Glycolysis Flashcards Preview

Phase 1 - S2 Metabolism, Endocrinology, Haematology > Glycolysis > Flashcards

Flashcards in Glycolysis Deck (65)
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1

how are carbohydrates broken down

1. amylase in the salvia and pancreas
2. disaccharidases break down disaccharides in the small intestine

2

what are dextrins

smaller subunits of carbohydrates

3

name 4 disaccahridases

lactase, sucrase, pancreatic amylase, isomaltase

4

what is lactose intolerance

when you don't have the enzyme lactase so cant break down lactose

5

what is primary lactase deficiency

absence of the lactase allele. Only occurs in adults

6

why is primary lactase deficiency only seen in adults

as children are born with lactase to break down breast milk, but they may not carry on expressing this gene into adult life

7

what is secondary lactase deficiency

deficiency caused by damage to the small intestine. Occurs in both adults and children

8

true or false: secondary lactase deficiency is reversible

true

9

what is congenital lactase deficiency

an extremely rare recessive defect in the lactase gene.

10

what are the symptoms of lactose intolerance

bloating, flatulence, diarrhoea, vomiting, rumbling stomach

11

how are monosaccharides absorbed into the intestinal epithelia cells

active transport by sodium dependant glucose transporter 1 (SGLT1)

12

which transporter do monosaccharides go through to enter the blood

GLUT2

13

how do monosaccharides enter cells from the blood

facilitated diffusion using GLUT1-GLUT5 transport proteins

14

where are GLUT 2 proteins found

kidney, liver, pancreatic beta cells, small intestine

15

where are GLUT 4 proteins found

adipose tissue, striated muscle

16

which cells have an absolute requirement of glucose (4)

1. RBC- no mitochondria so can only get energy from glycolysis no other sources
2. Neutrophils- use their mitochondria to produce free radicals so cant be used in energy production
3. Kidney Medulla - cortex require lots of oxygen so little reaches medulla
4. lens of the eye - no capillaries so no oxidative phosphorylation so relies on glycolysis

17

what does the uptake of glucose depend on

blood glucose concentration

18

what is stage 2 of energy release from carbohydrates

glycolysis

19

what occurs in phase 1 of glycolysis

2 ATP are used (investment)

20

why is phase 2 of glycolysis called the payback phase

4 ATP are produced

21

what is the net production of glycolysis from 1 molecule of glucose

2 NADH, 4 ATP, 2 Pyruvate

22

true or false: glycolysis is exergonic

true

23

what does hexokinase catalyse

conversion of glucose to glucose-6-Phosphate using energy from ATP. This makes the glucose negatively charged so prevents it passing out of membrane and makes the glucose more energetically favourable

24

what does phosphofructokinase catalyse

conversion of Fructose-6-P to Fructose-1,6-biphosphate using energy from ATP

25

what does pyruvate kinase catalyse

production of Pyruvate from Phosphoenolpyruvate which produces ATP

26

why are there so many steps and enzymes in glycolysis

allows parts to be reversed, allows for control, produces useful intermediates

27

how does glycolysis differ in the liver

it is driven by the supply of glucose rather than the need for energy. The liver also uses glucokinase which isn't inhibited by its products unlike hexokinase

28

true or false: glucokinase has a higher affinity for glucose than hexokinase

false

29

why are the 2 ATP using reactions in glycolysis irreversible

very negative delta G values

30

how is the reducing power captured in glycolysis

NAD+ accepts a hydrogen to become NADH