Transcription/translation

Question 1

transcription regulation

Answer 1

-transcription factors are PROTEINS
-move into the nucleus and attach to a promoter region close to target gene
-works by stimulating or blocking rna polymerase

Question 2

how does oestrogen cause gene expression

Answer 2

1)lipid soluble so can diffuse through phospholipid bilayer

2)specifcly binds to a receptor protein part of a TF

3) the TF enters the nucleus

4) the binding changes the shape of the TF and allows it to bind specificly to the promoter sequence of a particular gene

5) this allows RNA polymerase to attach to the gene and catalyse the transcription of the gene

6) mrna Is transcribe from the gene

7) mRNA Is translated into protein

-so oestrogen increases the expression of particular genes

Question 3

describe transcription

Answer 3

-occurs in the nucleus
-rewriting part of DNA into a strand of messenger RNA

1) section of DNA molecule uncoils and 2 strands are separated as hydrogen bonds are broken

2)one of these two strands acts as a template

3)individual RNA nucleotides line up along DNA , and nucleotide bases on template strand bind due to comp base paring

4) uracil to adenine

5)the individual RNA nucleotides are joined together using enzyme RNA polymerase , forming mRNA

6) the mRNA strand undergoes splicing where

7) mRNA strand leaves nucleus through. nucleur pore and attatches to a ribosome in the cytoplasm for translation .

Question 4

Describe translation

Answer 4

1) mRNA binds to a ribosome in the cytoplasm after leaving the nucleus through the nuclear pore

2) a tara mol with comp anticodon binds to the first codon of mrna at the ribosome

3) the ribosome has 2 binding sites so 2 tuna moles binds to two codons on the mrna

4) the amino acid on the first tuna mol attaches to the amino acid on the second tuna mol by a peptide bind during a condensation reaction using ATP to release emergy

5) the first tuna mol then moves away from the ribosome leaving the amino acid behind .It then collects another mol of same amino acid pool

6) the ribosome moves along the mRNA and other tRNA mols then join in the order determined by the codons on the mRNA

7) this process continues along the mRNA until all the codons have been read up to the stop codon

8) the polypeptide folds itself into its second and tertiary stark

the sequence of amino acids in this polypeptide has bee determined by the coons on the mRNA strand