Biology Test 142

Gibberellins are plant hormones that regulate various developmental processes. Applications of Gibberellins are-

Elongation of genetically dwarf plants, bolting and flowering in long-day plants Substitution of cold treatment, breaking of dormancy, parthenocarpy hormone tried with leaf and root culture of digitalis, showed higher production of digoxin, spraying juvenile conifers with gibberellins hastens the maturity period, the leading to early seed production, spraying sugarcane crop with gibberellins increase the length of the stem.
Hence, the correct option is (B).

Agarose gel electrophoresis is used to segregate DNA fragments according to the mass and size. Ethidium bromide is the fluorescent stain used in this technique. Ethidium bromide, when exposed to ultraviolet light, produces a fluorescent effect. Hence the DNA tagged by it can be traced quickly on the transparent gel.

Hence, the correct option is (A).

The demersal zone is the part of the sea or ocean (or deep lake) consisting of the part of the water column near to (and significantly affected by) the seabed and the benthos. The demersal zone is just above the benthic zone and forms a layer of the larger profundal zone.

Hence, the correct option is (C)

The eight steps of the citric acid cycle are a series of redox, dehydration, hydration, and decarboxylation reactions. Each turn of the cycle forms one GTP or ATP as well as three NADH molecules and one FADH2 molecule, which will be used in further steps of cellular respiration to produce ATP for the cell.

Hence, the correct option is (B).

The oropharynx is the middle compartment of the pharynx, i.e. throat; it is the region of the throat between the nasopharynx (top compartment) and hypopharynx (bottom compartment). The oropharynx includes the tonsils, tongue base, soft palate, and pharyngeal walls.

Hence, the correct option is (A).

Placental transfer of maternal IgG antibodies to the fetus is an important mechanism that provides protection to the infant while his/her humoral response is inefficient. IgG is the only antibody class that significantly crosses the human placenta.

Hence, the correct option is (A).

A Balbiani ring is a large chromosome puff. Balbianirings are diffused uncoiled regions of the polytene chromosome that are sites of RNA transcription and protein synthesis.

Hence, the correct option is (B).

Mitochondria were named by Carl Benda in 1898. Mitochondria are membrane-bound cell organelles (mitochondrion, singular) that generate most of the chemical energy needed to power the cell's biochemical reactions. Chemical energy produced by the mitochondria is stored in a small molecule called adenosine triphosphate (ATP).

Hence, the correct option is (A).

Endangered species, any species that is at risk of extinction because of a sudden rapid decrease in its population or a loss of its critical habitat. Previously, any species of plant or animal that was threatened with extinction could be called an endangered species.

Hence, the correct option is (C).

Free central is found in syncarpous gynoecium. In it, the ovary is unilocular and the ovules are borne on the axis in the center of the ovary. The septum is absent in the ovary.  For example, Primrose, Dianthus (Caryophyllaceae). 

Hence, the correct option is (B).