* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download The Cell PPT File
Survey
Document related concepts
Biochemical switches in the cell cycle wikipedia , lookup
Cell encapsulation wikipedia , lookup
Cellular differentiation wikipedia , lookup
Cell culture wikipedia , lookup
Cytoplasmic streaming wikipedia , lookup
Extracellular matrix wikipedia , lookup
Cell growth wikipedia , lookup
Organ-on-a-chip wikipedia , lookup
Signal transduction wikipedia , lookup
Cell nucleus wikipedia , lookup
Cytokinesis wikipedia , lookup
Cell membrane wikipedia , lookup
Transcript
THE CELL STRUCTURE AND FUNCTION MISS PANZICH 2A/B Human Bio Cells tissues organs systems Our cells are found everywhere! Imagine the cell like a factory containing many parts that have different functions. These parts are: • • • • • • • • • • Nucleus Cell membrane Cytoplasm Mitochondria Endoplasmic Reticulum Golgi Apparatus Ribosomes Vacuole Lysosome Cytoskeleton YOU WILL NEED TO KNOW AND LABEL ALL OF THESE ORGANELLES AND KNOW THEIR FUNTIONS (WHAT THEY DO)! Organelles • Organelles = the cell structures that are specialised for particular functions. Cell membrane • double layer made up of lipid molecules (phospholipids and cholesterol) + various proteins • A semi-permeable membrane that allows materials to pass – It is selective as to what materials will go through it (it will depend on the material) – and by what process. • Materials pass through the membrane in a number of different ways: – Passive transport (diffusion, osmosis), – Active transport (phagocytosis, pinocytosis) Cytoplasm • The material in which the cell contents are suspended • fills the space between the nucleus and the cell membrane • 75 –90% water • Substances are either – Dissolved: sugars and inorganic materials; – Suspended: proteins and lipids. • Protoplasm refer to the whole contents of the cell(cytoplasm and nucleus). Nucleus • Separated from the cytoplasm by nuclear membrane (double layer membrane with numerous gaps - nuclear pores). • contains DNA - which controls the type of protein a cell can make and the chemical reactions that occur in the cell (controls the cell activity) • When DNA is not duplicating, it is found as chromatin. In a dividing cell it found as chromosomes. Nucleolus • Within the nucleus is an area called the nucleolus. • Nucleolus mainly composed of RNA (ribonucleic acid) which plays a vital role in protein synthesis. • Both chromatin and nucleolus are suspended in the nucleoplasm. Ribosomes • small spherical organelles. • They could occur free in the cytoplasm or bound to endoplasmic reticulum membrane. • Make proteins via protein synthesis: amino acids are joined together to form proteins in a sequence determined by DNA. (i.e. take information from the DNA and use it to make proteins) Mitochondria: • spherical or elongated in shape. • Each has a double membrane (outer-smooth and inner-folded) • Known as the ‘powerhouse’ of the cell • Chemical reactions take place on the inner surface of the mitochondrion = site of cellular respiration whereby it produces energy (ATP) for the cell Endoplasmic Reticulum • Pair of parallel membranes form a network of channels. • endoplasmic reticulum provide a surface for chemical reactions, while the inner channels are for storing or transporting molecules. ROUGH ER (granular): ribosome's attached SMOOTH ER (agranular): no ribosome's STORE, TRANSPORT SA for REACTIONS Golgi Apparatus • flattened membranous bags stacked one upon the other. Ends are often expanded. • It modifies proteins and packages them for secretion from the cell. • It may add sugar, phosphate, sulphate, fatty acid etc… to the protein made at the ribosome. • At the edge of the Golgi apparatus the membrane pinches off to form a vesicle carrying the modified protein for transport outside the cell. Centrioles • pair of cylindrical structures close to the nucleus. • made up of a ring of microtubules triplets that are perpendicular to each other. • The pair of centrioles are also perpendicular to each other. • They play a vital role in cell division (mitosis) Lysosome • They contain digestive enzymes capable of breaking down lipids, proteins, nucleic acids, and some carbohydrates. • They also digest wornout organelles. • When particles enter the cell in a vesicle, a lysosome fuses with the vesicle and digests all the contents. Cytoskeleton • framework of protein fibres that gives the cell its shape. • Microtubules - hollow rods that fix organelles or move them • Microfilaments - move materials around cytoplasm/move whole cell. Cilia and flagella • some cells have fine projections that move materials past the cell or move the whole cell itself. • If projections are very fine and small they are called cilia (tiny hairs). • If projections are longer and only one or two are found they’re called flagella. (e.g. Sperm) Inclusions - extras • Are not part of the cell structure (e.g. melanin in skin / haemoglobin in RBC) • If the inclusion is a liquid that is capable of mixing with the cytoplasm, then it is surrounded by a membrane and known as a vacuole. Vacuoles are like a storage compartment. Rare in animal cells, more common in plant cells