<span>Answer:The blood-brain
barrier (BHE)
BHE is a barrier that's highly permeability selective and protects
the central nervous system from potential dangers like viruses, bacteria and parasytes that may be circulating int he blood. <span>It is composed of endothelial cells, astrocytes, pericytes.</span></span>
The genes in a population give forth the genetic variability across a population (genotypes). In addition, occasional mutations of these genes in a population increase this genetic variability. Hovever, natural selection only favours reproduction of individuals with genes that are favourable in the environment/habitat. Therefore, natural selection has no foresight but is rather pegged on being an ‘opportunistic’ process.
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Answer:
The absorbance of 460nm light by the treatment solutions was the test performed by the student.
Explanation:
Cell membranes are phospholipid bilayers which are mostly displayed by the 'fluid mosaic model' which consists of proteins, carbohydrate polymers and glycoproteins making them able to move around quite freely amongst the phospholipids. A normal membrane permeability test involves investigating the effects of a named variable on the membrane permeability of any vegetable such as beetroot whose biological name is Beta Vulgaris. The variables to investigate are the influence of solvents and temperature because these factors can change the fluidity of the membrane. Beetroot is an important item for this test because of the distinctive betalains pigment that its stem tuber contains. These pigments form an important signal indicating membrane fluidity as they are usually contained in the vacuole of intact beetroot cells. An instant or constant increase in membrane fluidity will cause the pigment to spill out of the cell, and the amount of pigment can be measured simply by using a colorimeter.
The above description is performed under the test of The absorbance of 460nm light by the treatment solutions.
Answer:
Explanation:
Active transport is the movement of molecules or substance from a region of lower concentration to a region of higher concentration across a cell membrane against the concentration gradient.
Active transport requires cellular energy and are of two types:
primary active transport that uses adenosine triphosphate (ATP), and secondary active transport that uses an electrochemical gradient.
Active transport helps in the uptake of glucose in the intestines.
Cotransport or secondary active transport is the movement of molecules across a membrane it uses electrochemical potential difference that is created by pumping ions in or out of the cell.
Cotransport helps in the transport of glucose across the cell membrane.