ࡱ> LNK @ bjbjVV :r<r<4&JJJJfT&r$AAA#######$&Rf($A@AAA$;,$A #A#"u# >ؠJK.I##4B$0r$_#(y(,u#&&(u#HAAAAAAA$$&&$J &&JThe Onion Cell: Lab MATERIALS Whole white onion **soaked in water overnight* Microscopes (2-3 students per scope) Microscope slides Water bottle Cover slips Eyedropper/pipette Iodine Tweezers Worksheet PROCEDURE Preparing the wet mount slide of onion skin 1. Break an onion slice in two. 2. Carefully pull the slice apart. 3. Use tweezers to pull off a very thin piece of onion skin (the thinner, the better) 4. Place the skin in the center of the slide. Try to keep it from folding; get it as flat as possible. 5. Add a drop of water to the onion skin and cover with a cover slip. 6. Press the cover slip down carefully to remove any air bubbles. 7. Place the slide on the stage of the microscope, set it to low power, adjust the focus so the onion slice is clear. Draw four or five cells as seen. Label the cell walls. 9. Switch to higher power and try to identify the cell membrane, nucleus, and cytoplasm. Staining the onion cells 1. Lift up the cover slip and add one or two drops of iodine to the slide. 2. Lower the cover slip and examine the cells on higher power. 3. Iodine stains different parts of the cells so that different organelles can be seen. Draw and label the cell wall, cell membrane, cytoplasm, and nucleus. DISCUSSION QUESTIONS 1. What is the general shape of the onion cells? 2. Describe what you saw without the stain. 3. Why do you think there are many cells close together? 4. Is the onion skin composed of one cell or many cells? 5. Why is it easier to see the onion cells after they are stained? 6. All plant cells have cell walls. What is the function of the cell wall? 7. Count the number of cells that are seen in the field of view under low power magnification and also under higher magnification. Compare the number of cells observed in each field of view. The Scientific Method: The Onion Cell Objective/Purpose: What is it that you want to find out? ___________________________________________________________________ Hypothesis: What do you think will happen? The ________________________________________________________________ Materials: What exactly do you need to do this experiment? ____________________ ____________________ ____________________ ____________________ ____________________ ____________________ ____________________ ____________________ ____________________ ____________________ ____________________ ____________________ ____________________ ____________________ ____________________ Method/Procedure: List all the steps that you take to do this experiment. ______________________________________________________________ Observations: What do you see? Record your data in a table or labelled diagram. Diagrams must be completed in pencil. _______________________________________________________________ Conclusions: Was your hypothesis correct? Explain. Answer questions here. ________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ ________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ ________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ ________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ ________________________________________________________________________________________________________________________________________________________________ The Onion Cell: Observations  Onion Cell: Low Power  Stained Onion Cell: __________ Power Lab Report: The Onion Cell Lab Report: The Onion Cell Scientist: _____________________ Class: _______________________ Overall Title page includes name, date, title Report is neat Report was handed in on time Purpose Is complete Hypothesis Written in 3rd person (no I, My, We or Our) Materials Written as a list The list is complete Procedure Reference is made to the worksheet Worksheet is attached for reference Observations 2 diagrams neatly completed 2 diagrams in pencil 2 diagrams are accurately labelled Observations are clear and detailed Conclusion Question 1 is correct Question 2 is correct Question 3 is correct Question 4 is correct Question 5 is correct Question 6 is correct Question 7 is correct ___ 20Scientist: _____________________ Class: _______________________ Overall Title page includes name, date, title Report is neat Report was handed in on time Purpose Is complete Hypothesis Written in 3rd person (no I, My, We or Our) Materials Written as a list The list is complete Procedure Reference is made to the worksheet Worksheet is attached for reference Observations 2 diagrams neatly completed 2 diagrams in pencil 2 diagrams are accurately labelled Observations are clear and detailed Conclusion Question 1 is correct Question 2 is correct Question 3 is correct Question 4 is correct Question 5 is correct Question 6 is correct Question 7 is correct ___ 20  5P       'ѸѧƟƔƔƉ{pl]hch7 CJOJQJaJhdh7 5CJ\aJh7 hs5CJ\aJh7 hsCJaJh7 h/XNCJaJhL5CJaJ h7 hY*56CJ\]aJh7 h/XN5CJ\aJh7 hY*CJaJh7 hY*5CJ\aJh/XN5CJ\aJhY*h[LCJ(aJ(hY*hY*CJ(aJ( !Pu & I  L ; 7$8$H$gd/XN 7$8$H$gdY* 8  J N 89s)*gd7 $a$gd7 7$8$H$gdY*'7efr(TUf78}~O<CSF"*~h#CJOJQJh7 5CJOJQJhd5CJOJQJhdCJOJQJhd5CJ OJQJjhdUmHnHuhdh7 hd5CJ4aJ4h7 hch7 >*CJOJQJaJhch7 CJOJQJaJh7 CJOJQJaJ1*f8~OPSD5&gdddhgd7 gd7 -./012345678gdd89:;<=>?@ABCDEFG & F$Ifgdd & F$If^gdd $Ifgdd $Ifgdd 7$8$H$gdY*gdd!"*67BYopz & F$Ifgdd & F$Ifgdd & F$Ifgdd h$If`hgdd & F$Ifgdd & F$If^gdd $Ifgdd & F$Ifgdd*7BNPpz-{!"/PWox#LV$/ֵֵֵֵֵֵֵֵ֪hdh7 CJH*OJQJh7 5CJOJQJhd5CJ OJQJh7 5CJ OJQJh7 CJOJQJhdCJH*OJQJhd5CJOJQJhdCJOJQJ-4W{| !"&./Po $Ifgd7 $Ifgd7 @ $If^@ gdd & F$Ifgdd $Ifgdd & F$Ifgdd h$If`hgddopx#5KLV & F$Ifgd7 & F$Ifgd7 h$If`hgd7 & F$Ifgd7 $Ifgd7 & F$Ifgd7  & F$If^gd7 Vy$%0F\r @ $If^@ gd7 & F$Ifgd7 & F$Ifgd7 h$If`hgd7 $Ifgd7 & F$Ifgd7 qlgd7 kd$$IflF% t06    44 la21h:p7 / =!"#$% K 01h:p7 / =!"#$% P0 hq5 01h:p7 / =!"#$% s$$If!vh555#v#v#v:Vl t6555@@@ NormalCJ_HaJmH sH tH T@T d Heading 1$@&5OJPJQJaJmH sH tH DAD Default Paragraph FontRi@R  Table Normal4 l4a (k(No Listj@j d Table Grid7:V0!:4:: !Pu&IL;8JN 89s)*f8 ~  O P   S D 5 &-./0123456789:;<=>?@ABCDEFG!"*67BYopz4W{| !"&./Popx#5KLVy$%0F\r00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 0 0 0 0 00 0 000 0000 0 000 0 000 0 0 0 000 0 0 0 0 0 0 0000000 0 0 0 0 00 0l;0l;0l;0l;0l;0l;0l;0l;0l;0l;0l;0l;0l;0l;0l;0l;0l;0l;0l;0l;0l;0l;0l;0l;0l;0l;0l;0l;0l;0l;0l;0P%0'* *8oV8@(  (2  (2  B S  ? 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