1. A student observes some cells with a compound light microscope as shown in view A below.
What did the student most likely do to obtain view B?
(2) applied distilled water to the slide
(3) used electrophoresis
(4) used a higher magnification
(1) applied a biological stain to the slide

2. Homeostasis
Organisms regulate (control) themselves.

3. Homeostasis Organisms regulate (control) themselves.
They must maintain a constant internal environment or...

4. Homeostasis Organisms regulate (control) themselves.
They must maintain a constant internal environment or...
If conditions change (too hot, not enough O2, little food, danger!) cells respond (cool down, breathe, eat, run!).

5. Homeostasis Organisms regulate (control) themselves.
They must maintain a constant internal environment or...
If conditions change (too hot, not enough O2, little food, danger!) cells respond (cool down, breathe, eat, run!).
Cells must be able to detect, communicate and respond.

7. These are all examples of homeostasis!
What if you see the bus?
You realize you missed it.
You respond by running to try and catch it.
Your muscles need more ATP.
You breathe harder to get O2.
Your heart beats more to get O2 and glucose to cells.
You overheat and begin sweating.
These are all examples of homeostasis!

8. Feedback loops Something changes. Cells detect change.
Message sent to brain.
Brain “decides”.
Message sent to cells.
Cells respond.
Response causes change.

9. You LOST homeostasis! You maintain homeostasis! What happened here?
Why does the body temperature usually stay in a certain range?
You maintain homeostasis!

11. Brain
Neuronal message
Hormonal message
Hormonal message

12. The diagram here represents a model of blood sugar regulation.
The dashed line in the diagram represents
a digestive process
(2) a feedback mechanism
(3) cellular differentiation
(4) recycling of organic chemicals