A cell membrane is composed of a lipid bilayer in which many kinds of proteins are embedded. These proteins use energy to actively transport certain particles into and out of the cell. Which example BEST illustrates the condition in which molecules move across the cell membrane through active transport?

A. When molecules need to move from an area of lower concentration to an area of higher concentration.

B. When the cell wall is damaged or genetically modified and molecules cannot enter or leave the cell.

C. When molecules need to move from an area of higher concentration to an area of lower concentration.

D. When the amount of water is higher inside of the cell as compared to the area surrounding the cell.

answer; /// i believe the correct answer is (thrombocytopenia); (a)

the answer is: the „power stroke“ step.

muscle contraction can be divided into a few steps:

1. the release of ach (acetylcholine) in the synaptic cleft, binding of ach for its receptor and consequently opening of the ca channels.

2. the release of ca, binding of ca for the troponin

3. troponin shifting the tropomyosin, which was blocking the active site on the actin

4. myosin heads attaching to actin by breaking down atp to adp+ pi

5.   formation of the ‘cross-bridge’ on the active site of the actin filament by myosin head

6. “power stroke” -the cross bridge pulls actin, which slides over the myosin

9.     7. the release of adp completes the cross-bridge movement and atp attaches to myosin, breaking the actin-myosin cross bridge.

prophase is the first step in mitosis and will show one huge circle (nucleus) and centrioles - nothing is being done to it. metaphase is the third step and where the chromatids meet in the middle and the centrioles are at opposite ends. anaphase is the fourth step and where the chromatids start to split/separate. telophase is the second to last step where the chromatids start to split along with the centrioles, it looks like there is getting ready to be two different cells. if you follow this, then it should you to answer what it looks like. have a great day and i hope i you! if i did not answer your question or you are confused, let me know and i will you as much as i can.