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.
Polysaccharides at made up of 2 or more monosaccharides bonded together
Answer:
Regulatory sites e.g enhancers and silencers
Explanation:
Gene expression involves the synthesis of gene products usually proteins and RNA. However, a certain product might not be needed at all or in small quantity. Gene regulation mechanism is the process that makes this happen. Gene regulation is the mechanism that acts to induce or repress the expression of a gene.
Gene regulation involves controlling the rate and manner of gene expression which is achieved through a set of regulatory proteins called transcription factors. Transcription factors bind to specific regulatory nucleotide sequences and help to turn "on or off" specific genes in the DNA.
Transcription factors can either be ACTIVATORS or REPRESSORS depending on whether they boost or inhibit gene expression. The binding sites for these regulatory proteins called TRANSCRIPTION factors are the regulatory nucleotide sequences on the DNA called enhancers and silencers.
It really is impossible to predict such a matter. I mean, think about it, its nearly impossible to think about how earth would be impacted if the heat from the interior of the planet that powers plate tectonics were to suddenly cease to exsist, or if that heat never exsisted in the first place, because that is how planets are formed.
One thing is certain however, life wouldn't be the same without plate tectonics; in one case, the constont transgression/regression, sue in large part of tectonic forces acts as a evolutionary pump forcing life to evolve. EXAMPLE: the evolution of plants from marine to terrestrial settings. Without plate tectonics, life would certainly be dramatically different.
~This is an edgucated guess. :) I hoped i helped. :)
