Session 1 Lecture 2

Question 1

What is the general formula of a carbohydrate?

Answer 1

(CH2O)n

Question 2

What chemical groups do carbohydrates contain?

Answer 2

aldehyde, ketons and hydroxyl

Question 3

What is a monosaccharide?

Answer 3

Single sugar units 3-9 carbons

Question 4

What is a disaccharide?

Answer 4

2 sugar units together

Question 5

What is an oligosaccharide?

Answer 5

3-12 sugar units

Question 6

What is a polysaccharide?

Answer 6

10-1000s sugar units

Question 7

Give an example of a monosaccharide?

Answer 7

Glucose

Question 8

Give an example of a disaccharide

Answer 8

Sucrose

Question 9

Give an example of a polysaccharide

Answer 9

Starch

Question 10

What is sucrose made of?

Answer 10

Glucose and fructose

Question 11

What is lactose made of?

Answer 11

Glucose and galactose

Question 12

What is maltose made of?

Answer 12

Glucose and glucose

Question 13

What is step 1 of catabolism?

Answer 13

Breakdown to building block molecules

Question 14

Why can cellulose not be broken down by humans?

Answer 14

We don’t have an enzyme that will break down the beta 1-4 linkages present in cellulose

Question 15

What are the different types of lactose deficiency?

Answer 15

Primary lactase deficiency, secondary lactase deficiency and congenital lactase deficiency

Question 16

What is primary lactase deficiency?

Answer 16

Incense of lactase persistence allele

Question 17

What is secondary lactase deficiency?

Answer 17

Caused by injury to small intestine e.g. coeliac disease

Question 18

What is congenital lactase deficiency?

Answer 18

Autosomal recessive defect in lactase gene

Question 19

How are monosaccharides absorbed?

Answer 19

Active transport by sodium dependent glucose transported (SGLT1) into intestinal epithelial cells and then via facilitated diffusion using transport protein GLUT2 into blood supply

Question 20

What are the different transport proteins that can transport monosaccharides?

Answer 20

GLUT 1 - GLUT 5

Question 21

Where are GLUT 2 transporter present?

Answer 21

Kidney, liver, pancreatic beta cells, small intestine

Question 22

Where are GLUT 4 transporters present?

Answer 22

Adipose tissue, striated muscle

Question 23

What is special about GLUT 4 transporters?

Answer 23

They are insulin regulated

Question 24

All tissues can metabolise glucose, but which cells have an absolute requirement?

Answer 24

RBC, neutrophil, innermost cells of kidney medulla and lens of eye

Question 25

What is stage 2 of catabolism?

Answer 25

- Breakdown to metabolic intermediates | - Release of 'reducing power' and energy

Question 26

What is another name for stage 2 of catabolism?

Answer 26

Glycolysis

Question 27

What are the two phases of glycolysis?

Answer 27

Investment and payback

Question 28

What additional enzyme do you need for glycolysis to operate anaerobically?

Answer 28

PDH

Question 29

What is produced after glycolysis?

Answer 29

2 NADH, 2 ATP and 2 pyruvate

Question 30

What is the key control enzyme in glycolysis?

Answer 30

Phosphofructokinase-1

Question 31

In glycolysis, why do you need to first phosphorylate the glucose?

Answer 31

Make glucose negatively charged and prevents passage back across plasma membrane. Also inc reactivity

Question 32

What is the committing step of glycolysis?

Answer 32

Step 3 - fructose 6P to fructose 1,6 bisP

Question 33

What is the clinical application of glycolysis?

Answer 33

Rate of glycolysis up to 200x greater in cancer

Question 34

How is phosphofructokinase regulated in muscle?

Answer 34

Allosteric regulation - inhibited by high ATP and stimulated by high AMP

Question 35

How is phosphofructokinase regulated in the liver?

Answer 35

Hormonal regulation - stimulated by insulin and inhibited by glucagon

Question 36

Why inhibits production of hexokinase?

Answer 36

G6-P

Question 37

What happens if there is high [NADH] or low [NAD+]

Answer 37

High energy level signal and causes product inhibition of step 6 and inhibits glycolysis

Question 38

What causes pyruvate kinase to increase?

Answer 38

high insulin: glucagon ration (i.e. high insulin and low glucagon)

Question 39

Name two important intermediates in glycolysis?

Answer 39

Bisphosphoglycerate mutase and glycerol 3-phosphate dehydrogenase

Question 40

What does Bisphosphoglycerate mutate do?

Answer 40

Catalyses synthesis of 2,3-bisphosphoglycerate

Question 41

What does glycerol 3-phosphate dehydrogenase do?

Answer 41

Catalyses synthesis of glycerol phosphate

Question 42

Why is glycerol phosphate important?

Answer 42

Important to triglyceride and phospholipid biosynthesis

Question 43

What would happen to glycolysis when all the NAD+ is converted to NADH?

Answer 43

Glycolysis would stop

Question 44

Normally, how is NAD+ regenerated?

Answer 44

During stage 4 of metabolism

Question 45

Why is NAD+ regenerated in a different way in RBC?

Answer 45

RBC hae no stage 3 or 4 of metabolism because they have no mitochondria

Question 46

How is NAD+ regretted in a RBC?

Answer 46

Lactate Dehydrogenase (LDH) Converts pyruvate to lactate

Question 47

What is plasma lactate concentration determined by?

Answer 47

Relative rate of proaction, utilisation and disposal

Question 48

Deficiency in which 3 enzymes can cause galactosaemia?

Answer 48

Galactokinase, uridyl transferase and UDP-galactose epimerase

Question 49

What is the pentose phosphate pathway?

Answer 49

No production of energy, main product is NADPH and ribose sugars

Question 50

What is the start material for the pentose phosphate pathway?

Answer 50

Starts from glucose 6 phosphate

Question 51

What is the rate limiting step of the pentose phosphate pathway?

Answer 51

Glucose 6 phosphate dehydrogenase

Question 52

What is NADPH required for?

Answer 52

Reducing power for biosynthesis, maintenance of GSH levels and detoxification reactions

Question 53

What is C5-sugar ribose required for?

Answer 53

Nucleotides, DNA and RNA