Category: 1st Semester
Food Testing
| Chemical Tests for Nutrients in Food |  |
INTRODUCTION:
Cells are made up of small molecules like water; ions such as sodium and magnesium, and large organic molecules. There are four important types of large organic molecule in living organisms — proteins, carbohydrates (sugars & starches), lipids (fats), and nucleic acids. Proteins, carbohydrates, and fats serve as nutrients in the food that we eat.
In this experiment you will evaluate the nutrient content of unidentified food samples. You will use chemical reagents to test the unknown for specific nutrients. By comparing the color change a reagent produces in the unknown with the change it produces in the known nutrient, you can estimate the amount of that nutrient. Use small samples.
MATERIALS:
400-ml beaker
Hot plate
8 test tubes
Test tube rack
4 medicine droppers
Glass stirring rod
Tongs
Several unknown food substances
Glucose
Cornstarch
Non-fat dry milk
Lard
Distilled water
Benedict’s solution
Iodine-potassium iodide solution
10% aqueous sodium hydroxide solution
0.5% Copper sulfate solution
Sudan III solution
PROCEDURE:
Monosaccharide (simple sugar) test
1. Fill a 400-ml beaker to about 300 ml with water and heat on the hot plate.
Be sure to label all test tubes.
2. Place pea-sized portions of glucose and the unknown substance you are testing in separate test tubes. Add about 2.5 ml of distilled water and 10 drops of Benedict’s solution to each test tube. Mix with a stirring rod, or holding the tube between the thumb and index finger of one hand, thump it with the middle finger of the other hand to mix.
REMEMBER: If you use a stirring rod, wash it after every use, so you won’t contaminate one solution with another.
3. When the water boils, use tongs to place the test tubes in the water bath. Leave the test tubes in the water bath for 10 minutes.
Do not let the water bath boil hard. Control the boiling by turning the hot plate on and off as needed.
4. Remove the test tubes with tongs and place the tubes in a test tube rack. Unplug the hot plate to cool. When the tubes cool, an orange or red precipitate will form if large amounts of glucose are present. Small amounts of glucose will form a yellow or green precipitate. Record your observations in the DATA TABLE.
Polysaccharide complex sugar) test
5. Place cornstarch in a clean test tube and some of the unknown substance in another. Use a clean dropper to add 10 drops of iodine-potassium iodide solution to each test tube. Observe the results and record in the DATA TABLE.
Protein test
6. Place non-fat dry milk in a clean test tube and some of the unknown in another. With a clean dropper slowly add an amount of sodium hydroxide solution about equal to the amount of the milk sample, and mix carefully. Then add 10 drops of copper sulfate solution one drop at a time. Mix gently between drops. Observe the results and record in the DATA TABLE.
7. Repeat step 6 with the unknown substance.
Lipid test
8. Place a small piece of lard in a clean test tube and some of the unknown in another. Use a clean dropper to add 10 drops of Sudan III solution to each test tube. Mix well, observe and record your results in the DATA TABLE.
DATA TABLE:
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Mark your results in the appropriate boxes. Indicate relative amount by H for high, M for medium, L for low, or 0 for none. |
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| Monosaccharide test | Polysaccharide test | |||
|---|---|---|---|---|
| SUBSTANCE: | RELATIVE AMOUNT: |
SUBSTANCE: | RELATIVE AMOUNT: |
|
| Unknown | Unknown | |||
| Glucose | Corn starch | |||
|
|
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| Protein test | Lipid test | |||
| SUBSTANCE: | RELATIVE AMOUNT: |
SUBSTANCE: | RELATIVE AMOUNT: |
|
| Unknown | Unknown | |||
| Non-fat dry milk | Lard | |||
CONCLUSIONS:
Question 1 . What is the main nutrient in the unknown?
Question 2. What are the controls in this investigation?
Evolution & Phylogeny AP Study Guide
| Unit 6 Evolution & Phylogeny Study Guide | |
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Evolution Answers
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Evolution Answers |
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- In biological terms, what is a species? a group of organisms that are similar in form and structure
a group of organisms that can interbreed
a group of organisms that share common features
a group of organisms that have live in the same habitat - What is the Scala Naturae? an idea proposed by Darwin that suggests that all organisms share a common ancestor
an idea proposed by Plato that suggests organisms are all evolving toward an ideal form
an idea proposed by Aristotle that suggests that all organisms fit into an orderly scheme
an idea proposed by Wallace that suggests that organisms change over time - Creationism is not accepted as a valid scientific theory because: it violates the scientific principle of natural causality
it doesn’t offer a model to explain the diversity of life on earth
it cannot be disproven
all of these
- In biological terms, what is a species? a group of organisms that are similar in form and structure
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- The picture of the finches is used to illustrate: phylogeny of finches
change over time
specialization of beaks for different diets
natural selection - Which of the following was not an observation made by Darwin on his voyages: penguins use wings to paddle instead of fly
snakes have rudimentary hind limbs
the earth is very old
islands had species that did not exist on the mainland
- The picture of the finches is used to illustrate: phylogeny of finches
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- The image illustrates: vestigial structures
homologous structures
the fossil record
natural selection - Which of the following is an example of artificial selection: a panda’s thumb
the breeding of dogs
the galapagos finches
a giraffe’s neck - According to the theory of evolution by natural selection, which of the following is true: random mating is necessary for evolution to occur
variation does not exist between members of the same species
populations will change to better fit their environment
individuals will adapt to their environment - Which of the following are assumptions made with regards to the Theory of Evolution by Natural selection organisms compete with each other to survive
variations exist among organisms
not all organisms that are born survive to reproduce
all of these
- The image illustrates: vestigial structures
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- The image illustrates which of the following: artificial selection
acquired characteristics
homologous structures
vestigial structures - A panda’s thumb is considered an evolutionary contrivance because: it is assembled from wrist bones, and imperfect
it is perfectly structured to grab leaves
it is an structure that has no use
none of these - Which of the following outcomes would you predict for a population of bacteria exposed to a new antibiotic. over many generations, the bacteria would become resistant to the antibiotic
over a few generations, the bacteria would evolve into Archaebacteria
over a few generations, the bacteria would become extinct
over many generations, the bacteria would become more susceptible to the antibiotic - Which of the following is an example of convergent evolution: whales and sharks have similar body designs
bees and hummingbirds have similar body designs
bats and birds have similar body designs
all of these - Why is evolution called the “unifying theory of biology” because it explains the diversity of life on the planet
because it serves as a model to predict how organisms will change
it serves as a model to interpret relationships between organisms on the planet
all of these
- The image illustrates which of the following: artificial selection
- The image illustrates how peppered moths are related to other moths
how peppered moths adapted to a changing environment
how peppered moths became extinct
how peppered moths became two species
Evolution BI Worksheet
| EVOLUTION |  |
Section 14-1 Biogenesis
1. Define biogenesis.
2. What is spontaneous generation & give an example. Can spontaneous generation occur?
3. Describe Redi’s experiment and its results.
4. Describe Spallanzani’s experiment and its results.
5. Did Redi & Spallanzani’s experiments disprove spontaneous generation? Explain.
6. Describe Pasteur’s experiment and its results. Did it prove or disprove spontaneous generation?
Section 14-2 Earth’s History
7. What is the estimated age of the earth?
8. a. What is radioactive dating, and how is it used to tell the age of materials?
b. Use a science dictionary to look up and explain relative dating of fossils.
9. What is meant by half-life?
10. Name 3 radioactive isotopes and give their half-life.
11. a. What 2 scientists set up an experiment that simulated the atmosphere of early earth?
b. What molecules were made during this experiment?
Section 14-3 The First Life Forms
12. Why was there no oxygen in the early atmosphere?
13. Were the 1st cells probably aerobic or anaerobic? Why?
14. What gases did the early atmosphere contain primarily?
15. What bacteria live in harsh environments containing methane gas?
16. Oxygen didn’t become part of our atmosphere until what process started taking place?
Section 15-1 Fossil Record
17. What is a fossil?
18. In what type of rock are fossils usually found?
19. What is sedimentary rock?
20. From what part or parts of organisms do sedimentary fossils usually form?
21. How do sedimentary fossils form?
22. How do casts form?
23. What do you call imprint fossils?
24. Complete insect fossils can be found inside of a clear, golden material called ________________.
25. Who was one of the first scientists to study fossils?
26. In which rock layer or strata would the oldest fossils be found? The newest fossils?
27. Name the 4 eras of earth’s history in order beginning with the oldest & going to present day.
28. Which organisms appeared first in earth’s history?
29. Name the period in which each of these events occurred:
a. Humans appeared?
b. Mass extinction of dinosaurs?
c. Land plants appeared?
d. Birds appeared?
e. Fish appeared?
f. Reptiles appeared?
g. Modern mammals appeared?
30. What is true about fossils in the same rock layer or strata?
31. a. What is meant by mass extinction and give an example?
b. Has there been more than one mass extinction in earth’s history? Explain.
32. Radioactive isotopes are used to determine the ___________________ age of fossils.
Section 15-2 Theories of Evolution
33. What was Lamarck’s hypothesis about how species change?
34. What is meant by acquired trait?
35. What did Lamarck think had caused the webbed feet of water birds?
36. How did Lamarck think the offspring of these web-footed birds got their web-feet?
37. Can traits be passed in this way? Explain why or why not.
38. Was Lamarck’s idea of acquired traits proven or rejected?
39. Charles Darwin’s idea of how species change over time is called what?
40. Explain natural selection.
41. What other scientist came up with this same idea about evolution?
42. What was the name of the book that Darwin published with his ideas about evolution?
43. Explain how Darwin obtained all of his records & supporting evidence that led him to his theory of natural selection.
44. Describe the voyage of the H.M.S. Beagle.
45. What book did Darwin read that influenced his ideas when he sailed on the Beagle? Who was the author?
46. What unusual information did Darwin collect about the Galapagos finches on his voyage?
47. What forced Darwin to move ahead and publish his ideas?
48. State the 2 theories that sum up Darwin’s ideas about evolution & natural selection.
49. State Darwin’s Descent with Modification theory.
50. Darwin’s theory stated that all the Galapagos finches had descended from what?
51. State Darwin’s Modification by Natural Selection theory.
52. What idea, published in a book by Thomas Malthus, did Charles Darwin use?
53. According to Darwin, what limits the growth of populations?
54. How do populations of organisms adapt to their environment?
55. What is meant by the fitness of an organism?
Section 15-3 Evolution in Process
56. What are homologous structures and give an example?
57. What are analogous structures & give an example?
58. Which structures, homologous or analogous, show that organisms are more closely related?
59. What are vestigial structures & give an example?
60. Vestigial structures show __________________________ ancestry.
61. In the early stages, how do all vertebrate embryos compare with each other? What does this indicate?
62. Organisms with homologous (similar) _________________ & __________________ acids are probably more closely related.
63. What is co-evolution & give 2 examples of organisms that co-evolve?
64. Are a shark and a porpoise closely related? Explain your answer.
65. When does convergent evolution occur?
66. What is divergent evolution?
67. Divergent evolution usually results in new ________________________.
68. What is adaptive radiation & give an example?
69. How can adaptive radiation be sped up & give an example?
Section 16-1 Genetic Equilibrium
70. Do populations change quickly or slowly?
71. What is the study of evolution using genetics called?
72. Do individuals evolve?
73. Do populations evolve?
74. Variations in traits may be due to ___________________ factors or __________________.
75. Name the 3 ways variations in genotypes arise.
76. What is meant by the gene pool?
77. How many alleles exist for each trait in a gene pool?
78. How is allele frequency determined?
79. Determine the frequency of each allele in the following genotypes:
a. AA?
b. Aa?
c. aa?
80. How is phenotypic ratio determined?
81. What is the phenotypic frequency of white, pink, & red four-o-clocks in these crosses?
a. RR x rr ?
b. Rr x Rr ?
c. Rr x rr ?
82. The frequency of alleles or phenotypes in a cross must always add up to ______________.
83. What does the Hardy-Weinberg theory state about allele frequencies in a population?
84. List the 5 conditions that must hold true in the ideal population for Hardy-Weinberg to be correct.
85. Would the Hardy-Weinberg law apply to real populations?
Section 16-2 Disruption of Genetic Equilibrium
86. What effect does evolution have on a population’s genetic material?
87. Does evolution affect allele frequencies?
88. Any violations of the 5 conditions necessary for Hardy-Weinberg can result in _____________.
89. A change in genetic material is known as a _______________________.
90. Mutations occur constantly at _______________ rates unless an organism is exposed to ___________.
91. Most mutations are __________________, but some may be _____________________ & help the population evolve & survive.
92. Compare & contrast population immigration & emigration.
93. What is gene flow & give an example?
94. Does the Hardy-Weinberg law apply to small and medium sized populations?
95. What is genetic drift?
96. In what size populations does genetic drift apply & explain why?
97. Do all populations mate randomly? Explain.
98. What is the effect of matings of related individuals?
99. What is the most significant factor that affects genetic equilibrium?
100. Name the 4 types of natural selection & explain each.
a.
b.
c,
d.
101. Give an example of stabilizing selection using body size of lizards.
102. Give an example of directional selection using tongue length of anteaters.
103. Give an example of disruptive selection using limpets.
104. Explain the following — “genes of successful reproducers, rather than those of successful survivors, are amplified through natural selection.”
Section 16-3 Formation of Species
105. Do new species ever form? Do old species ever disappear? Explain your answer.
106. Define speciation.
107. Are all new species similar to their ancestral species? Explain.
108. What did scientists use for many years to help classify organisms?
109. What is morphology?
110. What are some limitations of using only morphology to identify organisms?
111. What is the biological species concept?
112. Does this concept help identify extinct species & why?
113. Members of a species are _________________similar & can __________________ to produce _____________________ offspring.
114. What does speciation begin with & does it affect mating?
115. Name 2 important types of isolation.
a.
b.
116. Define geographic isolation.
117. Give an example of how this type of isolation could occur.
118. What happens to the 2 subgroups after being geographically isolated from each other?
119. Define reproductive isolation.
120. Name & describe the 2 types of reproductive isolations.
a.
b.
121. Not recognizing mating calls or having different breeding times are examples of what type of isolation?
122. An infertile mule produced when a donkey and a horse mate is an example of ______________________ isolation.
123. Speciation often requires ______________________ of years.
124. Can some species form more quickly than others? Explain.
125. Does fossil record support a slow, gradual or more “instant” change in species?
126. A more “instant” formation or change occurs in ___________________, not millions of years.
127. What is this type of quicker species formation called?
128. What does punctuated equilibrium mean?