Glycobiology

Question 1

In rare cases, acarbose treatment may lead to hypoglycemia, low blood sugar level. Which of the following methods may be a quick fix for the resulting hypoglycaemia?
A) quickly drink a can of Diet Coke
B) quickly take a tablet of glucose
C) quickly eat a bowl of steamed rice
D) quickly eat a lot of bread

Answer 1

B) quickly take a tablet of glucose

Question 2

Monosaccharides, the products of polysaccharide and disaccharide digestion, enter the cells lining the intestine via specialized transport system.
What is the source of free energy for this transport?
A) Na+
B) K+
C)ATP
D)Glucose

Answer 2

C) ATP

Question 3

Which feature listed below does not belong to glycogen?
A) is only found in mammals
B) structurally resemble to amylopectin, but with fewer branches
C) posses alpha 1-4 glycosidic linkage
D) possess alpha 1-6 glycosidic linkage

Answer 3

B) structurally resemble to amylopectin, but with fewer branches

Question 4

What is a glycan?

Answer 4

A glycan is a molecule with glycosidic bonds, including sugars.
It has a non reducing end and a reducing end
It’s highly branched
Carbohydrates can be modified
Glycoproteins = glycan

Question 5

What are the two types of glycans?

Answer 5

N-glycans (asn) and O- glycans (serine,threonine, tyrosine)

Question 6

What is the role of erythropoietin?

Answer 6

Erythropoietin is a glycoprotein hormone that stimulates red blood cell production
Produced in the kidney
NEEDS to be glycosylated in order for it to work properly
Can be used to treat anemia
Can be used as a blood doping agent for endurance sports

Question 7

What is the role of glycans on red blood cells?

Answer 7

A random non-enzymatic modification of glucose is glycation which leads to protein denaturation (loss of function)
High amount of glycation is a way to diagnose diabetes
The different types of blood are given because of the different oligosaccharide antigens attached (key for the immune system to work)

Question 8

What is the digestive process of carbohydrates?

Answer 8

Digestión starts at the mouth with an enzyme called amylase.
In the small intestinal lumen a complex carbohydrate is broken down by the pancreatic amylase, the enzyme maltase breaks it into glucose. Glucose gets absorbed into the epitelial cell of intestinal villus which have a basic pH. Then it goes into the blood.

Question 9

Why is too much glucose toxic?

Answer 9

Glucose toxicity means a decrease in insulin secretion and and increase in insulin resistance. It worsens diabetes

Question 10

How can you target carbohydrate digestion to treat diabetes?

Answer 10

Acarbose can be used which inhibits amylase and maltase stopping the production of glucose, ergo stopping the glucose absorbance.

Question 11

Glycogen is the storage of carbohydrate within mammalian …. And ….
It forms as a large polysaccharide polymer synthesized from glucose in the process of …. (Catalyzed by the enzyme glycogen synthase)
Irregularly shaped, glycogen ranged from a few hundred to 30,000 glucose molecules linked together, much like amylopectin.
It’s compact triture produces the dense glycogen granules within cells, which is equivalent to 2000 calories.

Answer 11

Muscle
Liver
Glycogenesis
more branched than amylopectin

Question 12

What maintains the blood glucose homeostasis?

Answer 12

Alpha-glucosidase inhibitors break the alpha-glycosidic linkage
Acarbose inhibits the action of amylase and maltase = reduces glucose

Question 13

What is the difference between glycation of proteins and glycoproteins?

Answer 13

Glycation of proteins is random and non enzymatic
Glycoproteins are intentional, enzymatic and required for protein function