TLS Online TPP Program

#Question id: 17075


What are the disadvantages of using polyclonal antibodies?

#Unit 12. Applied Biology
  1. Batch-to-batch variability as produced in different animals at different times
  2. High chance of cross-reactivity due to a recognition of multiple epitopes
  3. Production cost is too high
  4. Both A& B
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TLS Online TPP Program

#Question id: 2954

#Unit 2. Cellular Organization

Cyclin concentrations are highest during which periods of the cell cycle?

TLS Online TPP Program

#Question id: 12348

#Unit 10. Ecological Principles

The following equation represents a hypothetical relationship between fitness (w) and shoot: root ratio (r) in individuals of a plant species: w = 10r-10r2. At what value of shoot: root ratio (r), do these plants achieve maximum fitness? (Use decimal notation, not fractions or percentage)

TLS Online TPP Program

#Question id: 16953

#Unit 4. Cell Communication and Cell Signaling

The ability of any stem cell to self-renew and differentiate depends on the structural organization and cellular function of specialized anatomic microenvironments known as stem cell niches. These sequestered regions are typically populated by a supportive network of stromal cells. Stem cell niche stromal cells express soluble and membrane-bound proteins that regulate cell survival, proliferation, differentiation, and trafficking. Which statements is true about HSCs?

TLS Online TPP Program

#Question id: 2585

#Unit 2. Cellular Organization

Which of the following is the correct sequence that describes the excitation and contraction of a skeletal muscle fiber?

A. Tropomyosin shifts and unblocks the cross-bridge binding sites.

B. Calcium is released and binds to the troponin complex.

C. Transverse tubules depolarize the sarcoplasmic reticulum.

D. The thin filaments are ratcheted across the thick filaments by the heads of the myosin molecules using energy from ATP.

E. An action potential in a motor neuron causes the axon to release acetylcholine, which depolarizes the muscle cell membrane.

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