L6- Carbohydrates 1 Flashcards

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

catabolism

A

breakdown of larger molecules into smaller ones

- energy released

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

catabolic reaction involve

A

oxidation-release of H atoms

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

H atoms become

A

reducing powers

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

anabolism

A

synthesises larger important cellular components from smaller molecules
- uses energy

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

anabolic reactions are

A

reductive (uses H+ released In catabolism)

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

sources of catabolism metabolism

A

amino acid (most excreted)
fatty acids
glucose
alchohol

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

acetyl co A

A

is an intermediate for all source of catabolism

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

Body composition predominately

A

lipids and proteins (even though we take in more CHO than lipids and proteins)

  • we are only 1% CHO
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

how many stages of catabolism

A

4

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

stage 1

A

breakdown of molecules into molecules that can be absorbed

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

stage 2

A

glycoluysis

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

stage 3

A

Kreb/TCA cycle

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

stage 4

A

electron transport chain

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

formula of CHO

A

(CH2O)n

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

CHO contain which groups

A

aldos enad ketose groups

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

monosacchirdes

A

3-9 carbons

  • glucose
  • fructose
  • galactose
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

disaccharides

A

2 units

  • sucrose
  • maltose
  • galactose
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

oligosaccharides

A

(3-12 units)

- dextrin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

polysacchride

A

10-1000 units

  • glycogen
  • starch
  • cellulose
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

glucose is a

A

major source of sugar in the blood (5mM)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

all tissue can metabolise

A

glucose

22
Q

which cell have an absolute requirement for glucose

A
  • RBC
  • neutrophils
  • innermost cells of kidney medulla
  • lens of the eye
23
Q

uptake of glucose depends on

A

[glucose]

24
Q

the CNS uses … as fuel

A

glucose (approx 140g/24h) and no the rfules

25
Q

in starvation mode the brain can evolve energy from

A

ketone bodies- body needs time to adapt

26
Q

digestion of CHO starts in

A

mouth- amylase

27
Q

amylase in the mouth breaks down starch nd glycogen to

A

dextrins

28
Q

amylase does not work in

A

the pH of the stomach

29
Q

amylase is released by the

A

pancreas

amylase- converts dextrin to monosaccharides

30
Q

disaccharide attach to

A

the brush border fo the membrane of epithelial cells

31
Q

cellulose is

A

indigestible

32
Q

why is cellulose indigestible

A

no enzyme to breakdown the B1-4 linkage present in dietary fibre
- alpha and beta bonds are different

33
Q

how are monosaccharides absorbed int he blood

A

Gut into epithelial cells
- Active transport (low to high conc)- energy coming from a sodium dependent glucose transport (SGLT1)

Passive transport from cells to capillaries
Passive transport (high to low conc)
- Using GLUT transporters

34
Q

GLUT transporters

A

Glucose uptake into cells from blood in via facilitated diffusion using transport proteins (GLUT1-5)
- GLUTs can be hormonally regulated.

35
Q

GLUT 1

A

fetal tissue, adult erythrocytes, BBB

36
Q

GLUT 2

A

kidney, liver, pancreatic beta cells, small intestines

37
Q

GLUT 3

A

neurones and palcenta

38
Q

GLUT 4

A

adipose tissue, striated muscle

39
Q

GLUT 4 is regulated by

A

insulin

40
Q

GLUT 5

A

spermatozoa and intestine

41
Q

lactose intolerance causes

A

Causes… Bloating, flatulence, vomiting, diarrhea etc.

42
Q

types of lactose deficiency

A
  • primary lactase deficiency
  • secondary lactase deficiency
  • congenital lactase deficiency
43
Q

primary lactase deficiency

A

• Primary lactase deficiency
o Only occurs in adults
o Absence of lactase persistence allele
o High prevalence in Northwest Europe

44
Q

secondary lactase deificnecy

A
o	Damage to small intestine 
	Gastroenteritis 
	Coeliac disease 
	Crohns disease 
	UC 
o	Occurs in both infants and adults  
o	Generally reversible
45
Q

• Congenital lactase deficiency

A

o Extremely rare
o Autosomal recessive defect in lactase gene
o Cannot digest breast milk

46
Q

stage 2 (glycolysis)- function

A

o Oxidation of glucose
o Production of 2 NADH/ glucose molecule
o Synthesis of 2 ATP molecules from ADP/ glucose molecule
o Production of 2 pyruvate (C3) / 1 glucose molecule (C6)

47
Q

features of glycolysis

A

o Central pathway of carbohydrate catabolism
o Occurs in all tissues
o Cytosolic
o Exergonic and oxidative- releases energy and hydrogen
o No loss of CO2
o With one additional enzyme (LDH), the pathway can operate anaerobically
o Irreversible pathway

48
Q

key enzymes of glycolysis

A

Key enzymes: Hexokinase (key glucose sensor), Phosphokinase-1 and pyruvate kinase

49
Q

why so many steps in glycolysis (10 enzymes, 5 coenzymes, 9 intermediates)

A
  • Chemistry easier in small stages
  • Efficient energy conservation
  • Gives versatility
    o Interconnection with other pathways
    o Production of useful intermediates
    o Allows part to be used in reverse
  • Can be controlled
50
Q

glycolysis clinical application

A
  • Can be used in the diagnosis of cancers
    o Rate of glycolysis up to 200 times greater in cancer
    o Can measure uptake of FDG
    (radioactive modified hexokinase substrate)
    o Imaging with positron emission tomography