MBG PART TWO: Lecture 4

Question 1

What happens during reverse transcription?

Answer 1

Get DNA from an RNA Template

Question 2

What are telomeres?

Answer 2

End of chromosomes

Question 3

What is Telomerase?

Answer 3

Prevents shortening of chromosomes

Question 4

What does RNA contain?

Answer 4

The base uracil in place of thymine

Question 5

What sugar does RNA have?

Answer 5

A ribose sugar

Question 6

What type of structure does RNA have?

Answer 6

A tertiary structure (tRNA’s)

Question 7

When may RNA interact as functional units?

Answer 7

In the ribosome (quaternary structure)

Question 8

Is RNA less stable than DNA?

Answer 8

Yes.

Question 9

Why is RNA less stable than DNA?

Answer 9

The presence of the 2’OH group in ribose causes it to react intramolecularly with the 3’OH site resulting in phosphate bond breakage.

Question 10

Why use an unstable RNA?

Answer 10

RNA revolved first (evolution aspects) and because RNA can form many tertiary structures allowing it to have different conformations for different functions, whereas DNA is only double stranded.

Question 11

What is ncRNA?

Answer 11

Does not code for proteins

Question 12

What is mRNA?

Answer 12

Messenger RNA

Question 13

What is Transcription?

Answer 13

Synthesis of RNA from DNA templates

Question 14

What are cellular RNAs synthesized from?

Answer 14

DNA templates

Question 15

What RNA’s are transcribed in both prokaryotic and eukaryotic cells?

Answer 15

mRNA
rRNA
tRNA

Question 16

What RNA is only produced in prokaryotes?

Answer 16

CRISPR RNA crRNA

Question 17

What viruses can copy RNA directly from RNA?

Answer 17

Retroviruses

Question 18

What direction is RNA synthesized in?

Answer 18

5’ to 3’ using the 3’ to 5’ DNA template strand.

Question 19

What is RNA synthesis in regards to the DNA template strand?

Answer 19

Complementary and Anti-parallel

Question 20

What will the RNA template strand match?

Answer 20

The DNA non-template strand

Question 21

What can transcription utilize?

Answer 21

Either DNA strand as the 3’ to 5’ template, but transcription always occurs in the 5’ to 3’ direction.

Question 22

What are the three components needed for transcription?

Answer 22

1.) DNA Template

2.) 4 Ribonuceloside Triphosphates (rNTPs)
- A, U, G, C

3.) DNA dependant RNA polymerase.

Question 23

How is the 5’ to 3’ RNA molecule different from the DNA non-template strand?

Answer 23

The uridine in the RNA replaces thymidine

Question 24

What is the DNA non-template strand known as?

Answer 24

DNA sense

Question 25

What is RNA synthesis catalyzed by?

Answer 25

RNA polymerases and it always proceeds in the 5’ to 3’ direction

Question 26

What subunits does a core RNA polymerase consist of?

Answer 26

a, B, B’, omega, sigma

Question 27

Do you need primers for transcription in a prokaryotic gene?

Answer 27

No due to the promoter regions

Question 28

What is the function of Alpha subunit?

Answer 28

Involved in the assembly of the tetrameric core (2 of these - a2)

Question 29

What is the function of Beta?

Answer 29

Contains the ribonucleoside triphosphate (rNTP) binding site

Question 30

What is the function of Beta Prime?

Answer 30

Contains the DNA template binding region

Question 31

What is the function of omega?

Answer 31

Helps to stabilize the tetrameric (a2, B B’ ) core

Question 32

What is the function of sigma?

Answer 32

It binds to the RNA polymerase tetrameric core and assists in the correct initiation of transcription specifically at the promoter region of the prokaryotic gene. Many type of sigma factors which allows for specificity