Biology Questions

Electrons are stripped from water in the light reactions of photosynthesis. Light provides the energy to excite electrons.

ATP and NADPH are both products of the light reactions and are used to power the Calvin cycle.

Mitochondria are present in both plant and animal cells.

A vitamin is an organic molecule that is an essential micronutrient that an organism needs in small quantities for the proper functioning of its metabolism.

There are 13 essential vitamins that our body need. They are categorized into 

1. Water soluble

2. Fat soluble

Water-soluble vitamins dissolve in water, which means these vitamins and nutrients dissolve quickly in the body. Unlike fat-soluble vitamins, water-soluble vitamins are carried to the body’s tissues, but the body cannot store them.

Water-soluble vitamins are Vitamin B1, B2, B3, B5, B12, B6, B7 & B9 and Vitamin C.

Fat-soluble vitamins are soluble in fats. They are absorbed by fat globules that travel through the small intestines and into the general blood circulation within the body. Unlike water-soluble vitamins, fat-soluble vitamins are stored in the body when they are not in use.

Fat-soluble vitamins are - Vitamin A, D, E and K.

23 chromosomes are in a human gamete.

Human somatic cells have 46 chromosomes(23 pairs) but a gamete(germ cell) gets half the amount, i.e. 23 chromosomes, (one from each pair). There will be half the number of chromosomes an organism has in its somatic cells (all other body cells except gametes).

For example in humans, the somatic cells contain 46 chromosomes which are the diploid number (2n) and each sperm and egg has 23 chromosomes where one of them is the sex chromosome.

Genes are located on DNA present in the chromosome. Chromosomes are present in the nucleus of the cell.

Cretinism is a disease caused by hypothyroidism(less thyroxine formation).The symptoms of the disease are retardation  of mental, physical and sexual developments. Potbellt, protruding tongue, dry skin etc are also indicative of this disease.