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Question 1

Ecology

Answer 1

study of how organisms interact with each other and their natural environment

Question 2

Central dogma of molecular biology

Answer 2

flow of information in all living organisms from DNA to RNA to proteins

Question 3

success of prokaryotes depends on

Answer 3

their small size
their ability to reproduce rapidly
their ability to obtain nutrients and energy from diverse sources

Question 4

Metabolism

Answer 4

chemical reactions by which cells convert energy from one form into another and build and break down molecules

Question 5

Virus

Answer 5

either RNA or DNA, surrounded by a protein coat and sometimes a lipid envelope
non-living: cannot harness energy from own environment, cannot read information in genetic material to form proteins of their own, cannot regulate movement of substances across membrane, cannot replicate on own

Question 6

How a virus infects a cell

Answer 6

binds to the cell’s surface
inserts its genetic material into cell
uses cell machinery to produce more viruses
infected cell may produce more viruses by lysis or breakage of the cell
new virus can then infect more cells
genetic material of virus may integrate into DNA of host cell

Question 7

Divergence

Answer 7

evolutionary theory predicts that new species arise by the divergence of populations through time from a common ancestor
closely related species are likely to resemble each other more closely than they do more distantly related species

Question 8

Phylogenetic trees are organised according to

Answer 8

morphological observations
molecular observations
comparisons of DNA
comparisons of fossils

Question 9

bacteria in evolution experiments

Answer 9

ideal as reproduce rapidly
large population means mutations likely to form in nearly every generation, even though the probability that any individual cell will acquire a mutation is small

Question 10

Pros: human footprint

Answer 10

advances in agriculture

inadvertently help other species to expand

Question 11

Cons: human footprint

Answer 11

poaching
hunting and fishing
habitat destruction

Question 12

inductive reasoning

Answer 12

deriving generalisations from a large number of specific observations

Question 13

Deductive reasoning

Answer 13

prediction of results that will be found if a hypothesis is correct
the hypothesis is then tested by carrying out experiments/observations to see whether or not the results are as predicted

Question 14

prions

Answer 14

misfolded version of a protein
alpha helices replaced by beta sheets
PrpC and PrpSc
Prp found in brain
Spread of PrpSc causes breakdown of brain material and formation of spongy areas (Mad Cow disease)
PrpSc enters from food or infected bodily fluids
Could also be inherited where PrpC converts spontaneously into PrpSc at a low rate

Question 15

Viruses

Answer 15

protein coat or lipid envelope
cannot metabolise or reproduce
can respond to environmental stimuli and enter a host cell
once inside, use host resources to multiply

Question 16

Giruses

Answer 16

10x larger than normal viruses in size and contained genetic material
encode many genes and machinery to reproduce alone but many essential components for this still absent so they still require invasion of a host cell to multiply

Question 17

Protozoan parasites

Answer 17

eukaryotic
can be parasitic- live on or in a host to the detriment of the host
can be both asexual and sexual

Question 18

parasitoids

Answer 18

reproduce by laying eggs into body of another living organism
eggs become larvae, larvae grow, parasite larvae eats out of its living organism

Question 19

Parasitic wasps

Answer 19

Wasp attacks aphid, lays egg inside it
Aphid dies, egg becomes larvae
Wasp hatches from aphid and can then go on to insert eggs into other aphids
Used to control aphid reproduction and as a natural alternative to pesticide by sprinkling dead aphid over plants

Question 20

Wolbachia

Answer 20

Some mosquitos have a bacteria called Wolbachia which does not allow dengue to grow well inside, and therefore cannot be transmitted between people
When male with wolbachia and female without mate, offspring do not have wolbachia
When female with wolbachia and male without mate, offspring have wolbachia
When both have wolbachia and mate, offspring also have wolbachia
Using this knowledge, mosquitos with wolbachia were selected to mate and produce offspring, increasing population of mosquitos with wolbachia, reducing dengue