PLANT CELL

By: Rohit SharmaClass: IX-BRoll No. 13

CELL

Cell is the basic functional and structural unit of life. It was discovered by Robert Hooke in 1665 while examining a thin slice of cork. Cell got its name from a Latin word ‘cella’, meaning ‘a small room’. Cell mainly consists of nucleus, cell membrane, cell wall and cell organelles. Cells are mainly of two types-(a)Plant Cells(b)Animal Cells

STRUCTURE OF A CELL

PLANT CELLPlant cells are cells that are in plants. Plant cells are like animal cells but they have a cell wall and chloroplasts. Their Distinctive feature includes:a)Plasma membrane or cell membraneb)Cell wallc) Nucleusd)Cytoplasme)Mitochondriaf) Lysosomesg)Plastidsh)Vacuolesi) Endoplasmic Reticulum(ER)

STRUCTURE OF A PLANT CELL

PLASMA MEMBRANE OR CELL MEMBRANE

It is the outermost covering of the cell that separates it from its external environment. It allows the entry and exit of only some components in and out of the cell. Therefore, it is also called selectively permeable membrane.

CELL WALLIt is only located in plant cell. It lies outside the plasma membrane. It is mainly composed of cellulose. Cell wall permits the cells of plants to withstand very dilute external media without bursting. Because of their walls, such cell can withstand much greater changes in the surrounding medium than animal cells.

CELL WALL

NUCLEUSIt is an spherical oval body stained structure. It has a double layered covering called nuclear membrane, which allows the transfer of material from inside the nucleus to its outside. The nucleus contains chromosomes, which are visible as a rod-shaped structures only when the cell is about to divide.

Nucleus consists of:-1. Nuclear membrane2. Nucleoplasm3. Nucleolus4. Chromatin material

1. NUCLEAR MEMBRANEIt is the double layer covering of nucleus having pores which allow transfer of materials from inside of the cell to the cytoplasm

2. NUCLEOPLASMIt is the fluid enclosed by nuclear membrane. It contains enzymes, ribosome, nucleolus and chromatin thread.

3. NUCLEOLUSIt is the dense spherical body present within the nucleus. It consists of DNA, RNA, protein and enzymes for the synthesis of lysosomes. It is also known as factory of ribosomes.

4. CHROMATIN MATERIALIt is the thread-like intertwined mass of chromosome material and composed of DNA and proteins. It is condensed into two or mare thick ribbon like structures called chromosomes during the division of the cell.

CYTOPLASMCytoplasm is a gel-like substance, present in the cell membrane and holding all the cell organelles in eukaryotes.

MITOCHONDRIAIt is a double membrane bounded structure organelle. It is also called ‘the power house of the cell’.

LYSOSOMELysosomes are a kind of waste disposal system of the cell. Lysosomes help to keep the cell clean by digesting any foreign material as well as worn-out cell organelles. They contains digestive enzymes capable of breaking down all organic material.

PLASTIDSThese are the largest cell organelle found in plant cells only. They are called ‘Kitchen of the cell.' Plastids are of three types- Chromoplasts (colored plastids) Leucoplasts (white or colorless) Chloroplasts

VACUOLE

Vacuoles are fluid filled membrane bound clear spin the cytoplasm. They are filled with water and the variety of substances like minerals, sugar, carbohydrates, acids, pigments, and metabolic wastes in solution.

GOLGI APPARATUSIt was described by Camillo Golgi(1898). It is present in all the eukaryotic cells except RBC.It consists of membrane bound vesicles arranged parallel to each other in stacks called cisterns. In plant cells, Golgi apparatus are known as dictyosomes.

ENDOPLASMIC RETICULUM(ER)

It is a large network of membrane bound cubes and sheets. The ER membrane is similar in structure to the plasma membrane.It provides mechanical support to the cell.There are two types of ER:-a) Rough Endoplasmic Reticulum(RER)b) Smooth Endoplasmic Reticulum(SER)RER helps in the synthesis and transport of proteins and SER takes part in the synthesis and storage of lipids and steroids.

ENDOPLASMIC RETICULUM(ER)

Basis Animal Cell Plant Cell

Cell wall none yes

Plastids no yes

Vacuole One or more small vacuoles

One, large central vacuole

taking up 90% of cell volume

Shape round rectangular

Centrioles Always present Only present in lower plant forms

Lysosomes Occur in cytoplasm

Usually not evident

Plasma Membrane Only cell membrane

Cell membrane & cell wall

Chloroplast Don’t have chloroplast

Have chloroplast

DIFFERENCE BETWEEN PLANT AND ANIMAL CELL

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