Answer:
A. donation of excited electrons by chlorophyll a to a primary electron acceptor
Explanation:
Photosystems are structures located at the thylakoid membrane that act to harvest energy light in order to convert it into chemical energy. Each photosystem is composed of a light-harvesting complex and a core complex, which in turn is composed of a reaction center. The photosynthetic reaction centers are multi-protein complexes that use light energy to catalyze the electron transfer across the chloroplast thylakoid membrane against a thermodynamic gradient. Moreover, antenna pigments are pigments that capture the energy from photons in order to transfer energy to other pigments in the photosystem (e.g., chlorophyll B and carotenes are antenna pigments, whereas chlorophyll A is the core pigment). Light energy absorbed by antenna pigments in the photosystems is transferred to the reaction center chlorophyll A molecules, thereby exiting electrons in the reaction center. A reaction center consists of two chlorophyll A molecules, which donate electrons to the primary electron acceptor.
Antarctic fish species requires an adaptation to cold environment. Living at cold temperature environment would demand certain biological responses such as cutaneous respiration, enlarged blood vessels, and producing greater amounts of fat. Most of these fat are composed of higher phospolipid levels which are primarily due to phosphatidylethanolamine. This phospolipid is responsible for destabilizing cell membranes and make it more fluid thereby allowing unrestricted blood flow. The fatty acid composition of the membrane lipid is important for membrane fluidity, this is mainly attributed to unsaturated fatty acids which are responsible for decreasing the order of membrane lipids thereby decreasing viscosity. At extremely low temperatures, organisms with low concentration of unsaturated fatty acids would freeze cell membranes. That's why antarctic fishes have higher levels of unsaturated fatty acids.
Cytoplasm maintains the internal pressure in the cell.
Answer: Filtration
Blood that is going to be filtered enters the first part of the nephron,
the glomerulus, which is a tuft
of capillary vessels. The glomerulus is inside a "sac" called a
glomerular capsule.Together, the glomerulus and the glomerular capsule
form the renal corpuscle, which is the filtering unit.
D prevents repeating. experiments have to be repeated to be reliable.
