Category: Curriculum Map

Caught Red-Handed

 

Caught Red-Handed  

 

Introduction:

Bacteria are everywhere. They have evolved the ability to inhabit almost every surface on the planet; however, they are invisible to the naked eye due to their small size. Bacteria have been found living in the deepest part of the ocean, in volcanic vents, in boiling hot springs, and even deep in polar ice caps. Many species of bacteria live inside of other organisms in a harmless commensalistic way such as the intestinal bacteria, Escherichia coli. Bacteria can reproduce at very rapid rates whenever conditions are favorable, as often as every 20 minutes doubling in number. The bacterial population is kept in check by the natural defenses of the host, such as the immune system and proper washing habits. When these natural defenses fail, bacteria can quickly become a problem. Some bacteria produce poisons or toxins that can be life-threatening if the bacterial population isn’t controlled by our natural defenses.

The United States Centers for Disease Control (CDC) states that the best way to prevent bacterial spread and infection is through the use of proper sanitary techniques. Perhaps the most critical step in this prevention is the use of proper hand washing. When improperly washed, your hands are one of the most easily colonized areas of your body and many of our behaviors involve the use of our hands.  Proper hand washing requires the use of water as hot as you can stand, soap, and lots of rubbing. The soap and water serve to destroy bacteria, and the rubbing helps slough off dead skin cells along with lots of bacteria.

Objective:

Students will examine:

  1. The spread of bacteria through surface contact
  2. Surface washing techniques to reduce the spread of bacteria

Materials (Part A):

Black light, Glo-Germ powder, lotion or Glo-Germ oil, hand soap, water, paper towels, pencil, lab sheet

Procedure (Part A):

  1. Choose one student in the lab group and have them spread a SMALL AMOUNT of Glo-Germ powder or lotion evenly over the entire surface of their hands. Be sure to include hard to clean areas such as around & under the fingernail.
  2. Have another student use the Black light to check your hands for the fluorescent “germs”.
  3. Estimate the percentage of your hand that you have covered with Glo-Germ powder and record this percentage in your data table 1 under time “0”.
  4. Wash your hands for 10 seconds and then recheck your hands with Black light and record the percentage of “germs” remaining.
  5. Repeat step 5 for washing times of 30 seconds, 60 seconds, and 120 seconds.
  6. Return Glo-Germ powder, lotion, or oil to lab cart. 

Data Table 1

 

Time of Wash in Seconds Percent of Hand Covered with “germs”
0 (initial observation)
10
30
60
120

 

Materials (Part B):

Tennis ball, “play” money, stuffed toy, pencil, lab sheet

Procedure (Part B):

  1. Choose a different member of your lab group and use the Black light to check their hands for the presence of germs.  IF they are “infected”, have them thoroughly wash their hands to remove the “germs”.
  2. Record the percentage of their hand that is covered with “germs”.
  3. Pick up the basket from the lab cart with your materials for part B.
  4. Handle the tennis ball for at least 20 to 30 seconds.
  5. After handling the tennis ball, have your hands rechecked with the Black light for “germs”.
  6. Record this percentage in data table 2.
  7. Return to your lab table and handle each of the other items ONE AT A TIME, checking for “germs after EACH item and recording this percentage in table 2.
  8. Return the black light and basket with handled items to the lab cart.

Data Table 2

 

Name of Item Percent Coverage
Initial Hand Coverage
Tennis Ball
“Play” money
Toy

 

Questions:

  1. If almost every surface we touch is inhabited by bacteria, why don’t bacterial infections occur more often?
  2. Name 3 ways you  might prevent the spread of bacteria each day.
  3. Name several bacterial diseases.
  4. Name and describe the 3 shapes of bacteria.
  5. Are all bacteria harmful? Explain your answer.
  6. What effect, if any, did increased washing time have on the percentage of “germ” coverage on your hands?
  7. Name 3 areas of your home that are most susceptible to bacterial contamination. Explain steps you could take in each of these areas to prevent the spread of bacteria to other places in your home.

Optional:

Create a graph based on the data from table 1.

Title _____________________________

 

Catalase Peroxide Lab

 

 

Enzyme Rate of Catalase

 

 

Introduction:

Enzymes are molecular substances found in cells.  Enzymes act as catalysts and most are proteins.  Enzymes bind temporarily to one or more of the reactants of the reaction they catalyze. In doing so, they lower the amount of activation energy needed and thus speed up the reaction.
 Not only do enzymes economize energy usage, but also provide a variety of other functions. Cells uses an enzyme (catalase) to rid itself of a poisonous substance (hydrogen peroxide). The rate at which this occurs depends on the amount of catalase that is available. In this lab we are going to measure the time it takes for a disc of filter paper, soaked with different concentrations of enzyme, to make its way to the top of a plastic vial filled with peroxide.  Rate of enzyme activity = distance (depth of hydrogen peroxide in mm)/time (in sec).

Catalase catalyzes the decomposition of hydrogen peroxide into water and oxygen.  One molecule of catalase can break 40 million molecules of hydrogen peroxide each second.

catalase
2H2O2 —–> 2H2O + O2

Objectives:

Students will prepare various dilute solutions from a 100% enzyme solution.
Students will determine how enzyme concentration affects reaction rate.

 

Materials:

6 medicine cups for dilutions, *catalase stock solution, clear plastic vial, forceps, 18 filter paper disks, Hydrogen Peroxide (H2O2), paper towel, apron, safety glasses, watch with second hand, marker, metric ruler, calculator

* The enzyme has been prepared for you as follows: 50g of peeled potato was mixed with 50 ml cold distilled water and crushed ice and homogenized in a blender for 30 seconds. This extract was filtered through cheesecloth and cold distilled water was added to a total volume of 100 ml. Extract concentration is arbitrarily set at 100 units/ml. ENZYME SHOULD BE KEPT ON ICE AT ALL TIMES!!

Procedure:

  1. Make a series of dilutions of the enzyme catalase using the following table.

 

Final Quantity Needed Concentration of Final Solution mL of Catalase mL of Water
10 ml 100% c10 0
10 ml 80% 8 2
10 ml 60% 6 4
10 ml 40% 4 6
10 ml 20% 2 8
10 ml 0% 0 10

 

 

  1. Use a marking pencil and mark the enzyme solutions as follows: 100%, 80%, 60%, 40%, 20%, and 0%.
  2.  Fill a clear vial with 20 mL of hydrogen peroxide.
  3. Using your forceps, pick up one filter paper disk and submerge it in the 100% enzyme solution for 5 seconds. Continue to hold the disk with the forceps.
  4. Using your forceps, pick up one filter paper disk and submerge it in the 100% enzyme solution for 5 seconds. Continue to hold the disk with the forceps.
  5. Remove the disk from the solution and blot it dry, for five seconds, using your paper towel.
  6. Drop the disk in the hydrogen peroxide and measure the time it takes for the disk to rise up from the bottom. Begin timing as soon as the disk touches the surface of the hydrogen peroxide.
  7. Use the metric ruler to measure the distance the disk sinks into the hydrogen peroxide. multiply by two to determine the entire distance the disk traveled. Enter the time and distance the disk traveled in the column for Trial 1 in the data table below.

 

 

% Catalase

Time in seconds

Distance in millimeters

 Reaction Rate mm/s
Trial 1 Trial 2 Trial 3 Avg. Trial 1 Trial 2 Trial 3 Avg.
100
80
60
40
20
0

 

  1. Repeat the above steps for the remainder of the solutions. Remember to use clean filter paper each time you use a different solution. Enter the times and distances for trial 2 and 3 in their appropriate columns.

Analysis & Conclusion:

1. Which concentration of catalase had the fastest reaction time?

2. Which concentration of catalase had the slowest reaction time?

3. What is catalase & why is it important to cells in your body?

 

 

4. How did you know that catalase was present in the above compounds?

 

5. What 2 substances form when catalase breaks down hydrogen peroxide?

 

6. What type of organic compound is catalase?

7. Produce a line graph of the above data. Use the enzyme concentration as the independent variable and the reaction rate as the dependent variable.

Graph Title:__________________________________________________

Legend:

8.  Based on the graph and overall slope of the line, what can you conclude about the effect of enzyme concentration on reaction rate?

 

 

 

Cell Division Worksheet Ch 8 BI

 

Cell Division

 

 

Section 8-1 Chromosomes

 

1. What molecule in cells stores the genetic information?

2. DNA is built of billions of subunits called __________________________.

3. What are chromosomes, & when can they be seen?

4. What is the shape of chromosomes, & what 2 things are they made of?

5. Each chromosome is a single ________________ molecule with ____________________.

6. What is the purpose of histones?

7. What is the purpose of nonhistone proteins?

8. Chromosomes consist of two identical _____________________ called _________________.

9. What is a centromere?

10. Draw and label the parts of a chromosome.

11. Chromatids _______________________ during cell division so the two new cells will each
receive _________________ chromatid.

12. How does DNA appear in a cell between cell divisions?

13. What is chromatin & when does it exist in cells?

14. How many chromosomes do prokaryotes have?

15. How many chromosomes do each of these organisms have:
a. humans?
b. dog?
c. fruit fly?

16. What are the two categories of chromosomes?

17. Give 2 functions of the sex chromosomes.

18. Name the 2 sex chromosomes & tell what combination determines a male and a female organism.

19. What are autosomes & how many autosomes are in human cells?

20. What are homologous chromosomes & how do they compare to each other?

21. What is a karyotype?

22. In a human karyotype, where would each of these be found:
a. sex chromosomes?
b. longest homologs?
c. autosomes?

23. What is the main difference between diploid & haploid cells?

24. What type of cells in human would be diploid? Haploid?

25. How are diploid cells abbreviated? Haploid cells?

26. When a haploid (1n) ______________________ cell combines with a haploid
_______________________ cell, the new cell will be ______________________
or ____________________________.

 

Section 8-2 Cell Division

 

27. All cells are derived from ___________________________________.

28. What is cell division?

29. Define binary fission.

30. Describe the stages in binary fission of a prokaryote.

31. How do the two new cells compare to each other after binary fission? How do they compare to the original cell?

32. What two main cellular parts must be divided in eukaryotic cell division?

33. Name the 2 types of cell division in eukaryotes.

34. Define mitosis.

35. What type of cell uses mitosis?

36. What effect does meiosis have on the chromosome number of a cell?

37. How do the cells produced by meiosis reestablish a complete set of chromosomes?

38. What is the cell cycle?

39. Draw & label all parts of the cell cycle. (Figure 8-5, page 149)

40. What is the time between divisions in the life of a cell called?

41. How many phases is interphase divided into? Cell division?

42. Name the 2 parts of cell division.

43. What happens to the cell in each of these two parts of cell division?

44. In what stage do cells spend most of their time?

45. What is the size of cells immediately following cell division?

46. Name the 1st stage of interphase & tell what happens to the cell.

47. What stage of interphase do cells enter once they become mature?

48. What happens to a cell during the S phase of interphase?

49. What is the last stage of interphase called & what is happening to the cell?

50. What is the Go phase and what type of human cells are in this phase?

51. Name the 4 stages of mitosis in order.

52. What cellular part actually divides during mitosis?

53. Describe everything that happens to a cell during prophase.

54. Sketch and label a picture of a cell in prophase.

55. What are centrosomes & when do they appear?

56. What type of cell has centrosomes?

57. What is found inside centrosomes?

58. Are centrioles found in both plant & animal cells? Explain.

59. What forms from centrioles & what is their function?

60. Name the 2 types of fibers that make up the mitotic spindle & describe each one.

61. Describe everything that happens to a cell during metaphase.

62. Sketch & label a cell during metaphase.

63. Describe everything that happens to a cell during anaphase.

64. Sketch and label a cell during anaphase.

65. Describe everything that happens to a cell during telophase.

66. Sketch & label an animal cell during telophase.

67. Mitosis is division of the _______________________, while ________________________
is the division of the cytoplasm.

68. Define cytokinesis.

69. Describe how cytokinesis occurs in animal cells & include a drawing (figure 8-7, page 151)

70. The ____________________ pinches a dividing animal cell into two new cells by the action
of ______________________________.

71. How does the cell plate from during cytokinesis of a plant cell?

72. Sketch and label a plant cell during cytokinesis (figure 8-8, page 151)

73. How do the new cells formed after mitosis & cytokinesis compare in size & chromosome number to each other and the original cell that divided?

74. The original cell that divides is called the _______________________ cell, while the
two new cells are called ____________________ cells. (from lecture)

 

Section 8-3 Meiosis

 

75. What is meiosis?

76. What type of cell undergoes meiosis?

77. Meiosis produces ___________________ reproductive cells called ____________________.

78. Name the 2 human gametes & tell their chromosome number.

79. What is the chromosome number for humans?

80. The fusion of a _________________ and an _____________ produces a
________________ with 46 (2n) chromosome number.

81. Cells starting mitosis & meiosis begin with a ____________________ set of chromosomes.

82. How many times do cells divide during meiosis?

83. What are the stages of meiosis called?

84. Explain what happens during Meiosis I to each of these structures:
a. chromosomes?
b. spindle?
c. nucleus?
d. nucleolus?

85. What is synapsis & when does it occur?

86. What is a tetrad?

87. How are genes aligned on homologous chromosomes?

88. Explain what happens during crossing-over?

89. Sketch and color a picture of chromosomes during crossing-over. (Figure 8-10, page 154)

90. What type of material is exchanged during crossing-over?

91. Crossing over results in genetic _______________________________.

92. Draw a cell during anaphase I and explain what is occurring.

93. What is independent assortment & what result does it produce?

94. Name 2 things that occur during telophase I.

95. How many cells are formed at the end of Meiosis I & how many copies of chromosomes does each cell have?

96. Is DNA copied before Meiosis II?

97. How many cells form at the end of Meiosis II and how many chromosomes do they contain?

98. In humans, meiosis occurs in the ___________________ and in the __________________
producing cells called ________________________.

99. Define spermatogenesis & tell where it occurs.

100. Sketch spermatogenesis (Figure 8-12a, page 155).

101. What are spermatids & how many form from meiosis?

102. Define oogenesis & tell where it occurs.

103. Sketch oogenesis (Figure 8-12B, Page 155).

104. Mature egg cells are called ___________________.

105. Explain how only one egg cell is formed instead of four from meiosis.

106. What are the 3 other products of meiosis called?

107. Define asexual reproduction.

108. Name 2 types of asexual reproduction.

109. Name a type of asexual reproduction in unicellular organisms.

110. How do the offspring of asexual reproduction compare to their parents?

111. Define sexual reproduction.

112. How do offspring from sexual reproduction compare to their parents?

113. Is there ever a case in sexual reproduction where offspring can be genetically alike? Explain.

114. What is the evolutionary advantage of sexual reproduction?

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Campbell Problem 12

Molecular Genetics Problem 12
12. About 5% of individuals with Downs syndrome are the result of chromosomal translocation. In most of these cases, one copy of chromosome 21 becomes attached to chromosome 14. How does this translocation lead to children with Down syndrome?

 

The case of having a chromosomal fragment joining to a nonhomologous chromosome is called translocation.

Children who have Down’s Syndrome will either have an extra chromosome 21, thus having a total of 47 chromosomes, or about 5% receive a combined 14-21 chromosome combination. (Chromosome 21 links to #14).

In meiosis, the combined 14-21 chromosome will actually behave as a single chromosome. Should this mutated gamete join a normal one during fertilization there will be three chromosome 21’s in the resulting zygote.

 

 

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Campbell Problem 13

Molecular Genetics Problem 13
13. Assume genes A and B are linked and are 50 map units apart. An individual heterozygous at both loci is crossed with an individual who is homozygous recessive at both loci. (a) What percentage of the offspring will show phenotypes resulting from crossovers? (b) If you did not know genes A and B were linked, how would you interpret the results of this cross?

 

a) 50 % because when the loci are at opposite ends of a chromosome they behave as if they were on different chromosomes.

Beginning with 100% recombination results in 50% and 50%

The resulting cross gives results almost identical to a normal Mendelian dihybrid cross, which can be symbolized as follows:

expected genotypes
 recombinant genotypes

 

b) You would assume that these genes were on separate chromosomes since they appear to segregate independently even though they are linked.

 

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