Cell Biology PDF

types of proter.-. e., amoeboi,,i :i':-r', Table 11" Chemical constituents of the :tt'aiLt anrl cytoplasm or cr-toso1 ts 1,. 2. 3. 4. 5. Oxygen 64.00 Carbon 18.00 Hydrogen 10.00 Nitrogen 0.3 Trace elements (Ca, P, Cl, S, K, Na, Mg, I, Fe) 0.5 Functions: 1,. m" Cytosol (cytoplasm) acts vitamins, ions...

types of proter.-. e., amoeboi,,i :i':-r', Table 11" Chemical constituents of the :tt'aiLt anrl cytoplasm or cr-toso1 ts 1,. 2. 3. 4. 5. Oxygen 64.00 Carbon 18.00 Hydrogen 10.00 Nitrogen 0.3 Trace elements (Ca, P, Cl, S, K, Na, Mg, I, Fe) 0.5 Functions: 1,. m" Cytosol (cytoplasm) acts vitamins, ions, etc. as studlgear a store of vital chemicals such as amino acids, glucose, 7 2. It is the site of certain metabolic pathways, such as glycolysis. Synthesis of fatty acid s, nucleotides, and some amino acids aiso take place in the cytosol. 3, Living cytoplasm I T is always in a state of movement. ii*! #**t#r6;xt:*if** A cell has to perform different functions with the help of its various membrane-bound organelles (Table 6): 1. It has to synthesize substances, e.g., protein synthesis by ribosomes, lipid synthesis on the surface of smooth endoplasmic reticulum (SER), photosynthesis of food (e.g., glucose, starch) by chloroplasts. 2. It has to secrete cell products, e.8., enzymes, hormones, mucus, etc. 3. It has to digest those substances which are taken up by the cell during endocytosis. Such intracellular digestion is done by enzymes of lysosomes. 4. It has to generate energy, e.g., synthesis of energy-rich ATP (adenosine triphosphate) by mitochondria. Membrane is a remarkable cellular structure. Every cell is bounded by a membrane and thus, keeps its own contents separate fron-r th.e erternal environment. Larger or more evolved cells, or cells from multicellular orsanlsr-r1.s. :,a\-e a great deal of metabolic activities to support their complicated structure or fr-tnct-,:n To keep metabolic activities of different types separate from each other, ce1ls har-e mernbiar,.'a-.'-r:-:r --:t:.rLeiles u'ithin themselves. Cell organeiles are "small organs" of the cel1 ancl are io'..:.,.'. i:'.--=--.-'.-: -r-. ,r',e cvtosol. They form iiving part of the cell and each of them has a defilute sha','; :.,.-. -:.. : ,'. r- ,: ;r-Lnction. Examples of such organelles are nucleus, mitochondria, chloroplasts, e:-.icp-...:-,- :.,:-.-*i:r, Golgi apparatus, lysosomes, ribosomes, etc. We have already discussedaboutthen;-,e.-...-',::::..-ioussection.Inthissection,wewilldiscussthecellularorganelles one by one. 32 The Fu-cc- ='-'^ -- - of Life: Cell