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TLS Online TPP Program

#Question id: 7264

The Dictyostelia social amoebas are found in a wide range of soil habitats. They can come together to form a fruiting structure, in which a proportion of cells are sacrificed to build the stalk and the remainder differentiate into resilient dormant spores. This multicellular life cycle is common to all Dictyostelids. It consists of an interconnected programme of cell movement and cell differentiation, and has been intensively studied in the model organism D. discoideum. Few mutants (Column A) and phenotypes (Column B) are listed in the table given below.

    Column A

    Column B

A. Loss of function of cAMP-dependent protein kinase (PKA)

i. cell develop normally but unable to germinate

B. Loss of function of RegA

ii. Loose aggregate form

C. Loss of function of adenylate cyclase B

iii. No aggregation

D. Loss of function of gp80

iv. accumulation of cAMP and PKA activation

 Match the correct mutant with the observed phenotype.

#Unit 5. Developmental Biology
  1. A-iv, B-ii, C-iii, D-i
  2. A-iv, B-iii, C-i, D-ii
  3. A-ii, B-iii, C-iv, D-i
  4. A-iii, B-iv, C-i, D-ii
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TLS Online TPP Program

#Question id: 11314

#Unit 10. Ecological Principles

What type of organism produces acids that degrade rocks and minerals?
TLS Online TPP Program

#Question id: 11315

#Unit 10. Ecological Principles

Carnivores that eat herbivores in a food chain are the _________________.
TLS Online TPP Program

#Question id: 12972

#Unit 10. Ecological Principles

Under  some  circumstances a  population  can  split  into  two  or  more  species  without  the  existence of  geographic barriers. All of the following genetically determined behaviours could provide conditions leading to speciation EXCEPT
TLS Online TPP Program

#Question id: 12971

#Unit 10. Ecological Principles

One group of ecologists has suggested that producers are limited by competition for resources, primary consumers (herbivores) are limited by predation, and secondary consumers (carnivores) are limited by food. If this were true, at which of the following trophic levels would one expect to find substantial evidence for competitive exclusion?
TLS Online TPP Program

#Question id: 12970

#Unit 10. Ecological Principles

In deep-sea hydrothermal vents near the Galapagos Islands, bacteria obtain energy by oxidizing hydrogen sulphide released from the vents. Giant tube worms, which lack mouths and digestive systems, harbour the bacteria in their tissues and use them as a source of organic molecules. Clams obtain energy by filtering bacteria directly from the water, and numerous crabs and octopi feed on the clams. In this unique ecosystem, the bactena are playing the role of
TLS Online TPP Program

#Question id: 12969

#Unit 10. Ecological Principles

In which of the following habitats would one expect to find the highest diversity of vascular plants?