Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Science for Medicine > Carbohydrates > Flashcards

Carbohydrates Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

What are examples of monosaccharides?

A

Glucose, galactose and fructose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are examples of polysaccharides?

A

Maltose, sucrose abd lactose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Where are the 3 areas that digestion occurs?

A

Mouth, duodenum and jejunum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Does digestion occur in the stomach?

A

Nope

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How are carbohydrates digested in the mouth?

A

Salivary amylase enzyme hydrolyses alpha (1->4) bonds of starch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How are carbohydrates digested in the duodenum?

A

Pancreatic amylase enzyme hydrolyses alpha (1->4) bonds of starch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How are carbohydrates digested in the jejunum?

A

Enzymes hydrolyse alpha (1->6) bonds, which removes glucose and hydrolyses sucrose and lactose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the 3 products of digestion?

A

Glucose, galactose and fructose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How is glucose absorbed?

A

Glucose is absorbed when it travels between the intestinal lumen into blood via epithelial cells. It is driven through the lumen by a high EC Na+ concentration which is maintained by an ATP-driven Na+ pump

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How is galactose absorbed?

A

Though concentration gradients

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How is fructose absorbed?

A

Its absorbed through the lumen into blood by binding to the channel protein GLUT5, where it moves down its concentration gradients

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is an isoenzyme?

A

An enzyme that catalyses the same reaction but has different Km’s and Vmax’s

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the connection between hexokinase and glucokinase

A

They are isoenzymes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are the differences between hexokinase and glucokinase?

A

Hexokinase- low Km and Vmax, can bind to glucose when [glucose] is low
Glucokinase- high Km and Vmax, can only bind to glucose when [glucose] is high

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

When does glucokinase bind to glucose?

A

Quickly after a meal and traps as much as possible in the liver

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Where is glucokinase found?

A

In the liver

17
Q

What is glycogen?

A

It is a polymer of glucose linked by alpha(1->4) subunits with alpha(1->6) branches every 8 to 12 residues. It is mostly found in liver and skeletal muscle

18
Q

How is glycogen produced?

A
  1. Glycogenin covalently binds glucose from UDP-glucose to form chains of approx. 8 sub-units
  2. Glycogen synthase extends the chains
  3. Glycogen-branching enzymes break the chain down to form 1-6 branching points
19
Q

How is glycogen degraded?

A

Glycogen phosphorylase moves glucose subunits one at time as G-6-P from the non-reducing ends of the branches

20
Q

What happens to glycogen in skeletal muscle?

A

It is not converted into glucose in the blood as there is no G-6-phosphatse so it enters glycolysis

21
Q

What happens to glycogen in the liver?

A

It is converted into G-6-P then glucose in the blood as a result of a drop in [BG]

22
Q

What is the function of glycolysis?

A

It is a metabolic pathway that saves some Ep from glucose as ATP via substrate level phosphorylation

23
Q

What is the net gain in glycolysis?

A

2x ATP, 2xNADH and 2x pyruvate molecules

24
Q

What happens to the pyruvate molecules produces in glycolysis?

A

It depends on what the body needs

25
Q

What 2 substances are involved in dehydrogenase catalysed reactions?

A

Lactate (lactate -> pyruvate) and pyruvate (pyruvate -> acetyl CoA)

26
Q

How is lactate converted into pyruvate?

A

By NAD+ during gluconeogenesis

27
Q

When is blood lactate used up?

A

During exercise

28
Q

What is the fate of blood lactate?

A

Gluconeogenesis converts lactate -> glucose in the liver due to a lack of supply of oxygen for oxidative phosphorylation to produce ATP so ATP is produced via substrate level phosphorylation which also produces lactate

29
Q

What is the Cori cycle?

A

Cycle between glycolysis in the tissues and gluconeogenesis in the liver. It is a metabolic pathway in which lactate produced by anaerobic glycolysis in the muscles moves to the liver and is converted to glucose

30
Q

What is the fate of absorbed galactose?

A

It joins glycolysis after through the conversion of G-1-P by UDP

31
Q

What is the fate of absorbed fructose?

A

It joins glycolysis by using ATP to form F-1-P then glyceraldehyde which then uses another ATP molecule to form glyceraldehyde-3-P

32
Q

What are the precursors of gluconeogenesis?

A

Lactate, amino acids and glycerol

33
Q

What are the functions of gluconeogenesis?

A

Converts lactate into glucose in the liver

34
Q

Is gluconeogenesis an exact reversal of glycolysis?

A

Nope, as 3/10 of the reactions in glycolysis are not reversible (not feasible) as they have a -ve delta G

35
Q

What is the process of gluconeogenesis?

A

The 3 reactions that are’t feasible are bypassed by enzymes that catalyse 4 different irreversible reactions

36
Q

What is the pentose phosphate pathway?

A

A metabolic pathway that produces NADPH and pentose sugars which are needed for nucleic acid synthesis and for the metabolism of the small amount of pentose sugars in the diet

37
Q

What are the 2 phases of the pentose phosphate pathway?

A

Oxidative phase and a non-oxidative phase

38
Q

What is the oxidative phase of the pentose phosphate pathway?

A

It is irreversible, generates NADPH and converts G-6-P -> pentose phosphate

39
Q

What is the non-oxidative phase of the pentose phosphate pathway?

A

It is reversible, interconverts G-6-P and pentose phosphate and forms many carbon sugars

Science for Medicine (19 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions