Plastids
• Pigment containing bodies.• Membrane bounded.
• There are three types of Plastids.
• Membrane bounded structure, having green pigment in photosynthesis plant.
• Green pigment –> organic compound –> chlorophyll helps cell to capture light energy to manufacture food.
• Chlorophyll –> resembles –> haem group of haemoglobin.
• Haem protein –> transport of O² –> has Fe++ as central atom while Chlorophyll –> Mg++ –> central atom.
• Diameter of chloroplast –> 4-6,μm.
Light microscope: Appeared as heterogeneous structure with small granules –> granna –> embedded in matrix.
Electron microscope: Chloroplast shows three main components. Envelope, Stroma, thylakoid.
Envelope: Formed by double membrane.
Stroma: covers most volume of chloroplast. A Fluid that surround thylakoids. Contain protein, some ribosomes and small circular DNA. In this partvof chloroplast –> Co² fixed –> manufacture suga. Some protein also synthesized
Thylakoid: Flattened vesicle –> arranged –> to form grana and intergrana.
Granum: Pile of Thylakoid –> stacked on each other –> like coins. One granum –> 50 or more piles of Thylakoid. Granum appears green (version–>): Chlorophyll molecules are arranged on the layers of Thylakoids. Membrane of grana –> site to nap(ATP formed) sunlight energy.
Intergranum: Non green part. Each granum is interconnect to one another by intergranum.
• Present bin petals of flowers and in ripened fruit.
• Help in dispersal of seed and pollination and fertilization.
• Found in underground parts of plant.
• Function –> Food storage.
1- Chloroplast:
• Self replicating organelle.• Membrane bounded structure, having green pigment in photosynthesis plant.
• Green pigment –> organic compound –> chlorophyll helps cell to capture light energy to manufacture food.
• Chlorophyll –> resembles –> haem group of haemoglobin.
• Haem protein –> transport of O² –> has Fe++ as central atom while Chlorophyll –> Mg++ –> central atom.
• Diameter of chloroplast –> 4-6,μm.
Light microscope: Appeared as heterogeneous structure with small granules –> granna –> embedded in matrix.
Electron microscope: Chloroplast shows three main components. Envelope, Stroma, thylakoid.
Envelope: Formed by double membrane.
Stroma: covers most volume of chloroplast. A Fluid that surround thylakoids. Contain protein, some ribosomes and small circular DNA. In this partvof chloroplast –> Co² fixed –> manufacture suga. Some protein also synthesized
Thylakoid: Flattened vesicle –> arranged –> to form grana and intergrana.
Granum: Pile of Thylakoid –> stacked on each other –> like coins. One granum –> 50 or more piles of Thylakoid. Granum appears green (version–>): Chlorophyll molecules are arranged on the layers of Thylakoids. Membrane of grana –> site to nap(ATP formed) sunlight energy.
Intergranum: Non green part. Each granum is interconnect to one another by intergranum.
2- Chromoplast:
• Impacts colour to plants other than green.• Present bin petals of flowers and in ripened fruit.
• Help in dispersal of seed and pollination and fertilization.
3- Leucoplast:
• Colourless, triangular, tubular or other shape.• Found in underground parts of plant.
• Function –> Food storage.
Nucleus
• In 1831, Robert Brown.• Controls the life and activities of cell.
• Early discovry –> doubtful –> due to prominence in many cells.
• Stands like a slightly darkerthan surrounding cytoplasm.
• Central space in animals and pushed towards Peliphery (outerside distal) in plants –> due to large vacuoles.
• Shape –> irregular or spherical in shape.
• Cell have one nucleus generally –> mononucleotide.
• With two nucleus –> binucleate, more than two multinucleate.
• Nucleus is visible only in non-dividing stage of cell.
• Have chromatin network and soluble sap –> nucleoplasm.
• Nucleus disappears in diving stage of cell and chromatin material –> replaced by –> Chromosome.
• Hereditary material –> in form of chromosomes controls all activities of cell.
• Nucleus chemical composition –> DNA, RNA, Protein and enzymes.
• Nucleus consists of nuclear membrane, nucleolus, nucleoplasm and chromosomes.
Nuclear Membrane:
• Separates nuclear content from cytoplasm.
• Other name –> Nuclear envelope –> two membranes.
• Outer membrane place –> in continues with ER.
• Inner membrane place –> enclose nuclear content.
• Outer and inner –> continuesat certain points results in formation of pore –> nuclear pore.
• Nuclear pore –> exchange of material between nucleus and cytoplasm. No –> highly variable.
• Undifferentiated cell –> egg –> 30,000 pores per nucleus.
• Differentiate cell –> erithromycin –> only 3 to 4 pores per nucleus.
• Each pore –> definite structure –> controls the traffic of substances passing through it.
Nucleolus:
• Darkly stained body in nucleus.• Without any membrane to separate it from nuclear material.
• One or more nucleoli in the nucleus.
• rRNA synthesized and stored in nucleolus.
• Composed of two region: a. Peripheral glanular area( precisor of ribosomal subunits. b. Central fibrill aera RNA + rDNA.
• Ribosomes assembled and expoted to cytoplasm (via–>) nuclear pore.
Chromosomes:
• Nucleus –> deeply stained because –> of chromatin material.
• During cell division –> chromatin material –> chromosomes darkly stained thread likr structure.
• Made up of arms and centromeres.
• Centromere –> Spindle fibres attached during cell division.
• Consists –> Two identical chromatids at beginning of cell division –> held together at centromeres.
Chromatid, exact replica of chromosome:
• Composition –> DNA and protein –> All the necessary information to control the activities of life –> located on chromosome –> form of genes that are transferred from one generation to another.
• Number of chromosome in all individuals at same species remain constant generation after generation.
Human –> 46 chromosome
Frog –> 26 chromosome
Onion –> 16 chromosome
Potato –> 48 chromosome
Garden pea –> 14 chromosome.
Chimpanzee –> 48 chromosome
Fruitfly (Dorsophilla melanogaster) –> 8 chromosome
Number of chromosome in normal body cells in diploid –> 2n. Germ cells contain n chromosome.
Prokaryotes:
• Nuclear material is with any nuclear membrane directly submerged in cytoplasm.
e.g: bacteria blue green algae.
• Lack many organelles thst eukaryotic cell have i.e mitochondria, ER, chloroplasts. ang golgi are absent.
• No nuclear membrane.
• No distint nucleus.
• DNA molecule directly suspend in cytoplasm.
• Small sized ribosomes 70s.
• Mitosis is missing cell divides by binary fission.
• Cellwall composed of Polysaccharides chain bound.
• Covalently –> to shorter chain of a acid form peptiglycan or malein.
• The entire cellwall –> regarded as single huge molecule –> sacculus.
Eukaryotes:
• Well defined nucleus. nuclear material is enclosed by double membrane.
e.g: all other unicellular and multicellular organisms such as –> animals, plants,fungi and protista
• 80s ribosomal unit.
• Mitosis present plant cell wall.
• cellulose, peetin hemicellulose.
Vacuoles
• Both in plants and animal cell• Abudant and large in plant cell –> occupy major portion –> force intracellular structures –> in thin peripheral layer.
• Single membrane bounded –> formed by –> coalesce of smaller vacuoles –> during plant growth and development.
Function:
• Expand plant cell without diluting the cytoplasm.
• Sites for storage of water and cell products or metabolic intermediates.
• Major contributor to turgor –> provides support for individual plants –> contributes to rigidity of leaves and younger parts of plants.
Centrioles
• Animal cells, some micro-organisms lower plants absent in higher plants.• Comtain two centrioles –> near the exterior surface of nucleus.
• Each centrioles –> nine mircotubules –> cylindral array futher composed of 3 tubules.
• Two centrioles –> right angle to each other just before cell division –> centrioles duplicate and one pair migrates to opposite side of nucleus.
• Spinelle then forms between them
• plsy role in cilia formation and location of furrowing during cell division.
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