Control of gene expression - 1.3

Question 1

Transcription

Answer 1

• RNA polymerase moves along DNA unwinding the strand
  -hydrogen bonds break
  -RNA synthesises a primary transcript of mRNA while adding RNA nucleotides to the strand - hydrogen bonds get added to the other strand
  -primary transcript of mRNA gets changed into the mature transcript of mRNA
  -mature mRNA can now leave the nucleus and travel to the ribosome

Question 2

what is gene expression?

Answer 2

the activation of certain genes to produce particular protiens

Question 3

RNA
-type of sugar
-bases
-number of strands

Answer 3

-ribose sugar
-adenine, uracil, guanine, cytosine
-one

Question 4

function of mRNA

Answer 4

carries a copy of DNA code from nucleus to the ribosome

Question 5

function of tRNA

Answer 5

found in cytoplasm where it binds to specific amino acids and transports to ribosome

Question 6

function of rRNA

Answer 6

forms a complex with protein molecules to make the ribosome

Question 7

what does a codon do?

Answer 7

code for a specific amino acid

Question 8

RNA splicing

Answer 8

• introns of the primary transcript are removed
  -exons are joined together to form the mature mRNA

Question 9

what types of RNA is required for translation

Answer 9

tRNA and rRNA

Question 10

what are ribosomes composed of

Answer 10

-rRNA and proteins

Question 11

what does tRNA consist of

Answer 11

-anticodon
-attachment site for amino acid

Question 12

process of translation

Answer 12

-begins at mRNA
-tRNA brings over specific amino acids
-tRNAs anticodons bind to codons by complimentary base pairing, translating the genetic code into a sequence of amino acids
-peptide bonds join amino acids together
-tRNA leaves ribosome as polypetide is formed

Question 13

what happens in RNA splicing

Answer 13

different protiens can be expressed due to alternative RNA splicing
-just depends on which exons are retained