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Lecture 2 cell components

Lecture 2 cell components






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  • Completely surrounds cell Is tough & resourceful ‘gate keeper”
  • (building blocks of protein) Cytoskeleton – creating “freeways” for movement of molecules
  • They keep cell alive and functioning according to genetic code
  • Master control of the cell
  • Nucleus – memory bank – stores genetic code command center – controlling the organelles
  • Most numberous corganelles in the cell ATP – adenosine triphosphate Site of many metabolic reactions Resemble a small bag with a larger bag inside of it - with inner folds
  • mRNA transcript – a DNA copy
  • Looks like stack of pancakes Modifies – adding carbohydrates – forming glycoproteins – like in the production of mucus removes some of the polypeptide chain and produces insulin removes part of polypeptide chain - insulin
  • Substances broken down – usable material diffuses out into the cell’s cytoplasm to be synthesized - like recycling indigestible material remains in lysosome and either migrates to the cell surface to be release by exocyto9sis or remains as an inclusion.
  • 2 centrioles within the centrosome each with a triplets of microtubules arranged in a cartwheel pattern
  • Interior of cell nsomething between a liquid and a gel Functions like reinforced girders Microtubules are tine internal framework of cilia and flagella, centrioles and the mitotic spindle Cells that have projections for moving substances along the surface of the cell or moving the cell itself use cilia (shorter) flagella (longer) Creates ‘freeways’ highways for the movement of molecules Cilia – flagella for movement - one just bigger than the other – found in respiratory mucosa lining the nasal cavity & paranasal sinuses – move mucose coating of those tissues Sperm propelled by flagella
  • Edema as a result of injured tissue – inflammatory response – tissue enlargement.
  • Cell membranes come close together but DO NOT COMPLETELY ATTACH. Attachments appear as dense bodies Attachment plaque located in the cell Desmosome – disc-shaped and like a “spot-weld” Hemidesmosome – nail and nail beds IMPORTA||NT _ hemidesmosomes = mechanism of attachment for epithelium to connective tissue by way of the basement membrane as in oral mucosa

Lecture 2 cell components Lecture 2 cell components Presentation Transcript

  • DEN 1114 Lecture 2 Professor Maria-Elena Bilello http://www.youtube.com/watch?v=1B4F2V0_yYg
  •       Cell Smallest living unit of organization: Epithelial cell, neuron, myofiber, chondrocyte, fibroblast, erythrocyte, macrophage. sperm Tissue Collection of similarly specialized cells: Epithelium, nervous tissue, muscle, cartilage, bone, blood Organ Independent body part formed from tissues: Skin, brain, heart, liver System Organs functioning together: Central nerous system, respiratory system, immune system, cardiovascular system
    • :
    http://www.youtube.com/watch?v=NiiLS_ovLwM&feature=related Criteria for Life Reproduction Ability to replicate ones self (going from one to two) Growth Ability to increase in size Metabolism The process by which substances are produced, maintained and destroyed and energy is produced Anabolism - put particles together (synthesis) from smaller ones (constructive metabolism) Catabolism – Complex molecules are broken down into simpler one and release energy(Destructive metabolism). Assimilation The conversion of absorbed food into the substance of the body Excretion Ability to eliminate respiration Total process of conveying O 2 to tissues & cells and the oxidation process whereby CO 2 & H 2 O are given off. Irritability Ability to respond to a stimulus Conductivity Ability to transmit that stimulus Homeostasis Ability to work together to maintain equilibrium (harmony)
    • Cell contains: Cell membrane Cytoplasm Organelles Cellular inclusions
    • Lipids
    • diffusion regulator (barrier)
    • Only allows substances
    • soluble in lipid to pass
    • through the membrane .
    • Proteins
    • Structural reinforcement - stabilize cell membrane
    • Receptor – hormones neurotransmitters immunoglobulins (antibodies )
    • Types of proteins:
      • Transmembrane proteins (transport materials through bi-layer)
      • Surface membrane proteins (receptors AB & hormones)
    • Semi-fluid portion Between liquid & gel (75-90%)
    • Contains -
    • Ions
    • Molecules - Amino Acids
    • Sugars - glucose & fructose
    • Cytoskeleto n
    • System of support
    • Contains –
    • microfilaments
    • intermediate filaments
    • microtubules
    These create stability and compartmentalize the cytoplasm. Chemical messages from the cytoplasm & membrane (the cellular environmental) influence gene activity. http://www.youtube.com/watch?v=kud4qUhsCxg&feature=related
    • Major Organelles:
    • Nucleus
    • Mitochondria
    • Ribosomes
    • Endoplasmic Reticulum
    • Golgi Complex
    • Lysosomes
    • Cytoskeleton
    • Nucleus
    • ‘ Command Central’
    • Contains:
      • DNA – deoxyribonucleic acid
      • RNA - ribonucleic acid
      • Nucleolus
    • DNA & RNA – Memory Bank (genetic coding)
    • control all functions of the cell
    • in the form of chromatin contains DNA - Chief nucleic acid– linked into chromosomes
    • PRODUCES - rRNA (ribosomal RNA)
    • - nucleotides of the 2 other types of RNA
    • *IMPORTANT for PROTEIN SYNTHESIS (No Nucleolus – No Protein Synthesis)
    • NUCLEAR ENVELOP - double-layered Membrane which may be pierced by nuclear pores .
    • NUCLEAR PORES – communicates between the nucleoplasm and the outer cytoplasm
    • http://www.youtube.com/watch?v=lTHY430ohJI
    • DNA
    • RNA
    • Deoxyribonucleic acid
    • Adenine cytosine
    • Guanine thymine
    • Chromatin – ‘loose’ DNA when no division is occurring (just strands)
    • http://www.youtube.com/watch?v=qy8dk5iS1f0&feature=related
    • Besides hereditary activity,
    • DNA directs synthesis of many
    • enzymes, proteins and
    • secretory products
    • mRNA – Messenger RNA
    • complementary copies of segments of DNA
    • tRNA – Transfer RNA molecules that bind to & transport amino acids units for protein systhesis
    • rRNA – Ribosomal RNA
    • Energy Production (Conversion) – ATP
    • Cristae – folds inside mitochondria
        • Cristae – contain enzymes on surface to aid in cell metabolism
        • cell function depends on the amount
        • (increase # mitochondria = increased cellular activity)
        • Increase # cristae = more active cell
    • * Cardiac muscle and the liver contain the most mitochondria.
    • http://www.youtube.com/watch?v=TgJt4KgKQJI&feature=related
    • Made in the Nucleolus from rRNA & protein molecules and assembled in the cytoplasm
    • Found: free in cytoplasm (bound to membranes)
            • within mitochondria
            • attached to mRNA molecule
            • bound to rough endoplasmic reticulum
            • outer nuclear membrane
    • Sequences protein chains
    • Within ribosomes – free amino acids are being joined together in accordance with the order specified by the mRNA transcript
    • Network of parallel membrane-bound channels
    • and folds which is continuous (connects) with
    • nuclear envelope.
    • Functions: modifies , stores , segregates and transports proteins
    Smooth Endoplasmic Reticulum (SER) Rough Endoplasmic Reticulum (RER) Free of Ribosomes Smooth – lipid/fat synthesis Ribosomes on outer surface Rough – protein synthesis
    • Composed of stacks of 3 to 20 flattened, smooth-membraned vesicular sacs – parallel to each other
    • Fuses with vesicles of protein molecules (hormones, enzymes, secretory products) from RER
    • Protein molecules are further modified concentrated and packaged.
    • Packaging – wraps larger #’s of molecules into a single membranous vesicle (using merocrine secretion)
    • Prepares proteins for export by EXOCYTOSIS
    • Produces lysosomes – a separate organelle
    • Function –Digestion
    • Intracellular & Extracellular
    • Vesicle – develops and pinches off Golgi complex
    • Enzymes of the lysosomes are produced on RER, transported for packaging to Golgi complex
    • lyses – to digest - breaks down particles (good & bad – foreign particles)during phagocytosis
    • Autolysis – self destruction
    • Caused by:
    • Powerful hydrolytic enzy mes and digestive enzymes
    • Main hydrolytic enzyme - hyaluronidase
    • * All cells – except red blood cells (RBC) have digestive activity
    • Function: Significant role in reproduction - cell division (mitosis)
    • Aids in spindle formation
    • Oval-shaped organelle
    • Always located near nucleus
    • Contains : Centrioles - pair of cylindrical structures
    • *Without self-replicating centriole-centrosome unit , animal cells cannot reproduce
    http:// www.youtube.com/watch?v=N0JCD3ofyIM
    • Function:
    • Support - a 3-dimensional
    • System that gives stability
    • Compartmentalizes the
    • cytoplasm for movement of molecules
    • Components: Microfilaments, Intermediate filaments
    • Microtubules
    • (these consists of specialized proteins)
    • Microfilaments:
    • Delicate, thread-like, not hollow
    • Maintain cell shape
    • Transport intracellular materials
    • Microtubules:
    • Slender, hollow, tubular
    • Assist microfilaments
    • Framework for cilia, flagella, centrioles
    • Intermediate filaments:
    • Thicker, thread-like
    • Examples:
    • Tonofilaments – role in
    • intercellular junctions
    • Keratin –found in calloused epithelial tissues
    • Inert (not active) substances that are produced in the cell to be used later - transient.
    • Vacuoles – spaces/cavities in the cytoplasm
    • Are released from storage by the cell as needed
    • water
    • Lipids and glycogen can be decomposed for energy from inclusions.
    • Melanin (a pigment) stored as inclusion in skin cells and oral mucosa.
    • Residual bodies such as old lysosomes & their digested material.
    • Fills the spaces between cells in a tissue
    • Serves as barrier
    • Serves as a medium for the exchange of gases & metabolic substances.
    • Produced by the cells.
    • Colorless, shapeless and transparent.
    • Tissue Fluid (interstitial fluid)
      • Dissolves, mixes, transports substance and carries out chemical reactions.
      • (contains small amount of plasma proteins)
      • Diffuses through capillary walls from plasma of blood.
      • Returns into blood as lymph by osmosis via the lymphatic system
    • The amount of tissue fluid varies.
    • Excess tissue fluid = EDEMA
    • CELL TO CELL -
    as in upper layers of skin as in gingival epithelium & tooth surface Attachment device - attachment plaque in the cell & tonofiliments http://www.youtube.com/watch?v=XdaUthOUvIo&feature=related
  • Hemidesmosomes as mechanism for attaching the epithelium to connective tissue such as in the oral mucosa by way of the basement membrane Desmosomes as mechanism for attaching upper layers of the skin
  • http://www.youtube.com/watch?v=W0HQt1MTrAc&feature=related