Refer to Campbell and Reece, 2010 –Chapter 6 and 7 p. 96-123 and 125-131,Edulink and learning guide notes
The study of cells and micro organisms haschanged over time with the change intechnology. These were studied in the beginning with handlenses, single lens microscope, light microscope Today we have electron microscopes. Two types of electron microscopes are usedtoday: SEM – Scanning electron microscopeand TEM – Transmission electron microscope.
Developed a microscopewith one lens. Discovered- bacteria- blood cells- spermatozoa- protozoa
Uses the concept cellfor the first time. He used it when helooked at themicroscopicstructure of corkcells.
Developed the cell theory:- Plants and animals are made of groupsof cells.- The cell is the basic unit of livingorganisms
Expanded the cell theory: He said that new cells formed by thedivision of existing cells
Expanded the celltheory more: He said that all cellscan be traced to theirorigin
All living organisms are made out of cells New cells are formed by the division ofexisting cells The cell houses genes, which are theblueprint for growth, functioning anddevelopment of cells The cell is the functional unit of lifebecause all chemical reactions of life takeplace inside the cell
A cell is the basic unit ofstructure and function inorganisms. Cells differ in size, shape and infunction. A cell consist of smallerstructures called organelles.
Prokaryotic or Eukaryotic cells. Only organisms of the domains Bacteriaand Archaea consist of prokaryotic cells –cells without a membrane bound nucleus. Protists, fungi, animals and plants allconsist of eukaryotic cells – cell with amembrane bound nucleus.
Porous Varies in thickness Consist of pectin (elasticity), cellulose fibrilsheld together with non-cellulose substances(hardens the cell when mature) and lignin(adds strength to cell especially in woodyplants) Cell wall is permeable and protects the insideof the cell. Middle lamella (layer of adhesive substances) –holds the cells together Plasmodesmata (pores) that connects thecytoplasm of the connecting cells – selectivelypermeable
Consist of 2phospholipid layersand proteins inbetween. The phospholipidlayers are parthydrophillic andpart hydrophobic
+/- 5µm, largest organelle in cell. Enclosed by a nucleomembranewith nuclear pores. Function:Protection and add to selectivepermeability. Filled with nucleoplasma, anucleolus and chromatin. Functionof chromatin: carries geneticmaterial in the form ofchromosomes. Function of nucleolus: Produce r-RNA
Consist of 2 membranes: Outer –and a highly convoluted innermembrane- These folds arecalled cristae – they increase thesurface area. Filled with matrix called stromathat contains DNA andribosomes. Function: Produce energy in theform of ATP by means ofcellular respiration
Enclosed by a doublemembrane Filled with stroma andthylakoids filled withchlorophyll arranged ingroups called grana. Ribosomes and starch grainsin stroma. Function: Photosynthesis
Membranous sac Filled with cell sap. Causes turgor pressure in thevacuole. Function: Stores varioussubstances, including waste. Helps with osmotic potential ofcell.
Endoplasmic Reticulum – Transportsystem in cell Ribosomes – Protein synthesis Golgi-apparatus – Make lysosomes andacts as transport system. Lysosomes – Intracellular digestion. Plastids e.g.– Leucoplasts – Storesstarch- Chromoplast – gives colourto flowers and fruit.* Centrioli – Mitosis in animal cells
The cell membrane has the ability toregulate transport molecules acrossits structure. This function is essential to the cell’sexistence. The fluid mosaic model helps toexplain how membranes regulate thecell’s molecular traffic.
Hydrocarbons, carbon dioxide andoxygen – non-polar So they can dissolve in the lipid bilayer ofthe membrane. They can cross the membrane withoutthe aid of membrane proteins. Polar molecules like, water and glucosemove slowly across the membrane andneed the aid of proteins to get acrossthe membrane.
Hydrophyllic substances can avoidcontact with the hydrophobic lipid bilayerby passing through transport proteins thatspan the membrane. Channel proteins – tunnel for polarmolecules to pass through membrane Aquaporins – channel proteins for thetransport of water
Carrier protein: Hold onto solutes thatwant to move across the membrane andchanges shape as it moves through themembrane. Each carrier protein is specific to what ittransports.
The microscope is an instrumentdesigned to observe objects too small tobe seen with the naked eye. The human eye cannot distinguishobjects much smaller than 0.1mm. The microscope act as an extension ofthe eye, allowing one to see smallerobjects.
STUDY HOW TO TAKE CARE OF THEMICROSCOPE AND HOW TO MAKE AMICROSCOPE SLIDE.