Answer:
Plasmolysis occurs when a <u>plant </u>cell is inmersed in a <u>3X salt solution</u>.
Explanation:
Plasmolysis is a phenomenon only observed in plant cells, and consists of cell dehydration accompanied by separation of the membrane and cell wall when the cell is exposed in a hypertonic environment.
When a plant cell is in a hypertonic solution —such as 3X salt solution— the permeability of its membrane allows water to escape, so the cell dehydrates and reduces its size. The cell wall is rigid and maintains its shape, but the cell membrane separates from it, which is known as plamolysis.
The other alternative answer combinations are not correct because:
- <em>Plamolysis does not occur in </em><u><em>animal cells</em></u><em>.
</em>
- <u><em>Pure water </em></u><em>does not produce plasmolysis.</em>
I believe it's Sympatric Speciation.
Hope I helped! ( Smiles )
:) !! hope this helps ! have a great day. :D
Answer:
a) true
Explanation:
It is absolutely right that in mammals dosage compensation occurs due to X-inactivation in females. It happens because in mammals like humans, females have XX and males have XY as allosomes. Because of the presence of two X chromosomes, each gene is present in 2 copies in females but in males only 1 copy is present as they have only one X chromosome. So in order to compensate for this kind of difference, one of the female X chromosomes undergoes inactivation and this phenomenon is known as dosage compensation.
The X chromosome undergoes inactivation because of its DNA modification and acts very different from other X chromosomes. Several methyl groups are added to the DNA of such X chromosome so as to inactivate it. In general such inactivated X chromosome is known as bar body which appears like a darkly stained structure.
Note: In other lower organisms like drosophila and C. elegans other mechanisms of dosage compensation exist.
In drosophila rather than inactivation of one chromosome in female, the transcription rate of one X chromosome of male is doubled so that it could produce as much transcripts as two X chromosomes of female are producing.
In C. elegans, both the X chromosomes are active but partially. The transcripts produced by two X chromosomes of female equalize the transcripts produced by one X chromosome of hermaphrodite counter part.
Meiosis is a process where a single cell divides twice to produce four cells containing half the original amount of genetic information. These cells are our sex cells – sperm in males, eggs in females. During meiosis one cell? divides twice to form four daughter cells.