Flashcards in Lecture 2 Deck (18):
What are the three types of single nucleotide changes?
Mutations that change gene products
Mutations that change the amount of gene product
Mutations that change the polypeptide length
Define a transition
A mutation to the same type of base.
E.g. Pyrimidine to pyrimidine
What is a transversion?
Mutation to a different type of base, so a purine converted to a pyrimidine.
What are the 4 subunits of Heamoglobin?
What chromosome is the gene that encodes the alpha subunits of heamoglobin located on?
Which chromosome is the gene that encodes the beta subunit of heamoglobin located on?
Who discovered sickle cell aneamia and when?
James herrick in the 1920s
What are the symptoms of sickle cell aneamia?
Susceptible to infection
Aneamia is acute when oxygen is limited
Red blood cells sickle
HbA precipitates in low levels of oxygen
What mutation causes sickle cell aneamia?
A glutamate to a valine on gene 6 of the beta polypeptide chain of heamoglobin.
(Remember codon 7 = amino acid 6)
What is the name of diseases caused by mutations in the beta-globin gene?
How do mutations reduce gene expression by affecting transcription or translation?
Alter promoter activity
Alter translation initiation at AUG
Prevent mRNA splicing
Reduce mRNA stability
How is Hb Leiden caused?
The beta chain of haemoglobin is 1 amino acid shorter than normal
What mutation causes Hb Lyon?
The beta chain is 2 amino acids shorter than normal
What mutation causes Hb Gun-Hill?
The beta chain of Hb is 5 amino acids shorter than normal
What is a chain termination mutation?
Base substitution that changes a sense codon into a stop codon. These can make the chain longer or shorter.
What does a frameshift mutation cause?
Single base additions/deletions
Who discovered transposable element insertions?