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.

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#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?

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#Question id: 7541

#General Aptitude

A train travelling at 54km/hr completely crosses another train having half its length and travelling in opposite direction in 18km/hr in 30 second. It also passes a railway platform in 40 seconds. The length of the platform (in meters) is

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#Question id: 33697

#Unit 2. Cellular Organization

Hb Kenya, another fused hemoglobin. The fusion must have resulted from unequal crossing over between 

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#Question id: 5334

#Unit 8. Inheritance Biology

The way sex determination in birds, Male birds have two Z chromosomes, and females have Z and W. which of the following is not possible during inheritance?

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#Question id: 5350

#Unit 8. Inheritance Biology

Which of the following most probable mode of genetic disorder?