| Probability Answers
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| Parents RR x rr | ||
| Offpring Rr | 1 x 1 = | 1 |
Answers to trihybrid probabilities:
RrYyGg x RrYyGg
a. 3/4 x 3/4 x 3/4 = 27/64
b. 1/4 x 1/4 x 1/4 = 1/64
c. 3/4 x 3/4 x 1/4 = 9/64
d. 3/4 x 1/4 x 1/4 = 3/64
Category: My Classroom Material
Project Due Dates
Project Due Dates
Last update August 9, 2010
Abstracts:
Due FIRST TUESDAY of each month!
ABSTRACTS
Cry of the Kalahari paper:
| Friday, October 29 | 1st quiz |
| Friday, November 12 | 2nd Quiz |
| Friday, December 3 | 3rd Quiz |
| Thursday, December 9 | Cry Paper Due! |
Leaf Collection Due:
Wednesday, September 27
Wildflower Collection Due:
Friday, May 13
Lab Reports Due:
| 1st nine WEEKS | |
| Lab 2 Enzyme Catalysis | |
| Lab 1 Osmosis & Diffusion | |
| 2ND NINE WEEKS | |
| Lab 4 Photosynthesis & Pigments | |
| Lab 5 Cellular Respiration | |
| Lab 3 Mitosis & Meiosis | |
| 3rd nine weeks | |
| Lab 8 Population Genetics | |
| Lab 6 Molecular Biology | |
| 4th nine weeks | |
| Lab 9 Transpiration | |
| Lab 10 Physiology of Circulation | |
| Lab 11 Behavior | |
| Lab 12 Dissolved Oxygen | |
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Properties of Water
| Properties of Water |  |
Introduction:
Water’s chemical description is H2O. As the diagram to the left shows, that is one atom of oxygen bound to two atoms of hydrogen. The hydrogen atoms are “attached” to one side of the oxygen atom, resulting in a water molecule having a positive charge on the side where the hydrogen atoms are and a negative charge on the other side, where the oxygen atom is. This uneven distribution of charge is called polarity. Since opposite electrical charges attract, water molecules tend to attract each other, making water kind of “sticky.” As the right-side diagram shows, the side with the hydrogen atoms (positive charge) attracts the oxygen side (negative charge) of a different water molecule. (If the water molecule here looks familiar, remember that everyone’s favorite mouse is mostly water, too). This property of water is known as cohesion.
All these water molecules attracting each other mean they tend to clump together. This is why water drops are, in fact, drops! If it wasn’t for some of Earth’s forces, such as gravity, a drop of water would be ball shaped — a perfect sphere. Even if it doesn’t form a perfect sphere on Earth, we should be happy water is sticky. Water is called the “universal solvent” because it dissolves more substances than any other liquid. This means that wherever water goes, either through the ground or through our bodies, it takes along valuable chemicals, minerals, and nutrients.
Water, the liquid commonly used for cleaning, has a property called surface tension. In the body of the water, each molecule is surrounded and attracted by other water molecules. However, at the surface, those molecules are surrounded by other water molecules only on the water side. A tension is created as the water molecules at the surface are pulled into the body of the water. This tension causes water to bead up on surfaces (glass, fabric), which slows wetting of the surface and inhibits the cleaning process. You can see surface tension at work by placing a drop of water onto a counter top. The drop will hold its shape and will not spread.
In the cleaning process, surface tension must be reduced so water can spread and wet surfaces. Chemicals that are able to do this effectively are called surface active agents, or surfactants. They are said to make water “wetter.” Surfactants perform other important functions in cleaning, such as loosening, emulsifying (dispersing in water) and holding soil in suspension until it can be rinsed away. Surfactants can also provide alkalinity, which is useful in removing acidic soils. 
Pre-Lab Questions (Click here)
Materials:
Box of small paper clips, small plastic container, eyedropper, cup, stirring rod, water, liquid soap, plastic tray
Procedure (Part A) Cohesiveness of Water:
- Estimate how many paper clips will fit into a completely full cup of water. Record this number in data table 1.
- Place your small container on a tray to contain any water that may spill.
- Fill a plastic cup with tap water.
- Pour tap water from your cup into your small container.
- Continue to add water by eyedropper until the top surface appears rounded.
- Slowly add paper clips one at a time to the cup keeping count of all paper clips that you add.
- Stop adding paper clips to the container whenever water spills from the top.
- Record your paper clip count. Compare the actual number of paper clips to the estimated number.
Procedure (Part B) Soap’s effect on Surface Tension:
- Again estimate how many paper clips will fit into a completely full cup of soapy water. Record this number in data table 2.
- Place your small container on a tray to contain any water that may spill.
- Fill a plastic cup with tap water.
- Add several drops of liquid soap & use a stirring rod to mix.
- Pour soapy water from your cup into your small container.
- Continue to add soapy water by eyedropper until the top surface appears rounded.
- Slowly add paper clips one at a time to the cup keeping count of all paper clips that you add.
- Stop adding paper clips to the container whenever water spills from the top.
- Record your paper clip count. Compare the actual number of paper clips to the estimated number.
Data:
Table 1
| Cohesiveness of Tapwater | ||
| Estimated Number of Paper Clips | Actual Number of paper Clips | Difference |
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Table 2
| Cohesiveness of Soapy water | ||
| Estimated Number of Paper Clips | Actual Number of paper Clips | Difference |
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Questions:
1. How did your estimated number compare to your actual number?
2. What happened to the surface of the water as more clips were added?
3. What property of water was shown in Part A?
4. How is this property of water used in nature?
5. Explain why water shows surface tension.
6. Explain why water is a polar molecule and include a diagram of several water molecules in a drop of water.
7. In order to clean a surface, what must happen to surface tension?
8. What is the job of a surfactant?
9. Name a surfactant used in Part B?
10. Using your data from Part B, explain what proof you gathered in Part B to support your answer to question 9.
Preap Photosynthesis Study Guide
| Photosynthesis Review |  |
1. What is the term for the ability to perform work? ______________________.
2. Animals that Cannot make their own food are called ________________________.
3. Most organisms use an energy storage molecule called ____________________ _______________________ or simply (_______).
4. Light of different colors is different in ______________________ and _________________________.
5. During photosynthesis, a Reduction Reaction _________ ______________ to a molecule.
6. Oxidation is a process that makes a molecule __________________ electrons.
7. Disk-shaped structures with photosynthetic pigments are known as __________________.
8. The process by which autotrophs convert sunlight into energy is called ___________________________.
9. A molecule that can absorb certain light wavelengths and reflect others is a ________________________________.
10. What are the most common group of photosynthetic pigments in plants? ___________________________
11. Stroma are gel-like matrix (a solution) that surrounds the ________________________.
12. Photosynthesis occurs in two stages called:
A.______________________________________________
B.______________________________________________
13. Plants that use only the Calvin Cycle for photosynthesis are called ______________.
14. CAM Plants can survive in dry, hot deserts because they can fix carbon at ____________________________.
15. What substances do Autotrophs or producers use to make food?
A._____________________________________
B._____________________________________
C._____________________________________
16. The addition of an electron to an atom or a molecule is called _________________.
17. The loss of an electron to an atom or a molecule is called ____________________.
18. Organisms that CAN produce their own food are called ______________________.
19. An important waste product of photosynthesis is _______________________.
20. Photosynthesis occurs in what organelle of plants and algae? _________________________.
21. The Thylakoids are surrounded by a gel-like matrix (solution) called __________________.
22. An object that absorbs all colors appears _____________________.
23. What are the light collecting units of the Chloroplast? __________________.
24. Carbon fixing reactions occur in a pathway called the _____________________ _________________.
25. Chlorophyll reflects and transmits what color? _________________________.
26. An object that reflects all colors appears ____________________________.
27. Folded Thylakoids that resemble stacks of pancakes are called ________________________________.
28.The pigments that absorb violet, blue and red light. __________________________
29.The Enzyme that adds a phosphate group to ADP. _________ __________________ to form _________________.
30. What do we call the component colors of white light? ______________________ ___________________________
31. What clusters of pigments are called. ____________________________
32. A five-carbon carbohydrate in the Calvin cycle. _____________________________
33. A three-carbon molecule in the Calvin cycle.______________________________
34. A Series of linked chemical reactions is called a __________________________ ____________________________.
35. The pigments that absorb blue and green light are called ________________________.
36. The oxygen atoms in the oxygen gas produced in photosynthesis come from ________________________ __________________________.
37. Both C4 and C3 plants use the ____________________ _________________ for carbon fixation.
38. Where does the energy required for the Calvin cycle originate? From ______________ and __________________ produced by the ____________________ _____________________.
39. Protons are move into the thylakoid using energy from ___________________ in the __________________________ __________________________.
40. At the end of photosystem I transport chain, electrons combine with ______________ to form ______________________.
41. Carbon atoms are fixed into organic compounds in the _____________________ ______________________.
42. To produce the same amount of carbohydrate, C4 plants require less ___________________ ____________________ than C3 plants.
43. Where in the chloroplast do the light reactions occur? ________________________
44. Where in the chloroplast do the reactions of the Calvin cycle occur? ______________________________
45. What product of the light reactions of photosynthesis is released and does not participate further in photosynthesis? _________________________________
46.Which environmental factor will cause a rapid decline in the photosynthesis rate if the factor rises above a certain level? ___________________________________
47. Accessory pigments differ from chlorophyll a in that they are _______________ directly involved in the ___________________ _____________________ of photosynthesis.
48. What structure that is found in the thylakoid membrane is important to chemiosmosis? ___________
_____________________________.
49. _______________________________________________________ is the protein in the _____________________________________ membrane that adds a phosphate group to ADP.
50. Chemiosmosis relies on a(n) ____________________________________________________ of protons across the thylakoid membrane.
51. Write the chemical equation for photosynthesis.____________________________________
_____________________________________________________________________________
52. ATP synthase is a multifunctional protein. By allowing protons to cross the thylakoid membrane, it functions as a(n) _______________________________________________, and by catalyzing the synthesis of ATP it functions as a(n) ______________________________.
53. H+ represents an ion or in photosynthesis a(n) _____________________________________.
DIRECTIONS: Answer the questions below as completely and as thoroughly as possible. Answer the question in essay form (not outline form), using complete sentences. You may use diagrams to supplement your answers, but a diagram alone without appropriate discussion is inadequate.
1. Describe the internal structure and external structure of a chloroplast.
2. Explain what happens to the components of water molecules that are split during the light reactions of photosynthesis? (HINT: Name the three products that are produced when water molecules are split during the light reactions and explain what each product is used for.)
3. Explain the difference between the roles of photosystem I and photosystem II in photosynthesis?
4. Explain why the leaves of some plants look green during the summer then turn yellow, orange, red,
or brown during the fall?
5. What plant structures control the passage of water out of a plant and carbon dioxide into a plant? Explain
how they control the passage of water out of a plant and carbon dioxide into a plant.
6. What happens to the electrons that are lost by photosystem II? What happens to the electrons
that are lost by photosystem I?
7. Photosynthesis is said to be “Saturated” at a certain level of CO2. Explain what this means?
8. Explain how is ATP synthesized in photosynthesis? What is this process called?
9. What is the fate of most of the PGAL molecules in the third step of the Calvin cycle and Why is this important?
What happens to the remaining PGAL molecules? What organic compound can be made from PGAL?
10. Explain how CAM plants differ from C3 and C4 plants? How does this difference allow CAM
plants to exist in hot, dry conditions?
11. Define biochemical pathway and explain how the Calvin cycle is an example of a biochemical pathway.
In what part of the chloroplasts does the Calvin cycle take place?
12. Explain how the function of the chloroplasts is related to its structure.
13. What roles do water molecules play in photosynthesis?
14. Describe the structure and function of the thylakoids of a chloroplasts.
15. What role do accessory pigments play in photosynthesis?
Properties of Water
Properties of Water
Introduction
Water covers about three quarters of the earth’s surface and makes up about three quarters of our body weight. In fact, without water, life would not be possible. This simple fact is why scientists are constantly looking for water on other planets – the presence of water could indicate the presence of life.
We have discussed some of the properties of water in previous lessons. This lesson will consider water’s properties in more depth. As you read about the characteristics of water, take some time to think about how these characteristics relate to the fields of water and wastewater treatment.
Water Molecule
As you should remember, water is represented by the formula H2O. The picture below can also be used to represent water.
Lesson 5 explained how hydrogen bonds form between water molecules. The ability of water molecules to form hydrogen bonds, as shown below, causes many of water’s unique characteristics. For example, you should recall that hydrogen bonding makes water an excellent solvent.
Temperature
Introduction
Water is unique in that it is found as a gas, a liquid, and a solid at natural earth temperatures. In contrast, most other substances are naturally found in only one or two states. This property of water is integral to our daily lives, and is especially important in the hydrologic cycle.
On this page, we will consider how water is influenced by temperature. The surrounding air temperature can change the temperature of water, change water’s state, and change water’s density.
Specific Heat Capacity
Specific heat capacity is the amount of heat required to raise the temperature of one gram of a substance by one degree Celsius. Every substance has its own specific heat capacity, with the specific heat capacity of water being 1 cal/(g°C).
The specific heat capacity of water is much higher than that of other common substances. For the sake of comparison, the specific heat capacity of oil is about 0.5 cal/(g°C) and the specific heat capacity of aluminum is about 0.2 cal/(g°C). This means that it takes a lot more heat to raise the temperature of water compared to the amount of heat it would take to raise the temperature of oil or aluminum.
The high specific heat of water helps the earth’s temperature remain moderate since water traps heat during the day and releases it slowly at night. As a result, the temperature on earth’s surface does not vary very widely, ranging from extremes of 134°F to -129°F. For comparison, the moon has no liquid water and its temperatures can range from 240°F to -290°F. (The lack of atmosphere on the moon, along with other factors, also contributes to the wide range of temperature.)
Boiling Point
Water also has a very high boiling point, meaning that liquid water turns into water vapor at a higher temperature (212°F) than would be expected due to the size and weight of the molecule. The high boiling point of water is due to the hydrogen bonds which tend to hold water molecules together, preventing them from breaking apart and entering the gaseous state.
Since it takes such a large amount of energy to change the state of water, sweating is a very effective method of cooling the body. In order to evaporate, the sweat requires the input of a great deal of heat energy, some of which comes from our bodies. So, as our sweat evaporates, we begin to feel cooler.
Density and Expansion
As you should remember from ENV 110, density is the ratio of mass to volume. Dense objects feel heavier and tend to sink while less dense objects feel lighter and tend to float.
The density of most objects changes slightly as the temperature changes. In general, warmer temperatures tend to make substances less dense because the greater random kinetic energy makes the molecules spread out. The amount that objects expand when heated is known as the coefficient of expansion.
The density of water, once again, is a special case. Water is most dense at 39°F, and as it cools or warms from this temperature, the water expands slightly. This means that ice is slightly less dense than cold water, which is why ice floats on the surface of bodies of water. The floating ice slows the freezing process by insulating the water underneath, which contributes to the moderate temperatures on earth. In addition, the layer of ice prevents many lakes from freezing solid, allowing fish and other organisms to survive under the ice.
The changing density of water at different temperatures is also responsible for turnover. Turnover occurs when the water on the surface of a lake cools in the fall. Eventually, this cold water will become more dense than the warmer water beneath, so the cold water will sink to the bottom and the warm water will rise to the surface. When lakes are used as the water source for water treatment plants, turnover can cause abrupt changes in the quality of the raw water.
Other Properties
Surface Tension
In a body of water, hydrogen bonds between water molecules are constantly pulling the molecules in many different directions. However, at the water’s surface, the molecules are only being pulled from side to side and down, with no hydrogen bonds pulling them upwards. This results in a skin of water at the surface in which the molecules are held together very tightly.
Surface tension is a measurement of the amount of force required to break this skin on the surface of water. Other liquids have a surface tension as well, but the surface tension in water is quite strong due to the hydrogen bonds. The pictures below show some examples of the results of water’s strong surface tension.
Surface tension is what holds drops of water together in a round shape. Surface tension allows both water striders and paperclips to float on water even though they are more dense than the water. In addition, surface tension allows you to fill a cup slightly over the brim with water.
Capillary Action
Surface tension is also responsible for another phenomena known as capillary action. Capillary action occurs when water climbs upward through a small space, defying gravity due to the forces of adhesion and surface tension. The image below shows one example of capillary action – a narrow straw was placed in a cup of water and the water crept upwards through the straw.
What causes the movement of water during capillary action? The first factor is adhesion, the attraction between water and another object. In this case, adhesion attracted the water within the straw to the surface of the straw. Molecules of water which came in contact with the straw tended to move upward along the inside of the straw, as shown below:
Water’s surface tension is so strong that, as water is pulled upward along the straw’s walls, the water in between tends to be pulled upward also. The downward pull of gravity prevents the central water from rising quite as high as the water which is adhered to the straw, so the result is a meniscus, as shown in the first picture in this section.
Capillary action is important in moving water upwards through small spaces. Plants depend on capillary action to move water upward from the roots to the leaves. In the soil, capillary action also tends to move water upward between the soil particles.
Review
Water has many unique properties, many of which are based on its molecules’ ability to form hydrogen bonds. Water is found at earth’s temperatures as a solid, liquid, and gas. It has a high specific heat capacity and boiling point. Water is most dense at 39°F. Water also has a strong surface tension.