Question 21

When blood sugar levels are low, ___________will have a stimualtory effect on glycogenphosphorylase.

Answer 21

glucagon. - glucagon wants to stimulate the break down of glycogen granules (glycogenolysis) to release free glucose into the blood, and raise blood sugar back up. Glycogenphosphorylase is the enzyme that breaksdown glycosidic bonds in glycogen granules during glycogenolysis.

Question 22

Glycogenesis is the process of generating glycogen granules from excess glucose, to keep for storage. The two important enzymes for this process are:

a. Branching enzymes.
b. Glycogenphosphorylase.
c. Debranching enzymes.
d. Glycogen synthase.

Answer 22

a. branching enzymes
b. Glycogen synthase.

Question 23

While travelling you can’t find a place to eat, and end up missing both breakfast and dinner. In order to sustain cellular function, which of the following processes will be occuring at a high rate?

a. Glycogenesis.
b. Cellular respiration.
c. Aerobic glycolysis.
d. Glycogenolysis.

Answer 23

d - glycogenolysis - which will break down glycogen granules and release free glucose into the blood.

Question 24

Which process can be described as a mechanism by which non-carbohydrate molecules are metabolized to produce glucose?

a. Glycogenolysis.
b. Glycolysis.
c. Gluconeogenesis.
d. Glycogenesis.

Answer 24

Gluconeogenesis.

Question 25

The unique enzymes of gluconeogenesis are used to circumvent specific irreversible steps of glycolysis. Which of the following correctly pairs an enzyme from glycolysis with its corresponding enzymes used in gluconeogenesis? a. Phosphofructokinase; Fructose-1,6-biphosphate. b. Pyruvate dehydrogenase; pyruvate carboxylase and PEP CK. c. Hexokinase/glucokinase. d. Pyruvate kinase/glucose-6-phosphatase.

Answer 25

a - phosphofructokinase; fructose-1,6- biphosphate.

Question 26

An investigator is measuring the activity of various enzymes involved in reactions of itermediary metabolism. One of the enzymes has greatly decreased levels, compared to reference values. The buffer assay contains citrate. Which of the following enzymes will likely be directly effected by the use of citrate? a. Fructose-2,6-biphosphate. b. Isocitrate dehydrogenase. c. Phosphofructokinase-1 d. Pyruuvate carboxylase.

Answer 26

C - phosphofructokinase-1 When the citric acid cycle slows down, citrate will accumulate, and it will function as an allosteric negative regulator of phosphofructokinase-1. This will cause an effect on the phosphofructokinase-1 because it is the rate limiting step of glycolysis.