4.1 DNA, GENES AND CHROMOSOMES

Question 1

define the term exon

Answer 1

base sequence of DNA that codes for a polypeptide

Question 2

contrast DNA in the nucleus and DNA in a prokaryote/chloroplast/mitochondria

Answer 2

1. nucleus associated with histones whereas p/c/m is not
2. nucleus is linear whereas p/c/m is circular
3. nucleus has introns whereas p/c/m doesn’t
4. nucleus is longer than p/c/m
5. nucleus has more genes than p/c/m

Question 3

compare DNA in eukaryotes against DNa in prokaryotes

Answer 3

1. nucleotide structure is identical
2. nucleotides joined by phosphodiester bonds
3. DNA in mitochondria and chloroplast is similar to DNa in prokaryotes

Question 4

differences in chromosomes structure which may affect staining in observation

Answer 4

1. difference in association with histones
2. differences in base sequences
3. differences in supercoiling