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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