Carbohydrates 1

Question 1

Describe the covalent bond in a disaccharide

Answer 1

Hydroxyl group of one monosaccharide forms a covalent bond with an anomeric carbon of another monosaccharide

Question 2

What is meant by anomeric?

Answer 2

Carbon 1 of one monosaccharide is the mirror image of the other carbon on the other monosaccharide (this is true I think for a beta glycosidic bond)

Question 3

Name three important disaccharides

Answer 3

Maltose, lactose and sucrose

Question 4

What is the direct breakdown product of starch?

Answer 4

Maltose

Question 5

Why is maltose considered a reducing sugar?

Answer 5

Anomeric Carbon 1 is available for oxidation

Question 6

Where is sucrose made?

Answer 6

Plants

Question 7

Is sucrose reducing or non-reducing?

Answer 7

Non-reducing

Question 8

Homopolysaccharides?

Answer 8

Single monomeric species

Question 9

What are heteropolysaccharides?

Answer 9

Have two or more monomer species

Question 10

What are the two different forms of starch?

Answer 10

Amylopectin and Amylose

Question 11

What proportion of starch is amylose?

Answer 11

20-25%

Question 12

What proportion of starch is amylopectin?

Answer 12

75-80%

Question 13

Describe the structure of amylose?

Answer 13

D-glucose units with alpha 1-4 linkage

Question 14

Describe the structure of amylopectin

Answer 14

Branches occur every 24-30 monomers
Branches linked with alpha 1-6 glycosidic bonds

Question 15

How many reducing ends does starch have in comparison to the non-reducing ends?

Answer 15

Many non-reducing
Not many reducing

Question 16

Describe the overall shape of amylose and amilopectin

Answer 16

Form alpha helices

Question 17

What is the difference in structure between amylopectin and glycogen?

Answer 17

In glycogen, branches occur much more frequently (every 8 to 12 units)

Question 18

Where can you fin the glycogen in the body?

Answer 18

90% in the liver (replenishes blood sugar during starvation)
10% in the skeletal muscles (catabolism produces atp for contraction)

Question 19

What effect does storing the glucose in the polymers have on compactness?

Answer 19

Makes them more compact

Question 20

Amylopectin and glycogen are said to have many non-reducing ends, why might this be beneficial?

Answer 20

Synthesis and degradation to and from individual monomers becomes easier and therefore fast

Question 21

What difference does storing polymers in the cell have on osmosis?

Answer 21

Polymers are osmotically inactive-
If free glucose were to be stored inside the cell then a lot of energy would be needed to keep the glucose inside the cell (since glucose concentration inside the cell would be much higher than glucose concentration outside the cell).

Question 22

What are glycoproteins?

Answer 22

Proteins that have carbohydrates covalently attached

Question 23

What is the range in carbohydrate content of eukaryotic extracellular protein?

Answer 23

Between 1 and 80 percent by mass

Question 24

What is the possible effect of the carbohydrate on the protein?

Answer 24

Increase the proteins solubility
Influence protein folding and conformation
Protect it from degradation
Act as communication between cells

Question 25

What are glycosaminoglycans ?

Answer 25

Unbranched polymers made from repeating units of hexuronic acid and an amino sugar - found in mucus and synovial fluid around the joints

Question 26

What are proteoglycans?

Answer 26

A compound consisting of protein bonded to glycosaminoacid groups (mucopolysaccharide groups)
There is more protein than carbohydrate usually

Question 27

Where can you find glycosamionglycans?

Answer 27

Found on the surface of cells or in between cells in the extracellular matrix

Question 28

What type of tissue are proteglycans involved in?

Answer 28

Connective tissue

Question 29

Where can you find glycoproteins?

Answer 29

Outer plasma membrane and the extracellular matrix, in the blood and also within the secretory system

Question 30

Where might you find glycoproteins?

Answer 30

Cytoplasmic and nuclear proteins

Question 31

What happens when glycosmainoglycans fail to get broken down?

Answer 31

Build up in connective tissue, leads to loss in cell architecture and function, leads to problems in endothelial structures as glycosaminoglycans can build up between the endothelial cells. Bones tend to be stunted, joints tend to be inflamed and severely damaged.

Question 32

What is dementia caused by?

Answer 32

The build up of cerebrospinal fluid, enlarged ventricular spaces.