1. Ch.7-4 & 8-1 Homeostasis and Cell Energy
Cells

2. POINT > Define homeostasis
POINT > Compare homeostasis in unicellular and multicellular organisms
POINT > Identify mechanisms of cell communication
POINT > Describe ATP structure
POINT > Explain how ATP is used by cells

3. POINT > Define homeostasis
Most cells can only survive in a relatively narrow range of physical and chemical conditions Homeostasis is the maintenance of relatively constant internal physical & chemical conditions

4. POINT > Compare homeostasis in unicellular and multicellular organisms
If an organism is unicellular, the single cell must be able to: -Find sources of energy or food -Keep conc. of water & minerals within certain levels -Respond to environment -Grow & reproduce

5. POINT > Compare homeostasis in unicellular and multicellular organisms
In multicellular organisms cells are specialized to perform particular tasks and to communicate with one another
Specialized cells cooperate to maintain homeostasis of the organism

6. Specialized cells are organized Tissues
POINT > Compare homeostasis in unicellular and multicellular organisms
Specialized cells are organized
Tissues

7. Four types of animal tissues:
POINT > Compare homeostasis in unicellular and multicellular organisms
Four types of animal tissues:
1. Epithelial tissue: skin, lining of digestive tract and body cavities
2. Connective tissue: fat, bone, blood, cartilage, tendons and ligaments

8. Four types of animal tissues:
POINT > Compare homeostasis in unicellular and multicellular organisms
Four types of animal tissues:
3. Muscle tissue
4. Nervous tissue

9. Specialized cells are organized: Tissues Organs Organ Systems
POINT > Compare homeostasis in unicellular and multicellular organisms
Specialized cells are organized:
Tissues
Organs
Organ Systems

10. WB CHECK:
Compared to cells in multicellular organisms, unicellular organisms
have less homeostasis to worry about
have specialized roles in homeostasis
must carry out all homeostasis tasks
What are four types of animal tissue?

11. POINT > Identify mechanisms of cell communication
In multicellular organisms cells must be able to communicate with each other
1. Cellular junctions hold cells firmly together and allow messages & signals to pass quickly from one cell to another

12. POINT > Identify mechanisms of cell communication
2. Proteins and cell membrane carbohydrates act as receptors: A receptor is a location that a signal molecule can bind to, and cause a change to cellular activity

13. POINT > Identify mechanisms of cell communication
This process, when a signal on the outside of the cell causes a cellular change, is called signal transduction

14. POINT > Identify mechanisms of cell communication
Receptors and signal transduction allow cells to communicate with other cells that are not nearby

15. POINT > Identify mechanisms of cell communication

16. WB CHECK: Cell surface receptors are usually composed of lipids
play no part in homeostasis
can receive messages from other cells
hold cells tightly together
How can cells next to each other communicate?

17. POINT > Describe ATP structure
Adenosine tri-phosphate (ATP)
ATP is a compound used by cells to release energy

18. POINT > Describe ATP structure
ATP is composed of:
Adenine
Draw &
Label Me!!

19. POINT > Describe ATP structure
ATP is composed of:
Ribose Sugar

20. POINT > Describe ATP structure
ATP is composed of:
Three phosphate groups

22. POINT > Explain how ATP is used by cells
ATP begins as ADP (Adenosine Diphosphate). A phosphate is added to form ATP Phosphate bonds store energy

23. POINT > Explain how ATP is used by cells
ATP phosphate bonds can break to reform ADP
Breaking phosphate bonds releases energy

24. Break phosphate bonds
to release energy
ATP
Energy stored by forming phosphate bonds
ADP

25. WB CHECK: The energy in ATP is stored in the phosphate bonds
in the ribose sugar
in the adenine
in the nucleus
Which has more energy, ADP or ATP?

26. POINT > Explain how ATP is used by cells
ATP is used for:
1. Active transport
Ex. Sodium-Potassium (Na-K) pumps move Na+ out of cell and K+ into cell
2. Muscle contraction
3. Creating motion with flagella & cilia

27. POINT > Explain how ATP is used by cells
ATP is used for:
4. Making proteins
5. Responding to chemical signals at surface
6. Allows nerve cells to communicate with each other

28. WB CHECK: What are two things ATP is used for in cells?
What are the three parts of an ATP molecule?

29. POINT > Explain how ATP is used by cells
Cells use ATP very rapidly to drive energy-requiring processes
A human uses about their body weight in ATP every day! Yet….
Human body has only about 250g of ATP at any time
Each ATP is recycled x/day (ATP ↔ADP)

30. Homework: Read pages 214-217, 226-228 Assess page 217 #1-2 Assess page 228 #1-2 Workbook pages 127-8