TLS Online TPP Program

#Question id: 34120


The dynamic nature of DNA binding to the histone core structure is important, because many DNA-binding proteins strongly prefer to bind to histone-free DNA. Such proteins can recognize their binding site only when it is released from the histone octamer or is contained in linker or nucleosome-free DNA.

Which of the following statement stands untrue for above fact

#Unit 2. Cellular Organization
  1. DNA-binding site for a given protein on nucleosome can be found anywhere on wrapped DNA
  2. A binding site near position 73 of the 147 bp tightly associated with a nucleosome is rarely accessible. 
  3. Binding sites near the ends (position 1 or 147) of the nucleosomal DNA are most frequently accessible.
  4. Mechanism of exposure is due to unwrapping of the DNA from the nucleosome, rather than to the DNA briefly coming off the surface of the histone octamer
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TLS Online TPP Program

#Question id: 2825

#Unit 2. Cellular Organization

Metaphase chromosomes can be identified

a. by shape.                 

b. by the size and number of introns.

c. by banding patterns with Giemsa reagent.

d. by chromosome painting.

TLS Online TPP Program

#Question id: 2826

#Unit 2. Cellular Organization

An open reading frame (ORF) is defined as a DNA sequence that

a. begins with a start codon.               

b. ends with a stop codon.

c. contains 50 codons.   

d. contains approximately an equal frequency of A, T, G, and C.

TLS Online TPP Program

#Question id: 2827

#Unit 2. Cellular Organization

Two related genes that are derived from a gene duplication event are considered to be

a. homologous.                                   

b. paralogous.

c. orthologous.                       

d. members of a gene family.

TLS Online TPP Program

#Question id: 2828

#Unit 2. Cellular Organization

A transcriptionally active gene compared with a transcriptionally inactive gene would be expected to

a. contain acetylated histones.           

b. contain unacetylated histones.

c. be sensitive to DNase I.                 

d. be resistant to DNase I.

TLS Online TPP Program

#Question id: 2829

#Unit 2. Cellular Organization

Scaffold-associated regions

a. are the chromosome attachment points for the mitotic spindle.

b. can insulate transcription units from each other.

c. are the points at which DNA interacts with histone proteins.

d. are found between transcription units.

TLS Online TPP Program

#Question id: 2830

#Unit 2. Cellular Organization

The NtrC protein from E. coli
a. is a σ54 RNA polymerase.             
b. stimulates transcription of the glnA gene.
c. is activated by a protein kinase called NtrB.
d. binds both to an enhancer site upstream of the glnA gene and to RNA polymerase.
e. has ATPase activity.