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PowerPoint® Lecture Slides prepared by Barbara Heard, Atlantic Cape Community Ninth Edition College Human Anatomy & Physiology CHAPTER © Annie Leibovitz/Contact Press Images 3 © 2013 Pearson Education, Inc. An Introduction to Cells • Sex Cells (Germ Cells) • Reproductive cells • sperm, oocyte • Somatic Cells • Soma = body • All body cells except sex cells © 2012 Pearson Education, Inc. Plasma Membrane • Cell environment? • what’s outside these cell? • Extracellular Fluid • watery medium that surrounds a cell • What prevents the extracellular fluid from entering cell? • Plasma membrane © 2012 Pearson Education, Inc. What’s making this up? EXTRACELLULAR FLUID Cytoplasm © 2012 Pearson Education, Inc. Lipids and Proteins Plasma Membrane Outside cell Hydrophilic Hydrophobic Hydrophilic © 2012 Pearson Education, Inc. Inside cell Two kinds of proteins EXTRACELLULAR FLUID Integral Peripheral proteins CYTOPLASM © 2012 Pearson Education, Inc. Diffusion and Osmosis • Plasma membrane is selectively permeable • selective based on: • Size • Electrical charge • Molecular shape • Lipid solubility © 2012 Pearson Education, Inc. Diffusion and Osmosis • Transport through a plasma membrane can be: • Active : requiring energy as ATP • Passive : no energy required • four types of transport: • Diffusion (passive) • Carrier-mediated transport (passive or active) • Vesicular transport (active) © 2012 Pearson Education, Inc. Diffusion and Osmosis • Passive transport think: • molecules [high] [low] • Concentration gradient • More solute in one part of a solvent than another • Following of a concentration gradient is Diffusion © 2012 Pearson Education, Inc. © 2012 Pearson Education, Inc. Diffusion and Osmosis • Diffusion can be • simple • pass through plasma membrane • Lipid-soluble • Dissolved gases © 2012 Pearson Education, Inc. Diffusion and Osmosis • Diffusion can be • Channel-mediated diffusion • Need a port/tunnel • Water-soluble compounds and ions • Interaction with the channel – leak channels © 2012 Pearson Education, Inc. EXTRACELLULAR FLUID Lipid-soluble molecules Channel protein Large molecules CYTOPLASM © 2012 Pearson Education, Inc. Small water-soluble molecules and ions diffuse through membrane channels Diffusion and Osmosis • Osmosis: A Special Case of Diffusion • Osmosis • diffusion of water across the cell membrane • depends on the amount of solute concentration in cell • three types of solutions: © 2012 Pearson Education, Inc. Diffusion and Osmosis • Osmolarity and Tonicity • Isotonic (iso- = same, tonos = tension) • No flow of water in or out of a cell • Hypotonic (hypo- = below) • Has less solutes and loses water through osmosis • Hypertonic (hyper- = above) • Has more solutes and gains water by osmosis © 2012 Pearson Education, Inc. Water molecules Solute molecules SEM of normal RBC in an isotonic solution © 2012 Pearson Education, Inc. SEM of RBC in a hypotonic solution © 2012 Pearson Education, Inc. SEM of crenated RBCs in a hypertonic solution © 2012 Pearson Education, Inc. Carriers and Vesicles • Carrier-Mediated Transport • Both passive and active • Facilitated Diffusion • Passive • too large to fit through channel proteins • two steps involved © 2012 Pearson Education, Inc. Figure 3-18 Facilitated Diffusion Receptor Bound © 2012 Pearson Education, Inc. Shape Change transport Carriers and Vesicles • Carrier-Mediated Transport • Active Transport (Primary or Secondary) • Active transport proteins • Move substrates against concentration gradient • Require energy, such as ATP • Ion pumps © 2012 Pearson Education, Inc. Carriers and Vesicles • Carrier-Mediated Transport • Primary Active Transport • Sodium–potassium exchange pump • Active transport © 2012 Pearson Education, Inc. Primary Active Transport EXTRACELLULAR FLUID Sodiumpotassium exchange pump CYTOPLASM © 2012 Pearson Education, Inc. Carriers and Vesicles • Carrier-Mediated Transport • Secondary Active Transport • point: something else “tags along” • Na+ concentration gradient drives glucose transport • ATP energy pumps Na+ back out © 2012 Pearson Education, Inc. Secondary Active Transport Glucose molecule Sodium ion (Na+) pump CYTOPLASM © 2012 Pearson Education, Inc. Carriers and Vesicles • Vesicular Transport (Bulk Transport) • Materials move into or out of cell in vesicles • Into (endocytosis) • Out of (exocytosis) • Endocytosis is active transport using ATP • 3 types © 2012 Pearson Education, Inc. Carriers and Vesicles • Endocytosis • Receptor-mediated endocytosis • Receptors bind target molecules • Coated vesicle carries materials into cell © 2012 Pearson Education, Inc. Carriers and Vesicles • Endocytosis • Pinocytosis • Small particles ingested - drank by the cell • Phagocytosis • Pseudopodia (pseudo- = false, pod- = foot) • Engulf large objects in phagosomes • Exocytosis (exo- = outside) • Granules or droplets are released from the cell © 2012 Pearson Education, Inc. Bloodstream Plasma membrane Pinosome formation Cytoplasm Pinosome fusion and exocytosis Surrounding tissues Pinocytosis © 2012 Pearson Education, Inc. Color enhanced TEM × 20,000 Plasma Membrane • What’s going on inside the cell? • liquid • bits (cell machinery) © 2012 Pearson Education, Inc. Organelles and the Cytoplasm • Cytoplasm • All materials inside the cell and outside the nucleus • Cytosol (intracellular fluid) • Nutrients, ions, proteins, and waste products • Organelles • ‘little organs’ with specific functions • some have no membrane • some have a membrane • Know Fig. 3-2 © 2012 Pearson Education, Inc. Organelles and the Cytoplasm • Nonmembranous Organelles • Six types 1. Cytoskeleton 2. Microvilli 3. Centrioles 4. Cilia 5. Ribosomes 6. Proteasomes © 2012 Pearson Education, Inc. Organelles and the Cytoplasm • Membranous Organelles • Six types of membranous organelles 1. Endoplasmic reticulum (ER) 2. Golgi apparatus 3. Lysosomes 4. Peroxisomes 5. Mitochondria 6. Nucleus © 2012 Pearson Education, Inc. Organelles and the Cytoplasm • Mitochondria • Mitochondrion takes chemical energy from food • Produces energy molecule ATP © 2012 Pearson Education, Inc. Nucleotides to store energy ATP = energy currency molecule Adenine + phosphates Phosphorilation: addition of high energy phosphates groups Adenine Ribose Adenosine Phosphate Phosphate High-energy bonds Adenosine diphosphate (ADP) Adenosine triphosphate (ATP) Adenine © 2012 Pearson Education, Inc. Phosphate Inner membrane Outer membrane Matrix Mitochondrion © 2012 Pearson Education, Inc. Cristae TEM × 46,332 CYTOPLASM Glucose Anaerobic Glycolysis Pyruvate ETC cristae Citric Acid Cycle MATRIX MITOCHONDRION Aerobic END RESULT : +/- 30 ATP per Glucose molecule © 2012 Pearson Education, Inc. Cell’s Control Center Chromatin Nucleolus Nuclear envelope Nuclear pore Important nuclear structures are shown here. © 2012 Pearson Education, Inc. Nucleus TEM × 4800 Nucleus Cell prepared for division Contents of the Nucleus Visible chromosome Nondividing cell whole point of DNA? Chromatin in nucleus Histones © 2012 Pearson Education, Inc. Protein Synthesis • Two processes are involved in protein synthesis • Transcription • DNA mRNA • Translation • mRNA AA polypeptide © 2012 Pearson Education, Inc. Protein Synthesis • So, how does transcription happen? © 2012 Pearson Education, Inc. DNA Template strand Coding strand RNA polymerase Codon 1 Codon 2 Promoter 1 Gene Triplet 2 2 Triplet 3 3 Triplet 4 4 Complementary triplets Triplet 1 mRNA strand Codon 3 Codon 1 Codon 4 (stop codon) 2 RNA nucleotide KEY Adenine Uracil (RNA) Guanine Thymine (DNA) Cytosine © 2012 Pearson Education, Inc. Protein Synthesis • After Transcription Translation • How does translation work? © 2012 Pearson Education, Inc. NUCLEUS mRNA Amino acid KEY Adenine Small ribosomal subunit tRNA Anticodon tRNA binding sites Guanine Cytosine Uracil © 2012 Pearson Education, Inc. Start codon mRNA strand Large ribosomal subunit © 2012 Pearson Education, Inc. Stop codon © 2012 Pearson Education, Inc. Peptide bond © 2012 Pearson Education, Inc. Small ribosomal subunit Completed polypeptide Large ribosomal subunit © 2012 Pearson Education, Inc. © 2012 Pearson Education, Inc.
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