PowerPoint Lecture Slides prepared by Barbara Heard, Atlantic Cape Community College Ninth Edition Human Anatomy & Physiology C H A P T E R 3 Annie Leibovitz/Contact Press Images 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
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
What s making this up? EXTRACELLULAR FLUID Cytoplasm Lipids and Proteins
Plasma Membrane Outside cell Hydrophilic Hydrophobic Hydrophilic Inside cell
Two kinds of proteins EXTRACELLULAR FLUID Integral CYTOPLASM Peripheral proteins
Diffusion and Osmosis Plasma membrane is selectively permeable selective based on: Size Electrical charge Molecular shape Lipid solubility
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)
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
Diffusion and Osmosis Diffusion can be simple pass through plasma membrane Lipid-soluble Dissolved gases
Diffusion and Osmosis Diffusion can be Channel-mediated diffusion Need a port/tunnel Water-soluble compounds and ions Interaction with the channel leak channels
EXTRACELLULAR FLUID Lipid-soluble molecules Channel protein Large molecules Small water-soluble molecules and ions diffuse through membrane channels CYTOPLASM
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:
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
Water molecules Solute molecules SEM of normal RBC in an isotonic solution
SEM of RBC in a hypotonic solution
SEM of crenated RBCs in a hypertonic solution
Carriers and Vesicles Carrier-Mediated Transport Both passive and active Facilitated Diffusion Passive too large to fit through channel proteins two steps involved
Figure 3-18 Facilitated Diffusion Receptor Bound 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
Carriers and Vesicles Carrier-Mediated Transport Primary Active Transport Sodium potassium exchange pump Active transport
EXTRACELLULAR FLUID Primary Active Transport Sodiumpotassium exchange pump CYTOPLASM
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
Secondary Active Transport Glucose molecule Sodium ion (Na + ) pump CYTOPLASM
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
Carriers and Vesicles Endocytosis Receptor-mediated endocytosis Receptors bind target molecules Coated vesicle carries materials into cell
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
Bloodstream Plasma membrane Cytoplasm Pinosome formation Surrounding tissues Pinosome fusion and exocytosis Pinocytosis Color enhanced TEM 20,000
Plasma Membrane What s going on inside the cell? liquid bits (cell machinery)
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
Organelles and the Cytoplasm Nonmembranous Organelles Six types 1. Cytoskeleton 2. Microvilli 3. Centrioles 4. Cilia 5. Ribosomes 6. Proteasomes
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
Organelles and the Cytoplasm Mitochondria Mitochondrion takes chemical energy from food Produces energy molecule ATP
Nucleotides to store energy ATP = energy currency molecule Adenine + phosphates Adenine Phosphorilation: addition of high energy phosphates groups Ribose Phosphate Phosphate Phosphate Adenosine High-energy bonds Adenosine diphosphate (ADP) Adenosine triphosphate (ATP) Adenine
Inner membrane Outer membrane Matrix Cristae Mitochondrion TEM 46,332
CYTOPLASM Glucose Glycolysis Anaerobic Pyruvate Citric Acid Cycle ETC cristae MATRIX MITOCHONDRION Aerobic END RESULT : +/- 30 ATP per Glucose molecule
Cell s Control Center Chromatin Nucleolus Nuclear envelope Nuclear pore Important nuclear structures are shown here. Nucleus TEM 4800
Nucleus Contents of the Nucleus Cell prepared for division Visible chromosome Nondividing cell whole point of DNA? Chromatin in nucleus Histones
Protein Synthesis Two processes are involved in protein synthesis Transcription DNA mrna Translation mrna AA polypeptide
Protein Synthesis So, how does transcription happen?
DNA Template strand Coding strand RNA polymerase Codon 1 mrna strand Promoter Codon 2 Gene Triplet 1 Triplet 2 Triplet 3 1 Complementary triplets 2 2 3 Codon 1 RNA nucleotide Codon 3 Codon 4 (stop codon) Triplet 4 4 KEY Adenine Guanine Cytosine Uracil (RNA) Thymine (DNA)
Protein Synthesis After Transcription Translation How does translation work?
NUCLEUS mrna Amino acid KEY Adenine Guanine Small ribosomal subunit trna Anticodon trna binding sites Cytosine Uracil Start codon mrna strand
Large ribosomal subunit
Stop codon
Peptide bond
Small ribosomal subunit Completed polypeptide Large ribosomal subunit