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Review Facts Review Facts About Living About Living

ThingsThings

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What Are the Main What Are the Main Characteristics of Characteristics of

organisms?organisms?1.1. Made of Made of CELLSCELLS2.2. Require Require ENERGYENERGY (food) (food)3.3. REPRODUCEREPRODUCE (species) (species)4.4. Maintain Maintain HOMEOSTASISHOMEOSTASIS5.5. ORGANIZEDORGANIZED6.6. RESPONDRESPOND to environment to environment7.7. GROWGROW and and DEVELOPDEVELOP8.8. EXCHANGEEXCHANGE materials with materials with

surroundings (water, wastes, surroundings (water, wastes, gases)gases)

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LEVELS OF ORGANIZATIONLEVELS OF ORGANIZATION

Living Levels:Living Levels:

1.1. CELLCELL (makes up ALL organisms) (makes up ALL organisms)

2.2. TISSUETISSUE (cells working together (cells working together

3.3. ORGANORGAN (heart, brain, stomach …) (heart, brain, stomach …)

4.4. ORGAN SYSTEMSORGAN SYSTEMS (respiratory, circulatory (respiratory, circulatory

…)…)

5.5. ORGANISMORGANISM

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THE CELLTHE CELL All living things are All living things are

made of made of cells.cells.

Cells are the basic unit Cells are the basic unit of life.of life.

Cells come from the Cells come from the reproduction of existing reproduction of existing cells cells (cell division).(cell division).

The MicroscopeThe Microscope

Learning ObjectivesLearning Objectives

By the end of this topic, you will be able By the end of this topic, you will be able to:to:

1.1. Name the parts of the microscope Name the parts of the microscope and their functions.and their functions.

2.2. Use the microscope to observe Use the microscope to observe biological specimensbiological specimens

3.3. Know the difference between the Know the difference between the light microscope and the electron light microscope and the electron microscopemicroscope

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First to View CellsFirst to View Cells In 1665, In 1665, Robert Robert

HookeHooke used a used a microscope to microscope to examine a thin examine a thin slice of slice of corkcork (dead plant cell (dead plant cell walls)walls)

What he saw What he saw looked like small looked like small boxesboxes

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First to View CellsFirst to View Cells Hooke is Hooke is

responsible for responsible for naming cellsnaming cells

Hooke called Hooke called them “CELLS” them “CELLS” because they because they looked like the looked like the small rooms that small rooms that monks lived inmonks lived in called Cellscalled Cells

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Anton van Anton van LeeuwenhoekLeeuwenhoek

In 1673, In 1673, LeeuwenhoekLeeuwenhoek (a (a Dutch microscope Dutch microscope maker), was maker), was first first to view organismto view organism (living things)(living things)

Leeuwenhoek used Leeuwenhoek used a simple, handheld a simple, handheld microscope to microscope to view view pond water & pond water & scrapings from his scrapings from his teethteeth

Compound MicroscopesCompound Microscopes

a.a. The The Eyepiece LensEyepiece Lens is is the lens that you look the lens that you look through.through.b.b. The The objective lensobjective lens is the is the lens that is immediately lens that is immediately above the specimen.above the specimen.

The microscopes used in our lab are called compound microscopes because they have two magnifying lens

The Objective LensesThe Objective LensesThere are three objective lenses:There are three objective lenses:

- the scanning lens with the 4X - the scanning lens with the 4X labellabel

- the low power lens with the 10X - the low power lens with the 10X labellabel

- the high power lens with the 40X - the high power lens with the 40X labellabel

Parts of the MicroscopeParts of the Microscope

The MicroscopeThe MicroscopeEyepiece

Nosepiece

Objective Lens

Stage

Clips

Light

Diaphragm

Course Focus

Fine Focus

Parts of the MicroscopeParts of the MicroscopePartPart FunctionFunction

LensesLenses MagnificationMagnification

StageStage To place the slide onTo place the slide on

ClipsClips Hold the slide in placeHold the slide in place

DiaphragmDiaphragm To control the amount of To control the amount of lightlight

Coarse Focus Coarse Focus KnobKnob

To focus the imageTo focus the image

Fine Focus KnobFine Focus Knob To precisely focus the To precisely focus the imageimage

LightLight To supply light to the objectTo supply light to the object

Learning CheckLearning CheckLabel the parts of the Label the parts of the

MicroscopeMicroscope

MagnificationMagnificationMagnification = the magnifying power of the eyepiece lens

x the magnifying power of the objective lens.

Example:

Eyepiece lens = 10XObjective lens = 4X

Total magnification = 10 x 4= 40X

Focussing The ImageFocussing The Image

The course focuscourse focus knob allows for dramatic or large movement of the objective lens.

The fine focusfine focus knob allows for very slight movement of the objective lens.

2.1.1 Microscopy.exe

The Stage and the The Stage and the DiaphragmDiaphragm

The stagestage has two metal clips to hold the microscope slide in place.

The diaphragmdiaphragm allows light to be focused onto the specimen through a hole in the stage.

Light MicroscopeLight Microscope

Elodea - Aquatic Plant

40X 400X

ELECTRON MICROSCOPEELECTRON MICROSCOPE

Electron MicroscopeElectron Microscope

Uses Electrons instead of lightUses Electrons instead of light

Electrons have much lower wavelength Electrons have much lower wavelength than lightthan light

Resolution is much betterResolution is much better

Magnification is much greaterMagnification is much greater

Images from Electron Images from Electron MicroscopeMicroscope

Bacteria

Cytplasm

Platelet

Now lets get Now lets get familiar with the familiar with the

light microscope by light microscope by using it!using it!

https://www.youtube.com/https://www.youtube.com/watch?v=jP9HtcAvGDkwatch?v=jP9HtcAvGDk

How to correctly use How to correctly use microscopemicroscope

 

Draw labelled diagrams of your observations under low power and under high power.

Learning CheckLearning CheckWhat is the function of each of What is the function of each of these parts of the Microscope?these parts of the Microscope?

Eyepiece Lens Eyepiece Lens Objective Objective LensLens

StageStage ClipsClips

DiaphragmDiaphragm Coarse Focus Coarse Focus KnobKnob

Fine focus KnobFine focus Knob Light Light

What have you learned?What have you learned?

Can you?Can you?

1.1. Name the parts of the microscope Name the parts of the microscope and their functions.and their functions.

2.2. Use the microscope to observe Use the microscope to observe biological specimensbiological specimens

3.3. Outline the differences between Outline the differences between the light microscope and the the light microscope and the electron microscopeelectron microscope

ENDEND