Organelles

Welcome to “Organelles” - BiologyPod Episode 1 2009 brought to you by Simon Cohen – [email protected] In this Podcast we will be looking at cell theory, different types of organisms and organelles within cells. Cell Theory all living organisms are composed of cells (and the products of cells) all cells come from other cells the cell is the smallest organisational unit of living things Different Organisms Prokaryote e.g. Bacteria may have a cell wall (or capsule) but no organelles, some contain chlorophyll (cyanobacteria) DNA Circular. Eukaryotic Protista e.g. Algae and Amoeba – mostly single celled organisms, some have cell wall, some contain chloroplasts. Eukaryote Fungi – like plants but non-cellulose cell wall and no chloroplasts Eukaryote Plants – Cellulose cell wall, chloroplasts and large central vacuole Eukaryote Animal – No cell wall, no chloroplasts small vacules. Organelles Cell membrane: (also called the plasma membrane) a fluid bilayer of phospholipid molecules enclosing the cytoplasm in all cells. It controls the movement of material into and out of the cell and communication between cells. Chloroplast: found in some cells of plant and some protests,; a green organelle (due to chlorophyll) where photosynthesis takes place. It is composed of a membrane folded into many layers called grana. Cytoplasm: the contents of a cell, other than the nucleus. Mostly water it also contains ions, salts, enzymes, food molecules and organelles (other than the nucleus.) Cytosol: the fluid, watery, component of cytoplasm between organelles. Endoplasmic reticulum: a network of intracellular membranes that links with the nuclear membrane. Endoplasmic reticulum may be rough (associated with ribosomes) or smooth (lacking ribosomes). It is involved with the production, processing, transport and storage of materials within the cell. Golgi apparatus: a stack of flat membrane sacs where the final synthesis and packaging of proteins into vesicles occurs before they are secreted from the cell. It is closely associated with the endoplasmic reticulum. Lysosomes: membrane-bound vesicles containing enzymes that break down waste materia. Mitochondria: organelles composed of many folded layers of membrane. Mitochondria are involved respiration, the energy transformations that release energy for use by the cell. Nucleus: a large organelle that contains genetic material (chromosomes composed of DNA and proteins) and controls cellular activities. It is surrounded by a double-layered nuclear membrane, containing pores that communicate with the cytoplasm Ribosomes: tiny organelles located in the cytosol, sometimes associated with endoplasmic reticulum. They are sites of production of proteins. Vacuole: a membrane-bound, liquid-filled space found in most cells. Plant cells typically have large fluid-filled vacuoles, containing cell sap, that provide both physical support through turgidity and storage. In other cells, vacuoles may be involved in intracellular digestion (food vacuoles) or water balance (contractile vacuoles). Vesicles: membrane-bound organelles often associated with transport in cell.