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Tuesday, February 06, 2007 @ 10:24 PM
pardon me
this is gonna be boring ultrastructure of cell protoplasm: cell membrane, cytoplasm [exist as cytosol:jelly like substance] and nucleus [not present in cell] nucleus: - nucleoplasm [jelly like substance]. contains genetic blueprint in the form of DNA-bearing chromosomes. - nuclear envelope: a membrane boundary consisting of 2 membranes. - nuclear pore: on nuclear envelope. allows for movement of water soluble substances[RNA] - nucleolus: responsible for synthesis and arrangement of ribosomes - nucleus: controls protein synthesis by controlling the production of messenger RNA - chromatin: thread like substances made of DNA and protein. contains hereditary information and instructions to carry out chemical reactions within itself. Endoplasmic Recticulum: - continous sheet of membrane enclosing a single internal space. joined frm the nuclear envelope. - involved in protein and lipids synthesis. [synthesis of membrane lipids, synthesis of transmembrane protein, synthesis of secretory membrane] -Rough endoplasmic recticulum folded sheet of membrane[faded] with black dots on it which are ribosomes. makes proteins for export more in white blood cell transmembrane protein inserted into membrane after production secretory proteins produced in lumen [antibiotics] -Smooth endoplasmic reciculum tubular cabohydrate metabolism synthesis of lipids [e.g phospholipids and steriods] detoxification of drugs Ribsomes: -small circular substance -consist of a large subunit and a small subunit -membrane-bound ribosomes produces membrane-bound proteins and secretory proteins -free ribosomes produces protein used by the cell Vesicles: -pinched off frm endoplasmic recticulum or golgi apparatus -transport protein Golgi apparatus: -vesicle frm ER joins golgi apparatus -site for carbohydrate synthesis -modification of products by ER [large proportion of carbohydrate synthesised attached as side chairs to proteins and lipids (to modify protein)] -modified protein sorted into different vesicles and transported to appropriate target -prominent in cells specialised in secretion Lysosomes -contains enzymes for digestion of proteins [controls intercellular digestion of macromolecules] -interior pH of 5. best environment for enzymes. membrane keeps acid in. -derived from golgi apparatus. proteins placed in lysosomes. hydrogen added to make it acidic. Peroxisomes -found in all eukaryotic cells. contains oxidative enzymes such as catalase to detoxify -use hydrogen peroxide produced by other enzymes to oxidise other chemicals -peroxisomes in liver and kidney detoxifies toxic substances that enter the blood stream. Mitochondrion -surrounded by 2 membranes [inner and outer mitochondrial membrane] -contains DNA and ribosomes -site of cellular respiration reaction, where "fuels" are oxidised and energy is released for cellular activities. Centrioles -facilitate cell division -has nuclues Cytoskeleton -provides a mechanical support for the animal cell which lacks a rigid cell wall -joins protein complexes and organelles frm different regions -structure to hold organelles in place and guide the movement of organelles -acts as tracks of transports -made of protein Flagella and cilia -involved inlocomotion -structure for movements -cilia are tiny like appandages extending frm the surface of the cell. usually found in large numbers on the cell surface -flagella are similar to cilia but longer -flagella found in sperm Chloroplasts -surounded by 2 membranes. inner and outer chloroplast membranes. in addition there is a 3rd membrane consisting of thylakoids. -site of photosynthetic reaction. contains chlorophyll that traps light energy and converts to chemical energy -example of broader class of plant organelle called plastids Vacuole -contains water and food substances in animal cells -contains sap [dissolved substances such as sugar, mineral salt and amino acid] in plant cells -storage compartment for nutrients and waste products. -controller of turgor pressure -regulate pH -degradative compartment -may contain anthocyanin. gives petal colour to attract insects or noxious chemical when plant is eaten or damaged to ward off insects. Cell wall -cellular. other hardening/waterproofing substances -primary cell wall [secreted by young plant cell. thin-walled and flexible] -secondary cell wall [deposited between primary cell wall and plasma membrane] Specialised cells Red blood cell: -biconcave shape increases surface area to volume ratio. oxygen diffuses in and out of entire cell at a faster rate -contains red pigment haemoglobin that transport oxygen frm lungs to other parts of the body -no nucleus, more haemoglobin therefore more oxygen Xylem vessels -long hollow tube made by xylem cells laid back to back. no cross-wall and protoplasm to allow flow of water through central space or lumen. condict water frm roots to stem and leaves -lignin deposited on wall od vessels. strengthens wall and prevents vessel frm collapsing. when bundled together, vessels can act as mechanical support for the plant. Root hair cell -long and narrow. increases surface area to volume ratio. allow better and efficient absorbing of water and mineral salts frm the soil. Simple Diffusion, Osmosis Diffusion -net movement of particles over a concentration gradeint -from high concentration to low concentration -proved when a bottle of perfume is opened and the whole room has the smell -diffusion in water -solid diffuse in water and gets a solution -permeable membrane allows all particles to pass through. hence, particles of solids are able to diffuse until the amount of molecules is the same on each side of the container Osmosis -net movement of water molecules through a partially permeable membrane -from high water potential to low water potential -water potential refers to the measure of the tendency of the water to move from one place to another. -as the partially permeable membrane only allows water particles to pass through, water molecules will move around until both end of the tube has the same number of water molecules. the water level at the end of the tube wif higher water potential will be lower than that of the end wif lower water potential -when placed in a solution with high water potential plant cell: becomes turgid. water enters the cell and vacuole expands. it pushes the contents against the cell wall. as the cell wall is strong and inelastic,an opposite force is acting on the water as it enters the cell. this prevents more water frm entering the cell. the turgidity of the cell is called turgor. the pressure exerted by the water on the cell wall is turgor pressure. the cell membrane is partially permeable. animal cell: cell swells as water enters. and may even burst as it does not hav a cell wall [lysed.] -when placed in a solution wif the same water potential no difference to the cell -when placed in a solution of lower potential plant cell: water escapes by osmosis. vacuole decreases in size and cytoplasm shrinks frm the cell wall. this is call plasmolysis. the cell is plasmolysed animal cell: water leaves the cell. cell shrinks and spikes appear on cell surface membrane. cell is crenated. process is crenation. -turgidity in plants. maintains shape of soft tissues in plant. most leaves and young plants able to remain due to turgor pressure within the cell. if turgidity is lost, plant wilts and die. -surface area to volume ratio the larger the surface area per unit volume, the faster rate of diffusion over a given concentration gradient. Cell division Mitosis -prophase: chromatin coils and shortens to form chromosomes. each chromosome consisting of 2 daughter chromatids joined by a centromere. Asters forms around centriole. Asters made of microtubules. two pairs of centrioles move to opposite ends of cell. nucleolus disappears. nuclear membrane disappears. spindle forms spindle fibre extending frm each end of the cell -metapahse: chromosomes move to equator of spindle. centromere of each chromosomes attached to spindle fibre -anaphase: each centromere spilts. spindle pulls chromatids apart of opposite ends of cell. once sepeerated, they are called daughter chromosomes. -telophase: s[indle fibre breaks down. nuclear envelope forms around chromosomes at each poles of cell. nucleolus forms, chromosomes uncoil and lengthen to become chromatin threads. -cytokinesis: division of cytoplasm. furrows or cleavage appear in cytoplasm between two nuclei. furrows deepen and identical daughter chromosome are produced. -important in growth of living organism. repairs worn outs and for asexual reproduction in plants. ---------------------------------------------------------------------------------- damn long i still hav meiosis gah. |
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SEE Yihui. monkey. 28nov.
proudly Singaporean. chaolaoshu. lurenjia. huizz. nyav. tankfc. chengho. 7duohua. 黃城夜韻. Operation Smile. S-SIX-BEE. ♥ LOVES NEWS. Tamamori Yuta. 蘇打綠. Kis-My-Ft2. Kato Shigeaki. Nishikido Ryo *WISHES Trip to Japan/Taiwan. Work in Esplanade. Perform on stage. Currently watching Lady~Saigo no Hanzai Profiling. Control. My Princess. worth $1,212,030. |
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Tuesday, February 06, 2007 @ 10:24 PM
pardon me
this is gonna be boring ultrastructure of cell protoplasm: cell membrane, cytoplasm [exist as cytosol:jelly like substance] and nucleus [not present in cell] nucleus: - nucleoplasm [jelly like substance]. contains genetic blueprint in the form of DNA-bearing chromosomes. - nuclear envelope: a membrane boundary consisting of 2 membranes. - nuclear pore: on nuclear envelope. allows for movement of water soluble substances[RNA] - nucleolus: responsible for synthesis and arrangement of ribosomes - nucleus: controls protein synthesis by controlling the production of messenger RNA - chromatin: thread like substances made of DNA and protein. contains hereditary information and instructions to carry out chemical reactions within itself. Endoplasmic Recticulum: - continous sheet of membrane enclosing a single internal space. joined frm the nuclear envelope. - involved in protein and lipids synthesis. [synthesis of membrane lipids, synthesis of transmembrane protein, synthesis of secretory membrane] -Rough endoplasmic recticulum folded sheet of membrane[faded] with black dots on it which are ribosomes. makes proteins for export more in white blood cell transmembrane protein inserted into membrane after production secretory proteins produced in lumen [antibiotics] -Smooth endoplasmic reciculum tubular cabohydrate metabolism synthesis of lipids [e.g phospholipids and steriods] detoxification of drugs Ribsomes: -small circular substance -consist of a large subunit and a small subunit -membrane-bound ribosomes produces membrane-bound proteins and secretory proteins -free ribosomes produces protein used by the cell Vesicles: -pinched off frm endoplasmic recticulum or golgi apparatus -transport protein Golgi apparatus: -vesicle frm ER joins golgi apparatus -site for carbohydrate synthesis -modification of products by ER [large proportion of carbohydrate synthesised attached as side chairs to proteins and lipids (to modify protein)] -modified protein sorted into different vesicles and transported to appropriate target -prominent in cells specialised in secretion Lysosomes -contains enzymes for digestion of proteins [controls intercellular digestion of macromolecules] -interior pH of 5. best environment for enzymes. membrane keeps acid in. -derived from golgi apparatus. proteins placed in lysosomes. hydrogen added to make it acidic. Peroxisomes -found in all eukaryotic cells. contains oxidative enzymes such as catalase to detoxify -use hydrogen peroxide produced by other enzymes to oxidise other chemicals -peroxisomes in liver and kidney detoxifies toxic substances that enter the blood stream. Mitochondrion -surrounded by 2 membranes [inner and outer mitochondrial membrane] -contains DNA and ribosomes -site of cellular respiration reaction, where "fuels" are oxidised and energy is released for cellular activities. Centrioles -facilitate cell division -has nuclues Cytoskeleton -provides a mechanical support for the animal cell which lacks a rigid cell wall -joins protein complexes and organelles frm different regions -structure to hold organelles in place and guide the movement of organelles -acts as tracks of transports -made of protein Flagella and cilia -involved inlocomotion -structure for movements -cilia are tiny like appandages extending frm the surface of the cell. usually found in large numbers on the cell surface -flagella are similar to cilia but longer -flagella found in sperm Chloroplasts -surounded by 2 membranes. inner and outer chloroplast membranes. in addition there is a 3rd membrane consisting of thylakoids. -site of photosynthetic reaction. contains chlorophyll that traps light energy and converts to chemical energy -example of broader class of plant organelle called plastids Vacuole -contains water and food substances in animal cells -contains sap [dissolved substances such as sugar, mineral salt and amino acid] in plant cells -storage compartment for nutrients and waste products. -controller of turgor pressure -regulate pH -degradative compartment -may contain anthocyanin. gives petal colour to attract insects or noxious chemical when plant is eaten or damaged to ward off insects. Cell wall -cellular. other hardening/waterproofing substances -primary cell wall [secreted by young plant cell. thin-walled and flexible] -secondary cell wall [deposited between primary cell wall and plasma membrane] Specialised cells Red blood cell: -biconcave shape increases surface area to volume ratio. oxygen diffuses in and out of entire cell at a faster rate -contains red pigment haemoglobin that transport oxygen frm lungs to other parts of the body -no nucleus, more haemoglobin therefore more oxygen Xylem vessels -long hollow tube made by xylem cells laid back to back. no cross-wall and protoplasm to allow flow of water through central space or lumen. condict water frm roots to stem and leaves -lignin deposited on wall od vessels. strengthens wall and prevents vessel frm collapsing. when bundled together, vessels can act as mechanical support for the plant. Root hair cell -long and narrow. increases surface area to volume ratio. allow better and efficient absorbing of water and mineral salts frm the soil. Simple Diffusion, Osmosis Diffusion -net movement of particles over a concentration gradeint -from high concentration to low concentration -proved when a bottle of perfume is opened and the whole room has the smell -diffusion in water -solid diffuse in water and gets a solution -permeable membrane allows all particles to pass through. hence, particles of solids are able to diffuse until the amount of molecules is the same on each side of the container Osmosis -net movement of water molecules through a partially permeable membrane -from high water potential to low water potential -water potential refers to the measure of the tendency of the water to move from one place to another. -as the partially permeable membrane only allows water particles to pass through, water molecules will move around until both end of the tube has the same number of water molecules. the water level at the end of the tube wif higher water potential will be lower than that of the end wif lower water potential -when placed in a solution with high water potential plant cell: becomes turgid. water enters the cell and vacuole expands. it pushes the contents against the cell wall. as the cell wall is strong and inelastic,an opposite force is acting on the water as it enters the cell. this prevents more water frm entering the cell. the turgidity of the cell is called turgor. the pressure exerted by the water on the cell wall is turgor pressure. the cell membrane is partially permeable. animal cell: cell swells as water enters. and may even burst as it does not hav a cell wall [lysed.] -when placed in a solution wif the same water potential no difference to the cell -when placed in a solution of lower potential plant cell: water escapes by osmosis. vacuole decreases in size and cytoplasm shrinks frm the cell wall. this is call plasmolysis. the cell is plasmolysed animal cell: water leaves the cell. cell shrinks and spikes appear on cell surface membrane. cell is crenated. process is crenation. -turgidity in plants. maintains shape of soft tissues in plant. most leaves and young plants able to remain due to turgor pressure within the cell. if turgidity is lost, plant wilts and die. -surface area to volume ratio the larger the surface area per unit volume, the faster rate of diffusion over a given concentration gradient. Cell division Mitosis -prophase: chromatin coils and shortens to form chromosomes. each chromosome consisting of 2 daughter chromatids joined by a centromere. Asters forms around centriole. Asters made of microtubules. two pairs of centrioles move to opposite ends of cell. nucleolus disappears. nuclear membrane disappears. spindle forms spindle fibre extending frm each end of the cell -metapahse: chromosomes move to equator of spindle. centromere of each chromosomes attached to spindle fibre -anaphase: each centromere spilts. spindle pulls chromatids apart of opposite ends of cell. once sepeerated, they are called daughter chromosomes. -telophase: s[indle fibre breaks down. nuclear envelope forms around chromosomes at each poles of cell. nucleolus forms, chromosomes uncoil and lengthen to become chromatin threads. -cytokinesis: division of cytoplasm. furrows or cleavage appear in cytoplasm between two nuclei. furrows deepen and identical daughter chromosome are produced. -important in growth of living organism. repairs worn outs and for asexual reproduction in plants. ---------------------------------------------------------------------------------- damn long i still hav meiosis gah. |
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