Class 9 biology Ch5 Important notes

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FUNDAMENTAL UNITS OF LIFE.

Cell- Basic structural and functional unit of life. It was first observed by Robert Hooke in 1665.

Types of cell- Prokaryotic cell and Eukaryotic cell .







COMPONENTS OF EUKARYOTIC CELL
Nucleus-The organelle that contains the cell's DNA and it is the control center of the cell. 
Ribosomes -The organelle in which amino acids are hooked together to make proteins. 
Endoplasmic Reticulum- The organelle that makes lipids, breakdown drugs and other substances and packages proteins for Golgi complex. 
Mitochondria - The organelle that breaks down food molecule to make ATP. 
Chloroplast - The organelle that uses the energy of sunlight to make food. 
Golgi Complex- The organelle that processes and transports proteins and other material out of cell. 
Large central vacuole - The organelle that stores water and other materials. 
Lysosome- The organelle that digests food particles, wastes,cell particles .

COMPONENTS OF PROKARYOTIC CELL

Cytoplasm- It is the semifluid substance of a cell which contains all organelle. 
Nucleoid- Undefined nuclear region containing nucleic acids. 
Pilli- Long hair like tubular micro fibres present in prokaryotic cell. 
Cell wall - It is found in plant cells outside the plasma membrane. It provides structural support to cell. 
Plasma membrane- It is semipermeable membrane composed of lipids and proteins . It controls the entry and exit of material in and out of cell. 
Flagella - Microscopic hair like structure involved in locomotion of cell. 
DNA- The genetic material of cell. 

ANIMAL CELL


PLANT CELL 
Que1)  Differentiate between Plant cell and animal cell. 

Que2) Differentiate between cell membrane and cell wall 
Que3) Differentiate between prokaryotic cell and eukaryotic cell. 
Que4) What is diffusion and osmosis through plasma membrane? 
Ans) Diffusion is a movement of substance from a region of high concentration to low concentration. Through this process carbon dioxide or oxygen can move across cell membrane. Osmosis is the movement of water molecules through selectively perimiable membrane. This movement is affected by amount of substances dissloved in water. 
Que5)  What are plastids and it's types? 
Ans) Plastids are the double membrane bound organelle found in plant cells. They are found in cytoplasm. Plants make and store food in plastids. They have their own DNA and Ribosomes.
Types of Plastids -
1) Chloroplast - Contains chlorophyll that absorbs sunlight  in photosynthesis. 
It produce and store glucose. 
2)Chromoplast- Contains carotenoids. 
It is found in flowers and fruits. 
3) Leucoplast- Contains no pigment. 
It is used to store starch. 
Que6) Fill ups type questions. 
1)Powerhouse of the cell  is mitochondria. 
2)Longest cell in human is nerve cell. 
3)Genes are located in chromosomes. 
4)Leucoplasts are colourless plastids. 
4)Ostrich's egg is the largest cell which is visible from naked eyes.
5)Chloroplasts and mitochondria contains DNA apart from nucleus. 
6)Lysosomes are sucidial bad of cell. 
7)First cell was discovered by Robert Hooke in 1665.
8)First living cell was discovered by Anton Van Leeuwenhoek in 1674.
9)Nucleus was discovered  by Robert Brown in 1831.
10)Plasma membrane or cell membrane is selectively permeable membrane. 
11)Cell is the smallest unit of life. 
12)Protein synthesis in a cell occurs in ribosomes. 



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