Some protozoans have special organelles called contractile vacuoles that continually eliminate excess water from the cell. the p
resence of these organelles tells you that the intracellular environment of the protozoan is _______________ relative to the extracellular environment.
The ability of an extracellular solution to make water move into or out of a cell by osmosis is known as its tonicity. Tonicity is concern for all living things, especially in in organisms lacking cell wall, <em>Paramecium</em> is one such protozoan. It has specialized structures called contractile vacuoles. A contractile vacuole collects excess water from the cell and release it out, keeping the cell from lysing as it takes on water from extracellular environment which hypotonic (a lower osmolarity than the cell’s cytoplasm) as compared to hypertonic environment inside <em>Paramecium</em>.
They can use a technique called Polymerase Chain Reaction. This can be done in a test tube or even in a organism. It usually relies on something called Thermostable DNA Polymerase and Taq polymerase. It requires DNA primers that is designed specifically for that DNA region (interest).
Why is internal Fertilisation important to animals?
Internal fertilization has the advantage of protecting the fertilized egg from dehydration on land. The embryo is isolated within the female, which limits predation on the young.
