Biology Questions

tRNA abbreviated as A transfer RNA is an adaptor molecule composed of RNA, typically 76 to 90 nucleotides in length, that serves as the physical link between the mRNA and the amino acid sequence of proteins.

The oval window is connected directly to scala vestibuli.

Polygenic inheritance involves the determination of a particular phenotypic characteristic by many genes, called polygenes(group of genes influencing a quantitative characteristic), each having a small effect individually.

Height and skin colour in humans are examples of Polygenic characters.

Plants grow in size both in height and in girth. Enlargement of cells already present cannnot contribute much to the growth. Only addition of more and more cells could increase the size of the plant considerably.

In the above given options, Retrovirus is the only virus which is not associated with cancer. Here the viruses which are associated with different types of cancer. They are:

Hepatitis virus which is associated with Liver cancer

Papillomavirus which is associated with Cervical cancer

Epstein-Barr virus which is associated with Burkitt's lymphoma.

ACTH means Adrenal Corticotrophic Hormone.

CRH - Corticotrophin Releasing Hormone produced by hypothalamus stimulates the pituitary gland to release the ACTH which in turn produces corticosteroid hormones by adrenal glands.

Hence, the given statement is TRUE.

Sexual reproduction results in gametes that combine two cells from different individuals. Meiosis also produces gametes. Haploids contain one set of chromosomes in each of their cells. Diploids cells contain two chromosome sets. For plants, haploid and diploid cells divide via mitosis. The plants’ haploid phase is called the gametophyte, and the diploid phase is called the sporophyte.

Sporophytes are diploid plants that use meiosis to produce spores. These spores are haploid cells that grow into haploid gametophytes. Megaspores grow into female gametophytes, and microspores grow into male gametophytes.

Gametophytes are haploid plants that use mitosis to make haploid gametes. These gametes are female in the form of an ovum (egg) or male in the form of sperm.

DNA is called the blueprint of life because it contains the instructions needed for an organism to grow, develop, survive and reproduce. DNA does this by controlling protein synthesis. Proteins do most of the work in cells, and are the basic unit of structure and function in the cells of organisms.