Gravitropism is the movement or growth of a plant in response to gravity. ... Plant shoots demonstrate negative gravitropism since they grow in the opposite direction of gravity. Gravity is sensed by specialized cells called statocytes, which have statoliths that sink inside the cell.

Explanation:

8 0

3 years ago

Cross bridge formation between myosin heads and actin molecules is caused by the elevation of calcium ion concentration in the c

Naily [24]

Answer:

by the sarcoplasmic reticulum's calcium ion pumps

Explanation:

Rigor mortis or postmortem rigidity, is a state caused by chemical changes in the muscles that occur post mortem and cause the limbs of the corpse to stiffen.

This occurs because after death, there is no cellular respiration and consequently, no oxygen nor ATP (ATP is required for the muscle relaxation).

Calcium enters the cytosol after death because it is released due to the deterioration of the sarcoplasmic reticulum and due to the breakdown of the sarcolemma. Ca2+ ions activate the formation of actin-myosin cross-bridging necessary for the contraction. Muscles are unable to relax, because myosin heads continue to bind with the active sites of actin and there is no ATP to destabilize the myosin-actin bond.

8 0

3 years ago

What structure is present on the second cervical vertebra (c2 or axis) that allows you to rotate your neck to say "no?" what str

Nat2105 [25]

<span>Dens (odontoid process) Hope this helps.</span>

5 0

4 years ago