topic 4 - natural selection and genetic modification

Question 1

how bacteria become resistant

Answer 1

new strain of bacteria happens to mutation

varying resistance to bacteria due to mutations (selection pressure is usually antibiotics)

due to antibiotics, less resistant bacteria die

more resistant bacteria survive
become more common and reproduce

resistant gene is passed on

Question 2

natural selection model answer

Answer 2

variation for (insert trait) because of sexual reproduction and mutations

there is a selection pressure (availability of food/mates/habitats)

the best adapted (insert species) outcompete the others

they survive and reproduce passing on their advantageous gene of (insert gene)

this is survival of the fittest

over generations, (insert trait) changes

Question 3

who’s ardi

Answer 3

a fossil who is 4.4 million years old
structure of feet suggested she climbed trees
ape like big toe
brain size same as chimpanzees
structure of her legs suggests she walked upright
her hand bone suggests she didn’t use her hands to help her walk like apes do

Question 4

who’s lucy

Answer 4

3.2 million years ago
arched feet
arms and legs size was in between size of apes and humans
brain slightly larger than ardi’s but still similar to chimp
leg bones suggest she walked upright and more efficiently

Question 5

who’s leakey

Answer 5

1.6 million years ago
more human like than lucy
big brain like human
better adapted to walking upright

Question 6

2.5-1.5 million years ago tools

Answer 6

simple stone tools they hit rocks together to make them sharp

Question 7

2-0.3 million years ago tools

Answer 7

sculpted rocks into shapes to produce more complex tools like simple hand axes

Question 8

300 000-25 000 years ago tools

Answer 8

more complex tools - flint tools and wooden spears, pointed tools

Question 9

200 000 years ago - present tools

Answer 9

flint tools widely used, arrowheads, fish hooks

Question 10

why are dating tools and fossils not accurate

Answer 10

rock layers can move over time

Question 11

what’s a pentadactyl limb

Answer 11

limbs with five digits

Question 12

what does pentadactyl limb suggest

Answer 12

species with it all evolved from a common ancestor that had it

Question 13

what are the 5 kingdoms

Answer 13

animals
plants
fungi
prokaryotes - all single celled organisms without a nucleus
protists - eukaryotic (with a nucleus) single celled organisms

Question 14

why is five kingdom classification bad

Answer 14

out of date
using RNA sequencing, we found out that some members of prokaryote kingdom are not as closely related as first thought

Question 15

three domain system

Answer 15

archaea - look similar to bacteria but DNA and RNA sequences say they’re different. found in hot springs and salt lakes

bacteria - true bacteria e.g. E Coli

eukarya- broad range of organisms including fungi animals plants and protists

Question 16

selective breeding model answer

Answer 16

from existing stock, select ones with desired characteristics

breed them together

select best of the offspring and breed them together

continue over several generations

until desirable trait gets stronger and stronger

eventually all offspring will have desired characteristic

Question 17

how is selective breeding useful in agriculture

Answer 17

increases yield

Question 18

disadvantages of selective breeding

Answer 18

reduces gene pool - inbreeding

health problems - genetic defects e.g pugs breathing problems

new disease appears and due to less variation, less chance of resistant alleles

Question 19

benefits of cloned plants

Answer 19

all tasty fruit
pesticide resistance

Question 20

how to grow plants using tissue culture

Answer 20

tissue remove from tip of parent plant

tissue placed on a medium containing growth hormones

tissues produce shoots and roots

Question 21

advaantages of animal tissue in medicine

Answer 21

experiment on tissues in isolation

look at effect of particular substance on single tissue

Question 22

how animal tissue culture is carried out

Answer 22

extract tissue cells from animal

separate cells using enzymes

put them in a growth medium with nutrients to grow and multiply

after lots of cell division, cells can be split up again and placed into separate vessels to encourage more growth

stored for future use

Question 23

why are genetically modified crops good

Answer 23

increase food production - overpopulation

resistant to pests and can grow in drought conditions

combat deficiency diseases e.g. golden rice gives more vitamin A

Question 24

why are genetically modified crops bad

Answer 24

people can’t afford to buy food. lack of it isn’t an issue

fears that countries may become dependent on people who sell GM crops

poor soil can be an issue so even GM crops wont survive

Question 25

how to insert dna or gene into other organism

Answer 25

identify and locate insulin producing gene

remove gene using restriction enzyme which leaves complimentary sticky ends

identify and locate plasmid

cut plasmid with restriction enzyme

insert desired gene into plasmid using ligase enzyme

insert plasmid back into the bacteria

bacteria reproduces asexually and produces insulin