Cell Organelles  Aims:  Must be able to state the names and roles of the main cell organelles.  Should be able to describe and draw the structure of the main cell organelles.  Could be able to relate the structure of the organelles to the roles they perform.

Mitochondrion (ia)  ROLE: Production of ATP by oxidative phosphorylation (Aerobic Respiration).  Inner Matrix – contains enzymes for oxidative phosphorylation.  Also contains DNA, RNA and ribosomes – capable of duplication.  Inner membrane contains the electron transfer chain.  Site of attachment of the stalked particles – responsible for the production of ATP.

 ROLE: Protein synthesis.  FREE ribosomes produce cytoplasmic proteins.  Ribosomes bound to ENDOPLASMIC RETICULUM – Produce proteins for packaging and export.  Composed of two sub-units  Sub-unit is made of RNA and globular proteins. Ribosomes

Endoplasmic Reticulum  Large envelopes of membrane.  ROUGH – Ribosomes are attached to the surface.  Transport and Modification of proteins produced by the ribosomes.  SMOOTH – No Ribosomes present.  Involved in membrane synthesis. Also involved in steroid production.

 Made from modified SMOOTH ENDOPLASMIC RETICULUM. Like a stack of circular sacs.  Involved in final modification and packaging of proteins.  GLYCOPROTEINS and GLYCOLIPIDS are formed here.  Involved in the formation of LYSOSOMES and PEROXISOMES. Golgi Body (Apparatus)

Lysosomes  Membrane bound vesicle (stain very dark).  Cause AUTOLYSIS – cell destruction.  Act in the cell to destroy foreign macromolecules, bacteria, viruses.  Contain mixture of proteases, lipase, DNAase – involved in INTRACELLULAR DIGESTION.

 Membrane bound vesicle.  Contains enzymes which generate Hydrogen Peroxide (powerful oxidising agent which destroys bacteria).  Also contains enzymes which destroy Hydrogen Peroxide. Peroxisomes

Microtubules, Microfilaments  Make up cytoskeleton.  Microtubules are composed of tubulin, molecules usually arranged in highly ordered manor.  Microfilaments are often composed of actin and are involved in intercellular transport.  Microtubules are found in the spindle formed during cell division.

 Only found in Animal Cells.  Occur in pairs.  Composed of 9+2 microtubules.  Involved in the organisation of the mitotic and meiotic spindle which pulls chromosomes apart.  Responsible for cell polarity in Animals, determine the direction cell divides. Centrioles

Chloroplasts  Involved in photosynthesis:  Boundary is a double membrane – Inner extends to form a system of membranous sacs (LAMELLA / THYLAKOIDS), several together form GRANA.  Location for Light Dependent reactions of photosynthesis.  STROMA, semi-fluid substance between grana, contains enzymes needed in Light Independent reactions of photosynthesis.

 ROLE: Control of cellular activities.  Distinct spherical structure encased by a double membrane (EUKARYOTIC CELLS).  PROKARYOTIC CELLS have no membrane surrounding genetic material.  Contain one or more large inclusions – NUCLEOLI – Aggregation of RNA. Nucleus