Final

Question 1

Transcription vs translation?

Answer 1

Transcription: synthesis of RNA using a DNA template
Translation: synthesis of a polypeptide using the genetic information encoded in an mRNA molecule

Question 2

Transcription/translation in prokaryotes vs eukaryotes?

Answer 2

In prokaryotes, transcription occurs in the cytoplasm and translation occurs immediately: DNA ->mRNA ->protein
In eukaryotes, transcription and mRNA processing occur in the nucleus, and translation in the cytoplasm:
DNA ->pre-mRNA ->mRNA ->protein

Question 3

What is the correct hypothesis concerning the genetic code?

Answer 3

Three nucleotides code for one amino acid
64 amino acids (43 = 64 possibilities)

Question 4

Is the genetic code universal?

Answer 4

No, there are some variations in the genetic codes between some species yeast, ciliate…
Mitochondria also have their own genetic code

Question 5

Coding strand?

Answer 5

The nucleotide sequence of the sense strand corresponds directly to the sequence of an RNA
transcript which is translated into a sequence of amino acids.

Question 6

Noncoding strand?

Answer 6

The noncoding strand serves as a template during transcription, and its sequence is the reverse complement of the coding strand.
The noncoding strand is also known as the antisense strand, or negative-sense or negative (-) strand

Question 7

What is a non-synonymous mutation?

Answer 7

a mutation that is not silent, and changes the amino acid sequence, can have bad or good effects

Question 8

Effects of missense mutations?

Answer 8

Missense mutations can affect the primary, secondary and tertiary structures of a protein.

Question 9

What is a RNA polymerase?

Answer 9

An RNA polymerase opens the double-stranded DNA and adds ribonucleotides complementary to the template strand (only in the direction 5’ 3’)
RNA polymerases can initiate the synthesis of the RNA molecule no need for a primer

Question 10

What is a transcription unit?

Answer 10

sequence downstream from the promoter that is transcribe into an RNA molecule

Question 11

3 steps in DNA to RNA/ translation

Answer 11

Initation, elongation, termination

Question 12

Initiation in bacteria?

Answer 12

The RNA polymerases binds to the promoter and recognizes the template strand and the start point

Question 13

What does the sigma factor recognize?

Answer 13

TTGACA at position -35 (upstream of the transcription start site)
TATAAT at position -10 (upstream of the transcription start site)

Question 14

Initiation in eukaryotes?

Answer 14

Multiple specific proteins called transcription factors bind to promotor, RNA Poly 2 attacts to transcription

Question 15

What is the TATA box?

Answer 15

In eukaryotes, a specific DNA sequence called the TATA box allows the formation of the transcription initiation complex.
The TATA box about 25 nucleotides upstream from the transcriptional start point

Question 16

What is the transcription initiation complex?

Answer 16

Transcription initiation complex: Transcription factors + RNA polymerase II bound to the promoter.

Question 17

What is elongation?

Answer 17

10 to 20 DNA nucleotides are unwound at a time during transcription
The RNA polymerase II adds ribonucleotides to the 3’ end of the growing mRNA

Question 18

Termination in bacteria?

Answer 18

transcription ends at a terminator sequence the
The termination signal causes the polymerase to detach from the DNA and release the mRNA transcript
The transcription start/stop sites are not the start/stop codons

Question 19

Termination in eukaryotes?

Answer 19

the RNA polymerase II transcribes a sequence on the DNA called the polyadenylation signal sequence (AAUAAA)
proteins recgonize signal, cut mRNA 10-35 nucletides after

Question 20

Additions to 5 and 3’ ends

Answer 20

On the 5’ end: addition of a 5’ cap made of a modified Guanine, containing a methyl group
On the 3’ end: addition of a poly-A tail: 50-250 polyadenine (A) after the polyadenylation signal

Question 21

What is UTR

Answer 21

5’ UTR and 3’ UTR are untranslated regions (UTR), start codon is after

Question 22

We get rid of what when splicing

Answer 22

introns, using splicsosomes

Question 23

Splicing allows for….

Answer 23

Alternative RNA splicing, cut out sections to allow 1 gene for multiple proteins

Question 24

tRNA is…

Answer 24

complementray to mRNA, binds to reading frame, builds amino acid chain, anticodon loop at 3’ end

Question 25

tRNA has how many amino acids

Answer 25

20

Question 26

N teriminus is what

Answer 26

start codon

Question 27

What are polyribosomes?

Answer 27

mRNA can be tranlated simuntaneoulsy by multiple ribosomes called