Cells Anatomy Cells and Tissues Carry out all chemical activities Cells are the building blocks of all living things Tissues are groups of cells that are similar in structure and function Anatomy of the Cell Cells are not all the same All cells share general structures All cells have three main regions Nucleus Cytoplasm Plasma membrane The Nucleus Control center of the cell Contains genetic material (DNA) The Nucleus Three regions Nuclear envelope (membrane) Nucleolus Chromatin The Nucleus Nuclear envelope (membrane) Double membrane nuclear pores - exchange of material The Nucleus Nucleoli Sites of ribosome assembly Ribosomes move into the cytoplasm through nuclear pores The Nucleus Chromatin DNA and protein Present when the cell is not dividing Plasma Membrane Barrier for cell contents Double phospholipid layer Hydrophilic heads Hydrophobic tails Plasma Membrane Plasma Membrane Specializations Microvilli Finger-like projections that increase surface area for absorption Do all cells have microvilli? Plasma Membrane Specializations Membrane junctions Tight junctions Desmosomes Gap junctions Plasma Membrane Specializations Tight junctions Impermeable junctions Bind cells together into leak-proof sheets Desmosomes Anchoring junctions that prevent cells from being pulled apart (Think ANCHORS) Gap junctions Allow communication between cells (GAPS) Plasma Membrane Specializations Cytoplasm Cytoplasm is the material outside the nucleus and inside the plasma membrane Cytoplasm Cytosol Fluid that suspends other elements Organelles Little organs that perform functions Inclusions Stored nutrients or cell products Cytoplasmic Organelles Mitochondria Powerhouses of the cell Carry out reactions: oxygen used to break down food Provides ATP Cytoplasmic Organelles Ribosomes Sites of protein synthesis Found at two locations: Free in cytoplasm Part of the Rough ER Cytoplasmic Organelles Endoplasmic reticulum (ER) Fluid-filled tubules for carrying substances Cytoplasmic Organelles Rough ER Studded with ribosomes Synthesizes proteins Smooth ER Lipid metabolism and detoxification of drugs and pesticides Cytoplasmic Organelles Golgi apparatus Modifies and packages proteins: Extracellular fluid Plasma membrane Golgi vesicle containing membrane components fuses with the plasma membrane Golgi vesicle containing digestive enzymes becomes a lysosome Proteins in cisterna Lysosome fuses with ingested substances Membrane Transport vesicle Pathway 3 Pathway 2 Secretory vesicles Pathway 1 Golgi apparatus Golgi vesicle containing proteins to be secreted becomes a secretory vesicle Cisterna Rough ER Proteins Secretion by exocytosis Cytoplasmic Organelles Lysosomes Contain enzymes that digest worn-out or non-usable materials within the cell Cytoplasmic Organelles Peroxisomes Membranous sacs of oxidase enzymes Detoxify harmful substances Break down free radicals (highly reactive chemicals) Replicate by pinching in half Cytoplasmic Organelles Cytoskeleton Internal framework/structure Cytoplasmic Organelles Cytoskeleton Three different types: Microfilaments (largest) Intermediate filaments Microtubules (smallest) Cytoplasmic Organelles Centrioles Rod-shaped structure made off microtubules Direct the formation of mitotic spindle during cell division Cellular Projections Not found in all cells Used for movement Cellular Projections Cilia: move materials across the cell surface Located in the respiratory system to move mucus Flagella: propel the cell The only cell in the human body with flagella is sperm