Carbohydrates 1

Question 1

Why are carbohydrates described as ‘highly oxidisable’?

Answer 1

Carbs have high energy H atom-association

Question 2

How are carbs stored in animals and plants respectively?

Answer 2

Animals - glycogen

Plants - Starch

Question 3

Name the three most important hexose sugars in human biochemistry

Answer 3

Glucose, galactose and fructose

Question 4

How are disaccharides formed?

Answer 4

Formed from monomers that are linked by glycosidic bonds

Question 5

What is a glycosidic bond?

Answer 5

Covalent bond formed when hydroxyl group of one monosaccharide reacts with the anomeric carbon of another monosaccharide

Question 6

What is an anomeric carbon?

Answer 6

It is the carbon on the principle carbon on the glucose residue- the only residue that can be oxidised

Question 7

What are the three most important disaccharides in human biochemistry?

Answer 7

Maltose, Lactose and sucrose

Question 8

In what ways can we distinguish between polysaccharides?

Answer 8

• Their recurring monosaccharide units
• Length of their chains
• Types of bonds linking the monosaccharides
• Amount of branching the have

Question 9

Define a homopolysaccharide

Answer 9

Polysaccharide made of a single monosaccharide species

Question 10

Define a heteropolysaccharide

Answer 10

Polysaccharide made of two or more monomer species

Question 11

Describe the structure of starch

Answer 11

Contains two types of glucose polymer (amylose and amylopectin)

Question 12

Describe the proportion of reducing ends in starch

Answer 12

Low

Question 13

Describe the structure of glycogen

Answer 13

Polymer of glucose containing 1,4-glycosidic and 1,6-glycosidic bonds (making it extensively branched)

Question 14

Why store glucose as a polymer?

Answer 14

• Compactness
• Many non-reducing ends allows quick synthesis and catabolism
• Form hydrated gels (partial precipitation) therefor don’t effect osmolarity

Question 15

What are glycoproteins?

Answer 15

Proteins with covalently attached carbohydrates

Question 16

What are some functions of glycoproteins?

Answer 16

1. Increase protein solubility
2. Influence protein folding/configuration
3. Protect protein from degradation
4. Act as communication between cells

Question 17

Glycosaminoglycans (GAGs) are made of what?

Answer 17

Un-branched polymers made from repeating units of hexuronic acid and an amino-sugar

Question 18

Where are GAGs found?

Answer 18

Mucous and synovial fluids

Question 19

How are proteoglycans formed?

Answer 19

From GAGs covalently attaching to proteins

Question 20

Where are proteoglycans found?

Answer 20

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

Question 21

Why types of tissues are proteoglycans found in?

Answer 21

Connective tissues

Question 22

Where in the body are glycoproteins usually found?

Answer 22

Outer plasma membrane and extra-cellular matrix. Can also be found in blood and within cells in the secretory system (Golgi complex)

Question 23

What are Mucopolysaccharidoses?

Answer 23

A group of genetic disorders caused by the absence or malfunction of enzymes required for the digestion of GAGs

Question 24

Describe the natural history of a mucopolysaccharidoses disease

Answer 24

Over time, GAGs build up in connective tissue, blood and other cells - these deposits cause damage

Question 25

What are some of the related pathologies of Mucopolysaccharidoses?

Answer 25

Severe dementia, heart problems, inflamed bones and joints