TLS Online TPP Program

#Question id: 31379


The cadherin catenin complex is extremely important during compaction from a morula to the blastula. Transition of early embryonic cells into a blastula differed depending on the presence or absence of calcium ions. In addition, an investigator blocked the expression of β-catenin using vivo morpholinos to detect its effect simultaneously on compaction. Which one of the following conditions will lead to the most successful transition of the morula into the blastula?



#Unit 5. Developmental Biology
  1. The blastula will continue to develop even when calcium ions are absent, since β-catenin will get activated automatically by cadherins.
  2. In the absence of calcium ions, calcium ionophores will assist development even when vivo morpholinos to β-catenin are introduced.
  3. Presence of calcium ions will enhance development when vivo morpholinos to cadherins have been introduced to the early embryo.
  4. Presence of calcium ions are essential for activation of cadherin and β- catenin, so that actin gets mobilized and compaction ensues.
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TLS Online TPP Program

#Question id: 2807

#Unit 2. Cellular Organization

Huntington’s disease is an example of

a. an autosomal recessive disorder.    b. an autosomal dominant disorder.

c. a sex linked recessive disorder.      d. a sex linked dominant disorder.

TLS Online TPP Program

#Question id: 2808

#Unit 2. Cellular Organization

A microsatellite is a type of polymorphism that

a. results from the change of a single nucleotide.

b. changes the recognition sequence for a restriction enzyme.

c. results from a variable number of repetitive sequences.

d. results from a chromosomal inversion.

TLS Online TPP Program

#Question id: 2809

#Unit 2. Cellular Organization

In the human genome, one centimorgan or a 1 percent recombination frequency represents, on average, a distance of about

TLS Online TPP Program

#Question id: 2810

#Unit 2. Cellular Organization

Which of the following steps is required to generate a knockout mouse?

a. microinjection of DNA into the pronucleus of a fertilized mouse egg

b. introduction of DNA into mouse embryonic stem cells

c. selection for cells containing the gene targeted insertion

d. expression of Cre protein during embryonic development

TLS Online TPP Program

#Question id: 2811

#Unit 2. Cellular Organization

RNA interference is a method for inhibiting the function of specific genes using

a. single-stranded DNA.                     

b. double-stranded DNA.

c. single-stranded RNA.                     

d. double-stranded RNA.

TLS Online TPP Program

#Question id: 2812

#Unit 2. Cellular Organization

Which of the following statements is (are) true of the human genome?

a. 1.5 percent of the genome corresponds to protein coding sequences.

b. The median length of an intron is 10 kb.

c. 10 percent of the genome is transcribed into pre mRNA precursors.

d. Most human exons contain 500–1000 base pairs.