Cell Structure 9th Samrala G Ldh

PRESENTED BY:- 9TH A JASWINDER SURINDER SUMANPREET HARDEEP NAVJOT VANDHANA

CELL The cell is the basic structural and functional unit of plants and animals.

PARTS OF PLANT CELL 1. 2. 3. 4. 5. 6.

Cell wall Plasma membrane Cytoplasm Nucleus Vacuole Endoplasmic reticulum 7. Mitochondria 8. Plastids 9. Ribosome 10.Golgi apparatus

CELL WALL It is an outer rigid protective, supportive covering of plant cells.

FUNCTIONS OF CELL WALL 1.It provides a definite shape to the cell. 2.It protects plasma membrane and internal structure from the pathogens and mechanical injury. 3.Growth of the cell wall determines the growth of the cell.

PLASMA MEMBRANE Every kind of cell is bounded by a thin, delicate, living and trilaminar membrane called plasma membrane.

FUNCTIONS OF PLASMA MEMBRANE 1.Plasma membrane is selectively permeable, therefore, it allows only selected substances to pass inward. 2.Plasma membrane binds the semi-fluid content of the cells. 3.It protects the cell from injury.

CYTOPLASM The space between the plasma membrane and the nucleus is filled by an amorphous, translucent, homogenous, colloidal liquid called Cytoplasmic matrix.

FUNCTIONS OF CYTOPLASM

It helps in intracellular distribution of molecules, enzymes and nutrients within the cell. 2. It helps in exchange of materials between different cell organelles. 1.

NUCLEUS The nucleus is an important, centrally located spherical cellular component. Nucleolus is a part of nucleus. It is rich in proteins and RNA molecules. It is the site of ribosome formation.

FUNCTIONS OF NUCLEUS

1.Nucleus play important role in Metabolism. 2.Nucleus also play vital role in cell division. 3.Nuclus control all cell activities so it is called director of cell.

VACUOLE These are fluid filled and membrane bounded spaces. In mature plants cells the small vacuoles fuse to form a single large vacuole. Vacuoles are bounded by a membrane known as Tonoplast. They are filled with a fluid called Cell Sap.

FUNCTIONS OF VACUOLE 1. It stores water. 2. They play an important role in growth by helping in the elongation of cells. 3. They impart color. The anthocyanin gives color to flowers, fruits, buds and leaves.

ENDOPLASMIC RETICULUM

Endoplasmic reticulum is a complex network of membrane bounded tubules that runs through the cytoplasm. ER is of two main types-Smooth and rough.

FUNCTIONS OF ENDOPLASMIC RETICULUM 1.Endoplasmic reticulum divides the cytoplasm into small compartments, it gives rigidity to the cell, thus it acts as a skeletal frame work of the cell. 2.It helps in intracellular transport hence known as the circulatory system of the cell. 3.It provides a large surface area inside the cell for various physiological activities.

MITOCHONDRIA Typically mitochondria are sausage shaped, but these may be granular, filamentous, rod-shaped also. Each mitochondria is bounded by two unit membranes-a smooth outer membrane and an inner membrane which is folded inwards to form cristae.

FUNCTIONS OF MITOCHONDRIA 1.These are the sites for the production of energy rich molecules and are, therefore called ‘power house’ of the cell. 2.Mitochondria provide important intermediates for the synthesis of several biochemicals like chlorophyll, cytochromes etc. 3.Synthsis of many amino acids occur in mitochondria.

PLASTIDS These organelles are found only in plants cell. Plastids are of three typesChromoplast, chloroplasts and leucoplasts.

FUNCTIONS OF PLASTIDS 1.Chromoplast provides color to flowers and fruits. 2.Chloroplast helps in photosynthesis so are called kitchen of the cell. 3.Leucoplasts helps in the storage of food.

RIBOSOMES These are found in all cells, both Prokaryotes and eukaryotes except in mature sperms and RBCs. Each ribosome has two sub-units a smaller sub-unit and a larger sub-unit. Ribosome's are composed of RNA and Protein.

FUNCTIONS OF RIBOSOMES 1.Ribosomes help in protein synthesis inside the cell. Hence they are called protein factories of the cell.

GOLGI APPARATUS It is present near nucleus. It is absent in prokaryotes. It is made up of cisternae, vacuoles, tubules.

FUNCTIONS OF GOLGI APPARATUS 1.Golgi apparatus helps in the secretion of mucous, enzymes and hormones. 2.It helps in the storage of secretary products. 3.It helps in the formation of cell plate during cell division. 4.The pectic material necessary for the formation of cell wall are synthesized and secreted by the Golgi complex.

Name different parts marked by arrows below in the diagram.

REFERENCE

SCIENCE FOR 9TH CLASS

BY PUNJAB SCHOOL EDUCATION BOARD