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TLS Online TPP Program

#Question id: 7177

Following statements are regarding to the early development in nematodes. Which of the following is incorrect?

#Unit 5. Developmental Biology
  1. At the 4-cell stage, the EMS cell requires a signal from its neighbor (and sister cell), the P2 blastomere. Usually, the EMS cell divides into an MS cell (which produces mesodermal muscles) and an E cell (which produces the intestinal endoderm).
  2. If the P2 cell is removed at the early 4-cell stage, the EMS cell will divide into two E cells, and endoderm will be produced.
  3. If the EMS cell is recombined with the P2 blastomere, however, it will form endoderm; it will not do so, however, when combined with ABa, ABp, or both AB derivatives.
  4. Specification of the MS cell begins with maternal SKN-1 activating the genes encoding transcription factors such as MED-1 and MED-2. 
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TLS Online TPP Program

#Question id: 2821

#Unit 2. Cellular Organization

Which of the following is (are) encoded by multiple genes present in the human genome?

a. ribosomal RNA       b. transfer RNA                       c. histone            d. lysozyme
TLS Online TPP Program

#Question id: 2822

#Unit 2. Cellular Organization

Transposition by a bacterial insertion element

a. occurs at a frequency of approximately 1 in 10^3 cells per generation.

b. can inactivate an essential gene.    

c. is mediated through a RNA intermediate.

d. requires the enzyme transposase
TLS Online TPP Program

#Question id: 2823

#Unit 2. Cellular Organization

Transposition by a retrotransposon requires activity of which of the following enzymes?

a. RNA polymerase                b. reverse transcriptase

c. DNA methylase                  d. DNA polymerase
TLS Online TPP Program

#Question id: 2824

#Unit 2. Cellular Organization

Plant mitochondrial DNA

a. is the same size as human mitochondrial DNA.

b. encodes a 5S mitochondrial rRNA.

c. contains multiple copies that recombine with each other.

d. uses the standard genetic code.
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.