The Cell- Class 8 Notes

  Chapter - The Cell 

Ø The tiniest of organisms called Unicellular Organisms.                                                

Ø A Tissue is a group of similar cells that perform a particular function.                    

Ø The cell is the known as Functional unit of life                                                         

Ø The lens that is close to the specimen placed on a stage is called the  Objective.    .

Ø The lens through which you can see is called Eyepiece.                                                

Ø Cells , tissues , microorganisms and so on that are viewed through a microscope are called Specimens.                                       .

Ø The stained specimen is placed in a liquid medium on a glass slide ,and a coverslip is placed over it this process is called  Mounting.

Ø Different mediums are used to preserve Permanent Slides , which can be stored for long time .

Ø Cheek cells are Epithelial tissues.

Ø Guard Cells which regulate the opening of the stomatal pores of leaves.

Ø .The ones within vc green structural are  Algae.

Ø .The matter inside the cell membrane called Cytoplasm.

Ø .Cell wall is made up of  Cellulose.

Ø .Cytoplasm consists of a jelly like fuelled with various structures such as the nucleus floating in these structures are called Organelles.

Ø .Power house of cell is Mitochondria.

Ø .The control room of cell Nucleus.

Ø .Inside nuclear there thread line structure called  chromosomes.

Ø .The chromosomes form a dense tangle refer to a Chromatin.

Ø .Chromosomes carry Genes which order to perform all its function.

Ø .Plastid contain the green pigment Chlorophyll and responsible for photosynthesis.

Ø .Only green parts of plants have Chloroplast.

Ø .Chromoplast contains pigment which gives fruits and flowers their colour.

Ø .Leucoplast store food and are found in the storage organs of plants.

Ø .Vacoule is the sack like structure filled with fluid.

Ø .The outermost region formed by a single row of closely fitting ,flat, rectangular cells is called the Epidermis.

Ø .In roots epidermis layer is called Epiblema.

Ø .Ground tissue contain two zones Cortex And Pith.

Ø .Bundles near the centre form Cortex.

Ø .The central core of rounded cells form the Pith.

Ø .Vacuolar bundles made up of two tissues Xylem And Phloem .

Ø .Xylem is responsible for transporting water and minerals from the roots .

Ø .Phloem is responsible for transporting food from the leaves to the rest of the plant .

Ø .Vascular Bundles  are present in the leaf and root as well.

Ø .Blood is kind of Connective Tissue.

Ø .Adipose Tissue or what is generally known as fat it is also a kind of connective tissue.

Ø .The cells are suspended or embedded in a  Matrix.

Ø .In blood the matrix is liquid and it is called the Plasma.

Ø .Muscular Tissue contract and relax to make  different parts of body to move .

Ø .Connective Tissue connect muscles with bones .

Ø .Nerve cells are made up of Nervous Tissue.

Ø .A Nerve Cell has a long tail and short branches coming out in of it .

Ø .Nervous Tissue carry message from one cell to the other .

Ø .The Brain And The Spinal Cord  is made up of nervous tissue .

Detailed Notes:-

Epidermal cells: the slide you have prepared is a temporary slide in which you have water as the medium for mounting you will see rectangular cells separated by rigid walls and these are epidermal cells, found on the surface of the plant body. 

Cheek cells : cells from your cheek which are too protective cells are not rectangular nor are they bounded by a rigid wall as are they onion leaf peel this s is an essential difference between plant cell and animal cell plant cells have a rigid cell wall while animal cells do not in each check cell there is the nucleus

 

Guard cells: among the epidermal cells in the rhoeo peel  you will see bean-shaped cells these are guard cells.

Microorganisms: the cells in the drop of pond water are microorganisms the ones with green structures are algae, tiny organisms capable of photosynthesis the green structures are chloroplast.

 

 

Blood cells: in the blood smear, you will notice two types of cells 

 Difference between red blood cells and white blood cells 

Red blood cells : 

(1) The disc-shaped cells are red blood cells 

(2) Red blood cells do not have a nucleus 

(3) Red blood cells have a cell wall.

 

White blood cells : 

(1) The irregularly shaped cells are white blood cells 

(2) The prominent structure inside a white blood cells are its nucleus

 

 Cell membrane :  the covering of cell is called cell membrane it is also called plasma membrane it allows oxygen and nutrients to pass into the cell and let's wastes pass out of it this is called selectively permeable 

Cell wall: plant cells have an additional protective wall called the cell wall it is made up of cellulose.

Tissues: A tissue is a  group of similar cells that perform a particular function 

 

Difference between plant cells and animal cells

 

Epithelial tissue : epithelial tissue is protective. 

 

Connective tissue: connective tissue has cells suspended or embedded in a matrix.

 

Muscular tissue: muscular tissue help in the movement.

 

Nervous tissue: nervous tissue consists of nerve cells it makes up the brain and the spinal cord.

 

Ø .Written by - Anmol.