TLS Online TPP Program

#Question id: 5665


 Following statements are regarding to cortical granule reaction.

A. To initiating the slow block to polyspermy the release of Ca2+ that occurs when the sperm enters the egg is critical for activating the egg’s metabolism and initiating development

B. Calcium ions release the inhibitors from maternally stored messages, allowing these mRNAs to be translated

C. Calcium ions are not release the inhibition of nuclear division, thereby allowing cleavage to occur.

D. Udx1, the enzyme responsible for the reduction of oxygen to crosslink the fertilization envelope, is also NADPH-dependent

E. The fertilization envelope is elevated from the cell membrane by glycosaminoglycans which provides support for the blastomeres during cleavage

Which of the following combinations are correct?

#Unit 5. Developmental Biology
  1. A, B and C

  2. A, B and D

  3. A and D only

  4. A, C and E

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TLS Online TPP Program

#Question id: 5809

#Unit 8. Inheritance Biology

Based on the physiological adaptation theory, bacterial populations that had not been exposed to T1 infection:

TLS Online TPP Program

#Question id: 5808

#Unit 8. Inheritance Biology

Mitochondrial DNA polymerase does not have an error checking mechanism such as that of nuclear DNA polymerase. This would be expected to lead to a higher rate of which type of mutation in mitochondrial DNA?

TLS Online TPP Program

#Question id: 5807

#Unit 8. Inheritance Biology

Which of the following would be an example of a germline mutation?

TLS Online TPP Program

#Question id: 5806

#Unit 8. Inheritance Biology

Which of these is NOT a mechanism by which a chromosome rearrangement could affect gene function?

TLS Online TPP Program

#Question id: 5805

#Unit 8. Inheritance Biology

In Himalayan rabbits, the ears, feet, and muzzle are pigmented while the rest of the body is white. This is because they express an enzyme variant that is ineffective at body temperature but functions at the lower temperatures experienced by cells of the extremities. This is an example of:

TLS Online TPP Program

#Question id: 5804

#Unit 8. Inheritance Biology

The gene that is mutated in cases of cystic fibrosis encodes an ion transporter protein normally expressed in the respiratory and digestive tracts along with other locations. Individuals homozygous for the most common mutation in this gene (ΔF508) died at very early ages prior to the advent of advanced medical intervention. Despite this, the mutation exists at relatively high frequency in populations of European descent. One potential explanation is that heterozygotes for such mutations may be relatively immune to the lethal effects of diseases such as typhoid fever. Which statement below is most accurate?