Carbohydrates

Question 1

Define major carbs in our diet

Answer 1

Monosaccharides- fructose, galactose, glucose
Disaccharides- lactose, maltose, sucrose
Glycogen- glucose polymer
starch- (amylose & amylopectin)

Question 2

Outline the main carbs digestion

Answer 2

Mouth- amylase
Stomach- none
Duodenum & jejunum

Question 3

Describe the difference between hetrokinase & glucokinase

Answer 3

Glucokinase phosphylates glucose in the liver,
Hetrokinase in other cells e.g. muscle

Question 4

Describe glycogen synthesis

Answer 4

Taking glucose to glycogen
Liver muscle cells
Occurs during FED state/ absorption
Triggers insulin
GLUT 2/3 to take Glu into cell converted to glu-6-p then glycogen

Question 5

Describe glycogen degradation

Answer 5

Cutting up glycogen polymer into glucose
Occurs in liver/ muscle cells
When body is in fasting state
Uses glucagon hormone

Question 6

what enzymes are involved in glycogenolysis

Answer 6

Glycogen phosphylase breaks A- 1,4 glycosidic bonds and adds phosphates forming Glu-1-P
Branching enzyme forms free glucose

Question 7

Explain function of Glucose-6- phosphatase

Answer 7

Only works in endoplasmic rectillium of liver cells
Makes free glucose from Glu-6- p
T2 transports out E.R. Into cell

Question 8

Explain glycolysis

Answer 8

Oxidising glucose into (2) pyruvate, 2 net ATP & 2 NADH
Occurs in the cytoplasm

Question 9

What can pyruvate be converted into

Answer 9

Acetyl CoA (aerobic), Lactic acid (anaerobic)

Question 10

Explain GLUT receptors

Answer 10

GLUT1- RBCs, foetus, blood brain barrier
GLUT2- kidneys, liver, pancreas, GI
GLUT3- placenta, neurons, kidneys
GLUT4- muscle, fat/adipose ( insulin dependant)
LEts Glucose in and out of the cell

Question 11

Explain gluconegenesis (metabolism)

Answer 11

Forming new glucose not from carbs.
Occurs in the liver/ kidneys
USes glucagon/ cortisol hormone, lactic acid, glycerol, amino acids

Question 12

What is the fate of lactase

Answer 12

Circulating- go to liver to be reconverted into gluconegogenesis/glyconeogenesis
Oxidation to ATP, CO2 and H2O

Question 13

Explain lactate dehydrogenase

Answer 13

Enzyme that converts pyruvate to lactate
Converts NAD+ to NADH
Involved in glycolysis and gluconeogenesis

Question 14

Explain pyruvate dehydrogenase

Answer 14

Converts pyruvate to acetyl CoA
Converts NAD+ to NADH

Question 15

What is fructose used for

Answer 15

Metabolised in the liver and used for fat synthesis

Question 16

What is galactose used for

Answer 16

Energy storage and production, glycosylation (carb attaching to backbone of a protein)