Regulation of transcription and translation

Question 1

What are transcription factors

Answer 1

They are proteins

Question 2

What do Transcription factors do

Answer 2

Move from cytoplasm to nucleus
Bind to DNA at a specific DNA base sequence on a promoter region
Stimulate or inhibit transcription of target genes by helping or preventing RNA Polymerase binding

Question 3

role of oestrogen in initiating transcription

Answer 3

1)Oestrogen diffuses across the phospholipid bilayer as its lipid soluble
2)In Cytoplasm, Oestrogen binds to a receptor of an inactive transcription factor, forming a hormone receptor complex.
3)Inactive transcription factor changes shapes, resulting in active transcription factor
4) Diffuses from cytoplasm into nucleus and binds to specific DNA base sequence on a promotor region
5) Stimulating transcription of genes by helping RNA polymerase to bind

Question 4

RNA interference (RNAi)

Answer 4

RNA molecules inhibit translation of mRNA produced by transcription

Question 5

Micro-RNA (miRNA)

Answer 5

single strands (22-26 nucleotides long) both incorporated into a protein based RISC (RNA induced silencing complex)

Question 6

Small interfering RNA (siRNA)

Answer 6

Double stranded molecules 21-25 bp long, one strand incorporated into a protein based RISC

Question 7

How do miRNA/ siRNA work

Answer 7

miRNA/siRNA within a RISC Binds to a molecule of mRNA containing a sequence of bases complementary to its own and mRNA hydrolysed and the translation is stopped.