Transcription And Translation

Question 0

Describe role of transcription

Answer 0

Turn pre-mRNA TO mature mRNA

Question 1

Describe transcription

Answer 1

Initiation - promoter recognition and binding, tata box at 30
Elongation - the actual process of transcribing by RNA polymerase
Termination - sequence dependant termination of RNA chain growth

Needs RNA polymerase and NTP

Question 2

Describe process of translation

Answer 2

Initiation - AUG codon recognition, special methionine and RNA ribosome
Elongation - n to c chain growth, amino acyl tRNA read 5-3
Termination - stop codon recognition and dissociation of ribosome

Question 3

Define term gene

Answer 3

Unit of heredity a transcription unit, i.e. A length of DNA on a chromosome that codes for a protein as well as sequences necessary for its expression such as promoter and terminator and introns

Question 4

List processes involved in RNA maturation and explain their importance

Answer 4

Capping at 5’ end, protection against degradation
Addition of a poly a tail protection against degradation
Splicing to remove introns

Question 5

Explain the nature of the triplet code

Answer 5

Each codon corresponds to one aa
Degenerate to reduce effect of mutation
Non overlapping
Transcription is 5’-3’ producing n to c chain extension

Question 6

Comprehend the implications of degeneracy

Answer 6

Substitutions can lead to different primary sequence which can affect the tertiary
If affects stop codon -> longer chain
Degenerate reduces risk of mutation

Question 7

Compare and contrast gene expression in mammalian and bacterial cells

Answer 7

Bacteria have simpler promotors, different transcription factors, single RNA polymerase, coupled transcription/translation, no post transcriptional processing, simpler ribosomes