The human immunodeficiency virus (HIV) that causes the disease known as aids selectively infects helper T cells (CD4+).
This retrovirus also infects macrophages and dendritic cells. When CD4+ T cell numbers decrease below a critical level (due to the killing of this cells with different mechanisms), cell-mediated immunity is lost. As a result, the body becomes progressively more susceptible to infections, leading to the development of AIDS.
<span> HIV can be transmitted only via body fluids like blood, semen, pre-seminal fluid, rectal fluids, vaginal fluids, and breast milk, which means that people usually get or transmit HIV through sexual behaviours and use of the needle. For HIV infection, these fluids must come in direct contact with a mucous membrane or damaged tissue. Another way is to be directly injected into the bloodstream (from a needle for example).</span>
D - understanding the different ways people live, their culture, will break down the wall of judgment and discrimination, therefore people lear to accept each other and get along
Crossing over happens in Meiosis 1 only. In Prophase 1 a cells chromatin (chromatin = chromosomes that have not condensed yet) condense and pair up forming homologous chromosomes (paired = XX (2 chromosomes together)). When this happens segments/ alleles of the chromosomes pairing up swap over. This creates genetic diversity as each chromosome is different, it has parts from its pair. This leaves every chromosome unique and individual.
I hope this helps, sorry some of the vocab is rather technical. By the way I would suggest watching the
'Crash Course: Meiosis' on YouTube, this really helped me when I was learning this topic. :D
Sequential cleavage from the non-reducing terminals of glucose molecules is required for both glycogen degradation and polysaccharides hydrolysis.
Why non-reducing end is selected for digestion?
A polysaccharide's non-reducing end is the one where an anomeric carbon participates in the glycosidic connection. The elimination of carbohydrate remnants one at a time out from the non-reducing terminal occurs during glycogenolysis and polysaccharides hydrolysis.
- For example, several enzymes are involved in glycogenolysis in the liver and muscle.
- An example of such an enzyme is glycogen phosphorylase, which catalyzes the successive dissociation of the alpha 1->4 glycosidic bond that connects two glucose molecules at a non-reducing terminal of glycogen. The last glucose residue is eliminated as alpha-D-glucose 1-phosphate.
That is why non-reducing end of glucose is chosen for digestion or breakdown of the carbohydrate polymer.
Learn more about non-reducing here:
brainly.com/question/1832596
#SPJ4
Answer: D. Gymnosperms
Explanation: The Gymnosperms ( also known as Acrogymnospermae) are a group of seed-producing plants in which the ovules or seeds are not enclosed in an ovary. Examples of Gymnosperms are spruces, firs, and ginkgoes and pines.
