Flashcards in 4.1 Chromosomes, Genes, Alleles and Mutations Deck (8)
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1
Describe the structure of eukaryotic chromosomes
Eukaryotic chromosomes consist of DNA wrapped around histone proteins
2
Define gene
A heritable factor that controls a specific characteristic
3
Define allele
A specific form of a gene, occupying the same locus as other alleles of the gene
4
Define genome
The whole of the genetic information of an organism
5
Define gene mutation
A change in the nucleotide sequence of a gene
6
Define base substitution mutation
The change of a single base in a sequence of DNA, resulting in a change to a single mRNA codon during transcription
7
Describe and explain the effects of sickle-cell anaemia as an example of a base substitution mutation
• Sickle cell anaemia is inherited and cannot be passed on through infection
• Affected gene found on chromosome 11
• A base substitution mutation changes GAG to GTG causing glutamic acid to be replaced by valine
• The resulting amino acid change alters the shape of the haemoglobin, causing it to form fibrous, insoluble strands
• As a result, the haemoglobin are a lot less efficient at transporting oxygen, causing anaemia
8
