LEC: UNIT 9

Question 1

In eukaryotes, transcription occurs in the _____

Answer 1

nucleus

Question 2

DNA-dependent RNA polymerase synthesizes in what direction?

Answer 2

5’-to-3’

Question 3

T/F: only the ATP and GTP requires RNA polymerase

Answer 3

F. all ATP, GTP, CTP, and UTP does

Question 4

T/F. DNA-dependent RNA polymerase does not require a primer for its RNA synthesis

Answer 4

T

Question 5

T/F. Bacterial DNA-dependent RNA polymerase is a multi-subunit enzymes

Answer 5

T

Question 6

The __ factor has an important role in the recognition of the promoter

Answer 6

σ

Question 7

What is the role of the promoter?

Answer 7

DNA sequence that provide direction for RNA polymerase; directs the core complex to specific binding sites on the DNA

Question 7

The DNA-dependent RNA polymerase is made up of ___ (how many) core subunits aside from the σ factor?

Answer 7

5 (total of 6 subunits)

Question 8

serves as the template for RNA synthesis

Answer 8

Template (antisense) strand

Question 9

identical to the RNA transcribed from the gene, with U in the RNA in place of T in DNA

Answer 9

Coding (nontemplate/sense) strand

Question 10

____ (polymerase) binds to and transcribes only the template strand

Answer 10

RNA polymerase

Question 11

3 phases of transcription

Answer 11

Initiation
Elongation
Termination

Question 12

Promoter regions in prokaryotes (4)

Answer 12

• Pribnow Box /
• -10 region
• -35 region
• UP element

Question 13

Identify the phase of transcription: Recognition of promoter region by σ factor (closed promoter complex)

Answer 13

Initiation

Question 14

Identify the phase of transcription: RNA polymerase bind to DNA

Answer 14

Initiation

Question 15

Identify the phase of transcription: Unwinding of the DNA (open promoter complex)

Answer 15

Initiation

Question 16

Identify the phase of transcription: Addition of purine ribonucleotide triphosphate as the first base of RNA transcript.

Answer 16

Elongation

Question 17

Identify the phase of transcription: RNA polymerase initiates mRNA synthesis

Answer 17

Elongation

Question 18

Identify the phase of transcription: Dissociation of σ factor

Answer 18

Elongation

Question 19

Identify the phase of transcription: includes ρ-Dependent Mechanism and aρ-Independent Mechanism

Answer 19

Termination

Question 20

Identify the type of termination: extrinsic termination

Answer 20

ρ-Dependent Mechanism

Question 21

Identify the type of termination: intrinsic termination

Answer 21

aρ-Independent Mechanism

Question 22

Identify the type of termination: ρ factor recognizes the termination region; It weakens the interaction between the template and the transcript.

Answer 22

ρ-Dependent Mechanism

Question 23

Identify the type of termination: It is controlled by specific sequences, termination sites (contains palindromes in the template strand).

Answer 23

aρ-Independent Mechanism

Question 24

In aρ-Independent Mechanism , the newly synthesized RNA form a “_____” (appearance) loop

Answer 24

“Hairpin”

Question 25

RNA polymerase II consists of ___ (how many) subunits

Answer 25

12 (RBP1-RBP12)

Question 26

Compartment of RNA polymerase I

Answer 26

Nucleolus

Question 27

Compartment of RNA polymerase II

Answer 27

Nucleoplasm

Question 28

Compartment of RNA polymerase III

Answer 28

Nucleoplasm

Question 29

T/F: Mammalian cells possess five distinct nuclear RNA polymerases

Answer 29

F. They only possess THREE

Question 30

Prokaryotic mRNAs are synthesized on the bacterial ____ in direct contact with the ____ and are immediately available for translation.

Answer 30

nucleoid, cytosol

Question 31

What happens during the post-transcriptional modifications in the processing of eukaryotic mRNAs?

Answer 31

o Addition of 5’ capping
o Splicing of introns
o Polyadenylation of 3’ tail

Question 32

What happens during the capping of eukaryotic mRNA?

Answer 32

• Addition of GMP in an inverted orientation by guanylyl transferase
• Methylation of C7 at G by guanin methyltranferase

Question 33

Functions of 5’ cap

Answer 33

o Prevents 5’ end from being digested
o Aids in the transport of mRNA out of the nucleus
o Plays a role in the initiation of mRNA translation

Question 34

Identify the event: eukaryote genes frequently contain intervening base sequence that do not appear in the final mRNA of that gene product

Answer 34

Splicing of introns

Question 35

Expressed DNA sequence are called _____

Answer 35

exons

Question 36

Intervening DNA sequences that are not expressed are called _____

Answer 36

introns

Question 37

During the splicing reaction, when the exons are spliced together, a _____ forms in the intron

Answer 37

lariat

Question 38

Identify the event: exons are separated by intervening intron

Answer 38

the splicing reaction

Question 39

_____ is made up of snRNAs associated with snRNPs

Answer 39

Spliceosome

Question 40

This tail protects the mRNA from nucleases and phosphatases

Answer 40

polyadenylate “tail”

Question 41

A polyadenylate “tail” that is usually 100-200 nucleotides long, is added to the __’ (5’ or 3’) end before the mRNA leaves the nucleus.

Answer 41

3’

Question 42

Difference in the template of transcription and replication

Answer 42

Transcription: 3’&raquo_space;> 5’
Replication: 5’&raquo_space;> 3’; 3’&raquo_space;> 5’

Question 43

Which requires primer? (Transcription or replication)

Answer 43

Replication