Cell Structure and Cell Organisation
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Transcript of Cell Structure and Cell Organisation
Regulating the internal environmentCells bathe in the internal environment which contain interstitial fluid.The internal environment must be regulated to maintain its level. Do you know why?The constant internal environment ensure the cells to function optimally.The process involves in maintaining the balance of internal environment is called .homeostasisWhich type of mechanisms involves in homeostatic mechanism?Plasma membrane
OrganelleFunctionsCell membraneCell membrane forms a boundary to separate the content of a cell from outer environment.Cell membrane regulates the movement of substances into and out of the cytoplasm.Cell wallCell wall gives shape to a plant cell.Cell wall provides mechanical support for the plant cells.CytoplasmCytoplasm acts as a medium for biochemical reactions in the cell.NucleusNucleus contains genetic information that determines the characteristics and functions of the cell.Nucleus controls all the activities which take place in the cell. vacuoleVacuole regulates water balance in the cell.Vacuole acts as a storage place in a cell.Task 2.1.2 Complete the below table to state the functions of each organelle.MitochondrionMitochondria carry out cellular respiration to release energy in form of ATP.RibosomeRibosomes synthesise protein.Endoplasmic reticulumRough ER transports proteins made by ribosome.Smooth ER is the site of metabolic reactions synthesis of lipids and detoxification of drugs and poisons.Golgi apparatusGolgi apparatus process, package and transport carbohydrates, proteins, phospholipid and glycoprotein.LysosomeLysosome contains hydrolytic enzymes to digest complex organic molecules.Lysosome eliminates worn out mitochondria and other damaged organelles.Centriole Centriole functions during cell division in animal cells.ChloroplastsChloroplast traps sunlight and converts light energy into chemical energy during photosynthesisYou have learnt about the cellular components of animal and plant cells. Now, carry out a discussion among your group to compare and contrast the structure of animal and plant cells. You can present your findings by using table.Activity 2.1.3Animal CellPlant CellCORRECTIONSSimilarities:Both animal cell and plant cell have a nucleus, a plasma membrane, cytoplasm, Golgi apparatus, mitochondria, rough endoplasmic reticulum, smooth endoplasmic reticulum and ribosomes.
Differences:Animal CellPlant CellAnimal cell does not have fixed shape / regular shape.Plant cell has fixed/regular shape.Animal cell does not have cell wall.Plant cell has cell wall.Animal cell does not have chloroplasts.All green plants have chloroplasts.Animal cell does not have vacuole or if have, vacuoles are usually small and numerous.Mature plant cell has a large central vacuole.Animal cell has centrioles.Plant cell does not have centrioles.Animal cell stores carbohydrate in the form of glycogen.Plant cell stores carbohydrate in the form of starch.
Unicellular OrganismsHow does a unicellular organism perform its living processes?It depends on its cellular components which include the organelles. Specification / Differentiation
Multicellular organisms are made up of many types of cells. The cells undergo specialisation to become specific in order to perform different function. Therefore, certain organelles are found abundantly in the specific cells. For example, pancreatic cells which synthesise and secrete enzymes and hormones contain a high density of rough endoplasmic reticulum.The density of organelles in specific cells
Cell organisation in multicellular organismsCells Tissues Organs Systems Organism
Example of cell organisation in digestive system in a human
Cell organisation in mammalsCell organisation in plantsCells Tissues Organs Systems Organism
MeristematictissuesPermanenttissuesYoung, activelyDividing cellsDifferentionthin walls,large nuclei,dense cytoplasm,no vacuoles.Tips of roots and buds of shootsMature tissuesDifferentionarehaventlocated athavearehaveepidermal tissues,ground tissues,vascular tissues.consist of
Vascular tissueTransports materials in roots, stems & leaves
Xylem -carry water & minerals upfrom rootstube-shaped dead cellsonly their walls provide a systemof microscopic water pipes
Phloemcarry nutrients throughout plantsugars (sucrose), amino acids tube-shaped living cellsCorrective mechanismNormal value (set point)The value drops below the set pointCorrective mechanismThe negative feedback mechanismNormal value (set point)The value rises above the set point
Vacuole Sample Answer : Compare and contrast animal cell and plant cellAnimal CellPlant CellBoth animal cell and plant cell have plasma membrane, nucleus, cytoplasm, ribosomes, endoplasmic reticulum, Golgi apparatus and mitochondrion.Animal cell has centriole and lysosome.Plant cell does not have centriole and lysosome.Animal cell does not have cell wall, large central vacuole, and chloroplast.Plant cell has cell, wall, large central vacuole, and chloroplast.Animal cell has irregular shape.Plant cell has regular / fixed shape.Animal cell stores carbohydrates in the form of glycogen.Plant cell stores carbohydrates in the form of starch.Sample Answer: By giving appropriate examples, describe how different organelles work together to enable the cell to function in an orderly manner.Pancreas cell functions to produce enzyme. To produce enzyme, ribosome sends mRNA messenger to nucleus to copy DNA code. mRNA messenger returns to ribosome. Ribosome synthesise proteins based on the code. Proteins enters rough endoplasmic reticulum and is enclosed in vesicle. Vesicle with proteins fuses with Golgi apparatus. The proteins is modified to form specific enzyme. Then, the enzyme is enclosed in secretory vesicle. The secretory vesicle will fuse with plasma membrane and releases the enzyme out from the cell.