BIOL 140-04 a Tour of the Cell

7/29/2019 BIOL 140-04 a Tour of the Cell

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A Tour of the Cell

BIOL 140 Human Biology

Fall 2011Christine Simmons


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Lecture Objectives

Compare the designs and images produced by LM, SEM and TEM Distinguish between the structures of prokaryotic and eukaryotic

cells

Describe the structures and functions of the four cellularcompartments

Describe the structures and functions of the components of theendomembrane system

Compare and contrast mitochondria and chloroplasts Compare the structure and functions of the cytoskeletal elements,

extracellular matrix and junctions in the cell

Describe the four functional categories of organelles in eukaryoticcells

List and describe the three fundamental features of all organisms


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4.1 Microscopes reveal the world of the cell

Types of microscopes Light microscope (LM) Scanning electron

microscope (SEM)Transmission electron

microscope (TEM)

Magnification vs.resolution

Cell theoryAll living things are

composed of cell(s) andthat all cells come from

other cellsTable 4.1 and Figure 4.1A


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4.1 Microscopes reveal the world of the cell

Figures 4.1C-4.1F


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4.2 Most cells are microscopic

Most cells cannot be seen withthe unaided eye

Volume and Surface AreaSame volumeDifferent surface areas

Figures 4.2A and 4.2B


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4.3 Prokaryotic cells arestructurally simpler than eukaryotic cells

Prokaryotic cells Nucleoid region Cell wall Capsule

All cells have Plasma membrane Chromosomes

Ribosomes Cytoplasm

Two main divisions ofcells

Prokaryotic Eukaryotic

Prokaryotic cells includeArchaea Bacteria Figure 4.3


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4.4 Eukaryotic cells are partitionedinto functional compartment

Eukaryotic cells include Animals, plants, fungi, or

protists

Two types of eukaryotic cells Animal Plant

Four functional groups Manufacturing Breakdown of molecules Energy processing Structural support, movementand communication



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4.5 The structure of membranescorrelates with their functions

Plasma membrane separates the living cellfrom its environment

Controls the traffic of molecules into and outof the cell

Phospholipids are the main component ofbiological membranes

Hydrophilic headsHydrophobic tails



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4.6 The nucleus is the cells genetic control center

The nucleus contains most of the cells DNAControls cellular activities by directing protein

synthesis

DNA is housed as chromatin Nuclear envelope

Connects to ERHas pores

NucleolusrRNA synthesis

Figure 4.6


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4.7 Ribosomes make proteins foruse in the cell and export

Ribosomes carry out protein synthesis Free ribosomes

Cytoplasm Bound ribosomes

Attached at ER ornuclear envelope

Free ribosomes synthesizeproteins used in the cytoplasm

Bound ribosomes synthesizeproteins destined for secretion

Figure 4.7


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4.8 Overview: Many cell organelles are connectedthrough the endomembrane system

Many of the membranes within a eukaryotic cell arepart of the Endomembrane System Nuclear envelope Endoplasmic reticulum Golgi apparatus (and vesicles) LysosomesVacuoles Plasma membrane

Endomembrane system functions in synthesis,storage and export of molecules


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4.9 The endoplasmic reticulumis a biosynthetic factory

Two types of endoplasmicreticulum Smooth (SER)

Lack bound ribosomes Rough (RER)

Has bound ribosomes Smooth endoplasmic reticulum

Lipid synthesis Detoxifying enzymes Storage of calcium

Rough endoplasmic reticulum Synthesizes more membrane Synthesize, modify and package

proteinsFigures 4.9A and 4.9B


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4.10 The Golgi apparatus finishes, sortsand ships cell products

Transport vesicles from the ER go to the Golgiapparatus

Golgi apparatus functions as a molecularwarehouse and finishing factory

Receiving side Receives from ER

Shipping side Ships to areas of the

cell or to plasma

membraneFigure 4.10


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4.11 Lysosomes are digestivecompartments within a cell

Lysosomescontain digestiveenzymes

Breakdown foodRecycle cellular

components

Lysosomal storagediseasesTay-Sachs disease



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4.12 Vacuoles function in thegeneral maintenance of the cell

Variety of functions of vacuolesFood vacuoles

Digestion when fused with lysosomeCentral vacuole (plants)

Water/chemical storageContractile vacuoles

Water regulation



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4.13 A review of the structures involvedin manufacturing and breakdown

Figure 4.13


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4.14 Mitochondria harvestchemical energy from food

Mitochondria carry out cellular respirationChemical energy of food to chemical energy of ATPATP is the main source of energy for cellular work

Mitochondrial structureTwo membranes

Outer membrane

Inner membrane Folds = cristae

Two compartments Intermembrane space

MatrixFigure 4.14


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4.15 Chloroplasts convertsolar energy to chemical energy

Chloroplasts convertlight (solar) energyinto chemical energy

of sugar molecules

Two membranesInner and outer

membranes

Inside compartmentStromaThylakoids

Thylakoid spaceGrana

Figure 4.15


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4.16 Mitochondria and chloroplastsevolved by endosymbiosis

Mitochondria and chloroplasts have their ownDNA and ribosomes

Similar feature to prokaryotesCircular chromosomesReproduce by splittingDouble membrane

EndosymbiontsSmall prokaryotes that lived

within larger cells

Figure 4.16


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4.17 The cells internal skeleton helpsorganize its structure and activities

The cytoskeleton is a network of protein fibers thatextends throughout the cytoplasm Three fiber types

Microfilaments Intermediate filaments Microtubules

Figure 4.17


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4.18 Cilia and flagella movewhen microtubules bend

Cilia and flagella are involved incellular locomotion

Cilia Short and numerous Sweep fluid passed cell Human windpipe

Flagella Long and only a few per cellWhip-like motion Sperm cells

Figures 4.18A-C


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4.20 The extracellular matrix of animal cellsfunctions in support, movement and regulation

The extracellular matrix is a layer of fluid and fibersthat bind cells into tissues

Components of the ECM

Glycoproteins Fibrous proteins

Collagen Elastin

Integrins bindcomponents ofthe ECM to theplasma membrane

Figure 4.20


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4.21 Three types of cell junctions arefound in animal tissues

Three types of cell junctionsTight junctions

Seals around cells Prevent leakage of extracellular

fluid

Anchoring junctions Fasten cells together Common in tissues subject to

stretching or mechanical stress Gap junctions

Communicating junctionsAllow small molecules to pass

Figure 4.21


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4.22 Cell walls enclose and support plant cells

Presence of a cell wall distinguishes plant fromanimal cellsFunctions in protection and support

PlasmodesmataCirculatory and

communication network

between cellsShare water, nourishment,

and chemical messages

Figure 4.22


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4.23 Review: Eukaryotic cell structure can begrouped on the basis of four basic functions

All organismsConsist of cell(s)

surrounded by a

membraneHave DNA as the

genetic material

Undergo metabolism

BIOL 140-04 a Tour of the Cell

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