Questions

Enzymes play an essential role in each living cell of our body. Enzymes are globular proteins that control biological reactions. These are of two types.

1. Intracellular enzymes

2. Extracellular enzymes

Intracellular enzymes are found inside the cell.

Extracellular enzymes act outside the cell.

Enzymes are produced by exocrine glands.

Digestive enzymes of diverse specificities are secreted by the salivary glands, stomach, pancreas, and the small intestine.

All of the genetic information in a cell was initially thought to be confined to the DNA in the chromosomes of the cell nucleus.

It is now known that small circular chromosomes, called extranuclear, or cytoplasmic, DNA, are located in two types of organelles found in the cytoplasm of the cell.

These organelles are the mitochondria in animal and plant cells and the chloroplasts in plant cells.

Chloroplast DNA (cpDNA) contains genes that are involved with aspects of photosynthesis and with components of the special protein-synthesizing apparatus that is active within the organelle.

Mitochondrial DNA (mtDNA) contains some of the genes that participate in the conversion of the energy of chemical bonds into the energy currency of the cell—a chemical called adenosine triphosphate (ATP)—as well as genes for mitochondrial protein synthesis.

During most of the cell cycle, interphase, the chromosomes are somewhat less condensed and are not visible as individual objects under the light microscope. However during cell division, mitosis, the chromosomes become highly condensed and are then visible as dark distinct bodies within the nuclei of cells. The chromosomes are most easily seen and identified at the metaphase stage of cell division and most of the chromosome images in this gallery are pictures of metaphase chromomosomes.

The cell division takes place in mitosis stage.

Shobha Rajadhyaksha, also known as Shobhaa De (born 7 January 1948), is the author of the book "Superstar India: From Incredible to unstoppable ". She is an Indian columnist and novelist. De is best known for her depiction of socialites and sex in her works of fiction, for which she has come to be known as the "Jackie Collins of India".