Theme 2 Module 1

Question 1

DNA is often described as the “______” of the cell because it stores information needed for cellular processes

Answer 1

Blueprint

Question 2

What is the central dogma of cell biology?

Answer 2

The central dogma explains that DNA is transcribed into RNA, which is then translated into proteins. This flow of information goes from DNA to mRNA to protein

Question 3

The sequence of amino acids in a protein is determined by the sequence of bases in the

Answer 3

mRNA

Question 4

Who first proposed the central dogma of molecular biology?

Answer 4

Francis Crick in the late 1950s.

Question 5

What is the role of mRNA in gene expression?

Answer 5

mRNA is a copy of the gene that carries the information from DNA and is translated into a sequence of amino acids to form proteins.

Question 6

How does RNA differ from DNA?

Answer 6

RNA contains a ribose sugar instead of deoxyribose and uracil instead of thymine. RNA is also typically single-stranded.

Question 7

RNA contains the nitrogenous base ______, which pairs with adenine.

Answer 7

Uracil

Question 8

What happens during the process of transcription?

Answer 8

During transcription, a DNA template is used to generate a complementary RNA strand. The RNA sequence is determined by the nucleotide sequence of the DNA template

Question 9

What is the difference between the template strand and the non-template strand during transcription?

Answer 9

template strand is the DNA strand used to create the RNA transcript. The RNA sequence is complementary to the template strand, but it matches the non-template strand, except uracil replaces thymine

Question 10

What determines the sequence of nucleotides in an RNA transcript?

Answer 10

The sequence of nucleotides in the gene of the DNA template strand.

Question 11

What enzyme is responsible for transcribing RNA from DNA?

Answer 11

RNA polymerase

Question 12

The transcriptional starting point is indicated by specific ______ regions of the DNA, which are located upstream, or 5’ relative to the gene of interest

Answer 12

Promoter

Question 13

In what direction does RNA polymerase move along the template strand during transcription?

Answer 13

3’ to 5’ direction.

Question 14

RNA is synthesized in the ______ direction

Answer 14

5’ to 3’

Question 15

What stops RNA transcription?

Answer 15

The terminator sequence on the template strand.

Question 16

What happens to the transcriptional machinery after the RNA transcript is released?

Answer 16

It is disassembled, and transcription ends.

Question 17

Where is prokaryotic DNA located?

Answer 17

In a non-membrane-bound nucleoid region.

Question 18

In prokaryotes, the consensus nucleotide sequence ______ is positioned about 10 base pairs upstream of the start site of transcription.

Answer 18

TATAAT

Question 19

What is a consensus sequence?

Answer 19

consensus sequence is a common nucleotide sequence found in many different promoters, representing similarities in a specific region across different promoters

Question 20

What is the additional consensus sequence found in many prokaryotic genes, located approximately 35 nucleotides upstream of the transcription start site?

Answer 20

TTGCCA

Question 21

In prokaryotes, transcription initiation requires the RNA polymerase core enzyme to bind to a ______ factor, forming a holoenzyme

Answer 21

Sigma

Question 22

What role do sigma factors play in prokaryotic transcription?

Answer 22

Sigma factors help RNA polymerase bind to specific promoters, initiating the transcription of different genes

Question 23

What is formed when RNA polymerase binds to the promoter and opens the double-stranded DNA?

Answer 23

A transcription bubble.

Question 24

The RNA strand being synthesized is ______ to the DNA template strand and is formed in the ______ direction

Answer 24

Complementary; 5’ to 3’.

Question 25

How does RNA polymerase elongate the RNA transcript during transcription?

Answer 25

RNA polymerase moves along the DNA template, adding ribonucleotides one at a time, while the DNA is fed through the enzyme and then released after transcription.

Question 26

How can multiple RNA polymerase molecules transcribe a single gene simultaneously?

Answer 26

Multiple RNA polymerase molecules can follow each other along the DNA template, producing multiple RNA transcripts in parallel.

Question 27

What provides the energy needed to form phosphodiester bonds during RNA transcription?

Answer 27

The phosphate bond energy from incoming ribonucleotide triphosphates.

Question 28

Transcription terminates when RNA polymerase reaches the ______ sequences at the 3’ end of the gene

Answer 28

Terminator

Question 29

What is a Rho-independent terminator sequence?

Answer 29

It consists of inverted nucleotide repeats that form a G-C rich hairpin loop, pausing RNA polymerase and leading to the release of the mRNA transcript.

Question 30

What is a Rho-dependent terminator sequence?

Answer 30

It uses the Rho factor, a protein that binds to the RNA transcript, utilizes ATP to destabilize the RNA-DNA interaction, and releases the RNA transcript

Question 31

Transcrpition and transltion can ______ in prokaryotes cells

Answer 31

simentonously

Question 32

What is the key difference in the requirement for transcription initiation between prokaryotes and eukaryotes?

Answer 32

Prokaryotic RNA polymerase only requires a sigma factor to bind the promoter, whereas eukaryotic RNA polymerase needs several general transcription factors.