Cell Structure and Cell Structure and CompositionComposition
Prepared by:Ms. Bernabeth Jo T. Tendero
Major Parts of the CellMajor Parts of the CellNucleusCytoplasmCell Surface
NucleusNucleusRegion of the cell where the
genetic material is locatedGenerally oval-shaped or
spherical shapedMost conspicuous part of the cellRegulates and coordinates all the
activities of the cellDenser than surrounding
cytoplasm
Parts of the NucleusParts of the Nucleus
Parts of the NucleusParts of the NucleusChromosomes
- in form of chromatin- contains genetic information- Composed of DNA- Thicken for cellular division- Set number per species (i.e. 23 pairs for human)
ChromosomesChromosomes
ChromatinChromatin
Nuclear MembraneNuclear MembraneSurrounds the nucleusDouble membraneHas numerous opening called
nuclear pores which serves as pathways for exchange of materials between the nucleus and the cytoplasm
Nuclear MembraneNuclear Membrane
NucleolusNucleolusSpherical shapeVisible when cell is not dividingContains RNA for protein
manufacture
NucleolusNucleolus
CytoplasmCytoplasmProtoplasm found outside the
nucleusCollective term for cytosol and
organellesColloidal suspensionCytosol composed mainly of
water with free floating molecules
Viscosity constantly changes
OrganellesOrganellesDiscrete structures of a cell
having specialized functions
Centrioles: Helper in Cell Centrioles: Helper in Cell DivisionDivision
Paired cylindrical organelles near nucleus
Composed of nine tubes, each with three tubules
Involved in cellular divisionLie at right angles to each other
CentriolesCentrioles
Cytoskeleton: Framework of Cytoskeleton: Framework of the Cellthe Cell
Composed of microtubulesSupports and provides shapeAids movement of materials in
and out of cellsMicrotubules provide pathways
for certain cellular molecules to move about
CytoskeletonCytoskeleton
Endoplasmic Reticulum: Endoplasmic Reticulum: Manufacturers and Builders Manufacturers and Builders
of the Cellof the CellTubular network fused to nuclear membrane
Goes through cytoplasm onto cell membrane
Stores, separates and serves as cell’s transport system
Endoplasmic ReticulumEndoplasmic Reticulum
Endoplasmic Reticulum: Endoplasmic Reticulum: Manufacturers and Builders Manufacturers and Builders
of the Cellof the Cell2 types Rough Endoplasmic Reticulum (RER) - occurs as flattened sheets studded on its outer surface with small spherical bodies called ribosomes- aids in protein synthesis- prevalent in cells that specializes in secreting proteins
Rough Endoplasmic Rough Endoplasmic ReticulumReticulum
Endoplasmic Reticulum: Endoplasmic Reticulum: Manufacturers and Builders Manufacturers and Builders
of the Cellof the Cell2 types Smooth Endoplasmic Reticulum (SER) - occurs as tubes of membranes without
ribosomes attached- site for fat metabolism and forms vesicles for transporting large molecules to other cell parts
Smooth Endoplasmic Smooth Endoplasmic ReticulumReticulum
Golgi Apparatus: Packaging Golgi Apparatus: Packaging Counters of the CellCounters of the Cell
Discovered and named after Camillo Golgi in 1898 by observing nerve cells of an owl
A system of membrane-bound sacs that look like a stack of pancakes
Believe to be part of ER and where new membranes for the ER are manufactured
Believe to prepare proteins for secretion after they are released from the ER
Golgi ApparatusGolgi Apparatus
Lysosomes: Suicide Bags of Lysosomes: Suicide Bags of the Cellthe Cell
“Lyso” – dissolving power and “some” – body
Discovered in 1952Contains hydrolytic/digestive
enzymes for proteins, lipids and carbohydrates
Transports undigested material to the cell membrane for removal
Destroys cells when lysosomes burst
LysosomesLysosomes
Mitochondria: Powerhouses Mitochondria: Powerhouses of the Cellof the Cell
2nd largest organelle with its own DNA (mtDNA)
Double layered outer membrane with inner folds called cristae
Energy-producing chemical reactions (produces ATP) takes place on cristae
Controls level of water and other materials in cell
Recycles and decomposes proteins, fats and carbohydrates, and forms urea
MitochondriaMitochondria
MitochondriaMitochondria
Ribosomes: Protein Factories Ribosomes: Protein Factories of the Cell of the Cell
Composed of nucleic acids (RNA) and proteins
Numerous in cellsManufacture proteins
RibosomesRibosomes
RibosomesRibosomes
Vacuoles: Storage Tanks of Vacuoles: Storage Tanks of the Cellthe Cell
Membrane-bound sacs for storage, digestion and waste removal
Contains water solutionContractile vacuoles for water
removal
VacoulesVacoules
PeroxisomePeroxisomeContain enzymes that transfer
hydrogen to various substrate of oxygen to produce hydrogen peroxide
Use oxygen to break fats to use as fuel for cellular respiration
Detoxify alcohol and other harmful compounds
PeroxisomesPeroxisomes
Chloroplast: Site of Chloroplast: Site of PhotosynthesisPhotosynthesis
Plastid found in plant cellsContains green chlorophyll where
photosynthesis takes placeHas its own DNA and ribosomesDouble membrane bound
organelleMobile and move around the cell
through cytosleleton
ChloroplastChloroplast
Cell SurfaceCell SurfaceProtectively surrounds the cellPlasma membraneCell wallPlasmodesmata
Plasma MembranePlasma MembraneDouble layer of phospholipid
moleculesEach phospholipid is composed of
fats, phosphate and carbohydrates (oligosaccharide)
Protein molecules are embedded in phospholipids
Because of its structure the membrane has a semi-permeable property that allows only chosen substances to enter and leave the cell
Plasma MembranePlasma Membrane
Cell WallCell WallLies outside the plasma
membraneCompose of celluloseProtects the cells and provide
rigid structure for cellsRemains intact even after the
rest of the cell has died
Cell WallCell Wall
Cell WallCell Wall
Cell WallCell Wall
PlasmodesmataPlasmodesmatasmall channels that directly
connect the cytoplasm of neighboring plant cells to each other, establishing living bridges between cells
allow certain molecules to pass directly from one cell to another and are important in cellular communication
PlasmodesmataPlasmodesmata
PlasmodesmataPlasmodesmata