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Probability Notes Bi

 

Probability

 

Probability Facts:

  • Probability is the likelihood that an event will occur from random chance  
  • Probabilities are always between 0 and 1
  • Probabilities can be written as fractions, decimals or percentages
  • All possible events together must have a probability of 1
  • The probability that an event will not occur is 0
  • To find the probability of a particular event, we use this formula:

 

Number of successful events
(where a successful event is the result that you are looking )
Probability of an event = ———————————————
Total number of events

 

  • Whenever a coin is flipped, there is a 50% chance of getting heads & a 50% chance of getting tails.
  • The chance of inheriting one of two alleles from a parent is also 50%

Applying Probability to Mendel’s Peas:

  • During the late 1850’s, Gregor Mendel used the general rules of probability to explain the basic principles of heredity by breeding green peas in planned experiments
  • Different versions of genes are called alleles
  • For most genes, two alleles exist
  • If an organism has two different alleles for the same gene, the dominant allele will be expressed in the phenotype of the organism, while the recessive allele will not
  • Each parent will pass on one of its two alleles

Probability Laws:

  • The Law of Multiplication or Product Rule states that the chance of two or more independent events occurring together is the product of the probability of the events occurring separately
    Example: The chance of inheriting a specific allele from one parent & another allele from the other parent is 1/2  x  1/2 or 1/4
  • The following table shows the probability of the offspring genotypes whenever two heterozygous parents are crossed:

 

Parents     Rr  x  Rr
Offpring  RR 1/2  x  1/2  = 1/4
Offpring  Rr 1/2  x  1/2  = 1/4
Offpring   r r 1/2  x  1/2  = 1/4

Complete the following table for crossing 2 Homozygous parents: 

 

Parents     RR  x  rr
Offpring  Rr  

 

Click here for the correct answer

Example 1
Imagine we are rolling a fair dice. There are six equally likely outcomes: 1, 2, 3, 4, 5 and 6.

  1. What is the probability of getting a five?
    In this case there is only one successful outcome or event, 5.

 

Number of successful events
Probability of a five = ———————————————
Total number of events
     1
Probability of a five = ———-
     6

 

  1. What is the probability of getting an even number?
    In this case there are 3 successful outcomes, which are 2, 4 and 6.

 

Number of successful outcomes
Probability of an even number = ————————————
Total number of outcomes
     3
Probability of an even number = ———-
     6
     1
Probability of an even number = ———-
     2

 

Therefore the probability of getting an even number when rolling a dice is 50% or 1/2.

  • Now apply these numbers to the dihybrid cross RrYy  x  RrYy Probability of being R_ Y_ is 3/4 x 3/4 = 9/16  Probability of being R_ y_ is 3/4 x 1/4 = 3/16  Probability of being r_Y_ is 1/4 x 3/4 = 3/16 Probability of being r ryy is 1/4 x 1/4 = 1/16 This matches our 9:3:3:1 phenotypic ratio.

Example Problem:

Work a trihybrid cross of heterozygous parents   —    RrYyGg   x   RrYyGg

  1. What is the probability of having a dominant gene for all three traits?
  2. What is the probability of being recessive for all three traits?
  3. What is the probability of being dominant for 2 and recessive for one?
  4. What is the probability of being dominant for 1 and recessive for two?

Click here for the correct answers

  • The Law of Addition is used when considering the probability of either of two mutually exclusive events
  • The individual probabilities of the 2 exclusive events are added
    Example:     The probability of selecting the three of clubs or any ace from the deck is the sum of the individual probabilities:  Probability of selecting a three of clubs = 1/52
    Probability of selecting any ace = 4/52
    Total probability = 1/52 + 4/52 = 5/52

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:

  1. Estimate how many paper clips will fit into a completely full cup of water. Record this number in data table 1.
  2. Place your small container on a tray to contain any water that may spill.
  3. Fill a plastic cup with tap water.
  4. Pour tap water from your cup into your small container.
  5. Continue to add water by eyedropper until the top surface appears rounded.
  6. Slowly add paper clips one at a time to the cup keeping count of all paper clips that you add.
  7. Stop adding paper clips to the container whenever water spills from the top.
  8. 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:

  1. Again estimate how many paper clips will fit into a completely full cup of soapy water. Record this number in data table 2.
  2. Place your small container on a tray to contain any water that may spill.
  3. Fill a plastic cup with tap water.
  4. Add several drops of liquid soap & use a stirring rod to mix.
  5. Pour soapy water from your cup into your small container.
  6. Continue to add soapy water by eyedropper until the top surface appears rounded.
  7. Slowly add paper clips one at a time to the cup keeping count of all paper clips that you add.
  8. Stop adding paper clips to the container whenever water spills from the top.
  9. 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
 

 

 

Table 2

 

Cohesiveness of Soapy water
Estimated Number of Paper Clips Actual Number of paper Clips Difference
 

 

 

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?