DNA Basics And Genetic Code

Question 1

What do both eukaryotic DNA and prokaryotic DNA have?

Answer 1

• made of nucleotides containing deoxyribose, a phosphate group and a nitrogenous base
• nucleotides joined together by phosphodiester bonds to make a polymer chain

Question 2

Differences between eukaryotic and prokaryotic DNA?

Answer 2

• Eukaryotic DNA - Longer, linear, associated with histones
• Prokaryotic DNA - Shorter, circular, not associated with proteins
• In eukaryotic cells, a DNA molecule and the histone proteins form a chromosome

Question 3

Characteristics of mitochondria and chloroplast DNA in eukaryotic DNA?

Answer 3

• Same as Prokaryotic DNA - Shorter, circular, not associated with proteins

Question 4

What is a gene?

Answer 4

• base sequence of DNA that codes for:
  1. Amino acid sequence of a polypeptide
  2. A functional RNA

Question 5

What is a locus?

Answer 5

• every gene occupies a particular fixed position on a chromosome

Question 6

What is the genetic code and its three features?

Answer 6

Sequence of three DNA bases (triplet) codes for a specific amino acid:
- Degenerate
- Universal
- Non-overlapping

Question 7

What is Degenerate (genetic code)?

Answer 7

• single amino acid coded for by more than one codon

Question 8

What is universal (genetic code)?

Answer 8

• same triplet of bases codes for same amino acid in all organisms

Question 9

What is Non-overlapping (genetic code)?

Answer 9

• each base only part of one one triplet of bases that codes for one amino acid
• each codon of triplet bases is read as a discrete unit