Program learning material
- 1. PROGRAM LEARNING MATERIAL By sangam singh
- 2. NUCLEUS CYTOPLASM CELL THEORY ANIMAL CELL ORGANELLES E.R RIBOSOME GOLGI APPARATUS MITOCHONDRIA LYSOSOME NUCLEOLUS NUCLEOPLASM
- 3. Cell All living organisms are made up of cells. Cell is the basic structural and functional unit of complex organisms. Cells perform all the metabolic activities taking place at cellular level. The discovery of cells was possible with the invention of microscope. History of cell • Marcello Malpighi, in 1661, proposed that plants are made of tiny structural units called 'Utricles'. • Robert Hooke, in 1665, observed many tiny, hollow, room like structures in a thin slice of cork through a compound microscope and called them ‘cells’. • Leeuwenhoek, in 1674, with the improved microscope, discovered free-living cells in pond water for the first time. • Robert Brown in 1831 discovered the nucleus in the cell. • Purkinje in 1839 coined the term 'protoplasm' for the fluid part of the cell. • Schleiden in 1838 and Schwann in 1839 proposed the cell theory which stated that all plants and animals are composed of cells. • Rudolf Virchow in 1855 further expanded the cell theory by saying ‘omniscellula-e-cellula’, which means all cells arise from pre-existing cells. • Cell is derived from the Latin word "Cellula" which means "a little room".
- 4. Cell theory M.J.Scleiden and TheodreSchwann proposed cell theory for the first time. • Cell is the basic structural unit of all the organisms. • Preexisting cells only gave rise to new cells. • An organism has its body composed of cells. • A single cell transfers life from one generation to another generation. Microscopic examination of cells Plant and animal cells are only visible only under a microscope. • The microscopic examination of a plant cell enables us view a prominent vacuole, nucleus, and cytoplasm. • For the microscopic examination of an animal cell, spread the specimen on a glass slide, and add a drop of water and methylene blue. Cells with darkly stained spherical nuclei at their centre can be observed.
- 5. Nucleus: A true nucleus acts as the control centre of the cell. It is covered by a two layered, perforated nuclear membrane allowing substances to enter and leave the nucleus. Nucleus is filled with semifluid colloidal substance called as nucleoplasm in which float the nucleolus and the chromatin fibres. The nucleus contains chromosomes, which are composed of Deoxyribonucleic acid (DNA) and proteins. Functions of nucleus Nucleus controls all the activities of cell • As the nucleus carries genetic information in the form of DNA, it plays a major role in cell division and cell development. The functional segments of DNA are called genes. • Nucleus plays an important role in protein synthesis and transmission of characters from one generation to another generation.
- 6. Endoplasmic reticulum: It is a network of tubules and flattened sacs perform various activities in the cell. The space inside the endoplasmic reticulum is called as lumen. Endoplasmic reticulum serves as a channel for the transport of proteins between various regions of the cytoplasm. Two types of endoplasmic reticulum are Rough Endoplasmic Reticulum (RER) and Smooth Endoplasmic Reticulum (SER).
- 7. Ribosomes: These are naked granules with no membrane. They are found scattered in the cytoplasm or attached to the outside of the endoplasmic reticulum. They are the biofactories of proteins. Ribosomes can be free ribosomes scattered in the cytoplasm or bound ribosomes seen attached to endoplasmic reticulum. Ribosomes are made up of two subunits, the larger subunit and the smaller subunit. 70s ribosomes are present in prokaryotes and 80s ribosomes are present in eukaryotes. Functions of ribosomes • Ribosomes are considered to be the biofactories since they are the sites of protein synthesis. • They are the lodging sites for many enzymes participating in the process of protein synthesis.
- 8. Golgi apparatus: These cell organelles are named after the biologist, Camillo Golgi, who first described it. The Golgi consists of a stack of membrane-bounded cisternae located between the endoplasmic reticulum and the cell surface. Functions of Golgi apparatus • It synthesises certain biopolymers. • It also consists of some processing enzymes which alter some proteins and phospholipids synthesised by endoplasmic reticulum.
- 9. Mitochondria: These are cellular organelles termed as ‘power houses of the cells’. These are bounded by a double membrane. The outer membrane is smooth while the inner membrane is thrown into folds called as cristae. The cristae increase the area of cellular respiration. Both the membranes are separated by intermembrane space. Mitochondrial matrix is rich in respiratory enzymes The enzymes in the mitochondria oxidise glucose molecules to produce energy in the form of Adenosine Triphosphate or ATP. Functions of mitochondria • These synthesise energy rich ATP molecules. • These help in the synthesis of fatty acid, amino acids, steroids by providing them with biological intermediates.
- 10. Lysosomes: Lysosomes are membranous sacs filled with enzymes. The enzymes are hydrolytic enzymes which are capable of digesting cellular macromolecules. When the cell gets damaged, the lysosome may burst and its enzymes may digest the cell itself. Hence, lysosomes are called as ‘suicidal bags’. Functions of lysosomes • Help in killing foreign cells referred to as pathogens. • Help in destroying the diseased cells.
- 11. INSTRUCTIONS Read the content thoroughly. The questions are based on the content of slide. There are total five multiple choice questions. All the questions are compulsory to answer.
- 12. 1. Which statement of cell is a part of cell theory a) Cells are found in most living things b) Cells come only from other living cells c) All cells capture energy from sunlight d) Cells with cell walls do not have cell membranes
- 17. 2. The smallest unit that perform the basic activities of life is……. a) a tissue b) a cell c) an organ d) an organism
- 22. 3. One of the organelles which is considered as bio factories synthesizing protein……… a) Ribosome b) Endoplasmic reticulum c) Golgi apparatus d) Lysosome
- 27. 4. Which organelles known as power house of cell…….. a) Mitochondria b) Ribosome c) Endoplasmic reticulum d) Lysosome
- 32. 5. Which organelles helps in destroying the diseased cells……. a) Nucleus b) Chloroplast c) Lysosome d) Ribosome
- 37. THANK YOU