4The Eyepiece: This is the where you look into the microscope The Eyepiece: This is the where you look into the microscope. Eyepieces are usually labeled x10 or x15.The Objective Lens: There are usually three objective lenses. Typically these would be labeled X4, X10 and X40 on a school microscope.The Stage: Is the part of the microscope which holds the slide.The Slide: Is a rectangular piece of glass used to hold the specimen.A Coverslip: Is a piece of thin glass placed over the item you are examining on the slide.The Coarse Focus: is used to focus the microscope on the item you are examining.The Fine Focus: is used to change the focus slightly, so that the specimen (the item under examination) is very clear.The Light: is used to illuminate the specimen. In order to view something with a microscope. Some microscopes use a mirror instead of a light.The magnification of a microscope: Is calculated by multiplying the eyepiece power by the objective power. Therefore if we have a X10 eyepiece and have selected a x15 objective lens the magnification is 150. This means that the object we are looking at a specimen being magnified 150 times.
5Focusing with a Microscope Plug in and turn on.Lower stage completely.Turn nosepiece to low objective.Raise stage with coarse objective until specimen is seen. (Big knob)Fine focus the specimen.Centre specimen in the field of view.Rotate nosepiece to medium power objective.Refocus with fine adjustment.Re-centre the specimen.Refocus with fine adjustment. (Be careful not to break the slide.)Adjust the condenser. (Light)Start over to look at another specimen.Carrying and storage instructions.
6Microscope and Cells Microscope Demonstration Microscope Introduction Preparing a plant and animal cell slide
8Microscope History and Development Field of view and Magnification
9Early Microscopes - Anton Van Leeuwenhoek The father of microscopy, Anton Van Leeuwenhoek of Holland ( ).Anton Van Leeuwenhoek was the first to see and describe bacteria (1674), yeast plants, the teeming life in a drop of water, and the circulation of blood corpuscles in capillaries.
11Robert HookeIn 1665, the English physicist Robert Hooke looked at a sliver of cork through a microscope lens and noticed some "pores" or "cells" in it.Hooke was the first person to use the word "cell" to identify microscopic structures when he was describing cork.
14Compound Light Microscopes Uses lightHas two lensesMagnification limited to 2000x (400x at GMCS)
15Transmission Electron Microscope (TEM) Uses beams of electronsMagnification of xHas two limitations:Good only for thin specimensOnly dead cells can be observed
16Scanning Electron Microscope (SEM) Electrons are reflected from the surface of the specimenProduces a 3-d imageGood for the thicker specimensLacks the magnification and resolution of the transmission electron microscope
19Calculating the size of a specimen Example under med. objective Object size = Size of field of view Number of objects across field of viewObject size = 1.72 mmObject size = 0.1 mm
20Cell Basics (3) Microscope question sheet (HO) Do in class, distribute and go over together.The Cell – Need to know BasicsAnimal and Plant Organelles(colour HO)Compare Animal and Plant cells(Venn HO)
21The Cell – Need to know Basics Cells are the “building blocks” of the human body.Every part of your body – bones, skin, nerves, hair, and muscle – is made if cells.Different cells do different jobs and have different shapes and sizes.Cells contain smaller “insides” called organelles – all with different jobs.
22Organelles The largest and most important organelle is the nucleus. The nucleus controls everything that happens inside the cell. (Like the cells brain.)All cells are surrounded by a protective layer called the cell membrane.The cell membrane is semi-permeable, which means that it lets some substances pass through it, but not others.The rest of the cell is called cytoplasm. Cytoplasm is a liquid containing chemicals needed to keep the cell alive as well as hold the floating parts of the cell together.
25Venn Comparison of Animal and Plant Cells What are the two main types of cells?What is an organelle?What organelles are common to both types of cells?What are the organelles found only in plant cells?Why do you think that scientists refer to cells as the ‘basic” unit of life?
26Organelles and their Functions (4) Organelles and their Functions sheet pages (HO) – Go overHow does a cell relate to your school? (HO)Cells – How it works – video (HO)
27Organelles and their Functions Animal, Plant, bothCell MembraneProtects, determines what can enter and exit the cellBothCytoplasmGel-like substance holds all the organelles of the cellNucleusControls the activity of the cell. Contains DNAVacuoleStorage area in cells (water storage)Endoplasmic Reticulum (ER)Support and makes protein in the ribosomesMitochondriaUses food to produce energyCell WallSupports cell shape like a skeletonPlantChloroplastsUses Sun energy to make food
29Cells – How it works (video) Question sheet - HOCells Vocabulary Quiz - tomorrow
30Biological Drawings (5) Cells Vocabulary QuizRules for Biological Diagramming (HO)Epithelial cell exampleRubric for Biological DiagrammingBiological Drawing Lab (HO)
31Rules for Biological Diagramming Use unlined white paper and a sharp HB pencil.Leave an empty margin of about 1 cm all around your page.Print your name at the top right hand corner. (Use a ruler.)When drawing cells, choose only one cell and show the edge of neighboring cells to show the connection.Title your drawing. (ex. Figure 1 – Epithelial Cell.)Draw the outline of your subject with clear and unbroken lines. Your drawing should be about half the page. When possible, your drawing should be vertical.Use lines to show the out of visible structures. Do not shade or colour your drawings in any way. Keep the objects in proportion to one another.Use a ruler to draw horizontal lines from the structures to the right of the drawing to label (print). No crossing lines!Measure (in cm or mm) your diagram at its longest point; show measure on the left side of the diagram.At the bottom right corner, print the subject drawn, the magnification of the drawing, and the scale.
33Rubric for Biological Drawings Only pencil usedLeave a 1 cm margin 2Name printed on top right 2Ruler used for horizontal labeling 4Labels are printed to the right 4No shading is used 2Stipples are used appropriately 2Clear and unbroken lines 2Total Mark
34Biological Drawing Lab The first specimen you draw will take up this entire side of paper (handout).On the other side, divide your sheet into 4 squares each representing one biological drawing (total of 5).Be sure to follow all the steps properly and be NEAT!
35Preparing a wet mount notes. Lab Microscope Lab 1 (6)Preparing a wet mount notes.Lab
36Preparing a wet mount Obtain a slide, cover slip, and water bottle. Place a drop of water in the middle of slide.Obtain specimen.Place specimen in the drop of water.Holding the cover slip at a 45 degree angle to the slide, drag the cover slip into the water and gently lower until cover slip covers specimen and pushes air our from the specimen.To darken specimen:Obtain a bottle of iodine.Place a drop of iodine at the edge of the cover slip.Allow for iodine to move under the cover slip.Do MICROSCOPE LAB!
37Microscope and Cell Theory Test (7) Microscope TestImportance of Cell DivisionReproduction and Cell DivisionHow do cells divide
38Importance of Cell Division Have you ever wiped out on your skateboard or bike?Imagine how terrible it would be if every scratch or flaw on your skin remained.Cells come from pre-existing cells through the process of cell division.
39Functions of Cell Division Healing and tissue repair.To increase the number of cells (therefore increase the size of the organism).To replace dead and worn out cells.To create life (in unicellular organisms such as bacteria, and multicellular organisms such as humans).
40Why don’t cells just expand so we can grow, rather than divide? If the cell became too large, there would not be enough room to exchange materials through the cell membrane and the nucleus would get smushed therefore not allowing messages to be relayed efficiently.In short, cell division allows an organism to grow, while still maintaining a cell size that keeps the organism healthy.Cell division is one of the most studied, yet least understood areas of biology.
41Reproduction and Cell Division Organisms of all species reproduce. They may reproduce asexually or sexually.In asexual reproduction a single organism gives rise to offspring with identical genetic information. Ex. the cells of the human body, other than those found in the male testes and female ovaries and bacteria use asexual reproduction to produce offspring by the process of mitosis.Mother(46)Daughter(46)Daughter(46)Mitosis
42In sexual reproduction, genetic information from two cells is combined to produce a new genetically unique organism. Usually, sexual reproduction occurs when two specialized sex cells unite to form a fertilized egg called a zygote.Egg cell(23)Sex CellsSperm Cell(23)Zygote(46)