Carbohydrates 1

Question 1

What is the general structure of carbohydrates ?

Answer 1

( CH2O)n

Question 2

What is the required concentration of glucose in the blood?

Answer 2

5mM

Question 3

List a few tissues that require glucose

Answer 3

• the CNS
• red blood cells as they do not have mitchochondria
• neutrophils for endocytosis of pathogens
• inner cells of the kidney eg descending and ascending limb

Question 4

What is the first step of carbohydrate metabolism in the mouth ?

Answer 4

• amylase hydrolysed starch and glycogen into dextrins.

- pancreatic amylases hydrolyse dextrins / disaccharides into monosaccharides eg glucose , fructose , galactose.

Question 5

Who how is glucose absorbed into the blood after amylase hydrolyses dextrins into monosaccharides ?

Answer 5

1) glucose is actively transported into the intestinal epithelial cell via sodium dependant glucose transporter 1 ( SGLT1) via active transport. At this time , 2NA+ are also moved into the intestinal epithelial cell.
2) glucose then diffuses down a concentration gradient into the blood via GLUT2. At the same time , Na+/k+ atpase is working to pump 3NA+ into blood and 2k+ out of the blood.

Question 6

Whatwhat happens after glucose is absorbed into the blood ?

Answer 6

-glycolysis

Question 7

Define theterm cytosolic

Answer 7

Glycolysis occurs I’m all tissues

Question 8

Why is it cellulose digested in the GI tract ?

Answer 8

• because there aren’t any enzymes that can hydrolyse the beta glucose 1,4 linkages.

Question 9

What are symptoms of being lactose intolerant ?

Answer 9

• stomach bloating
• vomiting
• diorreah
• rumbling stomach

Question 10

What is the most common cause of lactose intolerance ?

Answer 10

• absence of lactase persistent allele - this is called primary lactase deficiency.
• this develops soon after a child becomes less reliant on milk ( eg at 2 years old when they have stopped being breastfed)

Question 11

What is the cause of secondary lactase deficiency?

Answer 11

• damage to the small intestine where lactase is produced. This can be due to cancer treatments such as chemotherapy, gastroenteritis ( infection of stomach and intestine), Crohns disease,

Question 12

What is the cause of congenital lactase deficiency ?

Answer 12

Autosomal recessive defect in lactase gene which is found in newborn babies.

-both parents must have a faulty copy of this gene in order for child to have it.

Question 13

Where in the body will GLUT2 will be found To help transport glucose into cells from the blood ?

Answer 13

S- small intestine

• kidneys
• liver
• pancreatic beta cells

Question 14

Where in the body would you find GLUT4 ?

Answer 14

Adipose tissue

• striated muscle
• it is insulin regulated