Gene Expression & Regulation

Question 1

What is the ‘Central Dogma’?

Answer 1

1. The total DNA in each cell constitutes the genome, which carries the genetic information required for making the whole organism
2. This information is stored in the nucleotide sequence of the genome
3. The DNA nucleotide sequence determines amino acid sequences of polypeptide chains & proteins
4. Information is transmitted via an intermediate, RNA

Question 2

What are the main levels of gene expression?

(5)

Answer 2

1. Genome
2. Transcription
3. RNA processing and nuclear exporty
4. Translation
5. Prosttranslation

Question 3

what are the bonds in DNA structures?

Answer 3

N-glycosidic bonds

H-bonds

Phosphodiester bonds

Question 4

what are the structures in DNA?

Answer 4

Double helix

Sugar-phosphate backbone

2-antiparallel chains

-Run 5’ to 3’

Question 5

What are the 5 different types of chromosome mutations?

Answer 5

• Deletions
• Duplications
• Inversions
• Translocations
• Change in number of chromosomes

Question 6

What is transcription?

Answer 6

strand DNA is copied into RNA by the enzyme RNA polymeras

U is incorporated instead of T

Question 7

What happens in RNA Processing?

Answer 7

Exons = coding regions are interrupted by Introns = non-coding regions

Exons and introns are transcribed together -> Primary transcript

Introns are removed before translation into protein in a process called splicing

Resulting in Mature mRNA …..Translation

Question 8

What happens in Translation?

Answer 8

During translation, anticodons of tRNA molecules form base pairs with codons on mRNA

Codons and anticodons each consist of 3 nucleotides

mRNA is decoded in a 5’ to 3’ direction, one codon at a time

Protein is synthesised from amino terminus (NH2)  carboxy terminus (COO-