TLS Online TPP Program

#Question id: 796


Which statement best describes the distinction between the purposes of the two RNAi pathways within the eukaryotic cell?

#Unit 1. Molecules and their Interaction Relevant to Biology
  1. miRNA-mediated gene silencing represents a back-up pathway should siRNA-mediated gene silencing be unsuccessful at silencing the target dsRNA

  2. siRNA and miRNA-mediated gene silencing pathways must both be active to successfully silence the target dsRNA

  3. miRNA and siRNA-mediated gene silencing represent evolutionary-independent pathways which confer identical silencing mechanisms on the target dsRNA

  4. siRNA-mediated gene silencing represents a cell defence mechanism against exogenous dsRNA; miRNA-mediated gene silencing is an integral gene expression regulation process

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TLS Online TPP Program

#Question id: 33425

#Unit 1. Molecules and their Interaction Relevant to Biology

An isozyme, located on the inner face of the inner mitochondrial membrane, regenerates fatty acyl–CoA and releases it, along with free carnitine, into the matrix

TLS Online TPP Program

#Question id: 4511

#Unit 3. Fundamental Processes

The proteins are not needed for the splicing reaction itself, because

TLS Online TPP Program

#Question id: 28782

#Unit 2. Cellular Organization

The rate of polymerization of actin filaments is given by rate constant K, in which_____
a) the addition of monomers is given by kon (M–1 sec–1
b) the addition of monomers is given by koff  (sec–1)
c) the loss of monomers is given koff (M–1 sec–1
d) the loss of monomers is given koff (sec–1)

TLS Online TPP Program

#Question id: 13020

#Unit 10. Ecological Principles

Experts in deer ecology generally agree that population sizes of deer that live in temperate climates are limited by winter snow. The deer congregate in ?yarding? areas under evergreen trees because venturing out to feed in winter is energetically too expensive when snowfall depths accumulate to above 40 cm. Deer often stay yarded until the spring thaw. Snow depth over 40 inches for more than 60 days results in high mortality due to starvation.  This observation best illustrates which of the following principles about factors that limit distribution of organisms?

TLS Online TPP Program

#Question id: 7146

#Unit 5. Developmental Biology

In Drosophila, the neuroectoderm is located ventrally during gastrulation, while in mice or frogs, the neuroectoderm is located dorsally. Which statement best describes how the two systems are similar or different?