TLS Online TPP Program

#Question id: 2684


In DNA tertiary structure, what is a histone octamer?

#Unit 2. Cellular Organization
  1. A complex consisting of eight positively charged histone proteins (two of each H2A, H2B, H3 and H4) that aid in the packaging of DNA

  2. A complex consisting of eight negatively charged histone proteins (two of each H2A, H2B, H3 and H4) that aid in the packaging of DNA

  3. A complex consisting of nine positively charged histone proteins (H1 and two of each H2A, H2B, H3 and H4) that aid in the packaging of DNA.

  4. A complex consisting of nine negatively charged histone proteins (H1 and two of each H2A, H2B, H3 and H4) that aid in the packaging of DNA.

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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.