Experiment 1: Preparation of biological materials for microscopic examination Introduction
Cell is the basement in all living things that is capable of integrating the essential life processes. It is also the basis for the different kinds of tissues found in a single organism. [Cell Biology, Biology, Neal O. Thorpe, !"#, page $% Cell can be in variety shape and si&e but it is depending on their function. The e'ample of those cell shapes are rods, spirals, shoe bo'es, spheres, daisies on their stalks, sno(flakes, string beans and blobs of )elly In some instances the shape of a cell that is dictated by its surrounding environment* this is apparently true of the neatly shaped rectangular cell packed in plant and of the spherical floating eggs of certain marine animals. The shape of other cells are often related to their function. Besides, groups of cells that possess similar traits are often found together in a places because they contain the common structures and functions. Cell is a biological unit (hich (hich can move, eat, eat, drink, drink, and even reproduce reproduce by itself. The cell acts acts as a special unit because it formed by a (ide range of structure called organelles that regulate (hat enters and leaves the cell, produce protein and chemical energy for structure and chemical function, and are involved in cell reproduction.[Biology, The +pectrum of ife, -eter ubusson, !!/, page0% The modern microscope has revealed an astonishing diversity in both the structure and functions of cell. By carrying this e'periment, (e can learn ho( to use microscope to investigate those cell structures and more understand the (orld of the cell. 1et, there are many types of microscope. The most common microscope is the optical microscope (hich has different magnifications such as #2', 22', and #22'. 3sually, 3sually, some cells can be taken easily from our surrounding area included human4s body. Cheek cell is the best choice because it can be easily obtained. +o, (e used used it as animal cell for this e'periment. 5ean(hile, 5ean(hile, for plant cell, (e used potato cell and onion cell. Aims To study the structure of cells To determine and observe the difference bet(een potato cell, animal cell 6cheek cell7 and plant cell 6onion cell7. To sho( that different cells have different structures and te'tures. To observe and compare the difference bet(een animal cell and cheek cell.
Materials +mall piece of potato, a piece of onion, cheek cell, toothpick, methylene blue solution, iodine solution, distilled (ater, filter paper. Apparatus
5icroscope, glass slide, cover slip, dropper, scalpel, forceps, tile Method 1) Observation Observa tion on starch s tarch grains grain s
. potato (as cut to obtain a smaller piece of it.
$. That small piece of potato (as placed on the center of the glass slide and enough pressure (as applied (ith fingers to s8uee&e it until small amount of )uice (as forced out. The piece of potato (as discarded leaving the )uice behind on the glass microscopic slide. 9. drop of (ater (as added to the potato )uice and the the glass slide (as covered (ith a clean cover slip. #. The slide (as e'amined under lo( po(er 62:7, then high po(er 6#2:7. dra(ing of #;/ starch grains (as made to illustrate the shape and other observable details for each, lo( po(er 62:7 and high po(er 6#2:7. <. The grains (as stained using irrigation techni8ue. 6Irrigation techni8ue= a drop of iodine (as placed at the opposite edge of the cover slip. s (ater (as absorbed by filter paper, iodine on the other side of the cover slip (ill be dra(n underneath it and sample (ill be stained.7 /. The iodine stained mount (as e'amined under lo( po(er 62:7 and high po(er 6#2:7. #;/ starch grains (ere dra(ed to illustrate their shape and structure. >ra(ings in the microscope data sheet (ere included in the result.
2) Observation on onion cells
. n onion (as cut into half and one of its fleshy scale petals (as removed. $. The onion petal (as snapped back(ards and forceps (as used to tear a(ay a piece of thin epidermal lining form inside the onion. cm s8uare piece of lining (as placed onto the microscopic glass slide. 9. drop of (ater (as placed on the onion epidermal lining and the lining (as covered (ith a cover slip. It (as e'amined under a microscope at lo( po(er 62:7 and then high po(er 6#2:7. dra(ing of the observation (as made, including only the details that (e had observed and the dra(ing (as labeled accordingly. #. The onion lining (as stained (ith iodine by irrigation techni8ue as described earlier. <. It (as e'amined again under lo( po(er 62:7 and high po(er6#2:7. #;/ of the onion cells (as dra(n in the microscope data sheet as observation. Its parts (ere labeled completely.
) Observation of chee! cells
. clean glass microscope slide (as obtained and a drop of (ater (as placed in the center of the slide. $. toothpick (as held flat against inner cheek and the inside of cheek (as gently scraped (ith the flat edge of a toothpick. The cheek cells (ere spread in the drop of (ater on a microscopic s*ide. 9. The specimen (as covered (ith a cover slip and air bubbles (ere avoided. #. It (as observed under high po(er6#2'7 and then a dra(ing of #;/ cells (as made. <. The details that can be observed in the preparation (ere included and labeled accordingly. /. The cheek cell slide (as stained (ith methylene blue by irrigation techni8ue. 0. The cell (as dra(n, putting in as much structures as (e had been able to be observed in the microscope data sheet as part of the results. abeling (as compulsory for the nucleus, nuclear membrane and cell membrane.
"esults Onion cells Iodine solution stained the nuclei bro(n and the cytoplasm light bro(n. • The main cell components seen (ere the cell (all, nucleus, cell membrane, • vacuole, cytoplasm and chloroplasts.
#hee! cells 5ethylene blue stained the epithelial cells of the cheek blue, so the cells (ere • easily seen. The main components seen (ere the nucleus, cell membrane and cytoplasm. •
$iscussion
?rom the results (e obtained after the e'periment is that the magnification of the microscope (ere in that (ay of 2@#, 2@2, 2@#2 and 2@22* also kno(n as #2@, 22@, #22@ and also 222@. t first, (e used #2@ to look our first slide= +tarch Arain under the microscope. It (as really clear to say that on the magnification of #2@, (e can only see the basic layout already, of the cell (hich in random circular shapes, (hile the magnification (as on 22@, the image (as slightly bigger and clearer (hile on #22@, (e can sa( the cell (all (ay more clearly and more detailed. In the ne't step of each e'periment, (e stained our samples in colors by using either iodine solution or methylene blue solution for all three sample during the second steps of each e'periment using irrigation techni8ue. ith the help of the color stained on the cell, it (as (ay more clearer and visible, it (as obvious to see the structure of the cells. ?or the first sample, the starch grain from potato, (e first noticed that there (ere a lots of spaces in bet(een cells and some of the shapes of the cell (as round in shape (hile some (ere oval shape. Irrigation method (as taken out to stain the starch grain in yello( color (ith iodine solution. ?or the second sample, onion cell. The first thing that (e observed under the microscope (as that they have cell (alls and they (ere closely packed in fi'ed shape* unlike potato cells that (ere having spaces in bet(een the cells. ith the help of modern science technologies and techni8ues, (e (ere able to see the sample clearly and bigger even on 22@ magnification. e (ere able to observe ho( nicely the cells (ere closely packed and distributed in fi'ed rectangular shape. By staining the onion cells in yello( (ith iodine solution by using irrigation method and vie(ed under the microscope (ith #22@ magnification, (e (ere able to see the cell membrane and the cell (alls even clearer since the color on the sample under the microscope (as getting denser and more contrasted after the cells stained in yello( (ith iodine solution. ?or the third sample, cheek cells that (e obtained from one of our group members. 3nder the microscope (ith #2@ magnification, (e able to observe that cheek cells (ere having irregular shape. e stained the sample in blue by using irrigation method again but (ith blue methylene solution for this e'periment. The
blue pigments of methylene blue solution appeared on the cells more denser and gave us the cheek cell a clear vision under microscope under both 22@ and also #22@ magnifications. Nuclei and the cell membrane (ere visible under the microscope (ith the methylene blues dyes. Based on the observation of the e'periment, (e can said that there (ere total difference that can be noticed on plant cell and animal cell. e observed and dre( it on the laboratory report for reference. In short, it (as obvious to see that plant cells have fi'ed shape (hile the animal cells have irregular shape and plant cells have cell (all (hile animal cells have no cell (all.
#onclusion
In this e'periment, (e have learnt that animal cells and plant cells do have some similarities. e also have studied the basic structures of a cell (hich are cell membrane, cell (all, nucleus and so on. Besides, (e also learnt the correct and proper (ays to use and handle a microscope. t magnification of #22 : of a microscope, (e can see the cells clearer compared to magnification of 22 :. In a nutshell, (e agree that animal cells and plant cells have similarities and differences. "eference
-g 9;/ , + evel and evel Biology 6C5BDI>AE7 +econd Edition,5arry Fones,
Dichard ?osbery , >ennis Taylor, Fennifer Aregory
-g $, Cell Biology, Neal O. Thorpe
-g $$, The Cell= 5olecular pproach , Aeoffrey 5. Cooper
-g <; <#, Ne( 3nderstanding Biology ?or dvanced evel ?ourth Edition, Alenn, +usan Toole
-g 0, Biology, The +pectrum of ife, -eter ubusson
n.a., n.a., Guman Cheek Cell lmb.cam.ac.ukHmicroscopes#schoolsHhumancheek.php
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