LAB 6

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Chemeketa Community College *

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Biology

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Dec 6, 2023

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Activity 1: Microscopes 1-1: Dissecting microscopes Dissecting microscopes, also known as stereo microscopes, are used during dissections to see a detailed view of the organs revealed during a dissection. These microscopes are most useful for observing the surface of specimens at a relatively low magnification. 1. o Place the metric ruler on the stage of the dissecting microscope and focus using the focusing knob on the side of the body. Use the magnification dial on the top or the side of the microscope to adjust to the lowest power (widest field of view). What power is the microscope at now? Record your measurement of the field of view diameter in mm in the table below. Now adjust the magnification to the highest power and measure the field of view diameter in mm. ' Convert the measurements to pum. 1mm=1000um View the letter “e” slide with the label in the upright position. View it in the dissecting microscope on the lowest power and the highest power. Add drawings to the provided spaces below. Use the dissecting scope to view the objects available at your table, on your person (like fingers, license, dollar bill), or collect items from around campus (leaves, bugs, flowers) to view under the dissecting microscope. Questions 1. Complete the table below. Magnification Diameter (field of view) | Diameter (field of view) " mm Hm Di ting Mi LowestPower | A0 5 e 00 UM e e L L J100n 2. Draw the letter “e” in the circles provided under section 1-3, accurately representing how much of the field of view the “e” takes up at the various magnifications. 1-2: Compound Microscope Overview Microscopes are fragile and expensive, and we want to maintain them in good working order. Your instructor will walk you through a tutorial on how to handle the microscope, understand its parts, and explain their functions. 1 Microscope Introduction a. Caring for the microscope and proper storage b. Parts and functions
c. Cleaning slides and lenses, situating the slide d. Locating objects at different magnifications Label OQ\) Make sure you can identify the following parts and explain what they do: e Arm Base Nosepiecej Stage / Stage clip (slide holder) ¥ Stage controls Course adjustmentj % Fine adjustment QQ‘(\(\S})‘\CD Ocular lenses (x2)¥ Objective lenses (x3) ¥ Condenser Lamp / Brightness adjusterJ o5 Questions 1. What kinds of things do you need to be aware of to make sure you don't damage your microscope? Weing 14 v ay i ¢ pose 2. When lookifg at a slide with*maximum magnification, the objective lenses should always be used in what order? (name the lens and give the magnification) Led i .0 \iQ\\DW A0 x Blue Hdx 3. What tools does the microscope have to regulate how much light passes through the specimen? bh%h n 0Y O\\m e oo d 56}: 4
Questions . Complete the drawings of the letter “e” below. *"”’\) e N | K S sk NS Dlssa;tmg microscope Naked eye S L e 40x total 100x total | 400x total magnification magnification magnification 2. What happens to the orientation (not the magnification) of the letter “e” when it is viewed in the compound microscope as opposed to with the naked eye? 11 oecornes ) ppe cl 1-4 Magnification, field of view, and depth of field You have already examined several differences in magnification by looking at the letter when you increase the magnification of an object, you can see less of that object. Or, in a more scientific term, your field of view decreases as magnification increases. Also notice that when you use a lower magnification, you can see most of the depth of the object in focus at the same time. When magnification is increased, only smaller depths of the object can be focused on at the same time. This means that the depth of field is decreased when magnification increases. We'll explore these phenomena further with this activity. ‘e”. You have seen that 1. Observe the magnification marked on the eyepiece and each of the three objective lenses. Record these values in the table below. Calculate the total magnification by multiplying the objective magnification times the ocular magnification.
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2. To measure the field of view: use the 4x (scanning) objective. Place a clear metric ruler under the stage clip so you can see the markings on the metric side of the ruler and measure the diameter of the field of view in mm. Record the value in the table below. Now measure the field of view with the 10x objective and record that value as well. You will not be able to directly measure the field of view for the 40x objective. _ To calculate the field of view for the 40x objective, we can use this ratio between magnification and field of view diameter: ) Lower power maghification Higher power diameter Higher power magnification | gwer power diameter A For example, if we measured the 10x field of view diameter to be 3mm, we could solve for the 40x field of view diameter as shown below: 10x High power diameter 40x Simplify this .~ fraction 3%rim N 3mm x 0.25 = high power diameter 0.75mm = high power diameter Muiiiply both sides by 3mm 4. When usihg compound microscopes, it's more typical to use micrometers (um) to measure objects. Convert the field of view diameter to pm. 5. To observe how depth of field changes, we will use the crossed-threads slide. Use the 4x objective to focus on the point where the three threads cross. Can you see all three threads clearly? Refocus on this point using the 10x and the 40x objectives. Are all three threads still equally clear? Answer the questions below about the depth of field. Questions 1. Complete the table below: Name of lens Magnification Diameter (field | Diameter (field of view) mm of view) pm Objective Ocular Total Scanning A LO ¢ “0 0 00| HODOKM Lowpover__| 10 0, [109 _ [7.00mm [2000 High power V\O {O)g 4*100 O“@W\m 60@ \/\YY\ : A—
2. Without using a ruler, how could you use the above information to figure out how big in pm the “e” is from the previous activity? Use your drawmgs to ewte the snze of the letter “e” jn Compmre, e YYACA v e | k 3. Is it ‘as clear to focus on all three threads at the 400x total magnification as it is at the 40x total magnification? If not, why? /Ar\’ \o 0+ \{\ A ’/f O X O X, o Comn u.z oNn 1 \(\é/ +ho: »eigig oA o HODx 1ts W‘\Ove ddfr@&“ Pocosed 4. What is the order of the colored threads on the slide? Top v €c Middle | ,Ulow Bottom 0| v 5. What can you conclude about the size of the field of view in relation to magnification? e field view g solley e Wigheye g MOAANA caa 0N ety 6. What'can you conc ude about the depth of field in relation to magnification? } 0S mO\ Hecahon cjoes VP | \(éQ, N ACYEeas e _ Activity Observmg prepared and live specimens It is helpful to observe fresh specimens in order to view things that only happen in living cells. Some cells move through their environment. Others show a cycling of their cytoplasm. Still others show metabolic changes, particularly if effective dyes or indicators are used. “Prepared” slides that have been stored in a cabinet cannot show such behaviors. Prepared slides are useful when studying the structures of organisms or tissues. Keep in mind that when looking at prepared slides, these are often stained in order to make the cells or specimen visible. The color something appears in a prepared slide is not always its true color if it were living. Most cells are small and must be magnified 100x or more to be clearly seen. Additionally, it may be useful to use dyes or stains when looking at live specimens, otherwise the cells appear as gray blobs. Specific dyes are absorbed by certain parts of the cell. For instance, the cell nucleus often stains a dark color. This isn’t because the nucleus is darker than the rest of the cell, it just absorbs more of the stain, making it more visible. It is also helpful to regulate the light when looking at both live and prepared specimens. Use the light adjustment knob and the condenser knob to change the amount of light that comes through and the contrast of the image. This will make parts of the cell, like the cell wall, stand out. Cells Cells are the simplest individual units of life, and humans are made of several trillion of them working together - to create a functional organism. You will need to understand the structure of cells and functions of organelles forever, so learn them now. There are two major categories of cells: prokaryotic cells like bacteria are relatively small with a simpler internal structure, and gukaryotic cells which comprise protozoa, animal, plant and fungal cells. Eukaryotic cells are much larger and contain nuclei and membrane-bound organelles. Cells come in a surprising variety of shapes and sizes and carry out very diverse functions, yet are all made of the same core parts:
Plasma membrane - Cells are enclosed by a border called the plasma membrane, made of a phospholipid bilayer with embedded proteins and attached carbohydrates. This controls the water level, the electrical charge, what enters and exits, and regulates chemical reactions. The plasma membrane is actually too thin to see with a light microscope, but we can assume it is at the outer edge of the cell. The membrane can be directly visualized with electron microscopy. Cytoplasm - The interior of the cell contains the organelles that carry out cell functions, and a viscous liquid called cytosol that helps hold things in place and : provides a medium through which molecules can move. “Nusiear envelope: i o L f : . membrane enclosing mitotic spindle and The combination of the cytosol and organelles is the the nucleus. Protein-lined FaINTAIR CTHH0s: cytoplasm. Organelles are generally too small to see potes ian"g;"v d"éitte"a‘ o Centrosome: microtubule- f . . g g organizing center. Wl.th a light microscope, .but we can L.lse electron Chro(:'na?t‘;: D'j% plus e microscopes to resolve images detailed enough to xSt = AOEIS: fibrous proteins that hoid Nucleolus: . organelles in place. show organelle structure. @%’é‘:fififggfii’?sn Microfilaments: fibrous proteins; o are formed. form the cellufar Nucleus - The large, darkly staining structure easily cortex seen in most eukaryotic cells is the nucleus. Prokaryotic peroxisome: cells do not have a nucleus or membrane-bound etholzes organelles. The nucleus stores and protects the DNA and is enclosed by the nuclear envelope. In humans, the DNA is divided into 46 pieces called chromosomes. Unless cells are dividing the individual chromosomes Endoplasmic are not visible, and the DNA is spread out in a relatively ~eticulum Rough: associated ing called chromatin. with ribosomes; loose cloud of string il dhosomen - membrane proteins. Smooth: makes lipids. Plasma membrane Lysosome: digests food and waste materials. Golgi apparatus: modifies proteins. Cytoplasm Mitochondria: produce energy. Activity 2-1: Prepared Slides Questions Skeletal muscle— Label the cell membrane, nucleus, cytoplasm. Continue practicing with the microscope by examining the following plant and animal cell slides. Notice the variation in the shapes and sizes of the cells, and that some cells may have extra or missing features. Draw your observations at high power, and label the cell membrane, nucleus, cytoplasm and any other distinguishing features. Label drawings with the slide name and maghnification, and answer the questions. 1. How would you describe the shape of these cells? How do you relate the shape of the cells to the function of this tissue? N _W\OYQ c(vml\ shicet \ice Moo Sim olece ok QG’%\(}‘L@‘V& T v'e e ~ "*""q{\ - ‘A:./’ | ; menoang/ 0 AV\Y\LUB \/\L\D Cony Y (7\(;}’\ ? Ske»letai .musc(ge \C'\}\,X'\Y\(;)) @Y‘B P{,rfi e | Total mag_L{( :
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Onion cells: Label the cell wall, cell membrane (you cannot see it but you can tell where it is), cytoplasm, and nucleus. 2. Plant cells have cell walls that animal cells do not. From what you know about the differences between plant and animal behavior, what do cell walls allow plants to do that would be bad for animals? T cey wall AA\owWS %Y'Jr MO ructiule metEtng | \Lss £Uoxi ol Tty wotd e oo HAr animma ls ao “fmz,b WOUIA Y e aiple 1D Ve Luna (simple squamous epithelium) - Label the cell membrane, nucleus and cytoplasm. 3. These cells are flat and exposed to gasses, why? How do these cell shapes allow lung cells to perform their primary function? Y ¢ RXPOSSeol 4o QOSY O % OXQGgon . e AP N e RICFACE, Cur a, \r\b\PmQ Collzct Move oy 4. Find a blood vessel (ask the instructor). The body has Lung many tubes like blood vessels. You are looking at a cross Total mag 1) section of a blood vessel. Explain and draw a cross section ofatube. +ing | 2 m\(‘v’ \/\? o\l owJ o Secnon RS \o- (@) C@\\(\V% ol ook 4\0\0@ Sperm - Label the cell membrane, nucleus, and flagella. 5. Sperm are tiny compared to the egg. From what you know about the function of the sperm, how is this cell specialized for its function? Na T Flageila P The Cptrm SWwim : (:: J Sperm Total mag H Q
S Blood - Label the reb and white blood cells. On the white blood cells label the cell membrane, cytoplasm, and nucleus (it's a weird shaped one!). On the red blood cells label the cell membrane. 6. Mature red blood cells do not have nuclei. From what you know about the function of red blood cells, why would it be beneficial that they would lack a nucleus? NS ey donT Ihove o NLCWS "K.) C&W’u\} iMoo { fi/ "ifi b ?;{’"\i» ‘E(J% iO \YO W Human blood Total mag 00 Activity 2-2: Fresh Slides Procedure - In this section you will prepare two of your own slides and draw your findings. These are wet mount slides, meaning they contain liquid and will need to be covered with a small plastic square called a coverslip. Wet mounts may use flat glass slides or depression slides. All biological materials should be disposed of in bleach beakers. Thoroughly wash your hands at the end of the activity. 1. Pond water - Pipette a small amount of pond water onto a depression slide, and cover it with a coverslip. Observe and draw your slide under high power. You may see a large variety of microorganisms, including protozoa, nematodes, hydras, and amoebae, algae and small animals. 2. Epithelial cheek cell (sub sheep blood, elodea, or human hair if necessary) - Obtain a flat slide, toothpick, and coverslip, and liquid methylene blue. Gently swab the inside of your cheek to smear off some of the stratified squamous epithelial cells that line the cavity. Wipe them on the slide, add a small drop of methylene blue, and the coverslip. Make sure to dispose of materials appropriately. Questions 1. Draw and label the live specimens observed. If possible, label the cytoplasm, cell membrane, and the nucleus. 2. Use the technique from the letter “e” to estimate the size of one cell from each live specimen. Specimen 2 Total mag_\ 0 O
3. What are the benefits and disadvantages of both prepared and live sample slides? Make sure to _include the type of information you can gather fromeach. TN N pye aved Slidles,thale 1S M e bngk{gg e s tnance 0€ Saum p{-‘fi“ LOS §, O\WO& e T 1"‘ S YO Vit =N AR JZumpULy 1ts easi e D S - ‘va;f YW LONR wc“\**l now i+ yeocts Activity 2-3: Oil Immersion Lens Procedure - Observe the instructor demonstration of bacterial slides. Because prokaryotic cells are so much smaller than the cells we have looked at so far, they will need even higher power magnification. Microscopes used for microbiology have a 4th objective lens that magnifies by 100X, for a total magnification of 1000X including the ocular lens. This lens is named because the light rays travel through a drop of oil that we add to the top of the slide. The oil refracts light to a greater degree than air, giving a clearer image than we could otherwise see. This setup shows the same bacterial slide at two different magnifications for comparison. The first is at 400x, the largest magnification we have used so far. The second is at 1000x. Observe the slide at both magnifications, and draw and label the bacterial cells seen with the oil immersion lens. 400x CWNLE A Activity 3: Internal Cell Structure 3-1 Electron Microscope Images Complete at home if not able to complete during lab. To do this take pictures of the images with your phones. Procedure - Examine the printed electron micrographs to see actual organelle structures and complete the chart. Feature Draw and describe what features make it recognizable - Somatining thar Mages it Plasma membrane vec Q%Y‘s% 2000l 1S Tha, ik OV olls Of~ BN s TS 11
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Mitochondria +Whe dhh SMODT %mfsq, con alsp 100k ot it Xiz2e Rough E.R. =L LSO el WAL w\ow;ef e £ c;\gg) O Y€(o %--*Y’\ 21e. Smooth E.R. e woce 0oF Yivos o s § locaton [\ Y\ (31’% N €¢C Golgi body +W3 Shq/ e mMoLes ] H' *E‘Ci@{é i, Yf’f@?}fli@@ 3-2 Cell Drawing Use a whole piece of paper for your drawing and attach to your lab. Try this with your notes closed to see how well you are understanding and retaining this information. Once done, check your work and circle the ones that were not 100% correct. This process helps you know where the holes in your knowledge are so you can study those concepts more! Draw a detailed picture of an “average” cell, label the organelles, and give functions of the organelles. List additional specialized structures that only some cells possess (related to movement, structure or size, for example) . Lab Review Questions 1. If you are looking for something on a microscope slide and can't find it, what might be the problem? What would you check and what are the next steps? & Y v - y tep ) Ve 100 ¥ e €2, IASARRVE(N £ “’yy\ NI - Coue 4oLvs, and N con 1 fina 0Oy tan Chnelk , moving T S%C&Q e }%%z% r\%fi / /\ s : L Qunping reaL or focls. e e phogniflcoon. W, Voe the 12 + \5%; Nt amouny o
2. Match the microscope parts to their functions. C/\ Scanning objective lens Q/ Stage !5 Lamp CA__ course adjustment '@ High-power objective lens Q, Ocular lens % Fine adjustment D Stage controls 3. Complete the following chart /;a./ Raises and lowers the stage a large degree /t{ Moves the slide right and left, backward and forward e’ Magrifies by 10X at the eyepiece @~ Magnifies by 4X _e7 Supports the slide j Magpnifies by 40X /g( Focuses the image under high power ;( Creates light in the field of view Feature Function Distinguishing physical Location in the cell in relation to characteristics other organelles asm YOU O\.QS NuQYoPp h b‘fl ANAL AV Y o e een +\We c-e\) zemb?ane g‘(b‘\ QCG’ wn for O\K%O‘ V\fi@lbp N M ol % "U YO p' leis n Nucleus Shoves C\S Yound, QO - s '\’\/\L VY\\O\C\.% ONA SPNNE Of e Ce\y Nucleolus \NANLS AU WS icl nucdl NYODI0 L FORWINT Ribosome W\O\\C QS %\O\* SPY\JUY\QA | V) _\/M Cy/ “.) )G‘l PYOYA () W BJpunifs L R R. pmj\umm * V\OL.S N POSO ML *‘r‘«\ OV ¢y, o e prohe ffl S aA\ls - SW&K o NUCYN S smooth ER. | NINPD \ ‘\'U\O*Q el WY ¢ Q\\ ce\\ 6‘(@(0\(5!2/ AYVOUL PRGPWL “;') : PoalGege DR N & |G STac ed, 0y e Golgi body Mn\ 7 YY\SL‘(Y\\@‘(SO \%% 0y %\ds & US : mvwxfi" ~ER L itochondria s €Ll Mitochondria (PYOCIUCH €Y1 Cx(\w}:){\)ack\@ WYL | N e Cy D Plotsm Lysosome |OY B oW SPMYQ SOCS HVLOL | \n Avie D plosn, WASTL AT bl K ~€V\C LOS e of 13
QOIVEShy Peroxisome | O X1M2.€5 YY)D\&(,\)\ \ m A N m? \SO Q\r\zw\\:vu«o UGTOPIAs A Cytoskeleton | PYONELLS t‘fi’\@ Aper sunoil insicll Tine B ’S}WE"*&““Q o 1D plodm. Cilia ACH O SENsory [nealy WY& OUrsicle. OF ¥ NLAPS ' N - il Mgy ont ot | AOGUS Q QN Fegeta | ARSI Thgi\ TAiee o enct 0€ cel 4. Name 3 organelles that have anabolic functions, and 3 organelles that have catabolic functlons What do they make or break down? Sy Use enL ANaoolic | vieOsIME, roygn €1, ST, ) rccia/wcf?dfyfi\m i b &,x mo\@cu oM Simple O ald Comp cotaoDlic it 0 CLvip nalYio s ngw\fi s rOH0S0 Nt = DA - Apium LOmp\x M e cuLd 5. Compare and contrast animal cells and plant cells. e w@xuflv c Cl Walls wqe/ VAC S\ Ore \00+h EU\LO\(&» \)f)\h A ‘wffs*\'cu\e . Show N ACyELLs, CAUNTEQ\L “""‘tfi\(”‘{” Cea‘w ‘i‘zg\\;@ cn\o Aol Lelly nave W‘?P g T \woflf\ oW, hyclaus, rO wonaic, P ¢ . Plant. ey into Simple oney oLve. MOYe 251, o, oSy WA Ug{‘{{j{@ Ny 6. What is meant by the “surface area” of an objec and why is it important? Describe several features of l €CA- | cells and organelles that influence the surface area. urkace greg =y YOTOL| owea o 0N OeCty (j,m\;ou\mw (ea \if\ne A net o e < W A microscope? e WA hT MiCy clLow NOO ot Se€ T L s Vow nowgn o7 SN V\JZ/\P i"" QU" vive. /rtg%tz ¢ @qfi cefl\ wJ ! ¢ A 4o Volumg T 7. What cell features can be seen wnth a ght microscope, and which ones require an iela o oww o l sl ff’} L avg2 ce ) w electron ? What are the advantages and disadvantages of these types of microscopy? CCLn Sée Dq,{g,gif 2 ). ‘sw‘i @l ¢ L\ V\?(:“} Jee Wit featuyes AVe 0, MNaki i L (v Y, i'fm i.fi«,;é l a (oufc:éa VOLUW vor | will Nnewre | i+ haurel | N\Q/ Nnot+ «Xd N oun R LLCkvon g,maLLLr 011s,itsS ouko s \) T RO Cown & e , %S Q)qowsme, Ccm S \Nfi«\f\ e EM Yo g %r o ‘ffis{)ku%}éfi"‘x ot te coloYorid the S liolegg {3 8. Compare and contrast the stru RSN ey ce\l du\/\S\(m 2 bacttna, Qom@% ho\ua W\mv- ON R m@ i cu naye CO\ varpone Celis \O!nou ce NS, o L gCUr" i plainge, ca’res found in prokaryotic and euk cre morg Z\W\’{DL-Q, m@leLr‘ b"\ N, N0 NuC leusy, Circol 9\/‘(" fi/’O?C fig Je s ‘iv\ QU ma\(’\e Ce\'»woux ancl cfrh%h oSl lete n, hove e, Cnomospnes, PN agoflL ceils e, e (iuis é‘L\’V\Ufzfgug J %;\}?”‘% Nbogs sy 14 - DNA-
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