<span>When Prophase is occur, during this stage, changes occur both in the cytoplasm and in the nucleus. Within the nucleus, the chromatin fibers become more tightly coiled and folded, forming discrete chromosomes that can be seen with the light microscope. The nucleoli disappear. Each duplicated chromosome appears as two sister chromatids joined together, with a narrow waist at the centromere.In the cytoplasm, the mitotic spindle begins to form as microtubules rapidly grow out from the centrosomes which begin to move away from each other.</span>
<u>Answer:</u>
In ecology, catastrophes permanently alter the physical structure of the existing environment.
<u>Explanation:</u>
- The ecological disturbances include flood, strom, plague, fires, earthquakes, tsunami, volcanic eruptions, climatic change and impact of humans on the environment like deforestation ,nuclear testing etc.
- These factors can have a visible impact on the structure of the earth and permanently alter the environment.
- The visible effects of these disturbances are global warming, extinction of selective species, change in the course of rivers, submergence of coastal areas, sudden movement of the tectonic plates and formation of sudden cracks on the earth's crust.
d. carbohydrates store energy for a long time :)
Explanation:
These questions are related to the extraction of DNA using detergents and ethanol.
1. Consistency and texture- the extracted DNA is white, spongy and moist or slime in nature.
2. Salt is used during the extraction process as the DNA is negatively charged molecule and to neutralize the negative charge which will allow the formation of precipitate.
3. The DNA is soluble in aqueous solution as the DNA is a negatively charged molecule therefore the negative charge makes it a polar molecule and it can form the interactions in the aqueous solution.
4. RNA could be present in the aqueous solution along with the DNA as both are the nucleic acid.
5. The base-pairing rule was suggested by the Chargaff who proposed that Adenine binds thymine and guanine binds cytosine.
5. The binding of adenine to thymine involves two hydrogen bonds and between guanine to cytosine involves three hydrogen bonds.
Chlorophyll, which gives plants their green color, enables plants to turn sunlight, CO2, water, and a few minerals into new plant tissue through a process called photosynthesis<span>.</span>
