Presentation on theme: "Cell The smallest unit of life that can perform all life processes."— Presentation transcript:
Cell The smallest unit of life that can perform all life processes.
“Life is macromolecules that can perform unique functions because they are enclosed in a structural compartment that is separate from the external environment. This separation allows living things to maintain a constant internal environment (homeostasis)”. Purves, pg. 61
“little wretched beasties” Antone van Leeuwenhoek - lenses
“cells” Robert Hooke
The Cell Theory (3 parts) 1. All organisms are made of one or more cells. 2. The cell is the basic unit of all living things. Theodor Schwann (zoologist) Matthias Schleiden (botonist)
All organisms are made of one or more cells The cell is the basic unit of all living things 3. All cells come from pre-existing cells Redi – spontaneous generation Pasteur – spontaneous generation
Structure and Function 2 types of cells prokaryote eukaryote Cells that DO NOT have a cell membrane around their nucleus. Example – Bacteria Cells that have a membrane around their nucleus. Plant and Animal Cells Eukaryote cells usually 10X larger than Prokaryote cells.
eukaryotic cells The basic Eukaryotic cell contains: Plasma membrane around their nucleus Cytoplasm (the semi fluid substance inside the membrane. A cytoskeleton – gives it shape, and allows for the cell’s motion. Has membrane enclosed organelles.
the plasma membrane Lipid bilayer with embedded proteins
plant cell wall cellulose
Cell Review: structure and function
the nucleus contains the genetic material
rough ER alters proteins folds into tertiary structures transports newly synthesized proteins
smooth ER site for hydrolysis of glycogen modifies (detox.) small molecules site for synthesis of lipids and steroids
golgi apparatus recieves proteins from ER – further modifications Concentrates, packages, sorts proteins Polysacc. for plant cell walls synthesized
secreting side receiving side
Vesicles and vacuoles The function and importance of vacuoles varies greatly according to the type of cell in which they are present.
Isolating materials that might be harmful or a threat to the cell. Breaking down products taken into the cell to be used in metabolism. Exporting unwanted substances from the cell. Allows plants to support structures such as leaves and flowers. Exporting manufactured products from the cell. functions of the vacuole include:
endocytosis and exocytosis taking in expelling Uses energy Encloses material in vesicles pinocytosis phagocytosis
special vesicles and vacuoles lysosomes contain hydrolytic enzymes - break down cellular waste products, fats, carbohydrates, proteins, and other macromolecules into simple compounds, which are then transferred back into the cytoplasm as new cell-building materials
autophagy - recycles the cell's organic material
special vesicles and vacuoles peroxisomes the most common vesicle in cells found in all eukaryotes contain enzymes to rid the cell of hydrogen peroxide (convert the hydrogen peroxide to water) some detoxify alcohol and other harmful compounds by transferring hydrogen from the poisons to molecules of oxygen (oxidation). others initiate production of phospholipids
special vesicles and vacuoles central vacuole contractile vacuole Helps maintain homeostasis for water balance (osmotic equilibrium)
central vacuole (plants ONLY) Maintaining internal hydrostatic pressure or turgor within the cell
contractile vacuole (animals ONLY) found in certain unicellular organisms pumps fluid from in the cell to the outside by alternately filling and then contracting
ribosomes site of protein synthesis
microfilaments & microtubules
microfilaments - actin intermediate filaments – protein polymers such as keratin
microtubules - conveyer belts inside the cells They move vesicles, granules and organelles via special attachment proteins. They also serve a cytoskeletal role. Structurally, they are linear polymers of tubulin (a globular protein). The tubulin molecules are the bead like structures. Microtubules may work alone, or join with other proteins to form cilia, flagella or centrioles.
Molecular "tags" on microtubules direct traffic inside cells