Operons are gene regulatory mechanisms that involve promoting and repressing genes that are involved in the metabolism of organic substances (i.e. sugars). Living organisms have the innate ability to metabolize glucose as the main source of energy. Although, in the absence of glucose, the organism must "learn" to use sugars other than glucose (such as lactose) in order to survive.
For instance, in the <em>lac </em>operon:
In the absence of glucose, various regulatory proteins promote the transcription of the gene related to the metabolism of lactose. This will ultimately lead to the production of the enzyme beta lactosidase which will enable the organism to use lactose as energy in the absence of glucose. This will therefore increase the chances of the organism for survival and will be naturally selected for evolution.
1. Osmosis
Recall that osmosis specifically refers to <em>water specifically</em> moving through a membrane in and out. In this case, water is moving out of cells through the cell membrane into the water.
2. Diffusion
Diffusion is the movement of molecules according to a concentration gradient. Because of this, diffusion is a form of passive transport because it does not require energy. In this case, oxygen is moving freely from the lungs into the bloodstream. This process does not take energy, and because oxygen is a small, non charged molecule, it can diffuse freely, therefore the process is diffusion.
3. Active Transport
The sodium pump is a prime example of active transport. Remember that when pumps are involved, it essentially means whatever is moving cannot move by itself, but rather needs force behind it, which is provided by the pump. Because sodium cannot simply move out of a nerve cell, this is a form of active transport.
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Answer:
its gonna be D
Explanation:
It can't be A, since cells only divide once they are past interphase
It can't be B, becuase cell division does have an order
It can't be C, becuase a dying cell is still a functioning one
And it is D becuase daughter cells are haploid, while parent cells are diploid
What term describes a species whose removal would affect many other species, both directly and indirectly: keystone species
Solarimeters are the instruments that measure solar radiation