Answer:
The hydrophilic part of the cell membrane is A, the phosphate head.
Charged molecules, such as K+ or Ca++ are unable to pass through the lipid bilayer because of their charge and must use a membrane protein to cross the cell membrane.
C, the lipid tails, are hydrophobic and repel water.
Depends on the magnification you are looking for... usually, a light microscope is enough (1000x max magnification)...
An electron microscope is powered by high energy beams and can magnify many times higher than the light microscope (where magnification is limited by the wavelength of light). The magnification of an EM is on the nano scale.
(P.S.: as a chemist, I'd always choose an EM over an optical microscope as I can always zoom in or out depending on my needs) ;)
None of these seem to be correct, but it seems c is due to a disproved myth that essentially is the only thing close to an answer.
Stars Like the Sun. When the core runs out of hydrogen fuel, it will contract under the weight of gravity. ... The upper layers will expand and eject material that will collect around the dying star to form a planetary nebula. Finally, the core will cool into a white dwarf and then eventually into a black dwarf.
To make ATP, cells must join together ADP & a phosphate using energy from food. A phosphate is removed from an ATP molecule in order to provide energy for the cell. Thus, the ATP molecule turns into an ADP molecule. We eat food which gives us energy to add another phosphate group to the ADP molecule, turning it into an ATP molecule. The cycle then begins again.
