Prophase is the first step in mitosis and many changes occur. Chromatin fibers become coiled into chromosomes, with each chromosome having 2 chromatids joined at a centromere. The mitosis spindle, composed of microtubules and proteins, form in the cytoplasm.
The iris focuses light rays before they enter the posterior portion of the eye
They are thus known as the "supporting cells" of the nervous system. The four main functions of glial cells are: to surround neurons and hold them in place, to supply nutrients and oxygen to neurons, to insulate one neuron from another, and to destroy and remove the carcasses of dead neurons (clean up).
A federal government is the type of government that combines aspects of both unitary and confederal government. The United States has a federal government.
Answer:
D) In case 1, both PS I and PS II completely lose function; in case 2, a proton gradient is still produced.
Explanation:
The light dependent reaction of photosynthesis, which produces the ATP and NADPH needed in the light independent stage of the process, includes complexes of proteins and pigments called PHOTOSYSTEMS. These photosystems (I and II) are key to the functionality of the light dependent reactions in the thylakoid.
The major pigment present in both photosystems is CHLOROPHYLL A, which absorbs light energy and transfers electrons to the reaction center. Chlorophyll B is only an accessory pigment meaning it can be done without. Hence, if all of the chlorophyll A is inactivated in the algae but leaves chlorophyll B intact as in case 1, both PS I and PS II will lose their function because Chlorophyll A is the major pigment that absorbs light energy in both photosystems.
In case 2, if PS I is inhibited and PS II is unaffected, a PROTON GRADIENT WILL STILL BE PRODUCED because the splitting of water into protons (H+) and electrons (e-) occurs in PSII. Hence, H+ ions can still be pumped into the inner membrane of the thylakoid in order to build a proton gradient even without the occurrence of PS I.
