Biology (Part-V) (Railway)

• By relaxing the blood vessels and regulating nerve function in the muscles leading to the heart, Sarpagandha brings down high blood pressure.

• It also facilitates the circulation of blood through the heart passages at a normal, healthy pace.

• It is given that 2n = 18, n is the haploid number of chromosomes.

• Out of the 18 chromosomes that the cell has, it contains 2 sex chromosomes and 16 autosomes.

• When rate of respiration exceeds rate of photosynthesis, plant will stop growing and die gradually of starvation.

• Initially the plant will use its stored food reserves and when the food reserves exhausts it will eventually die.

• Plants store energy in the form of starch, instead of glucose, because starch is insoluble.

• This means that starch will not affect the water concentration inside cells and also it will not move away from the storage areas within the plant.

• A mutation is a change to a gene's DNA sequence to produce something different.

• Some mutations can lead to genetic disorders or illnesses.

• It is a part of the digestive system that makes up part of the long pathway that food takes through the body, called the gastrointestinal (GI) tract.

• It systematically breaks food down, absorbs nutrients, extracts water, and moves food along the gastrointestinal tract.

• It reduces the amount of waste that will need to be recycled or sent to landfills and incinerators.

• Sweet potato is cultivated by vegetative propagation.

• Growers take stem cuttings from the vines, which then root and form new storage roots.

• Stamen is the male reproductive part and it produces pollen grains that are yellowish in colour.

• The pistil is the female reproductive organ. It is present in the centre of a flower and is made of three parts - Stigma, ovary and style.

Mitosis:

• The process of cell division by which most of the cells divide for growth is called mitosis. In this process, each cell called the mother cell divides to form two identical daughter cells.

• The daughter cells have the same number of chromosomes as the mother cell.

Meiosis:

• Specific cells of reproductive organs or tissues in animals and plants divide to form gametes, which after fertilisation give rise to offspring.

• They divide by a different process called meiosis which involves two consecutive divisions.

• When a cell divides by meiosis it produces four new cells instead of just two. The new cells only have half the number of chromosomes than that of the mother cells.