CHAPTERS 6-10🤍🤍

Question 1

describe how translation leads to the production of a polypeptide🤍

Answer 1

1. mRNA attaches to a ribosome and the ribosome moves to a start codon
2. tRNA brings a specific amino acid
3. tRNA anticodon binds to complimentary mRNA codon
4. ribosome moves along to next codon and another tRNA binds so 2 amino acids can be joined by a condensation reaction forming a peptide bond using energy from hydrolysis of ATP
   5.tRNA is released after amino acid joined polypeptide
   6.ribosome moves along mRNA to form the polypeptide until stop codon is reached

Question 2

explain the possible effects of a substitution mutation🤍

Answer 2

1. base/nucleotide in DNA is replaced by a different base/nucleotide
2. Changes one triplet so changes one mRNA codon
3. So one amino acid acid in polypeptide changes so tertiary structure may change if position of bonds change
4. Or amino acid doesnr change due to degenerate nature of genetic code or if mutation is in an intron

Question 3

explain the possible effects of deletion mutation🤍

Answer 3

*one nucleotide/base removed from DNA sequence
*changes sequence of DNA triplets from point of mutation
*changes sequence of mRNA codons after point of mutation
*changes sequence of amino acids in primary structure of polypeptide
*changes position of hyd,ion and di bonds in tertiary structure of protein
*changes tertiary structyre of protein

Question 4

explain how crossig over creates genetic variation🤍

Answer 4

*homologous pairs of chromosomes form a bivalent
*chiasmata form
*alleles of chromatids are exchanged between chromosomes
*creating new combinations of alleles on chromosomes

Question 5

explain the importance of genetic diversity🤍

Answer 5

Enables natueal selection to occur
as in certain environments a new allele of a gene might benefit its possesor
By resulting in a change in the polypeptide coded for that positivelt changes its properties
Giving possessor a slective advantage