<span>Cell membranes protect the cells that is why they are called the gatekeepers of the cell. A cell membrane can be internal or external like that of the case of eukaryotic cells with internal cell membrane. It is mostly made up of glycerophospholipids. This compound like other lipids is also soluble in water however, their unique geometry allows them to aggregate into bilayers without too much energy input. Cholesterol can also be found in the cell membranes however, it is not as abundant as the glycerophospholipids.</span>
Answer:
The reason why only 3 out of the 22 possible autosomal trisomies are seen in newborns, is because the rest of them are chromosomal abnormalities not compatible with life and thus an spontaneous abortion occurs. The embryos suffering from these trisomies do not survive for more than a few weeks in the uterus, so the miscarriage often goes unnoticed for the mother as she may not have realized she was pregnant.
The only trisomies that are allow fetuses to be born are: Patau Syndrome (trisomy 13), Edwards Syndrome (trisomy 18), and Down Syndrome (trisomy 21). Out of these three, people with Down Syndrome have the largest life expectancy.
Gregor Mendel, through his work on pea plants, discovered the fundamental laws of inheritance. He deduced that genes come in pairs and are inherited as distinct units, one from each parent. Mendel tracked the segregation of parental genes and their appearance in the offspring as dominant or recessive traits.
Answer:
Prokaryotes are the most primitive organism that exists on earth. They have the simplest form of body organization and they do not perform complex tasks.
The eukaryotic cell has nucleus in it and they have more complex machinery in their body to perform various tasks accordingly.
The nucleus of the prokaryotes are not enclosed in the nuclear membrane and it is dissolve in the cytoplasm. It lacks true nucleus.
Eukaryotes have nucleus enclosed inside nuclear membrane.