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TLS Online TPP Program

#Question id: 13161

Which of the following mechanism depends on the activation of heterotrimeric G proteins?

#Unit 4. Cell Communication and Cell Signaling
  1. During actin filament formation, the inactive formin is activated when its Rho-binding domain (RBD) binds to membrane-bound active Rho-GTP, resulting in exposure of the formin’s FH2 domain, which can then nucleate the assembly of a new actin filament.
  2. Rod cells sense light with the aid of a light-sensitive rhodopsin which is coupled to transducin. On absorption of a photon, the retinal moiety of rhodopsin is immediately converted from the cis isomeric form to the all-trans isomeric form, causing a conformational change that allows rhodopsin to bind the α subunit of transducin.
  3. Ras proteins are “switch” proteins and not directly linked to cell-surface receptors. Ras activation is accelerated by a guanine nucleotide exchange factor (GEF), which binds to the Ras∙GDP complex, causing dissociation of the bound GDP.
  4. During the regulation of microfilament organization, Cdc42 act as molecular switches, inactive in the GDP-bound state and active in the GTP-bound state.
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TLS Online TPP Program

#Question id: 10631

#Unit 10. Ecological Principles

To estimate the number of foxes m an area, a researcher conducted a mark-recapture survey. In the fast survey, he caught and marked 90 foxes. In his second survey a week later, he caught 120 foxes of which 40 were marked (recaptures). If you are told that the actual number of foxes in this area is 400, which of the following is a plausible explanation for the anomaly in the researcher's data? 
TLS Online TPP Program

#Question id: 10632

#Unit 10. Ecological Principles

Three different population growth pattern related to population density are shown in figure
TLS Online TPP Program

#Question id: 10633

#Unit 10. Ecological Principles

Following some characteristic feature of r selected species

A. late maturity

B. Provision of parental care

C. High mortality during early stages of life

D. large clutch size

What is the above combination is correct?
TLS Online TPP Program

#Question id: 10634

#Unit 10. Ecological Principles

Consider a population which is changing from one generation to the next as per the equation N(t) = R*N(t-1), where N(t) represents the size of the population at time t and R is a constant growth parameter. Under what condition is the population likely to go extinct?
TLS Online TPP Program

#Question id: 10635

#Unit 10. Ecological Principles

Three important biological parameters – generation time, per capita growth rate (r) and clutch size are a function of the organism‟s body size. Which of the curves (a) or (b) represents the correct relation of each of the parameters to body size?
TLS Online TPP Program

#Question id: 10636

#Unit 10. Ecological Principles

The demographic transition model depicts demographic changes from high- to low-level births and deaths in five stages


Stage 1 is characterized by total population numbers are low and the high birth rate is balanced by the high death rate.

B) Stage 2 is characterized by high population growth rate is results of high birth rate however, decline death rate

C) Stage 4 is characterized by decline in the proportion of the population in the reproductive age group and these changes stabilizes population size

D) Stage 3 is characterized by falling birth rates and death rates and population growth rate is zero due to the less numbers of people in the reproductive age group