Download Onion Cell - kryanscience

ANNOUNCEMENT:
•Photosynthesis & Resp. QUIZ RE-TAKES
•Next Monday & Tuesday during ELO
•Possibility to raise an I  C, or a C  B.
•You must be prepared to answer random questions
correctly in conversation (oral quiz)
April 7, 2009
Science 7
4-7-09 ~ POD
• Watch a review video
• http://streaming.discoveryeducation.com/
– “Introducing the Cell” 15 min
– Expectations?
• Discuss QUIZ on Thurs/Fri
• Onion and Cheek Cell LAB! 
– Analysis Questions
Questions from the video
1. Why is it important to learn about
cells?
2. What are 3 main differences
between plant and animal cells?
3. Why is the vacuole so big in plant
cells?
4. What is the importance of the cell
wall?
5. Why do muscle cells have more
mitochondria?
6. What do you need to study for the
quiz?
How to make a wet-mount slide …
1 – Get a clean slide and coverslip from your teacher. Careful of glass!
2 – Place ONE tiny drop of (iodine) in the middle of the slide. Don’t
use too much or the water will run off the edge and make a mess!
3 – Place the edge of the cover slip on one side of the water drop.
4 - Slowly lower the cover slip on top of the drop.
Cover
Slip
Lower slowly
* 45
degree
angle
5 – Place the slide on the stage and view it first with the lowest
magnification. Once you see the image, you can rotate the nosepiece
to view the slide with the higher powered lenses.
You do not need to use the stage clips
when viewing wet-mount slides!
Onion cell
Cheek cell
Onion and Cheek Cell Lab
What you will turn in at end of class:
• Drawings
• Analysis Questions
Onion & Cheek Cell LAB
•
Part 1: Cheek Cell
1. Place a tiny drop of iodine onto clean slide
2. Use a toothpick to scrape inside of mouth
(cheek)
3. Make a zig zag onto iodine droplet.
4. Don’t use stage clips
5. View on Low Power (4x)
6. Draw what you see on Figure 1
7. View on High Power (10x)
8. Draw what you see on Figure 2
1. Draw 2 or 3 cells
2. LABEL: Nucleus, cell membrane, and
cytoplasm
3. Use straight lines that do not intersect
Part 2: Onion Cell
1. Peel a thin layer of onion with forceps
2. Place the layer on the slide without folds
(throw away remaining onion piece)
3. Place 1 tiny of brom. blue on onion layer
4. Cover with cover slip
5. View under low power (4x)
6. Draw what you see in Figure 3
7. View under high power (10x)
8. Draw what you see in Figure 4
1. LABEL: nucleus, cell wall, cell membrane, and
cytoplasm
2. Use straight lines that do not intersect
What you don’t finish in class…
•
Becomes HOMEWORK
•
NUMBER off groups (3 per group)
1. Get microscopes
2. Get slide and slip cover
3. Directions, time keeper
ALL: Help with cleaning up
Clean Up Process
•
•
•
•
•
Please help!
Clean as you go…
Don’t drop the glass slides!!!
Re-use your slide and slipcover for
cheek and onion
When finished: Group Roles
1. Gently place glass slides in soapy bowl
2. Place plastic slipcover in different soapy
dish
3. Put microscopes away
Extensions…
• See me about looking at prepared
slides of little creatures!
• OR… view random items under
microscope such as:
– Piece of hair; especially split ends
– Paper towel
– Piece of pasta
• Draw them in the extra circles
(label the picture and note the
power of magnification)