genetics, variation and relationships between organisms

Question 1

genetic code is

Answer 1

degenerate, non overlapping, universal

Question 2

gene is a base sequence of DNA that codes for

Answer 2

amino acid sequence of a polypeptide
functional RNA

Question 3

mRNA vs tRNA

Answer 3

mRNA- long single strand, has codons
tRNA- single strand folded, has anticodons

Question 4

describe the process of transcription

Answer 4

1. helicase
2. one strand= template which is called the antisense strand
3. polymerase
4. splicing
5. mRNA moves out of nucleus

Question 5

describe the process of translation

Answer 5

1. mRNA attaches to ribosomes
2. tRNA collects from cytoplasm
3. tRNA binds to mRNA (CBP)
4. amino acids attach to tRNA
5. peptide bonds form
6. tRNA detaches
7. polypeptide chain forms till stop codon

Question 6

describe meiosis

Answer 6

• homologous chromosome pair pair up whereby crossing over at the chiasmata may take place
• daughter cells produced with one chromosome from each homologous pair
• chromatids separated producing 4 haploid daughter cells

Question 7

principles of natural selection in the evolution of populations

Answer 7

• random mutations= new alleles
• the new allele of a gene might benefit its professor leading to increased reproductive success
• advantageous alleles is inherited
• over many generations the new allele increases in frequency in the population

Question 8

directional selection

Answer 8

• phenotypes best suited will survive
• means population will move in direction of these individuals

Question 9

stabilising selection

Answer 9

• phenotypes with successful characteristics are preserved
• those of greater diversity are reduced
• individuals closest to the mean are favoured

Question 10

disruptive selection

Answer 10

• selection pressure toward the extremes creates two modal values

Question 11

genetic drift

Answer 11

random fluctuation in frequencies of alleles

Question 12

courtship enables

Answer 12

• recognise other members of the species
• identify a mate that can breed
• form a pair bond
• synchronise mating

Question 13

phylogenetic classification system

Answer 13

attempts to arrange species into groups based on their evolutionary origins and relationships

Question 14

Hierarchy

Answer 14

domain
kingdom
phylum
class
order
family
genus
species

Question 15

species diversity

Answer 15

number of different species and number of different individuals in a community

Question 16

genetic diversity

Answer 16

number of alleles in gene pool

Question 17

species richness

Answer 17

a measure of the number of different species in community

Question 18

index of diversity

Answer 18

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

Question 19

genetic diversity within can be made by comparing

Answer 19

the frequency of measurable or observable characteristics
the base sequence of DNA
the base sequences of mRNA
the amino acid sequence of the proteins encoded by DNA and mRNA

Question 20

species

Answer 20

group of organisms with similar features;
can (interbreed to) produce fertile offspring