-Homologous structures in different organisms
Answer:
using multiple origins of replication on each chromosome
Explanation:
Answer:
Watson and Crick proposed the double helical model of DNA.
Explanation:
- This model says that DNA exist as double helix. It has two polynucelotide strands running in opposite direction i.e the strands are anti-parallel.
- Each polynucleotide strand is made up of several nucleotide liknked together by phophodiester bonds.
- The two strands are not coiled upon each other but the double strand is coiled upon itself around a common axis like the spiral stair case. Here base pairs forms the stairs and backbone of two strands form railing. Back bone contains sugar and phosphate.
- The base pairing is specific, adenine always pairs with thymine and guanine always pairs with cytosine. Thus if we see any base pair, it consists of one purine and one pyrimidine.
- The two strands of DNA thus show complementary base pairing.
- The strands are held together because of hydrogen bonding between the bases in opposite strand.
- One full helical turn involves ten base pairs and the base pairs are stacked 3.4 A apart.
- This form is called as B-form of DNA.
Answer:
Atmosphere and geosphere is the part of the earth which is utilized in the nitrogen cycle.
Explanation:
In nitrogen cycle, the nitrogen which is present in the atmosphere comes down to the earth surface through rainfall. This nitrogen is absorbed by the earth and taken by roots of plants. Some amount of nitrogen is taken by many bacteria such as denitrifying bacteria which converts the soil nitrogen into atmospheric nitrogen and the nitrogen goes again to the atmosphere.
Aldosterone increases the reabsorption of sodium ions bringing more back into the blood.
<span>This is the main mineralocorticoid hormone of the adrenal gland. The function of the aldosterone is in the homeostatic regulation of blood pressure, plasma sodium (reabsorption) and potassium levels (excretion).</span>
