CELL:-

The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life .The cell was discovered by Robert Hooke in 1665. The word cell comes from the Latin cellula, meaning "a small room". The descriptive term for the smallest living biological structure was coined by Robert Hooke in a book he published in 1665 when he compared the cork cells he saw through his microscope to the small rooms monks lived in

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Multicellular organisms

Unicellular organisms

Category Animal Cell Plant Cell

Shape: Round (irregular shape) Rectangular (fixed shape)

Chloroplast: Animal cells don't have chloroplastsPlant cells have chloroplasts because they make their own food

Vacuole:One or more small vacuoles (much smaller than plant cells).

One, large central vacuole taking up 90% of cell volume.

Centrioles: Present in all animal cells Only present in lower plant forms.

Plastids: Absent Present

Cell wall: Absent Present

Plasma Membrane: only cell membrane cell wall and a cell membrane

Lysosomes: Lysosomes occur in cytoplasm. Lysosomes usually not evident.

IMPORTANT PARTS OF

ANIMAL CELL

CELL MEMBRANE

CYTOPLASM

NUCLEUS

ENDOPLASMIC RECTICULUM

GOLGI APPARATUS

LYSOSOMES

MITOCHONDRIA

VACUOLES

CELL MEMBRANEThe cell membrane or plasma membrane is a biological membrane that separates the interior of all cells from the outside environment. The cell membrane surrounds the cytoplasm of a cell and, in animal cells, physically separates the intracellular components from the extracellular environment. Fungi, bacteria and plants also have the cell which provides a mechanical support for the cell and precludes the passage of larger molecules. The cell membrane also plays a role in anchoring the cytoskeleton to provide shape to the cell, and in attaching to the extracellular matrix and other cells to help group cells together to form tissues. On December 29, 2011, chemists at Harvard University reported the creation of an cell membrane

CYTOPLASMThe cytoplasm is the gel-like substance residing between the cell membrane holding all the cell's internal sub-structures (called organelles), except for the nucleus. All the contents of the cells of prokaryote organisms (which lack a cell nucleus) are contained within the cytoplasm. Within the cells of eukaryote organisms the contents of the cell nucleus are separated from the cytoplasm, and are then called the nucleoplasm. The cytoplasm is about 80% water and usually transparent.It is within the cytoplasm that most cellular activities occur, such as many metabolic pathways including glycolysis, and processes such as cell. The inner, granular mass is called the endoplasm and the outer, clear and glassy layer is called the cell cortex or the ectoplasm.The part of the cytoplasm that its not held within organelles is called the cytosol. The cytosol is a complex mixture of cytoskeleton filaments, dissolved molecules, and water that fills much of the volume of a cell. The cytosol is a gel, with a network of fibers dispersed in water. Due to this network of fibres and high concentrations of dissolved macromolecules, such as proteins, an effect called macromolecular crowding occurs and the cytosol does not act as an ideal solution. This crowding effect alters how the components of the cytosol interact with each other. Movement of calcium ions in and out of the cytoplasm is thought to be a signaling activity for metabolic processes

NUCLEUSThe nucleus is a membrane bound structure that

contains the cell's hereditary information and controls

the cell's growth and reproduction. It is commonly the

most prominent organelle in the cell.

The nucleus is surrounded by a structure called the

nuclear envelope. This membrane separates the

contents of the nucleus from the cytoplasm. The

cell's chromosomes are also housed within the nucleus.

Chromosomes contain DNA which provides the genetic

information necessary for the production of other cell

components and for the reproduction of life.

ENDOPLASMIC RECTICULUMThe endoplasmic reticulum (ER) is

an organelle of cells in eukaryotic organisms that forms

an interconnected network of tubules, vesicles, and

cisternae. Rough endoplasmic reticula are involved in

the synthesis of proteins and is also a membrane factory

for the cell, while smooth endoplasmic reticula are

involved in the synthesis of lipids, including oils,

phospholipids and steroids, metabolism of

carbohydrates, regulation of calcium concentration and

detoxification of drugs and poisons. Sarcoplasmic

reticula solely regulate calcium levels.

The lacey membranes of the endoplasmic reticulum

were first seen by Keith R. Porter, Albert Claude, and

Ernest F. Fullam in 1945

GOLGI APPARATUSThe Golgi apparatus, also known as the Golgi

complex or Golgi body, is an organelle found in

most eukaryotic cells. It was identified in 1898 by the

Italian physician Camillo Golgi and named after him.

Part of the cellular endomembrane system, the Golgi

apparatus packages proteins inside the cell before they

are sent to their destination; it is particularly important in

the processing of proteins for secretion

Due to its fairly large size, the Golgi apparatus was one

of the first organelles to be discovered and observed in

detail. The apparatus was discovered in 1898 by

Italian physician Camillo Golgi during an investigation of

the nervous system

LYSOSOMESLysosomes are cellular organelles that contain acid hydrolase enzymes to break down waste materials and cellular debris. They can be described as the stomach of the cell. They are found in animal cells, while their existence in yeasts and plants are disputed. Some biologists say the same roles are performed by lytic vacuoles. Lysosomes digest excess or worn-out organelles, food particles, and engulf viruses or bacteria. The membrane around a lysosome allows the digestive enzymes to work at the 4.5 pH they require. Lysosomes fuse with vacuoles and dispense their enzymes into the vacuoles, digesting their contents

MITOCHONDRIAMitochondria are the cell's power producers. They

convert energy into forms that are usable by the cell.

Located in the cytoplasm, they are the sites of cellular

respiration which ultimately generates fuel for the cell's

activities. Mitochondria are also involved in other cell

processes such as cell division and growth, as well

as cell death. Mitochondria are bounded by a double

membrane. Each of these membranes is a phospholipid

bilayer with embedded proteins. The outermost

membrane is smooth while the inner membrane has

many folds. These folds are called cristae. The folds

enhance the "productivity" of cellular respiration by

increasing the available surface area.

VACUOLESA vacuole is a membrane-bound organelle which

is present in all plant and fungal cells and

some protist, animal and bacterial cells Vacuoles

are essentially enclosed compartments which are

filled with water containing inorganic and organicmolecules including enzymes in solution, though

in certain cases they may contain solids which

have been engulfed. Vacuoles are formed by thefusion of multiple membrane vesicles and are

effectively just larger forms of these. The

organelle has no basic shape or size; its structure

varies according to the needs of the cell.

The function and importance of vacuoles varies greatly

according to the type of cell in which they are present, having

much greater prominence in the cells of plants, fungi and certain

protists than those of animals and bacteria. In general, the

functions of the vacuole include:

•Isolating materials that might be harmful or a threat to the cell

•Containing waste products

•Containing water in plant cells•Maintaining internal hydrostatic pressure or turgor within the cell

•Maintaining an acidic internal pH

•Containing small molecules

•Exporting unwanted substances from the cell

•Allows plants to support structures such as leaves and flowers

due to the pressure of the central vacuole

•In seeds, stored proteins needed for germination are kept in

'protein bodies', which are modified vacuoles.