Microscopy & Cells Notes 2023 PDF

MICROS COPY & CELLS  WHAT I WILL ❏ Parts and functions of a microscope LEARN ❏ Total Magnification and Actual size of specimen ❏ Biological drawing magnification  PARTS & FUNCTION TABLE OF 0 OF A 1...

MICROS COPY & CELLS  WHAT I WILL ❏ Parts and functions of a microscope LEARN ❏ Total Magnification and Actual size of specimen ❏ Biological drawing magnification  PARTS & FUNCTION TABLE OF 0 OF A 1 CONTENTS 02 CALCULATI MICROSCOP ONS E Total magnification & Objective lens, Ocular Actual size of a lens specimen 03 BIOLOGICAL DRAWINGS Learn to draw and label  FUNCTION OF A 0 MICROSCO PE 1 IDENTIF Y THE PARTS OF A MICROS COPE Knob Knob  Functions of Part Eyepiece (ocular) lens Function microscope Lens closest to the eye. Usually magnifies image 10 times larger Objective lens 3 lenses of different strengths to look at the slide in more detail Stage Where the microscope slide is placed Diaphragm Controls the amount of light that goes into the microscope slide Light Projects light onto the microscope slide Base Keeps microscope steady Arm Holds eyepiece lens above the stage Coarse focus knob Used to get the microscope slide into focus so that the image can be seen clearly Fine focus knob Used to get the microscope slide into focus so that the image can be sharp and clear  HOW THE MICROSCOPE WORKS The surface of the lens in the compound microscope is convex (curved outwards), the light is bent, and the rays converge on a focal point. Beyond the focal point, the rays spread out again (magnifying the image) and an inverted image is formed in LOOKING THROUGH A 1) The specimen is placed on the MICROSCOPE stage 2) Your eye will view it through 2 lens Eyepiece/Ocular lens (10X) Objective lens (3 different magnifications: 4X, 10X, 40X) CALCULAT IONS 0 2  CONVERS IONS 1 cm = 10mm 1 cm = 10,000µm If the drawing size is 10.5cm, how many micrometres (µm) would that be?  TOTAL MAGNIFICATI MAGNIFICATION OF EYEPIECE LENS ON = X MAGNIFICATION OF OBJECTIVE LENS  QUESTIO EYEPIECE LENS: 10(X) N: TOTAL MAGNIFICATION: 40(X) WHAT IS THE MAGNIFICATION OF OBJECTIVE LENS?  THINK So how do we find out the actualABOUT size of the specimen? Actual Size (mm/µm) = Image size (mm/ µm) IT... Magnification  PRACTICE The image you are looking at is 1.5 mm long and you have drawn the image to a magnification of 100. Write down the : calculation you would use to work out the actual size of the object. (Do not omit your workings and units)  OBSERVED What you see through the lens SIZE In one of the oculars on your microscope, is an ocular scale (GRATICULE).  SPECIMEN GRATICULE: MEASUREME Scale printed onto the eyepiece lens of NT the microscope  SPECIMEN 2) If this cell is Practice! 1) Count the MEASUREME number of divisions viewed under a 40X objective lens, what is the actual size? NT the cell has span across.  SPECIMEN **MEMORISE THIS TABLE!** Note: -Graticule divisions -Eyepiece units -Graticule interval MEASUREME All mean the same thing - divisions Objective Total Graticule Lens Magnification scale 4X NT 40X interval 25𝝁m 10X 100X 10𝝁m 40X 400X 2.5𝝁m Note: 1000µm = 1mm  PRACTICE: **Actual size unit: always leave in µm Actual size = no. of divisions on eyepiece graticule x graticule scale interval This image is viewed at 40x objective lens. Width of plant cell is 24 eyepiece graticule interval. Actual size =  SUMMAR **MEMORISE THESE 2!** Y Actual size = no. of divisions on eyepiece graticule x graticule scale interval = _________ (divisions) x _________ (either 25/10/2.5µm) Magnification of drawing: Image size(Drawing size) Actual size 0 BIOLOGICAL DRAWING 3  MAKING A Large drawing on blank white paper (>5cm) Use only pencil BIOLOGICAL Name + date at top right DRAWING Clean lines (no shading) Label lines to the right drawn with a ruler Labels horizontal on the right No arrowheads Underlined title below drawing Calculations go below drawing If you need to shade, you must stipple (e.g. nucleus) Stipple are diagonal lines drawn  BIOLOGICAL DRAWING Wrong: no clean lines, a lot of shading Correct: neat, solid line  BIOLOGICAL Top: correct DRAWING ✔ Clean lines ✔ Labelling lines do not cross ✔ No shading Bottom: wrong ╳ Lines not clean ╳ Labelling lines cross ╳ Nucleus is shaded  BIOLOGICAL O utline – clean, DRAWING no broken line S ize - >5cm GRADING D etails – visible components L abel – ruler, no arrow head, left/right side  CELLS UNDER Elodea/Hydrilla Onion cells A MICROSCOPE  HOW TO PREPARE A SPECIMEN https://youtu.be/RfaSyfDBQzU HOW WET USING TO PREPARE MOUNT A (plant https://youtu.be/i2x3MKSJez4 SPECIMEN cell):USING Cheek cells under a microscope Leaf cells under a light microscope  Onion cells under a light microscope Which cell structure is missing in the onion cell? WHY? RULES OF THE MICROSCOPE 1. Using one hand, hold the arm of the microscope. The other hand would support the base. 2.Remove cover, write the microscope & lab number on the top right hand corner of your worksheet. 3.Plug the microscope into the power source and switch on the switch on both the power source and microscope. (REMEMBER: 2 switches on, 2 switches off) 4.Ensure that the objective lens is at its lowest magnification (RED:4x) 5.Turn eye piece around to face you/stage, arm facing back. 6.Place sample on stage and clip it to secure.  Magnification lens Coarse adjustment Fine focus knob knob 4x √ √ 10x √ √ 40x X √ How to magnify sample 1. Look through eyepiece at low power, use coarse adjustment knob. Once sample is located, use fine focus knob. 2. Without adjusting anything else, move the objective lens to medium power. Use the coarse adjustment knob first, followed by fine focus knob. 3. Once the sample is found, to view at highest power (40x lens), ONLY use the FINE FOCUS KNOB to focus image. 4. Once sample is located, draw observations. KEEPING THE MICROSC 1) Turn to low power lens, remove slide. OPE 2) Turn off both switches. 3) Turn eye piece back to arm. 4) Coil wire around. 5) Cover the microscope. 6) Return back to cabinets.