past papers

Question 1

function of nucleus

Answer 1

transcription
contains genetic material for polypeptide production

Question 2

why use biomass instead of no of individuals when collecting data to measure diversity?

Answer 2

too numerous to count

Question 3

how do properties of APs (hydrophobic and philic side) allow them to become positioned across the membrane and make a channel through which ions can pass?

Answer 3

• hydrophobic side next to fatty acid tails
• hydrophilic sides allow ion movement through membrane

Question 4

how many daughter cells does binary fission produce?

Answer 4

2

Question 5

how can 2 enzymes w diff amino acid seq catalyse same reaction?

Answer 5

active sites have sim tertiary structures
so form e-s complex

Question 6

diffs between DNA and tRNA

Answer 6

double stranded vs single
many nucleotides vs fe (NOT LONGER VS SHORTER)
thymine vs uracil (NOT T VS U)

Question 7

how to remove large organelles from cell contents

Answer 7

centrifuge
large organelles removed in early pellets

Question 8

why is a separate stain needed for rbc when og binds to DNA?

Answer 8

rbc dont have nucleus

Question 9

comp and cont starch vs cellulose

Answer 9

a glucose vs b
branched vs un
coiled vs straight
both glycosidic bonds
both polysaccharides
no microfibrils vs microfibrils

Question 10

describe complete digestion of starch by a mammal

Answer 10

1. Hydrolysis;
2. (Of) glycosidic bonds;
3. (Starch) to maltose by amylase;
4. (Maltose) to glucose by disaccharidase/maltase;
5. Membrane-bound (disaccharidase/maltase);

Question 11

explain how a mutation in DNA base seq could lead to the formation of non-functioning PAH.

Answer 11

change primary structure
change hydrogen bonds
substrate cant bind- not complimentary

Question 12

how could the structure of a chromosome differ over its length to result in a stain binding more in some areas?

Answer 12

difference in base sequences

Question 13

a sugar binds to an enzyme and rate increases more. how?

Answer 13

changes tertiary structure
changes shape of active site
more e-s complexes form

Question 14

what should scientists take into account to help accurately identify species that a bee belongs to after collecting them?

Answer 14

must allow close examination

Question 15

3 ways to improve method of data collection when investigating biodiversity of bees in diff areas

Answer 15

1. Collect at more times of the year so
   more points on graph/better line (of
   best fit) on graph;
2. Counted number of individuals in each
   species so that they could calculate
   index of diversity;
3. Collected from more sites/more years
   to increase accuracy of (mean) data;

Question 16

if value is greater than critical value, do you accept or reject the null?

Answer 16

reject

Question 17

compare and contrast structure and properties of triglycerides and phospholipids

Answer 17

1. Both contain ester bonds (between glycerol and
   fatty acid);
2. Both contain glycerol;
3. Fatty acids on both may be saturated or
   unsaturated;
4. Both are insoluble in water;
5. Both contain C, H and O but phospholipids also
   contain P;
6. Triglyceride has three fatty acids and
   phospholipid has two fatty acids plus phosphate
   group;
7. Triglycerides are hydrophobic/non-polar and
   phospholipids have hydrophilic and
   hydrophobic region;
8. Phospholipids form monolayer (on
   surface)/micelle/bilayer (in water) but
   triglycerides don’t;