1. Notes: An Egg-speriment

2. Why Do Astronauts Wear Space Suits? The space suit serves as an effective boundary between the external environment of space and the internal environment within the space suit. With out the barrier between the internal and external environments the astronaut would die.

3. What is Homeostasis? The body’s ability to maintain its internal environmental conditions despite changes in the external environment.

4. The Body as a container The body is a large and complicated container made up of many smaller containers called cells.

5. Cell Size Most cells are so small they require a microscope to see them. There are exceptions. A chicken egg is a single cell. It is protected by a hard shell surrounded by several soft membranes.

6. The Egg Yolk Although the egg is a cell, the yolk is not the nucleus. The nucleus of an egg is located inside the yolk and is barely visible. Contains water and more protein than the white, some fat and most of the vitamins and minerals.

7. Quantitative and Qualitiative Observations Quantitative observations that involve result that are measureable with standard scales. Mass in g Temp in degrees Celcius Quantity- something that you can measure (#’s!!!!) Qualitative- involve verbal descriptions

8. The Anatomy of an Egg 1. Shell 2. Shell Membranes 3. Air Cell 4. Albumen 5. Chalazae 6. Yolk 7. Germ Spot

9. Shell Bumpy and grainy texture 17,000 tiny pores Made of Calcium Semipermeable membrane Specialized coating to keep out bacteria and drugs

10. Inner and outer membrane Located between the egg shell and egg white Provide a defense against bacterial invasion Strong- made of keratin (protein)

11. Air Cell An air space that forms after the contents of the egg cools after being laid. Usually forms at the larger end of the egg Grows larger as the egg grows older

12. Albumin Egg white Comes from the Latin word “albus”… Think Albus Dumbeldore Contains 4 alternating layers of thick and thin albumin made up of approximately 40 different proteins.

13. Chalazae Opaque ropes of egg white Holds the yolk near the center of the egg The more prominent they are the fresher the egg

14. Vitilline Membrane Clear casing that encloses the yolk.

15. The Yolk Contains less water and more protein than the white Fat Most of the vitamins and minerals Feeds the developing embryo

16. Summary The human body is able to maintain constant internal environment despite changing external conditions. Cells are like individual compartments. By studying them we can see how they react to changing external conditions.