TLS Online TPP Program

#Question id: 1384


Mutations that block expression of the E-cadherin gene are thought to be an important step in metastasis. To better understand how loss of E-cadherin contributes to metastasis, scientists created two cell lines that differed in their expression of E-cadherin. One cell line expressed normal E-cadherin, but at 10% of the usual levels. The other cell line expressed normal E-cadherin at the usual levels, and also, at high levels a mutant form that included the cytoplasmic domain but lacked the rest of the protein. Both cell lines exhibited strongly reduced cell adhesion in culture. However, only the cell line with reduced expression of normal E-cadherin metastasized when introduced into mice.

Which of the following hypotheses is most consistent with the observations on cell adhesion and metastasis in these cell lines?

#Unit 4. Cell Communication and Cell Signaling
  1. Loss of E-cadherin releases signalling proteins that normally bind to its cytoplasmic domain, but promote metastasis when free.

  2. The cytoplasmic domain of E-cadherin binds proteins required for cell adhesion, but those proteins are not involved in metastasis.

  3. The E-cadherin transmembrane domain by itself is sufficient to promote the cell–cell adhesion that prevents metastasis.

  4. The loss of adhesion caused by inactivation of E-cadherin is sufficient to explain how E-cadherin mutations promote metastasis.

More Questions
TLS Online TPP Program

#Question id: 3487

#Unit 11. Evolution and Behavior

Which of the following is true of innate behaviors?

A) Genes have very little influence on the expression of innate behaviors.

B) Innate behaviors tend to vary considerably among members of a population.

C) Innate behaviors are limited to invertebrate animals.

D) Innate behaviors are expressed in most individuals in a population across a wide range of environmental conditions.

E) Innate behaviors occur in invertebrates and some vertebrates but not in mammals.

TLS Online TPP Program

#Question id: 3488

#Unit 11. Evolution and Behavior

According to Hamiltonʹs rule,

TLS Online TPP Program

#Question id: 3489

#Unit 11. Evolution and Behavior

 In a bird species A, the male alone builds the nest, incubates the eggs and feeds the nestling. In bird species B, it is the female that does all that. In bird species C, both sexes contribute equally to the above activities. In species A and B, the uninvolved partner may fly away and mate again. Which sex among A, B and C is most likely to develop colorful plumage during breeding season?

TLS Online TPP Program

#Question id: 3490

#Unit 11. Evolution and Behavior

Given below are some behaviors strategies.

A) Fixed action pattern, complex sequence of behavior, Once released and continuous to completion, even when there is change in surrounding environment

B)  natural selection select that territorial behavior that is benefit is greater than cost 

C) Imprinting, a form of learning in which a very young animal fixes its attention on the first object with which it has visual, auditory, or tactile experience

D) Donor benefits at a cost to the recipient, the behavior is altruistic; when the recipient benefits at a cost to the donor, the behavior is selfish.

Which one of the following correct combination of true and false?

TLS Online TPP Program

#Question id: 3491

#Unit 11. Evolution and Behavior

Some dogs love attention, and learns that if he barks, he gets attention. Which of the following might you use to describe this behavior?

A) The dog is displaying an instinctive fixed action pattern.

B) The dog is trying to protect its territory.

C) The dog has been classically conditioned.

D) The dog's behavior is a result of operant conditioning

E) The dog is displaying controlled by external stimuli

TLS Online TPP Program

#Question id: 3492

#Unit 11. Evolution and Behavior

A mother goat can recognize its own kid by smell, types of animal behavior

A) Operant conditioning

B) Learn behavior

C) Innate behavior

D)  Imprinting