Railway Science (Biology – Cell : Basic Unit of Life)

Lysosomes - It helps in the digestion, removes wastes and digests dead and damaged cells. Chloroplast - Present only in plant cells and contains a green-coloured pigment known as chlorophyll.
Golgi body - It is mainly involved in secretion of the cells and intracellular transport. Mitochondria (Powerhouse of the Cell) - An oval -shaped, membrane-bound organelle.

Cell - Discovered by Robert Hooke in 1665. The longest cell - Nerve cell. The largest cell in humans - Female ovum. Single-cell organisms; such as bacteria, protozoa, and other microorganisms are termed unicellular, while plants and animals that contain many cells are termed multicellular.

ATP (Adenosine triphosphate) is the principal molecule for storing and transferring energy in cells, which captures chemical energy obtained from the breakdown of food molecules and releases it to fuel other cellular processes.
Pyruvate is produced by glycolysis in the cytoplasm, but pyruvate oxidation takes place in the mitochondrial matrix (in eukaryotes).
Glucose has the molecular formula C₆H₁₂O₆ . It is found in fruits and honey and is the major free sugar circulating in the blood of higher animals.

4 stages of mitosis : Prophase - The chromosomes condense and become visible. The spindle fibers form and attach to the chromosomes. Metaphase - The chromosomes line up along the equatorial plate.
Anaphase - The sister chromatids separate and are pulled to opposite poles of the cell by the spindle fibers. Telophase - The chromosomes uncoil and the nuclear envelope reforms. The cell then divides into two daughter cells.

Rod and Cone cells : Located in the retina (a layer at the back of the eye). Rod cells : Responsible for vision at low light levels (Scotopic vision). They have a visual purple pigment called rhodopsin.
Cone cells : Active at higher light levels (Photopic vision), and are responsible for color vision as well as eye color sensitivity. They have a visual violet pigment called iodopsin.

All of the organelles in eukaryotic cells, such as nucleus, endoplasmic reticulum and mitochondria are located in the cytoplasm. Cytoplasm is composed of water, salts and proteins. The nucleus was discovered in the year 1831 by Robert Brown. Components (organelles) present in the cytoplasm - mitochondria, golgi bodies, ribosomes.

Cells store its energy in the form of Adenosine triphosphate (ATP) which can release energy whenever cells use it during the metabolic process of the cell cycle. RNA (Ribonucleic acid) - A molecule that helps in the synthesis of proteins in our body. Deoxyribonucleic acid (DNA) - The molecule that carries genetic information for the development and functioning of an organism.

This membrane is made up of proteins and lipids and is present in both plant and animal cells. It is called a selectively permeable membrane. The nerve cell (neuron) is the basic unit of communication in the nervous system and divided into three major parts of this microscopic structure are the cell body, dendrites, and axons. Organelles - A small structure in a cell that is surrounded by a membrane and has a specific function.

The origin of the word is derived from the Greek word 'kytos' which means 'hollow container'. Cell discovered by Robert Hooke (1665). Serology - Study of serum and other body fluids. Cytoplasm is the gelatinous liquid that fills the inside of a cell. Etiology in medicine is defined as the determination of a cause of disease or pathology.

It is a type of plant tissue that is found in the growing tips of plants (responsible for the growth of plants). Example : Apical.