Chapter 3 Cells KS Lecture PDF

Chapter 3. The series of events from cell formation to cell division, shown here, is called the cell cycle. 2019 Pearson Education, Inc.  Anabolic-building Basic...

Chapter 3. The series of events from cell formation to cell division, shown here, is called the cell cycle. 2019 Pearson Education, Inc.  Anabolic-building Basic Cell metabolism The chemical reactions that a cell carries out to Processes maintain life Catabolic-breaking down worn out or breakdown into smaller subunits of Cells Oxidation-reduction-convert energy of glucose into synthesis of ATP Transport of substances cell transports compounds it has ingested or produced for either release outside of cell of another location within the cell Communication with itself or surrounding environment and with other cells in the body Cell reproduction multiply through cell division which is necessary for growth and development as well as replacing old or damaged cells 2019 Pearson Education, Inc.  Figure 3.1 The basic components of a generalized cell. 2019 Pearson Education, Inc.  Three Basic Components of a Cell Plasma Membrane Provides structural support, communication with other cells, regulate transport, and cell id The plasma membrane forms a barrier between extracellular and intracellular(cytosol) Cytoplasm Consists of the fluid cytosol, organelles and cytoskeleton Cytosol-site of protein synthesis and functions in storage Organelles-molecular machines that compartmentalize its function Cytoskeleton-network of protein filaments that help in creating cell shape and hold organelles in place Nucleus Contains most of cell DNA and producing RNA which control function by coding for and creating proteins 2019 Pearson Education, Inc. Figure 3.2 Cell diversity. Note that cells are not drawn to same scale. Cell specialization is vital 2019 Pearson Education, Inc. Figure 3.3 The formation of a phospholipid bilayer. 1) Must have a portion that can interact with water-hydrophilic 2) A portion that does not interact with water to keep water in the ECF and cytosol separated. 2019 Pearson Education, Inc. Figure 3.3a The formation of a phospholipid bilayer. 2019 Pearson Education, Inc. Figure 3.3b The formation of a phospholipid bilayer. Phospholipid bilayer- forms the basis of the plasma membrane is every one of our cells 2019 Pearson Education, Inc. Figure 3.4 The fluid mosaic model of the plasma membrane. This model defines the plasma membrane structure with multiple parts whose arrangement is dynamic 2019 Pearson Education, Inc.  Membrane proteins Integral proteins-span the entire width of the membrane Peripheral proteins-found on one side of the membrane(some anchored and some float freely) Functions of membrane proteins Acting as channels-allow certain substances in/out Act as carriers-bind and transport substances in/out of cell Act as receptors-bind to chemical messenger(ligand), protein channel opens, changes triggered within a cell Act as enzymes-Enzymes are lodged within the membrane and catalyze various metabolic functions Provide structural support-maintain structural integrity Link adjacent cells-strengthen tissue, allow cells to communicate 2019 Pearson Education, Inc. Figure 3.5 Functions of membrane proteins. 2019 Pearson Education, Inc.  OTHER MEMBRANE COMPONENTS CHOLESTEROL-STABILIZES THE GLYCOLIPIDS AND GLYCOPROTEIN- STRUCTURE WHEN TEMPERATURE POLYSACCHARIDES ATTACHED TO LIPID CHANGES OR PROTEIN-FUNCTION IN CELL RECOGNITION 2019 Pearson Education, Inc.  Transport across cell membrane Plasma membrane acts as a fence with gates. It allows some things to pass, but not others. Selective permeability- selective about what permeates Passive transport-require no energy expenditure Active transport requires cells to expend energy in the form or ATP Transport depends on three variables Type of substance crossing membrane Membranes permeability to that substance Concentration of that substance in/out of the cell 2019 Pearson Education, Inc. Figure 3.6 Diffusion and equilibrium. Diffusion-movement of solute molecules from an area of higher solute concentration to a lower solute concentration 2019 Pearson Education, Inc.  Figure 3.7 Passive Simple diffusion-involves nonpolar solutes(such as hydrocarbons, O2, CO2) that go through phospholipid bilayer transport: without assistance from membrane protein simple and Facilitated diffusion-involves charged or polar solutes(ions and glucose) that cross phospholipid bilayer with the help of facilitated membrane protein diffusion. 2019 Pearson Education, Inc.  Figure 3.7a Passive transport: simple and facilitated diffusion. 2019 Pearson Education, Inc.  Uniporter-transports single solvent Antiporter-moves two different solutes in opposite directions Symporter-moves two solute is the same direction 2019 Pearson Education, Inc.  Figure 3.8 Passive transport: osmosis. 2019 Pearson Education, Inc.  Figure 3.8-1 Passive transport: osmosis. movement of solvent across a selectively permeable membrane from a solution with a lower solute concentration to a solution with a higher solute concentration 2019 Pearson Education, Inc.  Figure 3.8-2 Passive transport: osmosis. Results in a change of volume Diffusion stops when solute particles are equally distributed and concentration gradient is extinguished (has to do with osmotic pressure) 2019 Pearson Education, Inc. Figure 3.9 Tonicity: effects of isotonic, hypertonic, and hypotonic solutions on cell volume. 2019 Pearson Education, Inc. Figure 3.9a Tonicity: effects of isotonic, hypertonic, and hypotonic solutions on cell volume. 2019 Pearson Education, Inc. Figure 3.9b Tonicity: effects of isotonic, hypertonic, and hypotonic solutions on cell volume. A hypertonic extracellular solution causes a cell to lose water. The sell shrivels or crenate and possibly dies. 2019 Pearson Education, Inc. Figure 3.9c Tonicity: effects of isotonic, hypertonic, and hypotonic solutions on cell volume. A hypotonic extracellular solution causes a cell to swell and possibly rupture 2019 Pearson Education, Inc.  Active transport Requires energy to move solutes against their concentration gradient. Requires carrier proteins called pumps in the plasma membrane that bind and transport a solute across the membrane 2019 Pearson Education, Inc. Figure 3.10 Primary active transport by the Na+/ K+pump. 2019 Pearson Education, Inc.  Primary active transport pump The primary pump in the body is an antiport pump known as sodium-potassium pump Na+/K+ The sodium –potassium pump maintains a steep gradient by transporting 3 sodium ions out of the cell for every 2 potassium ions it moves into the cell. During physiological processes, sodium and potassium ions continue to leak back across the membrane, following their concentration gradients, so pumps must work continuously. Some cells use as much as 30% of ATP to fuel Na+/K pump. 2019 Pearson Education, Inc. Figure 3.11-1 Secondary active transport. Secondary Active transport uses ATP indirectly. The cell uses ATP to create a concentration gradient by pumping one substance across the plasma membrane. 2019 Pearson Education, Inc. Figure 3.11-2 Secondary active transport. The cell then harnesses the energy that potential energy to power active transport of another substance against its gradient. 2019 Pearson Education, Inc.  Large particles are transported in and out of a cell in small sacs called transport vesicles Vesicles form from pinched off parts of cell membranes. This transport is an active process and requires ATP There are two types of endocytosis 1)Endocytosis-bring substances into the cell Phagocytosis-cell eating Pinocytosis-cell drinking 2) Exocytosis-Molecules released from the cell and components are added to the plasma membrane 3) Transcytosis-molecules are brought into the cell through endocytosis transported through the cells other side through exocytosis 2019 Pearson Education, Inc. Figure 3.12 Endocytosis: phagocytosis. 2019 Pearson Education, Inc. Figure 3.13a Endocytosis: pinocytosis and receptor-mediated endocytosis. 2019 Pearson Education, Inc. Figure 3.14a Exocytosis. 2019 Pearson Education, Inc.  Figure 3.14b Exocytosis. 2019 Pearson Education, Inc. Figure 3.15 The cell and its organelles. 2019 Pearson Education, Inc. Figure 3.16 Structure of the mitochondrion. Mitochondria are involved in energy production, and are unique in that each mitochondrion contain its own DNA and enzymes 2019 Pearson Education, Inc. Figure 3.17 Function of the mitochondrion. There are two membranes 1) The outer membrane has large channels that allow molecules to enter the cytosol 2) The inner membrane is impermeable to most solutes except those which it has specific transport proteins 2019 Pearson Education, Inc. Figure 3.15-1 The cell and its organelles. Peroxisome-uses oxygen to strip hydrogen atoms from certain organic compounds to produce hydrogen peroxide Oxidize toxic substances Break down fatty acid Synthesize certain phospholipids 2019 Pearson Education, Inc. Figure 3.18 Schematic structure of the ribosome. Ribosome-non-membrane enclosed organelles that are the site of protein synthesis Each subunit is composed of a complex assembly of ribosomal proteins and ribosomal RNA 2019 Pearson Education, Inc. Figure 3.19 The endoplasmic reticulum. The ER’s folded phospholipid bilayer is continuous with the nuclear envelope 2019 Pearson Education, Inc.  Rough Endoplasmic reticulum(RER) membrane is covered in bound ribosomes 1) The polypeptides synthesized on bound ribosomes pass through the RER membrane into its lumen , where enzymes catalyze reactions that fold these polymers into their correct three- dimensional shape The RER recognizes proteins that have folded into an incorrect shape and sends them to the cytosol where they are degraded. Most proteins that enter the RER to be folded are secretory proteins destined to be exported by the cell. The RER is a membrane factory-the components for nearly every membrane including the plasma membrane are made. 2019 Pearson Education, Inc.  Smooth Endoplasmic reticulum(SER) lacks bound ribosomes and plays no role in protein synthesis Calcium ion storage – pumps calcium out of the cytosol and stores them Detoxification reactions- SER is well developed in cells that detoxify drugs like alcohol. The SER can nearly double in size when a person is exposed to certain drugs Lipid synthesis-SER synthesizes lipid membrane components phospholipids and cholesterol 2019 Pearson Education, Inc.  The Golgi Apparatus- located Figure 3.20 between RER and plasma The Golgi membrane, and function to modify, sort and package the apparatus. proteins and lipids produced by the ER for export. 2019 Pearson Education, Inc.  Lysosomes -membrane enclosed sacs that contain water and enzymes call acid hydrolases. Macromolecules are broken down to smaller units role in immune function- digest bacteria Degrade worn out organelles 2019 Pearson Education, Inc. Figure 3.21 Function of the endomembrane system. 2019 Pearson Education, Inc.  The Cytoskeleton Cytoskeleton Gives cell its characteristic shape and size; creates internal – dynamic framework structure; changes function Provides strength, structural integrity; anchoring sites’ based on support plasma and nuclear membranes and organelles needs of cell: Allows for cellular movement where protein filaments are associated with motor proteins Performs specialized functions in different cell types; for example, phagocytosis by macrophages, or contraction by muscle cells 2019 Pearson Education, Inc. Table 3.3 Cytoskeletal Filaments 2019 Pearson Education, Inc. Types of Filaments Actin filaments (microfilaments) – thinnest filament; composed of two intertwining strands of actin subunits Provide structural support, bear tension, and maintain cell’s shape Involved in cellular motion when combined with motor protein myosin Table 3.3 Cytoskeletal Filaments. Copyright © 2019, 2016 Pearson Education, Inc. All Rights Reserved Types of Filaments Intermediate filaments – ropelike; made of different fibrous proteins including keratin; strong, more permanent structures Form much of framework of cell; anchor organelles in place Help organelles and nucleus maintain both shape and size Help cells and tissues withstand mechanical stresses Table 3.3 Cytoskeletal Filaments. Copyright © 2019, 2016 Pearson Education, Inc. All Rights Reserved Types of Filaments Microtubules – largest filaments; hollow rods or tubes composed of tubulin; can be rapidly added or removed; allow for size and shape changes within cell Maintain internal architecture of cell; keep organelles in alignment Motor proteins dynein and kinesin allow transport of vesicles along microtubule network Form the core of cellular extensions called cilia and flagella Table 3.3 Cytoskeletal Filaments. Copyright © 2019, 2016 Pearson Education, Inc. All Rights Reserved  Figure 3.22 The centrosome with centrioles. When the cell is not dividing, the centrosome acts as a microtubule- organizing center for the cell’s cytoskeleton. The centrioles play a critical role in cell division 2019 Pearson Education, Inc. Figure 3.23 Microvilli. Microvilli-extensions that resemble a brush and seen in cells specialized for absorbtion; supported by actin filaments 2019 Pearson Education, Inc. Figure 3.24 Structure of cilia and flagella. Cilia are larger than microvilli and contain a core of microtubules associated with motor proteins (movable) 2019 Pearson Education, Inc.  Cellular Extensions Table 3.4 Cilia and Flagella. 2019 Pearson Education, Inc. Figure 3.25 The nucleus. The Nucleus Governs cell functions (determines the type of proteins that a cell makes and a rate at which to make them) Houses the cell’s DNA(contains the genes for almost every protein in the body) The genes are used within the DNA by different kinds of RNA to build our cells’ proteins 2019 Pearson Education, Inc.  An enclosing membrane called the nuclear envelope -outer membrane studded with ribosomes -inner membrane supported by intermediate filaments Membranes are joined by large protein complexes DNA and associated proteins 2019 Pearson Education, Inc. The nucleolus –ribosomes are assembled  Figure 3.27 Chromatin and chromosomes. Chromatin consist of one extremely long DNA strand and its associated proteins. The organization resembles beads on a string. Each bead is called a nucleosome and consists of the strand coiled around a group of proteins called histones 2019 Pearson Education, Inc.  Packaging DNA into this nucleosome structure reduces the length of chromatin by about 1/3 2019 Pearson Education, Inc.  Figure 3.27b Chromatin and chromosomes. Between rounds of cell division, the chromatin are loose During cell division the chromatin threads coil tightly into bar-like structures called chromosomes Paired and identical copies of the chromosomes are called sister chromatids joined at the centromere 2019 Pearson Education, Inc. Figure 3.27c Chromatin and chromosomes. Most human cells contain 2 sets of 23 chromosomes 2019 Pearson Education, Inc.  DNA makes proteins for all cells by carrying information that specifies the amino acid sequence for each of the body’s proteins and the nucleotide sequence for RNA strands. The process of making proteins from DNA via RNA is called protein synthesis 2019 Pearson Education, Inc.  99%of DNA coding is identical in humans, the remainder is unique and gives an individual his/her physical traits. IE: Ones tendency to tan or freckle. A gene called melanocortin-1 receptor codes for a membrane protein found in certain skin cells. When this protein is exposed and responds strongly to ultraviolet light a person demonstrates an even tan, however a slightly different variation of the same gene responds weakly, resulting in freckling. The production of a protein from a specific gene Is called gene expression 2019 Pearson Education, Inc.  Two processes that make up protein Transcription-the code specified by a gene is copied. Creating a strand of messenger RNA Translation-ribosomes read the nucleotide sequence of the messenger RNA strand and synthesize a polypeptide chain containing the correct amino acid sequence 2019 Pearson Education, Inc.  DNA-composed of long chains of nucleotides containing genes- segments of DNA, most specify amino acid sequences of proteins There are only 4 nucleotides in DNA, there are 21 different amino acids, so you need combinations of three nucleotides that serve as words to code for each amino acid. These words are called triplets 2019 Pearson Education, Inc.  During transcription each DNA triplet is transcribed into a complimentary three- nucleotide sequence of mRNA called a codon Then during translation each mRNA codon is matched with an amino acid This Photo by Unknown Author is licensed under CC BY Changes to DNA are called mutations 2019 Pearson Education, Inc. Unnumbered Figure 3.4_page 103 2019 Pearson Education, Inc.  Transcription Initiation – beginning of transcription; protein transcription factors bind to promoter region near gene on template strand of DNA; RNA polymerase also binds to promoter; DNA unwinds with aid of enzyme helicase 2019 Pearson Education, Inc.  Elongation-mRNA codon GCU bound to the complimentary DNA triplet CGA. After a section is copied the strands re-from the double helix 2019 Pearson Education, Inc.  Transcription Termination – when the last triplet of the gene is reached and newly formed pre-mRNA molecule is ready for modification Figure 3.29 Transcription. 2019 Pearson Education, Inc.  Transcription After transcription, transcript (pre-mRNA) isn’t ready; must first be modified in several ways Noncoding sections of gene do not specify amino acid sequence (introns); sections that do specify amino acid sequence are exons 2019 Pearson Education, Inc.  Transcription RNA processing – introns in pre-mRNA must be removed and exons spliced together When complete, mRNA exits nucleus through nuclear pore; enters cytosol, ready for translation into protein 2019 Pearson Education, Inc.  At the end of transription we have an mRNA strand that contains a copy of the triplet code in the DNA. This information is encoded in the Transcription to Translation language of nucleotides. Our cells need to translate into a language of amino acids. Translation involves another type of RNA that acts as a molecular translator-transfer RNA. Its job is to pick up a specific amino acid from the cytosol and transfer it to the growing polypeptide chain at the ribosome. 2019 Pearson Education, Inc.  Transfer RNA (tRNA) Transfer RNA is a single strand of RNA manufactured within the nucleus. This strand forms hydrogen bonds with itself to create the shape of a four- leaf clover. 2019 Pearson Education, Inc.  Transfer RNA (tRNA) At one end of the tRNA is a region called the anticodon which contains a sequence of three nucleotides that are complimentary to a specific mRNA codon 2019 Pearson Education, Inc.  Translation Initiation-mRNA transcript and tRNA bind to small ribosomal unit. The unit moves down the mRNA transcript looking for a specific nucleotide sequence called a start codon. A this point the large ribosomal unit binds to the small unit 2019 Pearson Education, Inc. Figure 3.31a-2 Translation. Elongation 2019 Pearson Education, Inc. Figure 3.31b-1 Translation. 2019 Pearson Education, Inc. Figure 3.31b-2 Translation. 2019 Pearson Education, Inc. Figure 3.32-3 Protein Synthesis At the end of translation, we have finished synthesizing a polypeptide, however it is not a functional protein until it is folded into its proper three –dimensional shape 2019 Pearson Education, Inc. Figure 3.32 Protein Synthesis 2019 Pearson Education, Inc. Unnumbered Figure 3.6_page 107 2019 Pearson Education, Inc. Unnumbered Figure 3.7_page 107 2019 Pearson Education, Inc.  Figure 3.33 The cell cycle. G1-normal metabolic functions/growing and rapid protein synthesis S –DNA synthesis- chromatin unwinds from histone proteins; base pairs duplicated building new DNA by using old as template G2-cellular growth. Proteins for cell division produced and centrioles are duplicated 2019 Pearson Education, Inc. Figure 3.34-1 DNA synthesis. DNA strands separate with enzyme helicase 2019 Pearson Education, Inc. Figure 3.34-2 DNA synthesis. An enzyme called primase catalyzes the reactions that build a very short segment of RNA called RNA primer 2019 Pearson Education, Inc. Figure 3.34-3 DNA synthesis. DNA polymerase catalyzes the addition of nucleotides to the new DNA strand DNA polymerase catalyzes DNA synthesis 2019 Pearson Education, Inc. Figure 3.34-4 DNA synthesis. End- result is two identical double helixes 2019 Pearson Education, Inc. Figure 3.35a-1 Interphase, mitosis, and cytokinesis. Interphase Nuclear envelope encloses nucleus Nucleolus is visible Chromosomes are indistinguishable Centriole pairs are duplicated 2019 Pearson Education, Inc. Figure 3.35a-2 Interphase, mitosis, and cytokinesis. Prophase Chromatin condense so sister chromatids are visible Nucleolus disperses Mitotic spindle forms Two centriole pairs separate and begin migrating to opposite poles Nuclear envelope fragments 2019 Pearson Education, Inc. Figure 3.35a-3 Interphase, mitosis, and cytokinesis. Metaphase Spindle fibers pull sister chromatids to align at the equator of the cell 2019 Pearson Education, Inc. Figure 3.35b-1 Interphase, mitosis, and cytokinesis. Anaphase Sister chromatids separate as spindle fibers shorten Daughter chromosomes are pulled toward opposite poles Cell elongates Cytokinesis begins(organelles and cytosol are separating 2019 Pearson Education, Inc.  Figure 3.35b-2 Interphase, mitosis, and cytokinesis. Telophase and Cytokinesis Nuclear envelope reassembles Nucleoli re-form Chromosomes are no longer distinct Cytokinesis continues and forms cleavage furrows Daughter cells separate 2019 Pearson Education, Inc.  Two genetically identical daughter cells that enter interphase Figure 3.35b-3 Interphase, mitosis, and cytokinesis. 2019 Pearson Education, Inc. Figure 3.36 Cancerous tumor of kidney cells. Cell division is monitored at specific points in the cell cycle. The most important checkpoint occurs in G1 Signals that regulate progression through checkpoints Nutrients in the ECF Growth factor in the ECF Density of cells in tissue Anchorage of cells in tissue Cells that cannot pass checkpoints and cannot be repaired undergo apoptosis 2019 Pearson Education, Inc.  Development of Cancer Normal: -Normal cell division, -Normal cell shape Hyperplasia: -accelerated cell division -but cells have normal shape Dysplasia: -accelerated cell division -cell shape begins to change -reversible? Metaplasia -accelerated cell division -cell shape changed -not reversible Anaplasia: New growth/tumor -cells no longer differentiated 2019 Pearson Education, Inc.  Tissues and Cancer: Metastasis: the process of spreading 2019 Pearson Education, Inc.  Which organelle is involved in energy production? A A. Nucleus B B. Mitochondria C C. Ribosomes D D. Peroxisomes E E. No clue 2019 Pearson Education, Inc.  What structure houses the cell’s DNA? A A. Mitochondria B B. Endoplasmic Reticulum C C. Nucleus D D. Nucleoli E E. Golgi Apparatus 2019 Pearson Education, Inc.  Which carrier protein moves two different solutes in opposite directions? One in the cell one out of the cell A Uniporter B Antiporter C Symporter D Deporter E No Clue 2019 Pearson Education, Inc.  What happens to a cell in a hypertonic solution? A No effect B Swell C Shrink D Explode E Change shape 2019 Pearson Education, Inc.  What is the cellular ingestion of droplets of the ECF? A Phagocytosis B Pinocytosis C Exocytosis D Transcytosis E No Clue 2019 Pearson Education, Inc.  What filaments form the core of cellular extensions (cilia and flagella)? A Actin Filaments B Intermediate Filaments C Microtubules D All of These E No Clue 2019 Pearson Education, Inc.  What is the process in which the mRNA strand is made? A Transcription B Translation C Transcendental D Copying E No Clue 2019 Pearson Education, Inc.  What phase of mitosis would you find DNA synthesis takes place? A Interphase G1 B Interphase S C Interphase G2 D Prophase E Telophase 2019 Pearson Education, Inc.