Carbohydrate metabolism

Question 1

The primary site within the human body where carbohydrate digestion occurs is the

Answer 1

Small intestine

Question 2

What conversion is accomplished by the process of glycolysis?

Answer 2

Glucose to pyruvate

Question 3

The first two intermediates in the process of glycolysis are

Answer 3

glucose-6-phosphate and fructose-6-phosphate

Question 4

. In the human body, under aerobic conditions and anaerobic conditions, pyruvate is converted to

Answer 4

Acetyl CoA and lactate

Question 5

The name of the process in which glucose 6-phosphate is converted to glycogen is

Answer 5

Glycogenesis

Question 6

Glycogen is converted to glucose in which of the following processes?

Answer 6

Glycogenolysis

Question 7

Which hormone promotes the uptake and use of glucose by cells?

Answer 7

Insulin

Question 8

In which of the following steps of glycolysis does substrate-level phosphorylation occur?

a. production of phosphoenolpyruvate
b. production of pyruvate
c. production of 2-phosphoglycerate
d. more than one correct response

Answer 8

b.production of pyruvate

Question 9

Which hormone increases blood glucose levels

Answer 9

Glucagon - moves glucose out of the cells and into the blood therefore bloody glucose levels will rise

Question 10

Irreversible steps of glycolysis

Answer 10

steps one, three and ten
the enzymes that catalyse these reactions are sites of allosteric control ( remember back to enzymes)
hexokinase 
phosphofructokinase 
pyruvate kinase

Question 11

Glycolysis - Step one

Answer 11

phosphorylation of glucose to glucose -6-phosphate
Endothermic reaction - requires energy
ATP used
catalysed by hexokinase

Question 12

Glycolysis - step 2

Answer 12

isomerisation of glucose 6-phosphate to fructose 6-phosphate

Catalysed by phosphoglucoisomerase

Question 13

Glycolysis - step 3

Answer 13

Phosphorylation of fructose 6-phosphate to form fructose 1, 6-bisphosphate

endothermic reaction (requiring energy) - ATP used

catalysed by phosphofructokinase

Question 14

Glycolysis - step 4

Answer 14

cleavage of fructose 1, 6- bisphosphate to form
1 x dihydroxyacetone phosphate
1 x glylceraldehyde phosphate

catalysed by Aldolase

Question 15

Glycolysis - step 5

Answer 15

Isomerisation of dihydroxyacetone phosphate to form glyceraldehyde 3-phosphate

Catalysed by Triosephosphate isomerase

Question 16

Glycolysis - step 6

Answer 16

oxidation of glyceraldehyde 3-phosphate to
1, 3-bisphosphoglycerate
NAD+ consumed and converted to NADH

Catalysed by glyceraldehyde-3-phosphate dehydrogenase

Question 17

Glycolysis - step 7

Answer 17

Substrate level phosphorylation of ADP

• carbon 1’s P given to ADP to form ATP
• catalysed by phosphoglycerokinase

1,3- bisphosphoglycerate becomes 3 phosphoglycerate

Question 18

Glycolysis - Step 8

Answer 18

Isomerisation of 3-phosphoglycerate to 2-phosphoglycerate

catalysed by phosphoglyceromutase

Question 19

Glycolysis - Step 9

Answer 19

2 -phosphoglycerate dehydrated to phosphoenolpyruvate

catalysed by enolase

Question 20

Glycolysis - Step 10

Answer 20

phosphoenolpyruvate transfers its phosphate group to ADP to form ATP and pyruvate

Catalysed by pyruvate kinase

Question 21

what is substrate level phosphorylation

Answer 21

the synthesis of ATP by direct phosphorylation - steps 7 and 10

Question 22

Which hormone assists the person to obtain energy from glucose and glycogen, during strenuous exercise?

Answer 22

Glucagon and adrenalin (epinephrine)

Question 23

The enzymes of glycolysis are located in the:

Answer 23

Cytoplasm

Question 24

Gylcogenesis

Answer 24

Glycogen making - stored in muscles and liver

Question 25

Glycogenolysis

Answer 25

Glycogen break down to form glucose

Question 26

Glycolysis

Answer 26

makes pyruvate from glucose

Question 27

Gluconeogenesis

Answer 27

Making glucose from non-carbohydrate sources

Question 28

B vitamins function as and what do they consist of ( NAD, CoA, FAD)

Answer 28

coenzymes in carbohydrate metabolism - without them the body would not be able to utilise carbs as an energy source ``` FAD = Riboflavin NAD = Niacin CoA = Pantothenic acid ```