Answer:
10
Explanation:
The cell cycle is composed of three states: interphase, cell division and resting.
The interphase is composed of 3 phases: G1, S and G2 (in this order). During this state the cell prepares itself for cell division. As part of the preparation the cell duplicates all its genetic material, that is, all its chromosomes. This duplication is done during the phase S.
During the meiotic cell division (composed of meiosis 1 and meiosis 2) a single diploid mother cell (with duplicated chromosomes) produces four haploid daughter cells. the meiosis 1 produces two haploid cells with duplicated chromosomes, and the meiosis 2 produces 4 haploid cells with normal chromosomes (no duplicated).
If a germ-line cell from a frog contains 10 picograms of DNA during G1, then this cell will have 20 picograms of DNA before the product of the first meiotic division, and will have 10 picograms at the begining of the meiosis 2 (i.e prophase II)
Answer:
<u>Some overall examples of biotic and abiotic factors are listed below.</u>
<u>Biotic factors: predators, competitors for food, competitors for space, parasitism, disease, animals, plants.</u>
<u>Abiotic factors: sunlight, wind, soil, atmosphere, water, temperature, humidity, UV radiation, salinity, pH levels.</u>
C. daughter cells from meiosis are not identical from parent cell
Answer:
Over 95% of incoming ultraviolet radiation is absorbed in :
A. The Stratosphere.
Explanation:
- Stratosphere is the second layer of the earth's atmosphere that lies next to the troposphere.
- This layer experiences very little turbulence of air and is very significant because of the presence of Ozone layer in it.
- The UV rays entering the Earth's atmosphere, photo dissociates ozone into O₂ and O. But these molecules quickly recombine to form ozone.Thus, stabilizing the concentration of ozone in the atmosphere.
- During this photo dissociation UV radiations loses much of its energy. Thus, 95% of incoming Ultraviolet radiation gets absorbed in the Stratosphere.
- Absorption of ozone UV radiation increases exponentially with the thickness of ozone layer.
Answer:
The correct answer is c) The first statement is true; the second is false.
Explanation:
To be able to perform its role, a hormone must bind a specific receptor in its target cell. The receptor can be located inside the cell (in cytosol) or in the surface of the cell (transmembrane receptor). By regulating the expression of the receptor, the target cell regulates the hormonal activity.
The number of hormone receptors in a cell is not constant, it can vary depending on sereral factors, such as the age of the organisms, the effect of several drugs, mutations or diseases.
