Carbohydrates

Question 1

What is a carbohydrate ?

Answer 1

A simple unit (CH2O)n

Question 2

What do carbohydrates occur as ?

Answer 2

• Simple sugars (monosaccharide and disaccharides)
• Complex glucose polymers (polysaccharides)

Question 3

What are the main fuctions of carbohydrate ?

Answer 3

• Primary: short-term energy generation
• Secondary: intermidiate-term energy storage
• Tertiary: structural components in cells

Question 4

What are monosaccharides?

Answer 4

• Aldehydes or ketones which contain a carbonyl group : a carbon oxygen double bound
• Depending on the number of C atoms they contain
  e.g. trioses (3)
  tetroses (4)
  pentoses (5)
  hexoses (6)
  heptoses (7)

Question 5

What is monosaccharide cyclisation ?

Answer 5

• Ring form is more energetically stable
• Aldehyde or ketone can react with -OH
• Monosaccharides that contain five or more carbons atoms form cyclic structures

Question 6

What are the name of the bonds in carbohydrates?

Answer 6

Glycosidic bonds

Question 7

Linking carbohydrates will form:

Answer 7

• Disaccharides (sucrose)
• Oligosaccharides (ABO glycolipids)
• Polysaccharides (cellulose)

Question 8

How do disaccharides form?

Answer 8

2 sugar residues joined together via condensation

Question 9

Examples of polysaccharides

Answer 9

• Glycogen
• Starch
• Cellulose

Question 10

What is the storage form of glucose ?

Answer 10

Glycogen

Question 11

What is the link of the main chian of glucose ?

Answer 11

a1→4 linked

Question 12

What is the link of the branches of glucose?

Answer 12

a1→6 linked

Question 13

What is starch used as ?

Answer 13

A nutritional reservoir in plants

Question 14

What are the 2 forms of starch?

Answer 14

• Amylose
• Amylopopectin

Question 15

What is the structure of amylose?

Answer 15

• Unbranched
• a-1,4-linked glucose residues
• Coils into a helical structure

Question 16

What is the structure of amylopetin?

Answer 16

• Branched (identical to glycogen)
• a-1,6-linked residue every 30 a-1,4-linkage

Question 17

What is the role of cellulose?

Answer 17

It has a structural role rather than a nutritional role

Question 18

How many glucose monomers does celulose have ?

Answer 18

8,000 to 10,000

Question 19

What is the structure of cellulose ?

Answer 19

• Unbranched glucose polymer
• b-1,4-linked residues
• multiple OH groups from hydrogen bonds
• forms long and streight chains
• Rigid, supporter structure

Question 20

What is the structure and role of Oligosaccharides?

Answer 20

• Contains 3-9 monosaccharides
• Linked by O or N glycosidic bonds

Question 21

Where can the oligosaccharides be found?

Answer 21

• Cell memebrane
• ABO blood grouping
• Cell recorgnition
• Cell walls

Question 22

Meaning ABO blood groups ?

Answer 22

• ABO regers to oligosaccharide chains (antigens) on red blood cells
• Group O - universal donor
• Group AB - universal acceptor

Question 23

What process are complex oligosaccharides involved in?

Answer 23

Cellular recorgnition (non repetitive sequence)

Question 24

What are oligosaccharides involved in ?

Answer 24

1. Bacterial and viral infections
2. Cancer metastatsis
3. Intercellular recorgnition processes

Question 25

Break down the word

Answer 25

• amino acids (peptido)
• sugar (glycan)

Question 26

where are peptidoglycans found ?

Answer 26

• Bacterial cell walls
• Responsible for their structure rigigity

Question 26

where are peptidoglycans found ?

Answer 26

• Bacterial cell walls
• Responsible for their structure rigigity

Question 27

What is the structure of gram positive peptidoglycans ?

Answer 27

• Many layers of peptidoglycans in cell wall
• Retain crystal violet dye when stained
• Purple when under miroscope

Question 28

What is the structure of gram negative peptidoglycans ?

Answer 28

• Cell wall in thin-inside is made of peptidoglycan
• Outer memebrane composed of phospholipids and lipopolysaccharides
• Thin wall cannot stop violent stain leeching out (pink)