Transcript cytoplasm
CELLS Structure and Function Cell = smallest unit of life Microtubules Intermediate filaments Actin filaments Centrioles Centrosome Lysosome Vesicle Cytoplasm Nuclear Envelope Chromatin Nucleolus Rough ER Smooth ER Ribosomes Mitochondrion Polyribosome Golgi apparatus Endoplasmic Nucleus Reticulum Cytoskeleton Features of the Human Cell Organization of the Cell • Plasma Membrane – boundary surrounding the cell • Genetic material: DNA – located in a membrane-bound nucleus for eukaryotic cells • Cytoplasm – Semi-fluid matrix containing enzymes and organelles (enzyme = biological catalyst) • Cytoskeleton – network of filaments and tubules in cytoplasm that maintains cell shape, allows movement Functions of Cell Features Structure Function(s) 1. Regulates passage of Plasma materials into and out of cell Membrane 2. Cell-Cell Recognition Functions of Cell Features Structure Nucleus Function(s) 1. Carrier of genetic material DNA + protein = chromatin 2. Governs cell activities 3. Directs cell reproduction 4. Surrounded by Membrane = nuclear envelope 5. Contains nucleolus— produces ribosomes Functions of Cell Features Structure Function(s) Ribosomes 1. Site of protein synthesis 2. Can be free in cytoplasm or attached to membranes Functions of Cell Features Structure SER RER Function(s) Rough Endoplasmic Reticulum (RER) 1. Produces proteins 2. Prepares proteins for export Smooth Endoplasmic Reticulum (SER) 1. Lipid Synthesis 2. Drug detoxification 3. Transport of proteins from RER Functions of Cell Features Structure Function(s) Golgi Apparatus Collects, modifies, packages and distributes proteins and lipids from ER Functions of Cell Features Structure Lysosome Function(s) Contains digestive enzymes to digest food in protists or destroy aging organelles Endomembrane System Rough Endoplasmic Reticulum Smooth Endoplasmic Reticulum Vesicle Golgi Apparatus Vesicle Lysosome Vesicle Plasma Membrane Functions of Cell Features Structure Peroxisome Function Removes harmful oxidants from cells Functions of Cell Features Structure Mitochondrion Function Captures energy from organic molecules, producing ATP Functions of Cell Features Structure Function(s) Cytoskeleton 1. Maintains cell shape 2. Anchors organelles and proteins 3. Allows for organelle movement and cellular movement in some cell types Functions of Cell Features Structure Function Centriole Gives rise to basal bodies that produce cilia or flagella Functions of Cell Features Structure Centrosome Function Organizes microtubules that attach to chromosomes in nuclear division Functions of Cell Features Structure Cilia and Flagella Function(s) 1. Move substances across cell surface in lungs, fallopian tubes 2. Cell movement in sperm Applying Your Knowledge 1. 2. 3. 4. 5. Cilium Rough ER Golgi apparatus Smooth ER Lysosome A. Which organelle produces proteins that will be exported from the cell? B. Which organelle contains digestive enzymes? C. Which site acts as a protein packaging and distribution center? Functions of Plasma Membrane Components Cell-cell recognition plasma membrane carbohydrate chain Controls access hydrophobic tails Outside hydrophilic heads phopspholipid bilayer filaments of cytoskeleton cholesterol Inside Regulates fluidity proteins Transport, signal reception, recognition Diffusion: Movement from from high low concentration to reach equal distribution - + charged molecules and ions H2O Diffuses through pores in membrane proteins aquaporin uncharged molecules - + Freely diffuse through phospholipid bilayer macromolecule phospholipid molecule protein Membrane is permeable to water only, net movement of water to inside Osmosis: Diffusion of Water Across a Selectively Permeable Membrane Isotonic solution maintains cell shape Cells gain water in a Hypotonic (lower salt) solution Equal movement into and out of cell when equilibrium is reached Cells lose water in a Hypertonic (higher salt) solution Facilitated Transport: Use of Carriers to Assist with Diffusion Outside K+ carrier protein glucose Inside Active Transport with Protein Carrier: Requires energy to transport from low high concentration Outside K+ K+ K+ P ATP ADP K+ Inside K+ Transporting Large Substances Endocytosis Formation of a vesicle from the plasma membrane to take in large substances vesicle vesicle Exocytosis Fusion of a vesicle with the plasma membrane to release large substances Summary of Transport Mechanisms • Passive: Do not require energy input – Diffusion – Osmosis – Facilitated Transport • Active: Require energy input – Active Transport – Endocytosis – Exocytosis Applying Your Knowledge 1. 2. 3. 4. 5. Facilitated Transport Endocytosis Osmosis Exocytosis Active Transport A. Which method controls the movement of water across a selectively-permeable membrane? B. Which method requires both energy and a carrier protein? C. Which method only allows materials to exit the cell? Cellular Respiration: Producing ATP from Glucose Inside cell electrons transferred by NADH glucose Requires Oxygen electrons transferred by NADH Citric acid cycle Glycolysis glucose pyruvate Electron Transport chain oxygen mitochondrion 2 ATP 2 ATP 32 ATP Outside cell Energy Yield from Glucose Without Oxygen, Fermentation Occurs Needed to continue glucose breakdown for energy NAD+ fermentation cytoplasm Electron carrier produced in glycolysis fermentation lactate when oxygen is available Training reduces Fermentation Enzymes: Biological Catalysts That Speed up the Rates of Metabolic Reactions Substrate 1 Substrates enter active site Substrate Active Site Enzyme 3 Product released; enzyme ready again 2 Shape change promotes reaction