Introduction to Cells Ch. 7 Ch. 7 Compound Light Microscope: allows light to pass through a specimen...

Introduction to CellsIntroduction to Cells

Ch. 7Ch. 7 Compound Light Compound Light MicroscopeMicroscope: allows : allows light to pass light to pass through a specimen through a specimen and magnifies the and magnifies the image with lensesimage with lenses

Electron microscopesElectron microscopes – use – use beams of electrons to beams of electrons to produce images.produce images.

Three-dimensional images!Three-dimensional images!

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The Discovery of the CellThe Discovery of the Cell

Robert Hooke – first to see and Robert Hooke – first to see and identify cork “cells.”identify cork “cells.”

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The Cell TheoryThe Cell Theory Cell Theory:Cell Theory:

1.1. All living things are All living things are composed of cellscomposed of cells

2.2. Cells are the basic living Cells are the basic living units of all organismsunits of all organisms

3.3. New cells are produced from New cells are produced from existing cellsexisting cells

-a cell divides to form two -a cell divides to form two identical cellsidentical cells

Virchow7-1

Other Inventors of Other Inventors of Cell TheoryCell Theory

Theodore Schwann - all animals Theodore Schwann - all animals are made up of cellsare made up of cells

Matthais SchleidenMatthais Schleiden - all plants are - all plants are made up of cellsmade up of cells

Schwann

Schleiden

Cells are the basic unit of lifeCells are the basic unit of life Unicellular Organisms: BacteriaUnicellular Organisms: Bacteria Multicellular Oganisms: Animal & Multicellular Oganisms: Animal &

Plant CellsPlant Cells

Pancreatic cell Blood cellMuscle cell

All Cells have 3 All Cells have 3 characteristics:characteristics:

1. surrounded by a barrier called a 1. surrounded by a barrier called a cell membranecell membrane

2. have biological information 2. have biological information ((DNADNA))

3. have cytoplasm3. have cytoplasm

Two Main Groups of CellsTwo Main Groups of Cells ProkaryotesProkaryotes

NO membrane bound NO membrane bound organellesorganelles

has circular DNA, no has circular DNA, no nucleusnucleus

cell functions carried out in cell functions carried out in cytoplasmcytoplasm

unicellularunicellular Example: BacteriaExample: Bacteria

Eukaryotes:Eukaryotes: membrane bound organellesmembrane bound organelles DNA is in the nucleusDNA is in the nucleus cell functions carried out by cell functions carried out by

organellesorganelles Most multicellularMost multicellular Example: Animal & Plant Example: Animal & Plant

CellsCells

Eukaryotic Cell StructureEukaryotic Cell Structure

NucleusNucleus – contains DNA that codes – contains DNA that codes for proteinsfor proteins

CytoplasmCytoplasm – the portion of the cell – the portion of the cell outside the nucleus; “jelly-like” fluidoutside the nucleus; “jelly-like” fluid



Nuclear MembraneNuclear Membrane – surrounds the – surrounds the nucleus.nucleus.

ChromosomesChromosomes – folded and twisted – folded and twisted strands of DNA in the nucleus.strands of DNA in the nucleus.

NucleolusNucleolus – makes ribosomes. – makes ribosomes.


Inside the NucleusInside the Nucleus


Inside the NucleusInside the Nucleus

Nuclear Envelope

Nucleolus



RibosomesRibosomes – site where cell makes – site where cell makes enzymes and other enzymes and other Proteins!Proteins!

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RibosomesRibosomes

Ribosome



Endoplasmic reticulum (ER)Endoplasmic reticulum (ER)– flattened, double-layered flattened, double-layered membranesmembranes site of chemical reactionssite of chemical reactions Rough ER – has ribosomesRough ER – has ribosomes Smooth ER – no ribosomesSmooth ER – no ribosomes



Endoplasmic Reticulum Endoplasmic Reticulum (ER)(ER)

Rough ER

Smooth ER



Golgi ApparatusGolgi Apparatus –sorts and packages –sorts and packages proteins.proteins.

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Golgi ApparatusGolgi Apparatus

Golgi Apparatus



LysosomesLysosomes – contain digestive – contain digestive enzymes.enzymes. Digest food, old organelles, Digest food, old organelles,

viruses/bacteria.viruses/bacteria.

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VacuolesVacuoles – temporary storage – temporary storage



VacuolesVacuolesVacuoles



MitochondriaMitochondria – – produces energy for produces energy for the cellthe cell ““Powerhouse of the Powerhouse of the

Cell!”Cell!”

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MitochondriaMitochondria

Mitochondria



ChloroplastsChloroplasts – converts light energy – converts light energy of the sun into sugars of the sun into sugars (Photosynthesis)(Photosynthesis) Found only in plantsFound only in plants..



ChloroplastsChloroplasts

Chloroplast



CentriolesCentrioles – separates – separates chromatids (DNA) during cell chromatids (DNA) during cell division division Found only in animals.Found only in animals.

CytoskeletonCytoskeleton – provides – provides structure for the cellstructure for the cell



Cell BoundariesCell Boundaries Plasma membranePlasma membrane – thin, flexible – thin, flexible

membrane that surrounds the cell.membrane that surrounds the cell.


Cell BoundariesCell Boundaries

Cell wallsCell walls – – firmfirm wall around the cell wall around the cell membrane found membrane found only in bacteria and only in bacteria and plants.plants. Protects & gives shape to cellsProtects & gives shape to cells

A

D

G

C

B

FE

3

34

6

8

7

Plasma Membrane Plasma Membrane

and Homeostasisand Homeostasis

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Homeostasis – Maintaining a BalanceHomeostasis – Maintaining a Balance

Plasma membrane - Plasma membrane - Semi-permeable, allows only certain materials to move in and out of the cell

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Cell Membrane Cell Membrane StructureStructure

Lipid Lipid BiBilayer – two sheets of lipids layer – two sheets of lipids (phospholipids)(phospholipids)

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Protein channels – help move material Protein channels – help move material across the cell membraneacross the cell membrane

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Cell Membrane Cell Membrane StructureStructure

Fluid Mosaic ModelFluid Mosaic Model

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Cellular TransportCellular Transport movement of material in and out of movement of material in and out of

cellscells

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Solution Solution ConcentrationConcentration::

# of molecules # of molecules per volume of per volume of containercontainer

* ** ** *

* * * * * * * * * ** * * * ** * * * *

High Conc.

Low Conc.

DiffusionDiffusion DiffusionDiffusion – – the movement of molecules the movement of molecules

from an area of from an area of HIGHHIGH concentration to an concentration to an area of area of LOWLOW concentration until concentration until EVENLY EVENLY SPREADSPREAD

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Diffusion of GasesDiffusion of Gases

OsmosisOsmosis Special type of Special type of diffusiondiffusion

The movement of The movement of WATER WATER from where it from where it is in is in high concentrationhigh concentration to where it is to where it is in in low concentrationlow concentration across a across a selectively permeable membraneselectively permeable membrane (cell membrane)(cell membrane)

Osmosis in cellsOsmosis in cells

1% salt solution + H20

10% salt 10% salt solution solution

-H20-H20

H20H20

Water flows from High to Low Concentration

Osmosis PracticeOsmosis Practice

Cell

90% H2O10% NaCl

90% H2O10% NaCl

Concentrations areequal, so no netmovement of water!

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Cell

90% H2O10% NaCl

80% H2O20% NaCl

Concentration ofwater is greater inthe cell than out, sowater will move out!

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Cell

80% H2O20% NaCl

90% H2O10% NaCl

Concentration ofwater is greateroutside the cell than in, so water will move out!

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PlasmolysisPlasmolysis Cell Cell

membranes membranes shrink or shrink or expandexpand

Dependent on Dependent on salt concen-salt concen-trationstrations

Facilitated DiffusionFacilitated Diffusion

Facilitated diffusion – when the Facilitated diffusion – when the plasma membrane “helps” particles plasma membrane “helps” particles pass through protein channels.pass through protein channels. No energy used.No energy used.

Active TransportActive Transport Active transport – when the plasma Active transport – when the plasma

membrane uses energy to move membrane uses energy to move particles against a concentration particles against a concentration gradient.gradient. Uses Transport ProteinsUses Transport Proteins

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EnEndocytosis – process by which docytosis – process by which a cell takes material into the a cell takes material into the cell by infolding of the cell cell by infolding of the cell membranemembrane phagocytosis & pinocytosisphagocytosis & pinocytosis

ExExocytosis – process by which a ocytosis – process by which a cell releases large amounts of cell releases large amounts of materialmaterial

BOTH REQUIRE ATP ENERGY!!!BOTH REQUIRE ATP ENERGY!!!

Moving large particlesMoving large particles

Active or Passive Active or Passive TransportTransport??

Which requires ATP energy?Which requires ATP energy?

Which goes with the Which goes with the concentration gradient?concentration gradient?

Which goes against the Which goes against the gradient?gradient?

Concentration Concentration GradientGradientHigh Concentration Low Concentration

* * * * * * ** * * * * * ** * * * * * *

* * * * * * * * *

* * * ** * * *

* * * *

Passive TransportPassive Transport Diffusion or Diffusion or

OsmosisOsmosis Going with Going with

the gradientthe gradient No ATP No ATP

energy energy requiredrequired * * * * * * * * * *

* * * * * * * * * *

High Conc. To Low Conc.

Active Active TransportTransport Against the Against the

gradientgradient Requires ATPRequires ATP Low to High Low to High

ConcentratioConcentrationsns

* * * * * * * * * * ** * * * * * * * * * ** * * * * * * * * * *

Facilitated Diffusion and Active Facilitated Diffusion and Active TransportTransport


Organization in Multicellular Organization in Multicellular OrgansismsOrgansisms

Tissues

Organs

Organ System

Organism

Cells


Plasmolysis in Elodea CellsPlasmolysis in Elodea Cells

Elodea in tap water

Elodea in 10% NaCl

Introduction to Cells Ch. 7 Ch. 7 Compound Light Microscope: allows light to pass through a specimen...

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