April 7, 2009Science 7

ANNOUNCEMENT:ANNOUNCEMENT:

•Photosynthesis & Resp. QUIZ RE-TAKESPhotosynthesis & Resp. QUIZ RE-TAKES

•Next Monday & Tuesday during ELO Next Monday & Tuesday during ELO

•Possibility to raise an I Possibility to raise an I C, or a C C, or a C B. B.

•You must be prepared to answer random You must be prepared to answer random questions correctly in conversation (oral questions correctly in conversation (oral quiz)quiz)

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 …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.

You do not need to use the stage clips when viewing wet-mount slides!

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.

4 - Slowly lower the cover slip on top of the drop.

Cover Slip

Lower slowly * 45 degree angle

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 Cell1. Place a tiny drop of iodine onto clean

slide2. Use a toothpick to scrape inside of

mouth (cheek)3. Make a zig zag onto iodine droplet.4. Don’t use stage clips5. View on Low Power (4x)6. Draw what you see on Figure 17. View on High Power (10x)8. Draw what you see on Figure 2

1. Draw 2 or 3 cells2. 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 41. 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 microscopes2. Get slide and slip cover3. Directions, time keeperALL: 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)