Answer:
Because they do not live in the extreme environments.
Explanation:
Cell membrane has a vital role in separating the external environment of cell from its external environment. Just like eukaryotic cell, cell membrane of bacteria is also composed of proteins and lipids (phospholipids).
If we compare the structure of ancient bacteria's and modern bacteria's cell membrane then we notice that in archaebacteria or ancient bacteria the phospholipids of cell membrane are linked with ether (means they have glycerol backbones). whereas in modern bacteria they are linked through ester linkages.
So, the stronger glycerol backbones give the archaebacteria more stable cell membranes through which they are able to resist harsh environmental stresses like salt lakes, volcanic stress, boiling mud and hot springs. As modern bacteria do not always have to live under such stresses thats why they donot have ether-linked cell membrane.
Hope it helps!
Lipids and proteins
(however our bodies mostly break down sugars e.g. glucose and are the only molecules we can break down without the need for oxygen)
There are 4 chromosomes that are visible at the beginning of Mitosis.
Answer:
Because of the chemical and structural nature of the phospholipid lipid by layer the lipid soluble molecule can just pass the lipid membrane and some small molecules can also pass freely.
Explanation:
as we know that the homeostasis is an important process for a living cell to maintain it self so for the the exchange of materials between the external and internal environment is must so for that it exchange material with the outside environment of the cell.as the cell membrane is semipermeable(mean allow some molecule to pass(lipid soluble) and not others(lipid non soluble) to pass through the membrane.the cell membrane is selectively permeable due to its nature and chemical composition the chemical composition is lipid and phosphate and glycerol(head) with fatty acid that may b saturated or unsaturated(tail).so finally all those molecule which are polar can not pass through the membrane and non polar can pass the membrane.The size of the molecule is also a factor on which the permeability depends.
Answer:
Streptococcus mutans.
Explanation:
Streptococcus mutans is the bacteria (it is still a microorganism) that predominatly causes tooth decay. It is present in all areas of the mouth.
