Scientists
can also glimpse the awful effects of Alzheimer's disease when they look at
brain tissue beneath the microscope:
Alzheimer's tissue has numerous fewer nerve
cells and synapses than a well brain.
<span>
<span>Plaques, unusual
clusters of protein particle, which are construct up between nerve cells.</span>
</span>
<span>
<span><span>Dead and dying nerve cells contain tangles,</span> which
are produce of twisted strands of a further protein.</span>
</span>
<span>Scientists
are not absolutely sure what causes cell death and tissue deficiency in the
Alzheimer's brain, but plaques and tangles are key suspects.</span>
Answer:
Dietary fiber refers to a group of substances in plant foods which cannot be completely broken down by human digestive enzymes. This includes waxes, lignin and polysaccharides such as cellulose and pectin. Originally it was thought that dietary fiber was completely indigestible and did not provide any energy.
Explanation:
That would be : adenine, thymine, guanine, and cytosine.
<span>Though both are unicellular, bacteria doesn’t possess a nucleus or cell organelles, except ribosomes, whereas amoebas possess a well-defined nucleus and all essential cell organelles.
Bacteria are prokaryotic. They do not have membrane-bound organelles. Their DNA is also not enclosed by an envelope. They do not possess a true nucleus.
Amoeba, however, is eukaryotic. Amoebas have a true nucleus, and it is enclosed by an envelope. The organelles are also membrane-bound.</span>
