evolution

Question 1

what did old evidence for evolution rely on

Answer 1

similarities in the apperance of living organisms and on fossil evidence

Question 2

problem with relying on morphology for understanding evolution

Answer 2

two species can look similar because they evolved to respond to similar niches

Question 3

what determines how long common ancestry there has been

Answer 3

the more mutations in the DNA in two species- longer theyve had common ancestor

Question 4

how to determine how long common ancestor lived

Answer 4

using an agreed mutation rate as a molecular clock

Question 5

problems with looking at DNA to see evolution

Answer 5

DNA degrades quickly and rate at which different parts of DNA mutate varies

Question 6

why is human evolution hard to follow

Answer 6

because of lack of fossils

Question 7

method of analysing DNA

Answer 7

PCR test

Question 8

what does the polymerase chain reaction do

Answer 8

amplifies minute samples of DNA and DNA profiling

Question 9

how many parasitic lice do humans have

Answer 9

head
pubic
body

Question 10

what do scientists do with evidence form DNA analysis

Answer 10

build diagrams that model the evolution of species from a common ancestor

Question 11

molecular phylogeny

Answer 11

the analysis of DNA to identify the inter relationship between different groups of organisms

Question 12

how is DNA used to make links between organisms

Answer 12

patterns in DNA identified
comparisons between amino acid sequences of similar proteins in different species

Question 13

gel electrophoresis

Answer 13

variation of chromatography which can be used to separate DNA and RNA fragments proteins of amino acids

Question 14

what does gel E seperate substances by

Answer 14

their charge and size

Question 15

where are the substances being compared placed in gel E

Answer 15

in wells of gel medium in a buffering solution with known DNA to aid identification

Question 16

when identifying DNA what cuts the DNA molecules in gel E

Answer 16

restriction endonucleases

Question 17

function of restriction endonucleases

Answer 17

cuts DNA into fragments at specific sites

Question 18

what are the DNA fragments added to in gel E

Answer 18

to gel that had dye which binds to fragments in gel and fluorsecent under UV light

Question 19

why is dye also added to DNA samples

Answer 19

doesnt bind to DNA but moves gel faster than DNA so current be turned off before all samples run off at end

Question 20

how do DNA fragments move in gel E

Answer 20

move to positive anode because of negative charge, move at different rates because of charge and mass.

Question 21

step after gel E complete

Answer 21

plate placed under UV light. DNA fluoreses and show pattern of movement

Question 22

what is added instead of gel when comparing amino acids in gel E

Answer 22

ninhydrin reacts with amino acids so they can show as purple patches and compared with known amino acids for identification

Question 23

ways to identify biochemical relations

Answer 23

analysis of blood pigments
analysis of sequences of amino acids

Question 24

endosymbiosis

Answer 24

two organisms adapted to live together that benefit each other

Question 25

endosymbiotic theory

Answer 25

eukaryotes evolved from prokaryotes

Question 26

endosymbionts

Answer 26

chloroplasts
mitochondria said to be first endosymbiont

Question 27

steps of mitochondria becoming symbiotic

Answer 27

• ancestral eukaryote cell next to prokaryotic aerboic capable organism
  -cell englufs pro as food
  oxygen levels dur to plants increase
  pro not digested and used in eu to digest oxygen in cellular respiration
  -pro become stable as mitochondria in ancestral cell and develop early aerobic eukaryote cell

Question 28

chloroplast becoming symbiotic

Answer 28

eu cell and pro cell which can photosynthesis
-cell engulfs photosynthetic cell as food#
-eu doesnt digest ph cell and cell grows faster because of pro
- become stable eukaryote from pro cell