L5 - VARIATION IN THE GENOME

Question 1

Types of mutation

Answer 1

• deletion
• insertion
• duplication
• incorrect nucleotide
• chemically modified nucleotide

Question 2

• allele
• homozygote
• heterozygote

Answer 2

• variant form of gene
• 2 identical forms of genes
• 2 different forms of genes

Question 3

if mutations occur in the genes what determines whether they affect the phenotype

Answer 3

whether they are RECESSIVE or DOMINANT

• RECESSIVE - need two forms of mutated gene
• DOMINANT - only need 1 form of mutated gene – to show a change in the phenotype - characteristic displayed by an organism

Question 4

another type of mutation -

compound herterozygote

Answer 4

2 different mutant gene

Question 5

mutations OUTSIDE protein coded regions cause

• PROMOTERS ;
• SPLICING
• 5’ cap site
• POLY A TAIL;

Answer 5

• promoters tell mRNA or RNA POLYMERASE??? what & where to copy
  result in altered levels of transcription

-splicing; low or no beta globin (haemoglobin subunit)
haemoglobin carries 02 from RS to rest of the body

• 5’ cap site - essential for mRNA to attach to ribosome
  same as poly A tail
  thus both alter levels of translation

Question 6

SNPS

Answer 6

SINGLE NUCLEOTIDE changes POLYMORPHISMS

Question 7

epigentic code

2 main methods of changing gene expression in this way

Answer 7

causes changes in gene expression by adding chemical groups and NOT by changing DNA base sequence

2 main methods

• methylation ; adding methyl groups stops TF binding
• histone modification (acetyl groups)

Question 8

mutations within coding region genes

• names of mutations
• their AFFECTS

Answer 8

insertion
deletion
single base pair change - SNPS

CAUSE;

• shift in the reading frame - just how u read it etc
• addition or removal of AA

nucleotide substitution
causes ; - could cause a change in the AA
OR NO CHANGE in the AA- as some AA are coded for by more than one codon
- truncated protein (or normal protein depending)