Chapter 6-7 Blackboard Quiz

What would be synthesized using 5’-CAGTTCGGA-3’ as a template?

3’-GTCAAGCCT-5’

What component is involved in the initiation of transcription?

Promoter

Promoter strength is related to the relative frequency of transcription

Initiation 

Transcription 

Formation of an RNA transcript complementary to the DNA anti-sense strand

 An operon encoding genes that are transcribed and translated continuously to provide the cell with constant intermediate levels of the protein products is said to be

Constitutive

The DNA sequence, to which repressors may bind, that lies between the promoter and the first structural gene is called the _____.

operator 

Full induction of the lac operon occurs when:

lactose levels are high and glucose levels are low

RNA polymerase binds to a specific region on DNA called a

promoter

You have discovered a bacterial operon involved in the synthesis of vitamin E. This operon is regulated by a repressor protein that binds to an operator sequence. Vitamin E is the allosteric effector of the repressor; i.e., the molecule that binds to the repressor to regulate its activity. Predict how vitamin E will influence repressor activity.

When vitamin E binds to the repressor, the repressor binds to the operator.

The prevention of expression of operons encoding substrate use pathways for substrates other than glucose when glucose is present is called_____________.

Catabolite repression.

During which stage of bacterial transcription is the σ subunit of the RNA polymerase involved?

Initiation 

What is almost always associated with high levels of transcription?

The presence of an UP element in a promoter

A ______ mRNA is one that codes for multiple polypeptides

polycistronic

Regulation of the tryptophan operon occurs through 

a tryptophan-activated repressor that binds to operator sites 

A major difference between transcription in bacteria and eukaryotes is that

transcription and translation are uncoupled in eukaryotes 

An operon of genes encoding enzymes in a biosynthetic pathway is

repressible

A riboswitch is a domain within certain mRNAs that has all of the following characteristics, except

All riboswitches are ribozymes 

CAP is said to be responsible for positive regulation of the lac operon because:

CAP bound to the CAP binding site increases the frequency of transcription initiation by RNA polymerase 

What 6 base pair sequences is likely to be recognized by a σ factor

5’ TTGACA 3’

What is not true about the bacterial sigma factor

Sigma has the ability to join ribonucleotides (NTPs) by phosphodiester bonds using DNA as a template.

Transcription in bacteria proceeds in the

5’→ 3’ direction only

A riboswitch regulates gene expression 

1. By influencing whether transcription continues to the end of a gene or operon 

2. By influencing whether a mRNA is translated 

Which part of a riboswitch-regulated mRNA binds to a regulatory metabolite molecule

the aptamer

Promoter strength

1. Refers to the relative frequency of transcription initiation

2. depends on the affinity of RNA polymerase for the promoter region

The process of making an RNA copy of a gene is called _____

transcription 

Rho-independent terminators have all of the following characteristics except :

sigma factor binding to the terminator triggers transcript release

RNA polymerase forms a phosphodiester bond between

two rNTPs (ribonucleotide triphosphates).

The TATA box (–10 or Pribnow box) has all the following characteristics except:

It is both transcribed and translated

Which statement regarding bacterial Rho is not true?

Rho rides along with RNA polymerase until a termination sequence is encountered.

A riboswitch is divided into two parts namely, expression platform and ________________.

aptamer