genetic info variation and relationship between organisms 3.4

Question 1

what is a genome?

Answer 1

complete set of genes in a cell

Question 2

what is a proteome?

Answer 2

complete set of proteins a cell can produce

Question 3

what are the structural differences between mRNA and tRNA

Answer 3

mRNA
- linear single shape
- triplet code (codon)
- less stable
- no amino acid region
tRNA
- clover shaped
- triplet code (anticodon)
- more stable
- amino acid region

Question 4

what is transcription?

Answer 4

production of mRNA from DNA

Question 5

what is translation?

Answer 5

production of polypeptides from the sequence of codons carried by mRNA

Question 6

what happens in transcription?

Answer 6

• DNA helix unwinds to expose bases and on strand acts as a template
• catalysed by DNA helicase
• DNA helicase breaks the hydrogen bonds between bases
• free mRNA nucleotides in the nucleus align with complementary bases on strand
• A/U C/G G/C T/A
• RNA polymerase bonds the nucleotides together to form RNA chain
• once copied mRNA is modified and leaves nucleus through nuclear pores

Question 7

how is pre-mRNA modified?

Answer 7

• introns are spliced out of pre-mRNA by protein splicesome
• leaves behind just coding regions (exons)

Question 8

what happens in translation?

Answer 8

• mRNA attaches to ribosome in the cytoplasm
• ribosome attaches at start codon
• tRNA that has complementary anticodon lines up with mRNA codon and binds
• tRNA brings specific amino acid
• amino acids joint together by peptide bonds using ATP (condensation reaction)
• tRNA released after amino acids joint to polypeptide
• ribosome moves along polypeptide until reaches stop codon
• polypeptide formed and now enters Golgi apparatus

Question 9

what is genetic diversity?

Answer 9

the number of different alleles of genes in a population

Question 10

what is the enabling factor for natural selection to occur?

Answer 10

genetic diversity

Question 11

what does natural selection lead to?

Answer 11

evolution

Question 12

what is evolution?

Answer 12

change in allele frequency over many generations in a population

Question 13

what are the advantages of natural selection?

Answer 13

leads to species being better adapted to their environment (anatomically, physiologically or behaviourally)

Question 14

how does natural selection occur?

Answer 14

• random mutations lead to new alleles to form
• if the allele increases the chances of survival in the environment they are more likely to reproduce
• this passes on advantageous allele to offsprings
• over many generations allele frequency increases in population

Question 15

what is directional selection?

Answer 15

one of the extremes are favoured and have an advantage

Question 16

when does directional selection occurs?

Answer 16

when there is a change in the environment (modal trait changes)

Question 17

what is stabilising selection?

Answer 17

modal trait remains the same and is favoured

Question 18

when does stabilising selection occur?

Answer 18

when there is no change in environment

Question 19

what happens to the standard deviation of stabilising selection over time?

Answer 19

decreases as extreme traits decrease

Question 20

what is an example of directional selection?

Answer 20

antibiotic resistance in bacteria

Question 21

what is an example of stabilising selection?

Answer 21

human birth weight

Question 22

what is the binomial naming system

Answer 22

all organisms universally named by their genus and species

Question 23

what is the taxonomy system?

Answer 23

domain, kingdom, phylum, class, order, family, genus and species - each group called taxa

Question 24

what is a hierarchy?

Answer 24

smaller groups within a larger group with no overlaps

Question 25

what are modern ways for accurate classification?

Answer 25

through DNA and mRNA sequence and immunology

Question 26

what are the three domains?

Answer 26

archaea bacteria and eukarya

Question 27

what are the five kingdoms?

Answer 27

animal plants fungi monera and protists

Question 28

what are species?

Answer 28

organisms are able to breed and produce fertile offspring

Question 29

what are courtship rituals?

Answer 29

sequence of actions that are specific to each specie and this is how members identify their own species to reproduce with

Question 30

what are the importance of courtship behaviours?

Answer 30

• ensures successful reproduction
• enables animals to recognise their own species
• synchronise mating behaviour (indicated mating season)

Question 31

when species have similar courtship behaviour what does this suggest?

Answer 31

they’re closely related since courtship behaviour is genetically determined

Question 32

what is species diversity?

Answer 32

number of different species and individuals within species within a community

Question 33

what is species richness?

Answer 33

number of different species in a particular area in a specifc time

Question 34

how does farming reduce biodiversity?

Answer 34

• destroying hedgerows
• selective breeding
• monoculture
• over grazing
• filling in ponds and draining wetlands

Question 35

what is index of diversity?

Answer 35

measures the relationship between the number of species in a community and the number of individuals in each species

Question 36

what is the formula for index of diversity?

Answer 36

D = N(N-1)
———-
total n (n-1)

Question 37

what does N and n represent in index of diversity?

Answer 37

N is the total number of organisms of all species
n is the total number of organisms in a specifc species

Question 38

how can genetic diversity within species or between species be made and compared in early times?

Answer 38

the frequency of measurable or observable characteristics

Question 39

how can genetic diversity within species or between species be made now after advanced gene tech?

Answer 39

1) studying base sequence of DNA
2) studying base sequence of mRNA
3) the amino acid sequence of proteins encoded by DNA and mRNA

Question 40

why does evolution occur?

Answer 40

random mutations in genetic material

Question 41

what does two distantly related species suggest?

Answer 41

it has been a long time since they shared common ancestor so more time allowing mutation to occur

Question 42

how to compare DNA or mRNA sequence?

Answer 42

the less similar in base sequence the less closely related species are

Question 43

how to compare amino acid sequence?

Answer 43

the more differences in amino acid sequence the less closely related species are

Question 44

what are the problems with comparing amino acid sequence?

Answer 44

two organisms may have same amino acid sequence but different DNA sequence because amino acid codes are degenerate. so less useful to compare close related organisms

Question 45

how do you investigate diversity?

Answer 45

take random sample of a population
collect data
calculate mean
calculate standard deviation

Question 46

what is standard deviation?

Answer 46

the spread of means

Question 47

what does a large or small standard deviation suggest for diversity?

Answer 47

large - large diversity
small - small diversity