Genes

Question 1

What are genes?

Answer 1

Sequence of DNA bases that codes for:
-The amino acid sequence of a polypeptide
- A functional RNA e.g. ribosomal RNA and tRNAs

Question 2

Locus

Answer 2

A gene occupies a fixed position, called a locus, on a particular DNA
molecules

Question 3

Describe the nature of the genetic code

Answer 3

Sequence of DNA triplets codes for sequence of amino acids.
Genetic code is:
-universal
-degenerate
-non-overlapping

Question 4

Universal

Answer 4

The same specific DNA base triplets code for the same amino acids in all living organisms

Question 5

Non-overlapping

Answer 5

Discrete, each base can only be used once and in only one triplet

Question 6

Degenerate

Answer 6

The same amino acid can be coded for by more than one base triplet

Question 7

Explain why, in eukaryotes, much of the DNA doesn’t code for polypeptides.

Answer 7

Between genes…
- Non-coding multiple repeats

Within genes
- Only exons code for amino acid sequences, which are separated
by one or more non-coding
sequences, called introns

Question 8

Mutation

Answer 8

A change in the base sequence of a gene

Question 9

Codon

Answer 9

A sequence of three bases (called a triplet) that codes for a specific amino acid. The base sequence of a gene determines the amino acid sequence in a polypeptide.

Question 10

Exon

Answer 10

sequence of bases in a gene that code for the polypeptide

Question 11

Intron

Answer 11

(In eukaryotes), sequences of bases in a gene that do not code for
polypeptides.

Question 12

Genome

Answer 12

the complete set of genes in a cell,

Question 13

Proteome

Answer 13

The full range of proteins that a cell is able to produce

Question 14

Alleles

Answer 14

different versions of the same genes
created through a mutation

Question 15

Homologous pair of chromosomes:

Answer 15

same size chromosomes with
same genes, but different alleles