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Transcript of Cell-cell biology

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    A Tour of the Cell

    Chapter 6

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    Objectives

    Be familiar with the regions of the cell andthe overall role of each region

    Be familiar with the basic organelles and

    their function

    Be familiar with the way neighboring cells

    can communicate

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    Cell Types

    All living organisms

    are made of cells Two kinds of cells

    Prokaryotic: lacks

    membrane boundstructures other than

    plasma membrane

    Bacteria

    Eukaryotic: contains

    membrane bound

    organelles enablingcompartmentalization

    leading to

    specialization animals, plants, protists,fungi

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    Cell Size

    Limits on cell sizedetermined by ability

    to perform metabolic

    processes Lower: can all

    necessary components

    fit Upper: can we regulate

    supplies adequately

    (surface to volumeratio)

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    Regions of a Eukaryotic Cell

    Nucleus: contains genetic material (DNA)necessary for cell regulation. Reference

    library

    Cytoplasm: consists of cytosol (cell fluid)

    and organelles (specialized structures that

    carry out metabolic activities of cell) Plasma Membrane: contains the cell and

    regulates movement of materials into/out ofthe cell

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    Cell Overview

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    Nucleus

    Control center of cell Dual membrane

    system that fuse to

    form nuclear pores DNA and Protein

    complexes called

    Chromatin

    Nucleolus: region of

    RNA within theNucleus

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    Nuclear Pore Structure

    To get materials into the

    nucleus there is a 27

    Amino Acid tag (zip code)

    added onto molecules and

    are assisted by proteinscalled importins

    To leave the nucleus

    exportin proteins, aspecific zip code, GTP

    and Ran are required

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    Import Summary

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    Ribosomes

    Sites of Proteinsynthesis

    May be free or bound

    Free make proteinstypically used in the

    cell

    Bound are attached tomembrane (ER) and

    make proteins typically

    for export

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    Endoplasmic Reticulum (ER)

    Part of theendomembrane system

    Smooth ER: site of

    lipid synthesis, detox,carbohydrate

    metabolism

    Rough ER: site of

    protein synthesis

    (contains bound

    ribosomes)

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    Golgi ApparatusWhen it absolutely, positively, has to leave the cell

    Finishes, sorts, andpackages

    manufactured products

    of the cell cis: receives products

    from ER

    trans: ships materials

    to other parts of cell

    (often the plasma

    membrane)

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    Lysosomes

    Membrane boundstructures responsible

    for the degradation of

    spent organelles andfood items

    Contain hydrolytic

    enzymes

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    Vacuoles

    Membrane bound

    storage areas for

    resources

    Named after theresource they contain

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    Mitochondria, Chloroplast

    Mitochondria: site of

    most ATP synthesis

    Chloroplast: site of

    carbohydrate synthesis

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    Peroxisomes

    Modify molecules

    through redox

    reactions (fatty acid)

    Produce peroxide as aresult (H2O2)

    Split into two as they

    grow

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    Cytoskeletal

    elements

    Provide structuralframework for the cell

    Movement of materialsinside and on the surface ofthe cell

    Microtubules

    grow from centrosome

    load bearing Microfilaments

    pulling forces

    Intermediate filaments pulling forces

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    Organelles of Motility

    Flagellum: moves the entire cell

    Cilium (cilia): moves things along the surface of

    the cell

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    Extracellular Surfaces

    Most cells have a

    combination of proteins,

    lipids and sugars that form

    an extracellular matrix Plants have a cell wall

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    What distinguishes one cells

    function from another?

    The quantity and type

    of organelles

    determine how the cell

    can function.

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    Communication is Critical Connections between cellsare called junctions

    Tight junctions: leak-proof connections

    between cells

    Desmosomes: fastencells together

    strengthening the tissue

    Gap junctions:provide cytoplasmic

    channels between cells

    Plasmodesmata: plantcell channels

    In order for many cells to

    function as a unit (as in

    multicellular organisms)there must be a minimal

    level of communication

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