1 cellular biology chapter 1. mosby items and derived items © 2006 by mosby, inc. 2 prokaryotes vs....
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Cellular BiologyChapter 1
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Prokaryotes vs. Eukaryotes Prokaryotes
Nucleus (single, circular chromosome) Cyanobacteria, bacteria, and rickettsiae
Eukaryotes Complex cellular organization Membrane-bound organelles Well-defined nucleus Higher animals, plants, fungi, and protozoa
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Cellular Functions Movement Conductivity Metabolic absorption Secretion Excretion Respiration Communication
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Eukaryotic Cell Nucleus
Nuclear envelope- Membrane around nucleus Nucleolus- organelles involved in cell division DNA- chemical blueprints of life
DNA replication- semi conservative method, repair with nuclear enzymes in some cancers sometime defective repair enzymes, and transcription – making mRNA and tRNA and r RNA from DNA gene templates
Histone proteins – bind to outside of DNA double helix and protect DNA as well as control what genes are expressed at what time.
Cell division – mitosis – Prophase – metaphase – anaphase – telophase – interphase. Cell cycle
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Eukaryotic Cell Nucleus
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Eukaryotic Cell Cytoplasm
Cytoplasmic matrix Cytosol Function Cytoplasmic organelles
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Eukaryotic Cell Cytoplasm
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Eukaryotic Organelles Ribosomes - organelles
rRNA made from DNA and 2 protein subunits Free ribosomes – independent from reticulum Attached ribosomes associated with ER
Endoplasmic reticulum – ER membrane complex inside cell Site of protein synthesis Smooth vs. rough endoplasmic reticulum
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Eukaryotic Organelles Ribosomes involved with
protein synthesis. Line up tRNA + aa, rRNA and mRNA with enzymes that attach aa’s into long polypetide strands
Endoplasmic reticulum –site where ribosomes produce proteins
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Eukaryotic Organelles Golgi complex – final processing site for
proteins, especially those destined to be secreted from the cell. Flattened, smooth membranes Secretory vesicles Proteins from the endoplasmic reticulum are
packaged in the Golgi complex Cisternae
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Eukaryotic Organelles Golgi complex
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Eukaryotic Organelles Golgi complex – usually
associate with ER and outer cell membranes. Site of final processing of proteins to be secreted out of cell
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Eukaryotic Organelles Lysosomes membrane bounded structures
Originate from the Golgi and contain lytic enzymes Catalyze and breakdown proteins, lipids, nucleic acids,
and carbohydrates Role in autodigestion Some vitamins can destabilize lysosome membranes
(retin A anti wrinkle cream) and cortisone stabilizes membranes preventing cellular breakdown (part of anti-inflamitory action
Peroxisomes Contain oxidative enzymes Break substances down into harmless products
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Eukaryotic Organelles Mitochondria
Surrounded by a double lipid–bilayer membrane Participates in oxidative phosphorylation Increased inner membrane surface area provided
by cristae Location where enzymes of the Krebs cycle are
located and where ATP is produced in the Electro transport chain reactions
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Eukaryotic Organelles Mitochondria
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Eukaryotic Organelles Vaults
Cytoplasmic ribonucleoproteins, shaped like octagonal barrels
Cellular trucks
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Eukaryotic Organelles Cytoskeleton
“Bones and muscles” of the cell Maintains the cell’s shape and internal
organization Permits movement of substances within the cell
and movement of external projections Microtubules
Centrioles
Microfilaments
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Eukaryotic Organelles Cytoskeleton
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Plasma Membrane Controls the composition of a space or
compartment they enclose Structure
Caveolae Lipids
Amphipathic lipids Hydrophilic and hydrophobic
Phospholipids, glycolipids, and cholesterol
Carbohydrates
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Plasma Membrane
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Plasma Membrane Proteins
Integral, peripheral, transmembrane Functions
Receptors Transport Enzymes Surface markers Adhesion molecules
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Plasma Membrane Plasma membrane protein functions
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Proteolytic Cascades Caspase-mediated apoptosis Blood coagulation cascade Matrix metalloproteinase cascade Complement cascade
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Membrane Fluidity
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Cell-to-Cell Adhesions Extracellular matrix
Production Fibroblasts
Collagen Elastin Fibronectin
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Cell-to-Cell Adhesions Extracellular matrix
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Cell-to-Cell Adhesions Cell junctions
Desmosomes Tight junctions Gap junctions
Gating
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Cell-to-Cell Adhesions Junctional complex
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Cellular Communication Direct linkup Gap junctions Hormonal Neurohormonal Paracrine Autocrine Neurotransmitters
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Cellular Communication
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Signal Transduction Extracellular messengers
Convey instructions to the cell’s interior Transfer, amplify, distribute, and modulate
Channel regulation Second messengers
Two pathways Adenosine monophosphate (cAMP) Ca++
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Signal Transduction
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Cellular Metabolism Metabolism
Chemical tasks of maintaining essential cellular functions
Anabolism Energy using
Catabolism Energy releasing
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Adenosine Triphosphate Created from the chemical energy contained
within organic molecules Used in synthesis of organic molecules,
muscle contraction, and active transport Universal fuel for all cell functions The Electron Transport Chain (cytochromes)
are involved with the production of ATP
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Cellular Energy Digestion Glycolysis - first step in the breakdown of glucose (6
Carbons) Occurs in the cytoplasm results in Pyruvate (2x 3Carbons) Anaerobic – no need for oxygen like mitochondria
reactions. If no O2 present pyruvate converted to Lactate Citric acid cycle
Also called Krebs cycle or the tricarboxylic acid cycle (TCA) in the mitochondria
Oxidative phosphorylation Occurs in the mitochondria
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Cellular Energy
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Membrane Transport Gradient Passive transport
Diffusion – follows concentration gradients Passive mediated transport – no energy needed Filtration – just like making coffee Osmosis – movement of water across membranes
Osmolarity vs. osmolality
Tonicity – describes hoe living cells react to solutions Isotonic (same size), hypertonic (shrinks cell), and hypotonic
(cells will swell when exposed to this kind of solution)
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Membrane Transport
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Membrane Transport
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Membrane Transport Active transport
Active transport pumps require ATP move charged ions and substances across membranes
Transport by vesicle formation Endocytosis
Pinocytosis Phagocytosis Potocytosis
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Active TransportIons and charged moleculesAs well as large chemicalsLike proteins need to beTransported across the Membrane barrier.
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Membrane Transport
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Electrical Impulses Resting membrane potential – caused by the
distribution of charged ions like Na & K Action potential – the flow of ions when the
membrane is disturbed Depolarization Threshold potential Repolarization Refractory period
Absolute and relative
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Propagation of an Action Potential
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The Cell Cycle Mitosis vs. cytokinesis Chromatin vs. chromosomes Interphase
G1 phase
S phase G2 phase
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The Cell Cycle
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The Cell Cycle Prophase Metaphase Anaphase Telophase
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Influences on the Cell Cycle Cellular division rates Growth factors
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Tissue Formation Founder cells Chemotaxis Contact guidance Cellular reproduction
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Tissue Formation
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Types of Tissue Epithelial tissue
Simple vs. stratified Squamous Cuboidal Columnar Pseudostratified Structures
Cilia and microvilli
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Types of Tissue Connective tissue
Ground substance Fibers Loose and dense connective tissue Elastic and reticular connective Cartilage, bone, vascular, and adipose
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Types of Tissue Muscle tissue
Smooth Striated (skeletal) Cardiac