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.
Answer: Option A
<u>Explanation:</u>
As temperature increases the rate of enzyme activity increases until it reaches approximately 37 degrees Celsius. As temperature increases beyond 37 degrees Celsius, the enzyme activity decreases. The activity decreases because the enzyme denatures.
Any enzyme has certain temperature, pH and pressure to maintain its activity. Only at the ideal or ambient parameters the enzyme works. Most of the enzymes that are present in the human body gets activated by 37 degrees and gets denatured beyond that temperature.
Red blood cells do not have a nucleus.
It does not consist of a cell membrane or a cytoplasm.
It simply only transports oxygen around the body.
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Hey there!
The correct answer would be - C.
Hope this helps!
