monosacharides

Question 1

how are carbohydrates synthesised in plants?

Answer 1

complex series of reactions involving photosynthesis

Question 2

what is the general formula of a carbohydrate?

Answer 2

(CH20)n

Question 3

what are some functions of carbohydrates?

Answer 3

storage of energy
structural
specialised roles when modified or complexed with other macro molecules (glycoproteins, glycolipids)

Question 4

what are some examples of unmodified carbohydrates?

Answer 4

monosacchraides- simple sugars
disaccharides- 2 linked monosaccharides
polysaccharides- 100s or 1000 units

Question 5

describe monosaccharides?

Answer 5

colourless
water soluble
most are sweet tasting
open chain and ring structures

2 families aldoses and ketoses (aldehyde or ketone compounds with multiple hydroxl groups)

Question 6

what are the 2 families

Answer 6

aldoses and ketoses and they have many hydroxl groups

Question 7

what are the rules for monosaccharides?

Answer 7

carbon skeleton with 3 or more carbon atoms

each carbon atom except one has an OH group

the other has a carbonyl (C=O) group (= aldehyde group or a ketone group)

Question 8

what is the rule of a ketose?

Answer 8

only has a CO group carbonyl group

Question 9

what is the rule of aldose?

Answer 9

has a carbonyl group but

In the case of aldoses, the carbonyl group is always found at the terminal carbon of the carbon chain.

Question 10

summarise aldoses?

Answer 10

carbonyl group at the end of a chain +aldehyde

asymetrical (chiral) centres at C2, C3, C4 and C5

Question 11

summarise ketoses

Answer 11

carbonyl group at C2 position= ketone

aysmetrical (chiral) centres at c3 c4 and c5

Question 12

ring formation?

Answer 12

only small proportion of open chain molecules: the rest are in cyclic or ring forms

in aqueos solution aldotetroses and all monosssacrides and anything above 5 carbons exist as cyclic structures

bond formation between the carbonyl group and an oxygen atom of a hydroxl group

Question 13

alderhydes can be reduced to what?

Answer 13

reduced to an alcohol group

Question 14

alderhyde groups can be oxidised to what?

Answer 14

carboxylic acid

Question 15

reducing carbohydrates?

Answer 15

when aldehydes are oxidised they are acting as reducing agents

therefore monosaccharides with aldehyde groups are reducing sugars

Question 16

reducing carbonhydrates pt2

Answer 16

ketoses can be reduced to form alcohols

they cant be oxidised

Question 17

whats important by ribose?

Answer 17

(+ deoxyribose) are important in nucleic acid structure

monosachraides,, aldoess pentoses reducing carbohydrates

Question 18

mannose

Answer 18

found naturally in some fruits and legumes

only a small amount is metabolised

Question 19

galactose?

Answer 19

hexose,aldose reducing carbohydrate

found in diary products

Question 20

fructose

Answer 20

hexose, ketose and is a reducing carbohydrate

poorly abosrobed on its own

can be deribed from sucrose

Question 21

glucose summarised?

Answer 21

most common carbohydrate

converted to starch or glycogen for storage

syntehsized by chloprhll in plants/ algae from c02 and sunlight

Question 22

glucose assay method?

Answer 22

add DNS reagent to sample of unknown concentration

Boil for 5 mins, cool, measure A540nm

Question 23

what is the range for normal glucose?

Answer 23

4-7 mmol/l

Question 24

why would anyone have low glucose

Answer 24

• low carbohydrate intake
  - xs medication
  - recent exercise levels

Question 25

why would someone have high glucose levels

Answer 25

• xs dietary intake
  - insufficient medication
  - recent inactivity
  - stress

Question 26

what are aldoses

Answer 26

monosaccharides that contain an aldehyde functional group (-CHO)

aldehyde group is typically found at one end of the sugar molecule.

Examples of aldoses include glucose,ribose

Question 27

what are ketoses

Answer 27

Ketoses are characterized by having a ketone functional group (C=O)
This ketone group is typically located at the second carbon atom,