BoC macromolecules L1

Question 1

Average size of nucleotide

Answer 1

300Da

Question 2

Average amino acid size

Answer 2

110 Da

Question 3

Size of glucose `

Answer 3

180 Da

Question 4

DNA and glycogen Mr…

Answer 4

over 10 MDa

Question 5

Small RNA Mr ~

Answer 5

50 kDA

Question 6

Proteins range of Mr

Answer 6

Insulin small, 5.5kDa, Titin large, 10MDa

Question 7

Draw glyceraldehyde in both forms

Answer 7

see notes (central carbon chiral)

Question 8

Chiral molecules…

Answer 8

Rotate plane polarised light left or right

Question 9

How are carbon atoms numbered in sugars

Answer 9

so carbonyl group has the smallest number

Question 10

Sugars are assigned D-configuration if…

Answer 10

chiral centre with the highest number is the same as chiral centre of D-glyceraldehyde ie OH group on right

Question 11

Fancy word for mirror images

Answer 11

Enantiomers

Question 12

In nature which configuration do sugars take

Answer 12

D config

Question 13

If a molecule has n chiral centres how many possible isomers are there?

Answer 13

2^n

Question 14

Sugars differing in only 1 chiral centre named…

Answer 14

epimers

Question 15

What is the intramolecular cyclisation reaction in glucose?

Answer 15

rotation of the bond between C4 and C5 allows the hydroxyl group on C5 to react with aldehyde on C1 to form a 6-membered ring structure called the pyranose ring

Question 16

What is the anomeric carbon?

Answer 16

The new chiral centre at C1 on glucose, previously the carbonyl carbon

Question 17

Draw alpha and beta glucose

Answer 17

see notes (alpha -oh C1 down)

Question 18

In solution sugars are in equilibrium between…

Answer 18

cyclic and open chain forms

Question 19

at 30 degrees a solution of D glucose contains…

Answer 19

2/3 beta-D-glucopyranose, 1/3 alphaD-glucopyranose, only a very small amount of linear form

Question 20

Draw chair and boat glucose configuration

Answer 20

see notes

Question 21

Which is more stable, boat or chair?

Answer 21

Chair because fewer clashes between oxygens

Question 22

In disaccharides where does the glycosidic bond occur?

Answer 22

Between the anomeric carbon one one sugar and a hydroxyl group on the other

Question 23

Draw maltose

Answer 23

see notes

Question 24

Why are disaccharides highly diverse?

Answer 24

There are 2 possible isomers of the anomeric carbon and these can react with a number of hydroxyl groups on the other sugar

Question 25

Which disaccharide polymerises to make cellulose?

Answer 25

Cellobiose, made of D-beta-glucose

Question 26

What gives cellulose strength?

Answer 26

Adjacent chains H bonding each other

Question 27

Describe glycogen

Answer 27

Energy store in liver/muscles, has 1-6 branch point ~every 10 monomers, alpha 1-4 linkages make it curved not straight like cellulose (with beta 1-4 linkages), made of D-alpha-glucose

Question 28

Describe starch

Answer 28

polymer of D-alpha-glucose, amylose=no branch points, amylopectin= branch points ~every 20 monomers (see notes)

Question 29

Why does glycogen have a more open energy structure?

Answer 29

ready access to enzymes that mobilise sugar monomers when energy is needed and re synthesise polysaccharides when it is plentiful

Question 30

specificity of starch/cellulose production in plant depends on…

Answer 30

ability of enzymes to discriminate between beta and alpha forms