Cell biology.pdf

BIOLOGY BOTANY  Old Question Model Question model Q.No.1. Very short question (1*7=7) Q.No.2.Short Question(3*5=15) Q.No.3.Long question (Any one) (7.5) a. Life cycle Or b. Family Q.No.4.Long question (8) a. Ecology  Zacharis Janssen(1590)-first microscope  Robert Hooke...

BIOLOGY BOTANY  Old Question Model Question model Q.No.1. Very short question (1*7=7) Q.No.2.Short Question(3*5=15) Q.No.3.Long question (Any one) (7.5) a. Life cycle Or b. Family Q.No.4.Long question (8) a. Ecology  Zacharis Janssen(1590)-first microscope  Robert Hooke(1665)-Cell He took piece of cork, prepare thin slice and observed under microscope and viewed honey comb like structure, named such compartment as Cella (latin-Cella- compartments)  Anton van leeuwenhoek (1675)- free living cells. Micrograph of Cork cells observed by Robert Hooke  Cell is structural and functional unit of life. Structural unit *Cell-Tissues-Organ-System-whole body Functional unit *Excretion, Reproduction, Respiration, Digestion-In unicellular organism *Division of labor-In multicellular organism` German scientist Schleiden (1838) and Schwaan (1839) found that animal tissues were made up of cells. They combined their views and proposed cell theory. Fundamental theories are: 1. All organisms are made up of cells. 2. Cell is made up of mass of protoplasm containing nucleus and plasma membrane with or without cell wall (theory given by Purkinje-1840) 3. Each cell arise from pre-existing cell (Concept of Modern cell theory-given by Rudolph virchow). 4. All cells are similar in chemical composition and metabolic activities. 5. Function of an organism is sum total of activities of constituent cell. 6. Every cell is totipotent. Cell theory donot cover all organisms. Has many exceptions: 1. Virus donot have cellular machinery (Cytoplasm and cell organelles). 2. Bacteria, Cyanobacteria do not have true nucleus. 3. Organism like Mucor, Rhizopus and Vaucheria’s body is coenocytic (Coenocytic hyphae: Body is not differentiated by partition wall and has many nucleus). 4. Mature mammalian RBC and sieve tube cells are without nucleus. 5. Paramecium are binucleated. 1. Independent existence 2. Whole genetic information is contained in a cell. 3. Cell converts micro into macromolecules and vice- versa. 4. Cell can manufacture energy and store it in form of ATP. 5. Cell can regulates flow of energy and flow of information. 6. Each cell has definite life span(RBC-4month,skin-2 to 4 weeks, pancreas cell-1 year, Bone cell-25 to 30 years) 7. Cell can respire and exchange gases.  Flow of energy Sunlight Green parts prepare food Transfer to non green parts break down of food(respiration) Release energy transfer to other trophic level  Flow of information in cell a. Intrinsic flow of information: DNA Transcription mRNA Translation Protein b. Extrinsic flow of information: Information is provided by certain stimuli, metal ions or hormones. Unicellular organism Multicellular organism 1.Organism made up of single cell. 1.Organism made up of many cells. 2.All functions is performed by single 2.Functions are performed by organ or cell. system. 3.There is no division of labour. 3.There is division of labour. 4.Small injuries can cause death of an 4.Small injuries donot harm the organism. organism. 5.Cell size is large. 5.Cell size is small. 6.Reproduction takes place only once. 6.Reproduction takes place many times. 7.Internal env. may not remain 7.Internal environment remain constant. constant. 8.They are nearly immortal. 8.They die after certain time period. Eg.Amoeba, Chlamydomonas etc Eg.Spirogyra,Hydra etc The ability of living, nucleated, vegetative cell to regenerate into complete organism (plant) is known as cellular totipotency. In 1902,the concept of cellular totipotency was given by Haberlandt. Later in 1932,White cultured tomato roots in culture medium from a single cell. But it was experimentally proven by steward and co- workers(1950).  Steward experiment of cellular totipotency. For this experiment root of carrot was taken. It was transversely cut and phloem tissues were extracted. Tissues were kept in test tube with liquid medium. Such medium has necessary vitamin, nutrient, growth hormone along with coconut milk. The tube is gently shaken due to which phloem cells were isolated. Cell gave cell clusters, from which few develop into rooted clumps. They were transferred into semi-solid medium which give rise to shoot. These plantlets were transferred into healthy natural environment that grow into complete plant. 1. Prokaryotic cell 2. Eukaryotic cell Prokaryotic cells are cells that do not have a true nucleus or membrane-bound organelles. They have incipient nucleus/nucleiod which lack nuclear membrane, nucleoplasm and nucleolus. Eg. Bacteria, Cyanobacteria Eukaryotic cells are cells that contain true nucleus and cell organelles, and are enclosed by a plasma membrane. Organisms that have eukaryotic cells include protozoa, fungi, plants and animals. Plant cell  Animal cell Difference between plant cell and animal cell?? Prokaryotic cell Eukaryotic cell 1.Primitive cell. 1.Advance 2.Incipient nucleus is present. 2.True nucleus is present. 3.DNA is naked and circular. 3.DNA is covered by histone protein and is linear. 4.Membrane bound cell organelles are 4.Membrane bound cell organelles are absent. present. 5.Cellular respiration is performed by 5.Cellular respiration is performed by Mesosome. mitochondria. 6.Ribosome is 70s type. 6.Ribosome is 80s type. 7.Cell wall is made up of murein or 7.Cell wall is made up of peptidoglycan. cellulose,chitin etc. 8.Cell division is amitosis. 8.Cell division is mitosis and meiosis. 9.Cyclosis/Cytoplasmic streaming is 9.Cyclosis is present. absent. 10.Exocytosis and endocytosis is rare. 10.It is common. 11.Gas vacoule is present. 11.True vacoule is present. Eg.Bacteria, cyanobacteria Eg.Mucor, Spirogyra etc Thank you!!!