transcription

Question 1

Why do we need mRNA between

DNA and Protein?

Answer 1

Because one mRNA molecule can make many
proteins therefore amplifying the process
Few mRNAs can translate may different proteins

Question 2

Gene expression

Answer 2

the process by which DNA

directs the synthesis of polypeptides through mRNA

Question 3

when does gene expression occur

Answer 3

Gene expression occurs through transcription of the
DNA into mRNA which then serves as the template
for protein synthesis

Question 4

what is Beadle and Tatum gene theory

Answer 4

scientists working with the mold Neurospora
crassa, hypothesized that a gene would encode for
an enzyme
- Today it is one gene one polypeptide because
some proteins are composed of more than one
polypeptide in order to be functional

Question 5

does the rna poly 2 need help to find the region of DNA to be transcribed

Answer 5

no

Question 6

the roles of transcription and translation in the flow of

genetic information in Eukaryotes

Answer 6

pre-mrna—> processed to mrna —> transported to cytosol—->translated into proteins

Question 7

The transcription unit in eukaryotes

Answer 7

one transcription unit = one gene

Question 8

the transcription unit of prokaryotes

Answer 8

one transcription unit = many genes

Question 9

what is transcription

Answer 9

the synthesis of

RNA under the direction of DNA

Question 10

what are the steps in transcription

Answer 10

Binding of RNA Polymerase II
• Unwinding of the DNA
• Initiation
• Elongation
• Termination

Question 11

what happens during DNA replication

Answer 11

both strands must be copied at the same

time

Question 12

when dna transcribed into rna how many can be copied at a time

Answer 12

only one strand is copied at a time, although both strands can be copied

Question 13

what does • RNA polymerase II do

Answer 13

elongates the RNA much
like DNA polymerase III
does for DNA but uses
ribonucleotides instead
of deoxiribonucleotides

Question 14

The stages of transcription components

Answer 14

Only one strand is
transcribed at a time
• The RNA polymerase II
untwists one turn of the
DNA helix at a time
• The terminator
sequence in prokaryotes
signal the end of
transcription
a promoter, the structural gene, and a terminator

Question 15

what is transcription direction

Answer 15

both strands of dna can be read

• but only one at a time
• reading can only be done in 3’ to 5’ direction

Question 16

how is rna synthesized (what direction)

Answer 16

in 5’ to 3’ direction much like DNA

Question 17

reading of coding strand, template, and rna

Answer 17

coding strand-5’ to 3’
template- 3’ to 5’
rna- 5’ to 3’

Question 18

does the eukaryote cells poly 2 needs help to find promoter region

Answer 18

yes!

Question 19

what are transcription factors

Answer 19

proteins involved in the process of converting, or transcribing, DNA into RNA

Question 20

how does RNA poly 2 start transcription

Answer 20

finds transcription proteins and binds to promoter region

Question 21

what are introns and exons

Answer 21

Introns are removed by RNA splicing as RNA matures, meaning that they are not expressed in the final mRNA product, while exons go on to be covalently bonded to one another in order to create mature mRNA

Question 22

are introns translated

Answer 22

no. they are spliced out by small snRNPs

Question 23

where do The 5 cap and the poly A tail get added and RNA splicing occur

Answer 23

nucleus

Question 24

what is Poli a tail

Answer 24

short sequence containing nucleotides made of adenine that protects the mRNA from degradations and guides it through the nucleopores to the cytosol

Question 25

what is 5’ cap

Answer 25

p is a guanine modified nucleotide added to the 5’ end
of the processed mRNA. It protects the mRNA from
degradation and guides it to the Ribosome for protein
synthesis

Question 26

what is pre-mrna hor heterogeneous

Answer 26

comprises the bulk of heterogeneous nuclear RNA –>completely processed, it is termed “mature messenger RNA”,