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.

#Question id: 1365

#Unit 4. Cell Communication and Cell Signaling

Which of the following best describes the structure of integrins?

#Question id: 29431

#Unit 6. System Physiology – Plant

The number of ATP molecules required for the complete assimilation of one molecule of CO2 in Calvin cycle is _____.

#Question id: 10286

#Unit 6. System Physiology – Plant

The enzyme aldolase, catalyzes a reversible aldol condensation, Fructose 1,6-bisphosphate is cleaved to yield two different triose phosphates, glyceraldehyde 3-phosphate, an aldose, and dihydroxyacetone phosphate, a ketose. There are two classes of aldolases such as;

A) Class I aldolases

B) Class II aldolases

i) Found in animals and plants

ii) Found in in fungi and bacteria

iii) formation of protonated Schiff base on enzyme and its active site contain lysine residue

iv) do not form the Schiff base intermediate and a zinc ion at the active site is coordinated with the carbonyl oxygen at C-2

In which of the following option is the given enzyme with its correct statements?

#Question id: 14734

#Unit 2. Cellular Organization

#Question id: 12991

#Unit 1. Molecules and their Interaction Relevant to Biology