Copyright © 2015 Wolters Kluwer Health | Lippincott Williams & Wilkins Chapter 3 Cells and Their Functions

Copyright © 2015 Wolters Kluwer All Rights Reserved Key Terms active transportfiltrationmitosis cancergenemutation carcinogenhemolysisnucleus chromosomehypertonicorganelle cytologyhypotonicosmosis cytoplasminterphasephagocytosis diffusionisotonicplasma membrane DNAmicrometerribosome endocytosismicroscopeRNA exocytosismitochondria

Copyright © 2015 Wolters Kluwer All Rights Reserved The Cell Cytology The study of cells The Cell The basic unit of life Shows life characteristics –Organization –Metabolism –Responsiveness –Homeostasis –Growth –Reproduction

Copyright © 2015 Wolters Kluwer All Rights Reserved Microscopes Microscope An instrument that magnifies structures not visible to the naked eye Types of microscopes: –Compound light microscope –Transmission electron microscope –Scanning electron microscope

Copyright © 2015 Wolters Kluwer All Rights Reserved Figure 3-1 Cilia photographed under three different microscopes. Microscopes (cont.)

Copyright © 2015 Wolters Kluwer All Rights Reserved Microscopes (cont.) ? Pop Quiz 3.1Which microscope is most commonly used in laboratories? A)Scanning electron microscope B)Transmission electron microscope C)Compound light microscope D)Simple light microscope

Copyright © 2015 Wolters Kluwer All Rights Reserved Microscopes (cont.) ? Pop Quiz Answer 3.1Which microscope is most commonly used in laboratories? A)Scanning electron microscope B)Transmission electron microscope C)Compound light microscope D)Simple light microscope

Copyright © 2015 Wolters Kluwer All Rights Reserved Cell Structure (cont.) General Cell Organization Plasma membrane Nucleus Cytoplasm –Cytosol –Organelles

Copyright © 2015 Wolters Kluwer All Rights Reserved Cell Structure (cont.) Plasma Membrane Encloses cell contents Regulates what enters and leaves cell Participates in many cell activities (e.g., growth, reproduction, cell-to-cell interactions) Plasma membrane components –Phospholipid bilayer –Cholesterol –Proteins

Copyright © 2015 Wolters Kluwer All Rights Reserved Cell Structure (cont.) Table 3-1 Proteins in the Plasma Membrane and Their Functions

Copyright © 2015 Wolters Kluwer All Rights Reserved Figure 3-3 The plasma membrane. Why is the plasma membrane described as a bilayer? Cell Structure (cont.)

Copyright © 2015 Wolters Kluwer All Rights Reserved Cell Structure (cont.) Plasma Membrane (cont.) Membrane potential –The difference in electric charge on either side of the plasma membrane –Caused by separation of positive and negative ions and proteins on either side of the membrane –Ion concentrations are determined by Channels Pumps Membrane potential allows the plasma membrane to act as a battery. It uses electrical energy to power membrane functions.

Copyright © 2015 Wolters Kluwer All Rights Reserved Cell Structure (cont.) Nucleus Largest organelle of cell Surrounded by a nuclear membrane Contains –Chromosomes Units of heredity; govern all cellular activity –Nucleolus Assembles ribosomes

Copyright © 2015 Wolters Kluwer All Rights Reserved Cell Structure (cont.) Cytoplasm Material between the nuclear membrane and plasma membrane –Cytosol Fluid portion of cytoplasm –Organelles Specialized cell structures that perform different cell functions

Copyright © 2015 Wolters Kluwer All Rights Reserved Cell Structure (cont.) Table 3-2 Cell Parts NameDescriptionFunction P LASMA MEMBRANE Outer layer of the cell; composed mainly of lipids and proteins Encloses the cell contents; regulates what enters and leaves the cell; participates in many activities, such as growth, reproduction, and interactions between cells MicrovilliShort extensions of the plasma membraneAbsorb materials into the cell N UCLEUS Large, membrane-bound, dark-staining organelle near the center of the cell Contains the chromosomes, the hereditary structures that direct all cellular activities NucleolusSmall body in the nucleusMakes ribosomes C YTOPLASM Colloid that fills the cell from the nuclear membrane to the plasma membrane Site of many cellular activities; consists of cytosol and organelles CytosolThe fluid portion of the cytoplasm; contains water, enzymes, nutrients, and other substances Surrounds the organelles; site of many chemical reactions and nutrient storage Endoplasmic reticulum (ER) Network of membranes within the cytoplasm. Rough ER has ribosomes attached to it; smooth ER does not Rough ER modifies, folds, and sorts proteins; smooth ER participates in lipid synthesis RibosomesSmall bodies free in the cytoplasm or attached to the ER; composed of RNA and protein Manufacture proteins Golgi apparatusLayers of membranesFurther modifies proteins; sorts and prepares proteins for transport to other parts of the cell or out of the cell MitochondriaLarge organelles with internal folded membranesConvert energy from nutrients into ATP LysosomesSmall sacs of digestive enzymesDigest substances within the cell PeroxisomesMembrane-enclosed organelles containing enzymesBreak down harmful substances ProteasomesBarrel-shaped organellesDestroy improperly synthesized proteins VesiclesSmall membrane-bound sacs in the cytoplasmStore materials and move materials into or out of the cell in bulk CentriolesRod-shaped bodies (usually two) near the nucleusHelp separate the chromosomes during cell division S URFACE PROJECTIONS Structures that extend from the cellMove the cell or the fluids around the cell CiliaShort, hairlike projections from the cellMove the fluids around the cell FlagellumLong, whiplike extension from the cellMoves the cell

Copyright © 2015 Wolters Kluwer All Rights Reserved Cell Structure (cont.) Surface Projections Structures that extend from the cell –Cilia Short, hairlike projections Move fluids around cells –Flagellum Long, whiplike extension from the cell Moves cell

Copyright © 2015 Wolters Kluwer All Rights Reserved Cell Structure (cont.) Cellular Diversity Cell shape is related to cell function. –A neuron’s long fibers transmit electric energy from place to place in the nervous system. –Small round red blood cells slide through tiny blood vessels. Cell organelle number is related to cell function. –Lipid-producing cells have lots of smooth ER. –Metabolically active cells have lots of mitochondria to manufacture ATP.

Copyright © 2015 Wolters Kluwer All Rights Reserved Figure 3-4 Cellular diversity. Which of the cells shown would best cover a large surface area? Cell Structure (cont.)

Copyright © 2015 Wolters Kluwer All Rights Reserved Cell Structure (cont.) ? Pop Quiz 3.2What is the main substance of the plasma membrane? A)Cholesterol B)Phospholipid C)Protein D)Steroid

Copyright © 2015 Wolters Kluwer All Rights Reserved Cell Structure (cont.) ? Pop Quiz Answer 3.2What is the main substance of the plasma membrane? A)Cholesterol B)Phospholipid C)Protein D)Steroid

Copyright © 2015 Wolters Kluwer All Rights Reserved Cell Structure (cont.) ? Pop Quiz 3.3Which organelle generates ATP? A)Centriole B)Golgi apparatus C)Mitochondrion D)Ribosome

Copyright © 2015 Wolters Kluwer All Rights Reserved Cell Structure (cont.) ? Pop Quiz Answer 3.3Which organelle generates ATP? A)Centriole B)Golgi apparatus C)Mitochondrion D)Ribosome

Copyright © 2015 Wolters Kluwer All Rights Reserved Movement of Substances across the Plasma Membrane (cont.) Selective Permeability Plasma membrane regulates what enters and leaves. Travel across membrane is based on several factors. –Molecular size –Solubility –Electrical charge Types of travel: –Movement that does not require cellular energy –Movement that requires cellular energy

Copyright © 2015 Wolters Kluwer All Rights Reserved Figure 3-5 Diffusion of a solid in a liquid. Movement of Substances across the Plasma Membrane (cont.)

Copyright © 2015 Wolters Kluwer All Rights Reserved Figure 3-6 Diffusion using transporters. How would a change in the number of transporters affect a solute’s movement by facilitated diffusion? Movement of Substances across the Plasma Membrane (cont.)

Copyright © 2015 Wolters Kluwer All Rights Reserved Figure 3-7 A simple demonstration of osmosis. What would happen in this system if the solute could pass through the membrane? Movement of Substances across the Plasma Membrane (cont.)

Copyright © 2015 Wolters Kluwer All Rights Reserved Figure 3-8 Osmotic pressure. What would happen to osmotic pressure if the concentration of solute were increased on side B of this system? Movement of Substances across the Plasma Membrane (cont.)

Copyright © 2015 Wolters Kluwer All Rights Reserved Movement of Substances across the Plasma Membrane (cont.) How Osmosis Affects Cells Another way to think about osmosis is in terms of solute concentration. Water Follows the Salt Low solute High water High solute Low water Osmosis

Copyright © 2015 Wolters Kluwer All Rights Reserved Movement of Substances across the Plasma Membrane (cont.) Table 3-3 Solutions and Their Effects on Cells

Copyright © 2015 Wolters Kluwer All Rights Reserved Figure 3-9 The effect of osmosis on cells. What would happen to red blood cells in the body if blood lost through injury were replaced with pure water? Movement of Substances across the Plasma Membrane (cont.)

Copyright © 2015 Wolters Kluwer All Rights Reserved Movement of Substances across the Plasma Membrane (cont.) Table 3-4 Membrane Transport ProcessDefinitionExample Do not require cellular energy (passive) DiffusionRandom movement of particles down the concentration gradient (from higher concentration to lower concentration) Movement of gases through the membrane, ions through an ion channel, or nutrients via transporters OsmosisDiffusion of water through a semipermeable membrane Movement of water across the plasma membrane through aquaporins FiltrationMovement of materials through a membrane down a pressure gradient Movement of materials out of the blood under the force of blood pressure Require cellular energy Active transport (pumps)Movement of materials through the plasma membrane against the concentration gradient using transporters Transport of ions (e.g., Na +, K +, and Ca 2+ ) in neurons Bulk transportMovement of large amounts of material through the plasma membrane using vesicles; also called vesicular transport EndocytosisTransport of bulk amounts of materials into the cell using vesicles Phagocytosis—intake of large particles, as when white blood cells take in waste materials; also pinocytosis (intake of fluid), and receptor-mediated endocytosis, requiring binding sites in the plasma membrane ExocytosisTransport of bulk materials out of the cell using vesicles Release of neurotransmitters from neurons

Copyright © 2015 Wolters Kluwer All Rights Reserved Figure 3-10 Phagocytosis. Movement of Substances across the Plasma Membrane (cont.)

Copyright © 2015 Wolters Kluwer All Rights Reserved Figure 3-11 Exocytosis. Movement of Substances across the Plasma Membrane (cont.)

Copyright © 2015 Wolters Kluwer All Rights Reserved Movement of Substances across the Plasma Membrane (cont.) ? Pop Quiz 3.4Which process uses transporters but not ATP? A)Active transport B)Endocytosis C)Facilitated diffusion D)Simple diffusion

Copyright © 2015 Wolters Kluwer All Rights Reserved Movement of Substances across the Plasma Membrane (cont.) ? Pop Quiz Answer 3.4Which process uses transporters but not ATP? A)Active transport B)Endocytosis C)Facilitated diffusion D)Simple diffusion

Copyright © 2015 Wolters Kluwer All Rights Reserved Movement of Substances across the Plasma Membrane (cont.) ? Pop Quiz 3.5Which method transports bulk amounts of material into the cell using vesicles? A)Active transport B)Endocytosis C)Exocytosis D)Osmosis

Copyright © 2015 Wolters Kluwer All Rights Reserved Movement of Substances across the Plasma Membrane (cont.) ? Pop Quiz Answer 3.5Which method transports bulk amounts of material into the cell using vesicles? A)Active transport B)Endocytosis C)Exocytosis D)Osmosis

Copyright © 2015 Wolters Kluwer All Rights Reserved Movement of Substances across the Plasma Membrane (cont.) ? Pop Quiz 3.6Cells crenate when they are placed in solutions that are A)Catatonic B)Hypertonic C)Hypotonic D)Isotonic

Copyright © 2015 Wolters Kluwer All Rights Reserved Movement of Substances across the Plasma Membrane (cont.) ? Pop Quiz Answer 3.6Cells crenate when they are placed in solutions that are A)Catatonic B)Hypertonic C)Hypotonic D)Isotonic

Copyright © 2015 Wolters Kluwer All Rights Reserved Protein Synthesis (cont.) Overview Proteins give a cell its structure and function. DNA directs protein synthesis. –Nucleotides make up DNA –DNA organized into genes –Genes organized into chromosomes RNA participates in protein synthesis but is not part of chromosomes.

Copyright © 2015 Wolters Kluwer All Rights Reserved Figure 3-12 Chromosomes and DNA. Protein Synthesis (cont.)

Copyright © 2015 Wolters Kluwer All Rights Reserved Protein Synthesis (cont.) Table 3-5 Comparison of DNA and RNA DNA RNA LocationAlmost entirely in the nucleusAlmost entirely in the cytoplasm CompositionNucleotides contain adenine (A), guanine (G), cytosine (C), or thymine (T) Sugar: deoxyribose Nucleotides contain adenine (A), guanine (G), cytosine (C), or uracil (U) Sugar: ribose StructureDouble-stranded helix formed by nucleotide pairing A–T; G– C Single strand FunctionMakes up the chromosomes, hereditary units that control all cellular activities; divided into genes that carry the nucleotide codes for the manufacture of proteins Manufacture proteins according to the codes carried in the DNA; three main types: messenger RNA (mRNA), ribosomal RNA (rRNA), and transfer RNA (tRNA)

Copyright © 2015 Wolters Kluwer All Rights Reserved Protein Synthesis (cont.) Table 3-6 The Genetic Code Amino Acid Transcribed DNA Triplet mRNAtRNA GlycineCCCGGGCCC ProlineGGGCCCGGG ValineCACGUGCAC PhenylalanineAAAUUUAAA The nucleotide triplet code in DNA and RNA is shown for four amino acids.

Copyright © 2015 Wolters Kluwer All Rights Reserved Protein Synthesis (cont.) Table 3-7 Role of RNA

Copyright © 2015 Wolters Kluwer All Rights Reserved Protein Synthesis (cont.) Two-Step Process of Protein Synthesis Transcription –First step; occurs in nucleus –DNA code is transcribed into mRNA by nucleotide base pairing Translation –Second step; occurs in cytoplasm –mRNA leaves nucleus and travels to ribosomes –Ribosomes and tRNA translate mRNA into protein’s amino acid sequence

Copyright © 2015 Wolters Kluwer All Rights Reserved Figure 3-13 Transcription. Protein Synthesis (cont.)

Copyright © 2015 Wolters Kluwer All Rights Reserved Figure 3-14 Translation. Protein Synthesis (cont.)

Copyright © 2015 Wolters Kluwer All Rights Reserved Protein Synthesis (cont.) ? Pop Quiz 3.7Which DNA nucleotide pairs with adenine? A)Cytosine B)Guanine C)Thymine D)Uracil

Copyright © 2015 Wolters Kluwer All Rights Reserved Protein Synthesis (cont.) ? Pop Quiz Answer 3.7Which DNA nucleotide pairs with adenine? A)Cytosine B)Guanine C)Thymine D)Uracil

Copyright © 2015 Wolters Kluwer All Rights Reserved Protein Synthesis (cont.) ? Pop Quiz 3.8Which RNA is transcribed from DNA? A)Amino acid B)Messenger RNA C)Ribosomal RNA D)Transfer RNA

Copyright © 2015 Wolters Kluwer All Rights Reserved Protein Synthesis (cont.) ? Pop Quiz Answer 3.8Which RNA is transcribed from DNA? A)Amino acid B)Messenger RNA C)Ribosomal RNA D)Transfer RNA

Copyright © 2015 Wolters Kluwer All Rights Reserved Protein Synthesis (cont.) ? Pop Quiz 3.9What is synthesized during translation? A)Amino acid B)Protein C)Starch D)Triglyceride

Copyright © 2015 Wolters Kluwer All Rights Reserved Protein Synthesis (cont.) ? Pop Quiz Answer 3.9What is synthesized during translation? A)Amino acid B)Protein C)Starch D)Triglyceride

Copyright © 2015 Wolters Kluwer All Rights Reserved Cell Division (cont.) Types of Cell Division Meiosis –Produces gametes (n) –Cuts chromosome number in half to prepare for union of egg and sperm during fertilization Mitosis –Produces somatic cells (2n) –Parent stem cell gives rise to two identical daughter cells

Copyright © 2015 Wolters Kluwer All Rights Reserved Cell Division (cont.) Preparation for Mitosis DNA replicates during interphase Identical strands held together at centromere until they separate during mitosis DNA replication during interphase Mitosis

Copyright © 2015 Wolters Kluwer All Rights Reserved Cell Division (cont.) Stages of Mitosis

Copyright © 2015 Wolters Kluwer All Rights Reserved Figure 3-15 The stages of mitosis. If the original cell shown has 46 chromosomes, how many chromosomes will each new daughter cell have? Cell Division (cont.)

Copyright © 2015 Wolters Kluwer All Rights Reserved Protein Synthesis (cont.) ? Pop Quiz 3.10During which phase of mitosis are chromosomes first visible? A)Anaphase B)Metaphase C)Prophase D)Telophase

Copyright © 2015 Wolters Kluwer All Rights Reserved Protein Synthesis (cont.) ? Pop Quiz Answer 3.10During which phase of mitosis are chromosomes first visible? A)Anaphase B)Metaphase C)Prophase D)Telophase

Copyright © 2015 Wolters Kluwer All Rights Reserved Cell Aging As cells multiply, changes occur that may lead to their damage or death. –Free radical injury –Enzyme injury –Gene mutation –Slowing cell activity –Apoptosis

Copyright © 2015 Wolters Kluwer All Rights Reserved Cells and Cancer (cont.) Development of Cancer Genetic mutations may cause uncontrolled cell division. Cells may spread (metastasize), producing cancer. Cancer cells form tumors, crowding out normal cells.

Copyright © 2015 Wolters Kluwer All Rights Reserved Cells and Cancer (cont.) Cancer Risk Factors Heredity Chemicals Radiation Diet Viruses

Copyright © 2015 Wolters Kluwer All Rights Reserved Cells and Cancer (cont.) ? Pop Quiz 3.11Which of the following is a cancer risk factor? A)A diet rich in fruits and vegetables B)A family history of cancer C)Regular exercise D)Regular use of sunscreen

Copyright © 2015 Wolters Kluwer All Rights Reserved Cells and Cancer (cont.) ? Pop Quiz Answer 3.11Which of the following is a cancer risk factor? A)A diet rich in fruits and vegetables B)A family history of cancer C)Regular exercise D)Regular use of sunscreen

Copyright © 2015 Wolters Kluwer All Rights Reserved Case Study Learning Objective 12.Use the case study to discuss the importance of the plasma membrane to the functioning of the body as a whole.

Copyright © 2015 Wolters Kluwer All Rights Reserved Case Study (cont.) Cystic fibrosis is an inherited disease Ben’s parents each carried a defective gene in their DNA and both had by chance passed copies of the gene onto Ben As a result, Ben was unable to synthesize a channel protein causing a defect in the movement of chloride into the cell Abnormal chloride channel function causes many organs to produce thick, sticky mucus resulting in effects on the entire body), for example, the lung (difficulty breathing), intestines (inadequate absorption of nutrients), pancreas (inability to produce digestive enzymes)

Copyright © 2015 Wolters Kluwer All Rights Reserved Word Anatomy (cont.)

Copyright © 2015 Wolters Kluwer All Rights Reserved Word Anatomy (cont.)

Copyright © 2015 Wolters Kluwer All Rights Reserved Word Anatomy (cont.)

Copyright © 2015 Wolters Kluwer All Rights Reserved Word Anatomy (cont.)