2. Reminders Biosphere Observations
Note: there will be NO tutorial on Friday!

3. Question of the Day
Question: Describe the structure and purpose of DNA. Answer: … … …
More than 25 types of elements
2’s Turn In:
p. 58 Connecting Concepts #33-35; Analyzing Data #38, 39
DNA Modeling Sheet

4. Organisms and pH Summarize the effects of HCl and NaOH on tap water.
1. Adding HCl and NaOH had large effects on the pH of tap water, greatly reducing and raising the pH respectively.
Summarize the effects of HCl and NaOH on biological materials, like orange juice and egg whites.
2. Adding HCl and NaOH had small effects on the pH of biological materials, changing their pH very little.
When you added HCl and NaOH to the buffer, was it more similar to a biological material or tap water?
3. The buffer acted more like a biological material than tap water.

5. Organisms and pH
Would buffers aid or hinder the maintenance of homeostasis within a living cell in a changing environment?
4. Buffers would aid the maintenance of homeostasis within a living cell in a changing environment by helping to keep the cell’s internal conditions stable.
What does the model suggest about a mechanism for regulating pH in an organism?
5. The data suggests that organisms have buffers for regulating their pH.

6. Inv. 4.3 – Enzyme Activity (Liver Lab)
Does the action of catalase change of time? Describe.
1. Catalase is an enzyme and can therefore be used again and again. It’s action changes as it starts to run out of a substrate (H2O2) to work upon, slowing down its apparent activity.
Based on the data from part B, how does temperature affect enzyme action?
Catalase functions at a wide range of temperatures. None of the temperatures were hot enough to denature the enzyme.
3. Based on your data from part C, how does pH affect enzyme action?
3. Catalase functions at a wide range of pH values but extreme acidities (pH 1) denature the enzyme, stopping its action.

7. Inv. 4.3 – Enzyme Activity (Liver Lab)
What is a buffer?
4. A buffer is a substance that helps prevent large changes in pH when an acid or a base is added to a solution.
Would the results from parts A, B, C, and D have been different if buffers had been used in them as well? If so, how?
5. The results from parts A, B, and C would not have differed if buffers had been used because there were no acids or bases added to those parts to affect the enzymes. In part D, however, adding buffers would have increased the enzyme activity because the enzymes would not have been exposed to any extreme acidities.
Summarize the general conditions necessary for effective enzyme action based on this lab.
6. Generally speaking, enzymes need moderate temperatures and pH values.

8. Inv. 4.3 – Enzyme Activity (Liver Lab)
Do you think the ideal conditions for each enzyme would be the same?
7. No, the ideal conditions for each (every) enzyme would not be the same because different enzymes need to function under different conditions, such as gastric enzymes found in the extreme acidity of the stomach or enzymes in bacteria living in hot springs.
How could you design an experiment to show how much faster H2O2 decomposes in the presence of catalase than it does without the enzyme?
Add 10 mL of H2O2 to two test tubes but only add 4 dots of catalase to one tube. Measure the amount of O2 gas produced using the same procedure as before.

9. Inv. 4.3 – Enzyme Activity (Liver Lab)
The liver we used was biotic but not alive. How is it that the enzyme was still active?
9. Enzymes are not alive; they are made of proteins and will be active as long as their active site is not changed through denaturation by extreme pH or temperature conditions or decomposed by bacteria.

10. Notes: Proteins, Lipids, Cellular Respiration, & ATP

11. Proteins Proteins are macromolecules made of units called amino acids
20 different essential amino acids in the human body
a chain of amino acids is a polypeptide
the polypeptide is folded into a protein
Amino Acids
Protein
Polypeptide

12. Lipids Lipid- macromolecule that is composed of mostly C and H
Examples: fats, oils, waxes
Synthesized from fatty acids and glycerol
Important for storing energy: contain more energy per gram than carbohydrates or proteins
Fat:
Oil:
Wax:

13. Cellular Respiration
Cellular respiration- how cells break down sugar for energy
Releases energy from glucose & stores it in ATP

14. ATP ATP- adenosine triphosphate
Important energy transfer compound in all organisms
“Small change” for temporary energy storage
Used for cell reactions, muscle action, firefly light, etc.
Energy is released when ATP is converted to ADP and low-energy phosphate

15. Computer Lab

16. p. 58 Connecting Concepts #33-35; Analyzing Data #38 & 39
At which temperature was the greatest amount of product formed?
33. The greatest amount of product was formed at 35°C.
34. Describe the results of each reaction. How can you explain these results?
34. The total product was doubled when the temperature of the reaction increased from 25°C to 35°C. It decreased to almost zero when the temperature was increased to 45°C. Enzymes work best at certain temperatures. The enzyme involved in this reaction works best at about 35°C. A much higher temperature denatures the enzyme.

17. p. 58 Connecting Concepts #33-35; Analyzing Data #38 & 39
At which time of the day is the pond most acidic?
a. between noon and 6:00P.M.
b. at noon.
c. between midnight and 6:00A.M.
d. at 6:00P.M.

18. p. 58 Connecting Concepts #33-35; Analyzing Data #38 & 39
39. Which of the following is the most reasonable hypothesis based on the result obtained? a. Pond water maintains constant pH throughout the day. b. pH of pond water changes as fish move around throughout the day c. Living things cannot survive in this pond because enzymes will be destroyed d. Changes in pH may be due to the activity of green plants responding to sunlight during the day

20. 10 Facts About The Skeletal System
Real Skeleton

21. 10. Your Bones Are Alive, Not Dead!
Bones have their own nerves and blood vessels
Mix of hard materials for strength and living cells for growing and repairing themselves

22. 10. Your Bones Are Alive, Not Dead!

23. 9. You Would Collapse Without a Skeleton

24. CAUTION: Graphic Image Ahead!

25. 8. Your Bones Protect Your Vital Organs

26. 7. Broken Bones Heal By Producing New Cells
New cells cover both ends of the broken part of the bone and close up the break.

27. 6. Exercise Strengthens Bones

28. 5. The Largest Bone in the Body is the Pelvis
Actually 6 bones fused together.

29. 5. The longest bone is the femur.
4. The Longest Bone in the Body is the Femur
5. The longest bone is the femur.
It makes up almost ¼ of the body’s total height.

30. 3. The Smallest Bone in the Body is an Inner Ear Bone
Called the stapes; same size as a grain of rice.

31. 3. The Smallest Bone in the Body is an Inner Ear Bone
Called the stapes; same size as a grain of rice.

32. 2. Babies Have More Bones Than Adults
Infant
300 bones at birth, 206 at adulthood.
Toddler
Teenagers? How many do the students have?

33. 1. After Death, Cartilage Rots Faster Than Bone
This is why the skulls of skeletons have no nose or ears.

34. Happy Halloween!