Energy production 1 (S1L2)

Question 1

What is the 1st stage of catabolism?

Answer 1

The breakdown of carbohydrates to building block molecules (monosaccharides)

Question 2

What enzyme, present in saliva, breaks down carbohydrates?

Answer 2

Amylase

Question 3

What are smaller subunits of carbohydrates (starch/glycogen) called?

Answer 3

Dextrins

Question 4

The pancreas produces an enzyme that helps in the breakdown process- what is it called?

Answer 4

Amylase

Question 5

What are disaccharidases attached to?

Answer 5

The brush boarder membrane of epithelial cells

Question 6

What is the role of disaccharidases?

Answer 6

Break down disaccharides into their constituent sugars

Question 7

Lactase and sucrase are enzymes active in the small intestine. Name two others.

Answer 7

Pancreatic amylase and isomaltase

Question 8

When does metabolism start?

Answer 8

When the nutrients have been absorbed

Question 9

Lactose is present in milk products and also..

Answer 9

Many processed foods

Question 10

Primary lactase deficiency involves the absence of what?

Answer 10

The lactase persistence allele

Question 11

Primary lactase deficiency only occurs in adults. True or false?

Answer 11

True

Question 12

Is secondary lactase deficiency genetic in origin?

Answer 12

No - caused by injury to small intestine

Question 13

Secondary lactase deficiency is irreversible. True or false?

Answer 13

False

Question 14

What is congenital lactase deficiency?

Answer 14

An autosomal recessive defect in lactase gene

Question 15

Name the transporter that takes glucose into the intestinal epithelial cells.

Answer 15

SGLT1

Question 16

What is co-transported at the same time as glucose?

Answer 16

2 Na+

Question 17

After entering into intestinal epithelial cells, glucose enters the blood stream via what?

Answer 17

GLUT2 transporter

Question 18

The GLUT family operate through active transport. True or false?

Answer 18

False - facilitated diffusion

Question 19

The are two sides to intestinal epithelial cells- what are they?

Answer 19

Apical and basolateral

Question 20

GLUT2 is found in the small intestine and kidney. Name two other places.

Answer 20

Liver and pancreatic beta cells

Question 21

What is the name of the insulin regulated glucose transporter?

Answer 21

GLUT4

Question 22

The standard blood glucose concentration level is what?

Answer 22

5mM

Question 23

Can all tissues metabolise glucose?

Answer 23

Yes

Question 24

What does an absolute requirement for glucose mean?

Answer 24

Glucose is essential as energy cannot be metabolised from any other source.

Question 25

Which cells have an absolute requirement for glucose?

Answer 25

RBCs, neutrophils, innermost cells of kidney medulla and lens of the eye

Question 26

What do RBCs NOT have that means they can only get energy from glycolysis?

Answer 26

mitochondria

Question 27

GLUT2 is the primary glucose transporter in the brain. True or false?

Answer 27

False- GLUT3

Question 28

The brain prefers glucose as a fuel. What can it also use in times of starvation?

Answer 28

Ketone bodies (but requires time to adapt to the condition)

Question 29

Outline stage 2 of catabolism

Answer 29

- breakdown to metabolic intermediates | - release of reducing power and energy

Question 30

Glycolysis can be broken down to two phases. What are they called?

Answer 30

Investment phase and payback phase

Question 31

The net gain in glycolysis is 4 ATP. True or False?

Answer 31

False. The net gain is 2 ATP

Question 32

Is there any loss of carbon molecules in the process of glycolysis?

Answer 32

No: glucose C6 goes to 2 pyruvate C3

Question 33

Glycolysis does not require oxygen to proceed. True or false?

Answer 33

True

Question 34

There are 3 key enzymes we need to know. What are they?

Answer 34

Hexokinase, phosphofructokinase-1 and pyruvate kinase

Question 35

The phosphorylation of glucose to G-6-P does what to glucose?

Answer 35

Makes it more neg charged, preventing passage back across plasma membrane

Question 36

Glucose to G-6P and fructose-6-P to fructose 1,6-bis-P have a key commonality...

Answer 36

They are irreversible

Question 37

How many NADH molecules are produced via glycolysis?

Answer 37

2

Question 38

The transfer of Pi to ADP to give ATP is called..

Answer 38

substrate level phosphorylation

Question 39

There are four irreversible steps of glycolysis. True or false?

Answer 39

False, there are three

Question 40

Does cancer increase or decrease the rate of glycolysis?

Answer 40

Increase

Question 41

Name the key enzyme regulator in glycolysis

Answer 41

Phosphofructokinase (PFK)

Question 42

Is PFK regulated allosterically or hormonally?

Answer 42

Both

Question 43

Glycolysis produces an intermediate that, when modified, regulates Hb O2 affinity. What is this intermediate?

Answer 43

1,3-bis phosphoglycerate

Question 44

What intermediate of glycolysis is important in the synthesis of fat?

Answer 44

Dihydroxyacetone-P

Question 45

When there is a low oxygen supply or no mitochondria, NAD+ is regenerated via what enzyme?

Answer 45

Lactate dehydrogenase

Question 46

Lactic acidosis occurs above what level of plasma lactate?

Answer 46

5 mM

Question 47

Can the kidneys still excrete lactate during the state of hyperlactaemia?

Answer 47

Yes

Question 48

Lactose is a disaccharide consisting of what sugars?

Answer 48

Galactose and glucose