Genetic code and Transcription I

Question 1

who coined the central dogma?

Answer 1

Francis Crick

Question 2

reverse transcription

Answer 2

“backwards” flow of genetic info

-make DNA from RNA template

Question 3

reverse transcriptase

Answer 3

enzyme that catalyzes the process of reverse transcription

Question 4

coding sequences that code for unique polypeptide chains

Answer 4

alternative splicing

Question 5

enhances the adaptability of the coding system

Answer 5

degenerate (>1 triplet)

Question 6

each nucleotide is a part of one triplet

Answer 6

non-overlapping

Question 7

codon

Answer 7

nucleotide triplet in mRNA

Question 8

unambiguous (genetic code)

Answer 8

each codon specifies a particular amino acid

Question 9

evidence for triplet nature of genetic code provided by who?

Answer 9

Crick and Brenner

Question 10

open ready frame

Answer 10

causes frameshift mutations

-contains no stop codons

Question 11

reading frame

Answer 11

sequence of consecutive, non-overlapping triplets

Question 12

start codon examples (2)

Answer 12

AUG, MET

Question 13

stop codon examples (3)

Answer 13

UAA, UAG, UGA

Question 14

third base of codon frequently does not change the specified amino acid, T or F?

Answer 14

True

Question 15

4 stages of transcription of mRNA from DNA

Answer 15

• binding
• initiation
• elongation
• termination

Question 16

sigma factor

Answer 16

promotes binding of RNA polymerase to specific DNA sequences

Question 17

when does initiation of RNA synthesis take place?

Answer 17

once the DNA is unwound

Question 18

transcription in bacteria (4 steps)

Answer 18

• RNA polymerase binds to sigma factor
• initation of synthesis
• enlongation
• termination (GC loop, or rho factor)

Question 19

bacterial promoter sequence (3)

Answer 19

• start point +1
• TATAAT box: -10 sequence
• -35 sequence

Question 20

U-RNA (3)

Answer 20

• processes pre-mRNA in the nucleus
• aids in regulation of transcription factors
• maintains the telomeres

Question 21

miRNA

Answer 21

small non-coding RNAmolecule

-regulation of gene expression

Question 22

3 classes of eukaryotic promoters

Answer 22

RNA polymerase I, II, III

Question 23

RNA polymerase I

Answer 23

• core promoters
• upstream control element
• improves promoter’s efficiency

Question 24

RNA polymerase II

-4 DNA sequences

Answer 24

• short initiator
• TATA box
• TFIB recognition element (BRE)
• downstream promoter element (DPE)

Question 25

upstream control elements (2)

Answer 25

• CAAT box

- GC box

Question 26

proximal control elements

Answer 26

those within 100-200 nucleotides o the start point

Question 27

enhancer elements

Answer 27

control elements more than 200 nucleotides from he start point

Question 28

RNA polymerase III

Answer 28

upstream promoter used for transcribing small RNA molecules

Question 29

RNA polymerase III promoter

Answer 29

entirely downstream from the start point

-for transcribing tRNA and 5S-rRNA