more past paper

Question 1

explain why fetal haemoglobin has curve to left

Answer 1

• higher affinity for oxygen
• load oxygen at lower partial pressure oxygen
• placenta has low partial pressure

Question 2

lack of NAD

Answer 2

lack of NAD

Question 3

what forms a photosystem ?

Answer 3

pigments

Question 4

what do accessory pigments do

Answer 4

absorb light and pass energy to reaction centers

Question 5

what are the holes called on insect body

Answer 5

spiracle

Question 6

define limiting factor

Answer 6

factor which determines rate when in short supply

Question 7

briefly describe collagen

Answer 7

• 3 polypeptide chains
• chains twist
• h bonds between chains
• cross links formed

Question 8

difference between cyclic and non cyclic photophos

Answer 8

cyclic only produces ATP, non also produces NADPH and oxygen

Question 9

where does chemiosmosis occur in photo synth ?

Answer 9

in the ETC,

protons move into thylakoid from stroma

Question 10

what do primary pigments do ?

Answer 10

pass electrons to ETC

Question 11

where is cardiovascular center ?

Answer 11

medulla oblongata

Question 12

what causes type 1 diabetes ?

Answer 12

beta cells not functioning so unable to produce insulin

Question 13

TB infective agent

Answer 13

myco bacteria

Question 14

define biodiversity

Answer 14

abundance of species and variety of alleles

Question 15

define phylogeny and how is it related to classification

Answer 15

• evolutionary relationship between groups of organisms
• basis of classification
• shows common ancestors

Question 16

apart from epistasis, what is a reason for not expected ratio of phenotypes ?

Answer 16

linkage - genes on same chromosome - no independent assortment - alleles inherited together

Question 17

why can molecule not cross membrane

Answer 17

too large to fit in between phospholipids

Question 18

state concern about GM bacteria

Answer 18

resistance to antibiotics

Question 19

how to test if bacteria is transformed

Answer 19

Use marker gene
Antibiotic resistance gene for transformed
Test for survival in antibiotic

Question 20

what needs to be done with mRNA strand to make insulin

Answer 20

make complementary DNA using reverse transcriptase

Question 21

define immune response

Answer 21

immune system cells (lymphocytes) activated in response to antigen

Question 22

EIA

Answer 22

EIA

Question 23

DNA replication is …

Answer 23

semi conservative

Question 24

state a stationary phase for TLC

Answer 24

silica gel

Question 25

what causes change of species due to geographical isolation

Answer 25

different selection pressures

Question 26

give two examples of Galapagos species affected

Answer 26

iguanas - predatation by cats

tortoise - hunted

Question 27

state two bad things about artificial selection

Answer 27

inbreeding

reduction in gene pool