semester 1

Question 1

name process that converts mRNA -> protein

Answer 1

translation

Question 2

what 2 DNA bases = purines and which ones = pyrimidines

Answer 2

purine = adenine and guanine
pyrimidines = cytosine and thymine

Question 3

what is the difference between amylose and amylopectin

Answer 3

amylose = i3- is incorporated into amylose helix - blue colour = formed
Amylopectin - no iodine reaction with this molecule - yellow colour = formed [no Iodine = incorporated]

Question 4

whats the function of the shine delgarno seqyence

Answer 4

it is a ribosome binding site - RNA polymerase binds to small subunit [30S]
it has a consensus of 5’ rGGAGG 3’

Question 5

list 2 protein denaturing agents

Answer 5

heat and change in pH

Question 6

Which of the following lipids is the major fuel store in the body?
(a) Glycerophospholipid (b) Triacylglycerol (c) Sphingolipid
(d) Sterol (e) None of these

Answer 6

Triacylglycerol

Question 7

what 2 antibiotics inhibit ribosome

Answer 7

streptomycin and erythromycin

Question 8

what is the function of lipases

Answer 8

when triacylglycerol stores are broken down to supply energy - this enzyme catalyses the release of 3 fatty acids from the glycerol backbone so it can be used to generate energy

Question 9

list 3 methods for testing the presence of reducing sugars

Answer 9

fehlings, benedicts and barfoeds tests [BBF]

Question 10

Does the presence of cholesterol in a biological membrane increase or
decrease the fluidity of the membrane? Explain.

Answer 10

decreases the fluidity as the rigid steroid ring system of cholesterol interferes with lateral movement of fatty acids

Question 11

What 2 transition metals are found in Folin-Ciocalteau reagent?

Answer 11

phosphomolybdic acid and phosphotungstic acid

Question 12

State Beer-lambert law

Answer 12

A=e.c.l=log10(i0/i) [there’s a linear relationship between concentration and absorbance]
A= absorbance
e= molar absorptivity
c=concentration
l= path length
i0 = incident light
i= transmitted light

Question 13

Which protein contains the non-standard amino acids, desmosine and
isodesmosine?

Answer 13

elastin

Question 14

What mutation causes sickle cell haemoglobin?

Answer 14

A.A substitution of a glutamic acid-> a valine on the outside a beta chain

Question 15

. Hexoses are very important sugars found in living organisms. Which of the 2
stereoisomers of hexoses are more common in nature?

Answer 15

D-glucose [aldohexose] and D-fructose [ketohexose]

Question 16

what are epimers

Answer 16

D sugars that differ in configuration @ only 1 single asymmetric carbon atom i.e. D-mannose and D-galactose

Question 17

describe the structure and function of glycogen

Answer 17

an energy store - an animal polysaccharide
- include polymers units of glucose joined by alpha1->4 glyosidic bond
- highly branched - every 10 units there’s an additional alpha 1-> 6 glyosidic bond which forms a branching point
it is made and stored mainly in the liver and muscle and can be broken down by enzyme glycogen phosphorylase to release individual glucose units which are then metabolised to provide energy