DNA, Genes And Chromosomes

Question 1

Prokaryotic DNA structure

Answer 1

• short, circular and not associated with proteins

- free floating since prokaryotes have no nucleus

Question 2

Eukaryotic DNA

Answer 2

• long, linear and associated with proteins called histones

- found in the nucleus

Question 3

Mitochondria and chloroplast DNA

Answer 3

• short, circular and not associated with proteins

- believed to be derived from bacteria

Question 4

Which two organelles were believed to once be bacteria?

Answer 4

Mitochondria and chloroplasts

Question 5

Gene

Answer 5

Base sequence of DNA that codes for the amino acid sequence of a polypeptide or functional RNA

Question 6

Gene characteristics

Answer 6

• occupy a locus

- has a stop codon and a start codon

Question 7

Locus

Answer 7

A fixed position on a DNA molecule which codes for a particular gene

Question 8

Codon

Answer 8

Triplet of bases that encode a specific amino acid

Question 9

4 DNA bases

Answer 9

Adenine, Thymine, Guanine and Cytosine

Question 10

4 RNA bases

Answer 10

Adenine, Uracil, Guanine and Cytosine

Question 11

Genetic code characteristics

Answer 11

• universal
• degenerate
• non-overlapping

Question 12

Why is the genetic code said to be universal?

Answer 12

Because it is the same genetic code used in all organisms

Question 13

Why is the genetic code said to be degenerate?

Answer 13

There are more codons than amino acids so some codons encode the same amino acid

Question 14

Why is the genetic code said to be non-overlapping?

Answer 14

Each basse is only part of one codon so they are read as separate units

Question 15

Exons

Answer 15

Coding parts of the DNA

Question 16

Introns

Answer 16

Non-coding parts of the DNA