transcription

Question 1

what happens in transcription

Answer 1

1. messenger rna is produced in nucleus from a template of a gene coding region of dna
2. mrna leaves nucleus to join ribosome (in cytoplasm)

Question 2

initiation

Answer 2

rna polymerase bonds to promotor region of DNA
unzips the dna

Question 3

promotor and terminator region

Answer 3

promotor: is a base sequence that signals the beginning of a gene, the strand to be copied and direction.

Question 4

elongation

Answer 4

1. free rna nucleotides join with complementary DNA nucleutides ( a-u)
2. RNA polymerase creates a covalent bond between nucleotides, creating a strand of pre-mrna.

Question 5

termination

Answer 5

1. RNA polymerase adds bases to the rna chain until it reaches termination region of dna
2. the single stranded pre-mrna strand detaches from the DNA and the two strands of DNA region

Question 6

introns and exons

Answer 6

certain sequences are non-coding

introns are nucleotides not needed, it is spliced/removed.

exons do code for amino acid sequence

Question 7

cap and poly-A tail

Answer 7

to protect mrna from being cut apart in the cell, a cap is added in the 5’ and a poly A tail is added in the 3’

Question 8

movement out of the nucleus

Answer 8

DNA code is now carried by single stranded mrna molecule (made of exons) out of the nucleus, through a nuclear pole, to the ribosomes,

Question 9

Direction of new rna nucleotides

Answer 9

new rna nucleotides added in 5’ to 3’ direction (templaate dna reads 3 to 5)

Question 10

Similarities between template dna strand and mrna

Answer 10

the base sequence in the mrna transcript is complementary to the sequence in the dna template strand.