Lecture4-Cell Structure.pptx

Cell Structure  Cell Theory All living things are composed of one or more cells 1665 – 1675 – Anton Robert von Hooke coins Leeuwenhoek 1830 – Schleiden “cell” discovers and Schwann bacteria prop...

Cell Structure  Cell Theory All living things are composed of one or more cells 1665 – 1675 – Anton Robert von Hooke coins Leeuwenhoek 1830 – Schleiden “cell” discovers and Schwann bacteria propose Cell Theory  Microscopy Light Microscopes – 2mm pin diameter – About 250 eukaryotic cells Electron Microscopes – Uses electron beems – 2μm resolution Light Electro n  Prokaryotic Cells Single-celled organisms with no membrane bound organelles  Prokaryotic Structures Cell membrane – Phospholipid bilayer Cell Wall & Capsule – Peptidoglycan – Penicillin Pilli – conjugation  Three domains of Life Bacteria Archaea Prokaryote s Eukarya Archaea vs. Bacteria – No peptidoglycan in cell walls – Phospholipids not as important for membranes – Decreased TCA cycle and glycolysis  Eukaryotic Cells Contain membrane bound organelles and nucleus – Nuclear Genetic Material – About 50 times larger than prokaryotic cells Eukaryotic Cell Structures Animal Cells Plant Cells  Plasma Membrane Made up of phospholipids Separates the outside from – Phosphate head group cytoplasm – 2 hydrocarbon tails – About 70% water Proteins – Ions and free molecules – Integral (membrane spanning) – Together comprise a liquid – Peripheral (membrane imbedded) called cytosol Outside cell cytosol  Cytoskeleton Network of protein fibers that hold a cell together inside – Microfilaments – Intermediate filaments – microtubules  Endomembrane System Membrane bound compartments within the cell membrane – Responsible for lipid and protein transport – Composed of Nuclear envelope Lysozomes Vesicles Endoplasmic reticulum Golgi apparatus  Nucleus Contains all DNA within a cell – Packaged into Chromosomes – Chromosomes bind together with proteins to form chromatin Nuclear envelope – lipid bilayer – Contains pores for passing ions, RNA, and other molecules Nucleolus – Largest structure in nucleus – Site of Ribosome assembly Endoplasmic Reticulum (ER) Composed of lipids and tubule proteins Continuous with nuclear envelope Interior space is called Lumen Two different types – Rough ER Rough with Ribosomes Synthesized proteins are dumped into lumen Transported out via vesicles – Smooth ER No ribosomes Synthesis of carbohydrates and lipids Storage of calcium ions  Vesicles and Vacuoles Membrane bound sacks that function in transport and storage Vacuoles slightly larger  Golgi apparatus Responsible for packaging, sorting, and tagging Tag molecules for different destinations  Lysosomes Function as garbage disposals Breakdown proteins, lipids, carbohydrates Recycle molecules Have low pH  Ribosomes Responsible for protein synthesis – Bound to ER or plasma membrane in eukaryotes – Free in cytoplasm of prokaryotic cells  Peroxisomes Membrane bound lipid and amino acid breakdown factories Creates H2O2 when breaking down molecules – Damaging to rest of the cell – Broken down before leaving  Cellular Energy Factories Mitochondria for animal cells – Site of ATP synthesis – Site of carbohydrate and lipid metabolism – Two bilayer membranes Folds in inner membrane called cristae Separate inner and outer membrane space – Contain their own DNA – Contain their own  Cellular Energy Factories Chloroplasts for Plant cells – Function in photosynthesis – Two membranes – Contain thylakoids Site of photosynthesis Stacked into granum – Imbedded in Stroma  Other plant specific structures Central Vacuole – Regulates the water levels of cells Cell wall – Composed of a rigid carbohydrate - cellulose