H. BiologyHOMEOSTASIS

THROUGH FEEDBACK

Living organisms use biochemical pathways in response to environmental conditions in order to maintain a constant internal environment

FEEDBACK MECHANISMS

The product of a process encourages the process

POSITIVE FEEDBACK

The product of a process inhibits the process

NEGATIVE FEEDBACK

HOMEOSTASIS IN PLANTS

Stomata open/close in response to environmental conditions

Pancreas secretes insulin/glucagon in response to blood sugar

HOMEOSTASIS IN ANIMALS

USING A MICROSCOPE

PARTS OF A LIGHT MICROSCOPE

1. Always carry the microscope with 2 hands one hand on the arm one hand on the base

HOW TO USE A MICROSCOPE

2. Plug the microscope into the electrical outlet & turn on the light switch

HOW TO USE A MICROSCOPE

3. Move the revolving nosepiece to LOW POWER!!!

HOW TO USE A MICROSCOPE

4. Place your glass slide on the stage under the clips. The specimen must be over the light

HOW TO USE A MICROSCOPE

5. Use the coarse adjustment to focus your specimen

HOW TO USE A MICROSCOPE

If you do not start on Low power…you will CRUSH/Break your slide!!!slides cost: $5-$10 each!!!

WARNING!!!

6. Once you find the object in the best focus possible center your specimen.

HOW TO USE A MICROSCOPE

7. Carefully rotate to medium power

8. Use the fine adjustment knoband center your specimen

HOW TO USE A MICROSCOPE

NEVER TOUCH THE

COARSE ADJUSTMENT ON

MEDIUM POWER!

You owe us one expensive piece of glass

OR…

9. Carefully change to high power

10. Use the fine objective knob and center your specimen

HOW TO USE A MICROSCOPE

NEVER TOUCH THE

COARSE ADJUSTMENT ON

HIGH POWER

Move back to low power and start over.

WHAT IF I CAN’T ANYTHING?