Biology Test 2

DNA is formed from chain of nucleotides, where each nucleotide has phosphoester bond.
A phosphodister bond is found in both DNA and RNA. It is the linkage of 3' carbon atom of one sugar molecule with the 5' carbon atom of another sugar molecule. The sugar is deoxyribose in DNA and ribose in RNA.

It is a process by which heredity information from a gene is used to synthesize functional gene products, usually proteins. These proteins are expressed as phenotypes in an organism as they control shape or may act as enzyme. Thus, at molecular level, gene expression is the mechanism by which a gene is able to express itself in the phenotype of an organism.

Wobbles hypothesis was proposed by Crick in 1966 to explain the degeneracy of the genetic code. Wobble’s hypothesis explains why multiple codons can code for a single amino acid.

Genetic drift leads to evolution by a change in relative frequency. It most common in small populations while in large populations the chances of finding a mate are higher.

The liver is the storehouse of glycogen but alcohol causes the storage of fat in the liver. It causes fatty liver syndrome. Gradually the liver hardens and dries up as its cells are replaced by a fibrous tissue. This kind of liver degeneration is called cirrhosis.

Eye of octopus and mammals i.e., cephalopods do not share homology but they share analogy. They are analogous structure, i.e., they are structurally similar and have the same function but they have evolved from different origins (different ancestors)

Population of tiger in India has decreased because of many reasons like their existence in geographically isolated populations (they do not interact with each other due to physical barriers), hunting and habitat destruction (humans hunt tiger for earning prestige, etc. humans destroy their habitat i.e., jungles to meet the needs of urbanization), and genetic drift by bottleneck effect wherein a chance event reduces the size of population and the populations that survive get allele frequencies different from that of the original population so the population’s gene pool lowers sharply.

Botulism is a rare fatal disease caused by a toxin produced by Clostridium botulinum. Food poisoning is caused by eating food that contains the botulism toxin produced by Clostridium botulinum.

Platelets transfusion is associated with HIV transmission whereas transfusion of option a, b and c, is not associated with HIV transmission because procedures involved in processing these products either inactivates or removes the virus.