Cell- is a structural and functional unit of living beings that consists of a membrane-covered mass of protoplasm. Cell was discovered by Robert Hooke in 1665.
Cytology- is the study of the form and structure of cells as well as their organelles with the help of a microscope.
Cytoplasm- A part of protoplasm filled within the space of nuclear membrane and cell membrane having cell organelle.
Hyaloplasm- Cytoplasm without cell organelle.
Compound- A substance that is formed by the chemical combination of two or more than two substances.
Protoplasm- The living substance present in the living cells. The cytoplasm and nucleoplasm together form protoplasm.
Amino Acid- Organic compounds with carboxyl and amino groups. These are the basic building block of protein.
Carbohydrate- Organic molecules containing carbon, hydrogen and oxygen in the ratio of CH2O. Example- glucose, starch, glycogen, sugar, cellulose.
Nucleus- A dense body in the centre of the cell having the nucleoplasm and chromosomes. It was discovered by Robert Brown in 1831 and is commonly called as ‘director of the cell‘.
Monosaccharide- Simple sugar, not digestible by hydrolysis. Example- glucose, fructose.
Disaccharide- A complex molecule of sugar having two molecules of glucose.
Polysaccharide- These are composed of several molecules of glucose joined together by glycosidic bonds.
Mucopolysaccharides- These are polysaccharides formed galactose and mannose. The most common example is mucilage which is produced by the plant as a slimy substance.
Callus- An unorganized and undifferentiated mass of tissue.
Totipotency- It is the inherent capacity of living cells to develop into different kinds of cells.
Adenosine Triphosphate (ATP)– An energy-rich compound that is found in all cells and serves as an energy source for various cellular functions.
Aster- Bundle of microtubule fibres radiating out from each cell pole during metaphase.
Basal Body- Cylindrical microtubule containing cell organelle lying at the base of cilia and flagella and similar in structure to centrioles.
Simple Proteins- These are the proteins that are composed of amino acids only. They form small globular molecules soluble in water or larger globular molecules insoluble in water.
Conjugated Proteins- These are formed by the binding of a simple protein with a non-protein called the prosthetic group. Example- nucleoproteins.
Nucleic Acid- Macromolecule or polymer of nucleotides in an unbranched chain; DNA and RNA.
Ribonucleic Acid (RNA)- A nucleic acid containing phosphate, ribose sugar and the nitrogen base, uracil, besides adenine, guanine and cytosine. Functions in protein synthesis.
Deoxyribonucleic Acid (DNA)- Genetic material; deoxyribose containing a nucleic acid that stores hereditary information in the form of code words and makes chromosomes and genes.
Purine- It is a nitrogenous base having 9 membered double ring.
Pyrimidine- It is a base that has a single 6 membered ring.
Translation- The synthesis of protein according to the information coded on mRNA.
Transcription- The process of RNA synthesis on a DNA template.
Cell Membrane- also called plasma membrane or plasmalemma is a delicate, thin elastic and semi-permeable membrane that surrounds all living cells.
Permeable Membrane- is one that allows all the substances (solvents) to pass through it.
Semi-permeable Membrane- also called selectively permeable membrane is one that allows only some selected solvents to pass through it.
Impermeable- A membrane that does not allow any substance to pass through it.
Osmosis– The tendency of water to move across a differentially permeable membrane from a dilute to a concentrated solution.
Differentially Permeable Membrane- Selectively permeable membranes found in living systems.
Diffusion- It is the movement of particles from a medium of higher concentration to a medium of lower concentration till the concentration of both media become equal.
Endocytosis- Intaking of large-sized liquid or solid macromolecules inside the cell through the plasma membrane.
Exocytosis-Expelling of cellular secretions or wastes out of the cell through the plasma membrane.
Pinocytosis- It is the process of taking liquid substance by a plasma membrane.
Phagocytosis(cell eating)- It is the process of engulfing solid particles.
Active Transport- It is the movement of the ions or molecules across a membrane against concentration gradients.
Passive Transport- It is the movement of ions or molecules across a membrane from high to low concentration along the chemical or electrochemical gradient.
Tonicity- The external osmotic environment of a cell forms the tonicity.
Isotonic- When the relative concentration of water and solutes on either side of the cell membrane is the same, the solution is called isotonic.
Hypertonic- Solution exerting greater osmotic pressure than the cytoplasm.
Hypotonic- Solution exerting lesser osmotic pressure than the cytoplasm.
Exosmosis- If during osmosis the water or solvent from the living cell diffuses out, the phenomenon is termed exosmosis.
Endosmosis-If during osmosis, the flow of water from surroundings into a living cell take place, the process is known as endosmosis.
Plasmolysis- As a result of exosmosis, the cytoplasm of the cell gets shrunk and moves towards the centre of the cell.
Crenation- The shrunken appearance caused by exosmosis in erythrocytes.
Lysosome- is a cell organelle that releases enzymes to hydrolyze the cell contents. Lysosomes also called suicide bags.
Cytokinesis- The division of cytoplasm during cell division.
Prokaryote- Organisms lacking a nucleus and membrane-bounded organelles in their cells. Example- bacteria, blue-green algae.
Eukaryotes- Organisms such as plants and animals, with a well-defined nucleus enclosed in a nuclear envelope and having one or more membrane-bounded organelles in their cells.
Tonoplast- The membrane surrounding the vacuole.
Suberin- A water-proofing material secreted by cork cells and endodermal cells.
Stroma- The granular matrix of the chloroplast.
Centromere- Region of the chromosome at which spindle fibril is attached during cell division.
Chlorophyll- Green photosynthetic, light-capturing pigment of plant cells, typically located in the chloroplasts.
Chloroplasts- are green plastids.
Chromoplasts- Yellow, orange, or red-coloured plastids containing various pigments like carotenes and xanthophyll, etc.
Leucoplats- A colourless plastid that stores proteins, lipids and starch.
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