W1- Lecture 4.3- Molecular Bio Of The Gene

Question 1

Why are 20,000 gene able to make so many more proteins ?

Answer 1

1- alternate splicing 
2- mutations 
-errors in gene expression 
-transcription errors 
-mRNA/splicing errors 
-mRNA translation errors

Question 2

Name all the the components of a eukaryotic gene ?

Answer 2

Promoter
5’ untranslated region 
Aug start codon 
Top signals 
3’ untranslated region 
Exons/introns 
Translation stop/start site 
Transcription start and stop site

Question 3

Describe what is meant by genetic code being degenerate?

Answer 3

More then one triplet codes for an Amino acid

Question 4

Mutation in what gene causes these diseases ?

Duchene Muscular Dystrophy
Spinal Muscular Atrophy-
Cystic Fibrosis-
Pulmonary Arterial Hypertension-
Breast cancer-

Answer 4

Duchene Muscular Dystrophy- Mutation in the DMD gene
Spinal Muscular Atrophy- Mutation in the SMN1 gene
Cystic Fibrosis-Mutation in the CFTR gene
Pulmonary Arterial Hypertension- Mutation in the BMPR2 gene
Breast cancer-Mutation in the BRCA1 and BRCA2 genes.

Question 5

The over expression of which transcription factor in found in a number of cancers ?

Answer 5

MYC - a proto-oncogene

Question 6

What is a Haploinsufficiency ?

E.g

Answer 6

Where one copy of a gene is not enough to produce a phenotype
E.g p53 gene

Question 7

Name an example of a dominant mutation

+ cause

Answer 7

TFCP2L3 gene and genetic deafness

Question 8

Describe how errors in alternate splicing can cause cystic fibrosis

Answer 8

Mutations in the Exon 7 of SMN1 gene.

As a results exon 7 skipped and protein produced non-functional

Question 9

Name three key translational proteins that mutations in causing disease.

Answer 9

Translation initiation factors
e.g. eIF2 gene - a neurodegenerative disease called Vanishing White Matter disease (VWM)

Release factors
e.g. eRF3 gene – gastric cancer

Mutations affecting the tRNA transfer proteins or the ribosome itself
E.g(rare types of anaemia and several neurodegenerative diseases)