Cell

The smallest structural and functional unit of an organism, typically microscopic and consisting of cytoplasm and a nucleus enclosed in a membrane. Microscopic organisms typically consist of a single cell, which is either eukaryotic or prokaryotic.

Cell theory

Image result for cell theory definition

In biology, cell theory is a scientific theory which describes the properties of cells. These cells are the basic unit of structure in all organisms and also the basic unit of reproduction.

Cell membrane

The semipermeable membrane surrounding the cytoplasm of a cell.

Nucleus

 a dense organelle present in most eukaryotic cells, typically a single rounded structure bounded by a double membrane, containing the genetic material.

Eukaryote

an organism consisting of a cell or cells in which the genetic material is DNA in the form of chromosomes contained within a distinct nucleus. Eukaryotes include all living organisms other than the eubacteria and archaebacterial.

Vacuole

a space or vesicle within the cytoplasm of a cell, enclosed by a membrane and typically containing fluid.

Lysosome

a space or vesicle within the cytoplasm of a cell, enclosed by a membrane and typically containing fluid.

 Cytoskeleton

a microscopic network of protein filaments and tubules in the cytoplasm of many living cells, giving them shape and coherence.

Centriole

a minute cylindrical organelle near the nucleus in animal cells, occurring in pairs and involved in the development of spindle fibers in cell division.

Ribosome

  a minute particle consisting of RNA and associated proteins, found in large numbers in the cytoplasm of living cells. They bind messenger RNA and transfer RNA to synthesize polypeptides and proteins.

Endoplasmic Reticulum

 a minute particle consisting of RNA and associated proteins, found in large numbers in the cytoplasm of living cells. They bind messenger RNA and transfer RNA to synthesize polypeptides and proteins.

Golgi Apparatus

a complex of vesicles and folded membranes within the cytoplasm of most eukaryotic cells, involved in secretion and intracellular transport.

Chloroplast

(in green plant cells) a plastid that contains chlorophyll and in which photosynthesis takes place.

Mitochondrion

Cell Wall

a rigid layer of polysaccharides lying outside the plasma membrane of the cells of plants, fungi, and bacteria. In the algae and higher plants, it consists mainly of cellulose.

Lipid Bilayer

The lipid bilayer is a thin polar membrane made of two layers of lipid molecules. These membranes are flat sheets that form a continuous barrier around all cells.

Selectively Permeable

All cells are enclosed with a cell membrane. A selectively permeable cell membrane is one that allows certain molecules or ions to pass through it by means of active or passive transport.

Diffusion

 the intermingling of substances by the natural movement of their particles.

Facilitated Diffusion

Facilitated diffusion (also known as facilitated transport or passive-mediated transport) is the process of spontaneous passive transport (as opposed to active transport) of molecules or ions across a biological membrane via specific transmembrane integral proteins.

Aquaporin

Aquaporin are integral membrane proteins from a larger family of major intrinsic proteins (MIP) that form pores in the membrane of biological cells.

Osmosis

a process by which molecules of a solvent tend to pass through a semipermeable membrane from a less concentrated solution into a more concentrated one, thus equalizing the concentrations on each side of the membrane.

Isotonic

denoting or relating to a solution having the same osmotic pressure as some other solution, especially one in a cell or a body fluid.

Hypertonic

having a higher osmotic pressure than a particular fluid, typically a body fluid or intracellular fluid.

Hypotonic

having a lower osmotic pressure than a particular fluid, typically a body fluid or intracellular fluid.

Osmotic Pressure

 the pressure that would have to be applied to a pure solvent to prevent it from passing into a given solution by osmosis, often used to express the concentration of the solution.

Tissue

any of the distinct types of material of which animals or plants are made, consisting of specialized cells and their products. 

Organ

 a part of an organism that is typically self-contained and has a specific vital function, such as the heart or liver in humans.

Organ system

 In biology, an organ system is a group of organs that work together to perform one or more functions. Each does a particular job in the body, and is made up of certain tissues.

Receptor

 an organ or cell able to respond to light, heat, or other external stimulus and transmit a signal to a sensory nerve.