i want bio ch cell of class 9 th full notes
Answers
Explanation:
Cells are the basic structural and functional unit of life. Cell was discovered by Robert Hooke. A number of cells can work together to form tissues and organs.
Cellular respiration
Cellular respiration is the process by which the food releases energy in the mitochondria. Cells absorb glucose from the food and burn it to produce energy.
Structural Organization of Cells
Prokaryotic & Eukaryotic cells
Two types of cell; Prokaryotic and Eukaryotic cells. Prokaryotic cells are primitive and lack well defined nucleus. Eukaryotic cells are more advanced and have well defined nucleus.
Cell structure in Eukaryotic cells
Eukaryotic cells have the most well defined structure. These cells have cell membrane, membrane bound cell organelles and a well defined nucleus. The nucleus has its own membrane called nuclear membrane.
For More Information On Prokaryotic and Eukaryotic Cells, Watch The Below Video:
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Cell membrane
Cell membrane is the outer covering of a cell.
It is made up of phospho-lipid bilayer membrane.
It is selectively permeable in nature.
The structure of a cell membrane is best described by the fluid mosaic model.
Diffusion
The movement of molecules from a region of their high concentration to a region of their lower concentration is known as diffusion.
Osmosis in selectively permeable membrane
Osmosis is the movement of water across a semi-permeable membrane. Osmosis is a selective process since the membrane does not allow all molecules to pass through it. Water is usually the only free flowing molecule across this membrane.
Isotonic, hypotonic solutions, hypertonic solutions
Isotonic solutions are those which have the same solute and pH concentration as the surrounding body fluid or the cytoplasm.
Hypotonic solutions contain lesser amount of solute concentration compared to the surrounding fluid and can force the cell to rupture due to excess input of water into the cell.
Hypertonic solutions contain higher concentration of solute compared to the surrounding fluid and thus push water out of cell, shrinking it.
Cell walls in plants
Plant cells are different from animals cells due to the presence of a cell wall. The cell wall is made of cellulose and gives a rigid structure to the plant cell.
Cell Organelles
Endocytosis
Endocytosis is the invagination of cell membrane, followed by pinching off forming a membrane bound vesicle. This is commonly seen in Amoeba.
Nucleus in cells
Nucleus is the processing unit of the cell. It is a double membrane bound organelle which contains the genetic material for inheritance.
Chromosomes
During the growth phase of the cell, the chromatin condenses into a much thicker structure called chromosome.
Chromatin
Chromatin is a thread like structure which serves as the genetic material present inside the nucleus of the cell. It is made up of DNA and protein molecules. The DNA contains the hereditary information needed for the structure and function of the organism.
Cytoplasm
Cytoplasm is the fluid found inside the cell. It gives the structure to the cell and houses different organelles of the cell.
Organelles
Organelles are structures present in the cytoplasm of the cell that help in several functions of the cell.
Endoplasmic Reticulum
Endoplasmic reticulum is a membrane like cell organelle that plays an integral role in the interpretation of the genetic information present in the nucleus.
Rough ER
Rough ER are the ones that have ribosomes on it. The ribosome is made up of nucleic acids and proteins. They are the site of protein synthesis. The Rough ER is also involved in the modification and folding of protein.
Smooth ER
Smooth ER do not have ribosomes and thus are not involved in protein synthesis. They are however, involved in the lipid metabolism and detoxifying poisonous molecules.
Golgi Apparatus
Golgi Apparatus is also called the post office of the cell. They package and transport the proteins across the cytoplasm.
Lysosomes
They are referred to as suicide bags of the cell as they contain potent enzymes that can digest a cell. Lysosome also help in defense by attacking a foreign object.
Mitochondria
Mitochondria are also called power plant of the cell. They generate ATP via the electron transport chain. They also have a DNA called mtDNA, which makes them semi-autonomous organelle.
Plastids
There are various types of plastids in different cells based on the pigment they contain. The chloroplast is the plastid where the photosynthesis occurs. Some of the other plastids are leucoplast and chromoplast.
Vacuoles
Vacuoles are large vesicles that hold water or air in them and give structural rigidity to the cell. Vacuoles are common in plant cells. In animals the vacuoles are either very small or absent.
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