Category: 1st Semester

Enzyme PowerPoint Worksheet

Enzymes
ppt Questions

Enzyme Structure & Function

1. Most enzymes are what type of macromolecule?

2. Most enzymes are ______________ or ______________ structures.

3. Enzymes act as ___________ in reactions.

4. Are enzymes permanently changed in the chemical reactions they are involved in?

5. Will an enzyme work on any substance? Explain.

 

6. Can enzymes be reused?

7. What ending is found on many enzymes?

8. Give 3 examples of enzymes with this ending.

 

9. How does an enzyme work?

 

10. What effect does an enzyme have on activation energy needed to start a reaction?

11. Hydrogen peroxide H2O2 is a common waste product of cells. Enzymes called catalases in cells break this down into harmless ________________.

12. What is meant by the term substrate?

 

13. What is meant by active site?

 

14. Sketch and label the enzyme-substrate complex.

 

 

15. What is meant by induced fit?

 

16. What induces an enzyme to change the shape of its active site?

17. List 4 factors that can affect enzyme activity.

 

18. What is the effect of high temperature on an enzyme (running fever)?

 

19. What temperature do most enzymes do best at?

20. Most enzymes like a pH near ______________.

21. To denature an enzyme means the enzyme becomes _______________ and can no longer work properly.

22. Name 3 inorganic substances (cofactors) that are often needed for enzymes to work properly.

 

23. Give an example of an enzyme & its needed inorganic substance.

 

24. Give one example of an enzyme inhibitor.

25. Explain how competitive inhibitors work.

 

 

26. If a competitive inhibitor blocks the active site, the ____________ can’t fit.

27. Explain noncompetitive inhibitors. 

 

 

28. Do noncompetitive inhibitors bind to the active site? Explain.

 

 

Extracting DNA

 

Extract DNA from Anything Living

 

Introduction:

Since DNA is the blueprint for life, everything living contains DNA. DNA isolation is one of the most basic and essential techniques in the study of DNA. The extraction of DNA from cells and its purification are of primary importance to the field of biotechnology and forensics. Extraction and purification of DNA are the first steps in the analysis and manipulation of DNA that allow scientists to detect genetic disorders, produce DNA fingerprints of individuals, and even create genetically engineered organisms that can produce beneficial products such as insulin, antibiotics, and hormones.

DNA can be extracted from many types of cells. The first step is to lyse or break open the cell. This can be done by grinding a piece of tissue in a blender. After the cells have broken open, a salt solution such as NaCl and a detergent solution containing the compound SDS (sodiumdodecyl sulfate) is added. These solutions break down and emulsify the fat & proteins that make up a cell membrane. Finally, ethanol is added because DNA is soluble in water. The alcohol causes DNA to precipitate, or settle out of the solution, leaving behind all the cellular components that aren’t soluble in alcohol. The DNA can be spooled (wound) on a stirring rod and pulled from the solution at this point.

 

Just follow these 3 easy steps:

Detergent, eNzymes (meat tenderizer), Alcohol

 

 

Objective:

To extract DNA from cells.

Materials:

Blender, split peas, salt, detergent, water, measuring cup and spoons, strainer, meat tenderizer, alcohol, test tube, glass stirring rod

Procedure:

  1. First, you need to find something that contains DNA such as split peas, fresh spinach, chicken liver, onion, or broccoli.

  1. Measure about 100 ml or 1/2 cup of split peas and place them in a blender.
  2. Add a large pinch of salt (less than 1 ml or about 1/8 teaspoon) to the blender.
  3. Add about twice as much cold water as the DNA source (about 200 ml or 1 cup) to the peas in the blender.
  4. Blend on high (lid on) for about 15 seconds.

  1. The blender separates the pea cells from each other, so you now have a really thin pea-cell soup.

And now, those 3 easy steps:

  1. Pour your thin pea-cell soup through a strainer into another container like a measuring cup or beaker.

  1. Estimate how much pea soup  you have and add about 1/6 of that amount of liquid detergent (about 30ml or 2 tablespoons). Swirl to mix.

  1. Let the mixture sit for 5-10 minutes.


The detergent captures the proteins & lipids of the cell membrane.

  1. Pour the mixture into test tubes or other small glass containers, each about 1/3 full.
  2. Add a pinch of enzymes to each test tube and stir gently. Be careful! If you stir too hard, you’ll break up the DNA, making it harder to see. (Use meat tenderizer for enzymes. If you can’t find tenderizer, try using pineapple juice or contact lens cleaning solution.)


The DNA in the nucleus of the cell is molded, folded, and protected by proteins. The meat tenderizer cuts the proteins away from the DNA.

  1. Tilt your test tube and slowly pour rubbing alcohol (70-95% isopropyl or ethyl alcohol) into the tube down the side so that it forms a layer on top of the pea mixture. Pour until you have about the same amount of alcohol in the tube as pea mixture.

  1. Alcohol is less dense than water, so it floats on top forming two separate layers.
  2. All of the grease and the protein that we broke up in the first two steps move to the bottom, watery layer.
  3. DNA will rise into the alcohol layer from the pea layer. You can use a glass stirring rod or a wooden stick to draw the DNA into the alcohol.
  4. Slowly turning the stirring rod will spool (wrap) the DNA around the rod so it can be removed from the liquid.

Questions:

1. Does the DNA have any color?

2. Describe the appearance of the DNA.

3. Do only living things contain DNA? Explain.

Frequently Asked Questions: 1. I’m pretty sure I’m not seeing DNA. What did I do wrong?

First, check one more time for DNA. Look very closely at the alcohol layer for tiny bubbles. Often, clumps of DNA are loosely attached to the bubbles.

If you are sure you don’t see DNA, then the next step is to make sure that you started with enough DNA in the first place. Many food sources of DNA, such as grapes, also contain a lot of water. If the blended cell soup is too watery, there won’t be enough DNA to see. To fix this, go back to the first step and add less water. The cell soup should be opaque, meaning that you can’t see through it. Another possible reason for not seeing any DNA is not allowing enough time for each step to complete. Make sure to stir in the detergent for at least five minutes. If the cell and nuclear membranes are still intact, the DNA will be stuck in the bottom layer. Often, if you let the test tube of pea mixture and alcohol sit for 30-60 minutes, DNA will precipitate into the alcohol layer.

2. Why does the DNA clump together?

Single molecules of DNA are long and stringy. Each cell of your body contains six feet of DNA, but it’s only one-millionth of an inch wide. To fit all of this DNA into your cells, it needs to be packed efficiently. To solve this problem, DNA twists tightly and clumps together inside cells. Even when you extract DNA from cells, it still clumps together, though not as much as it would inside the cell.

Imagine this: the human body contains about 100 trillion cells, each of which contains six feet of DNA. If you do the math, you’ll find that our bodies contain more than a billion miles of DNA!

3. Can I use this DNA as a sample for gel electrophoresis?

Yes, but all you will see is a smear. The DNA you have extracted is genomic, meaning that you have the entire collection of DNA from each cell. Unless you cut the DNA with restriction enzymes, it is too long and stringy to move through the pores of the gel; instead, all you will end up seeing is a smear.

4. Isn’t the white, stringy stuff actually a mix of DNA and RNA?

That’s exactly right! The procedure for DNA extraction is really a procedure for nucleic acid extraction. However, much of the RNA is cut by ribonucleases (enzymes that cut RNA) that are released when the cells are broken open.

 

Fermentation Rootbeer

 

FERMENTATION – MAKING ROOT BEER
David Fankhauser’s Main Page

 

Introduction:

Fermentation has been used by mankind for thousands of years for raising bread, fermenting wine and brewing beer. The products of the fermentation of sugar by baker’s yeast Saccharomyces cerevisiae (a fungus) are ethyl alcohol and carbon dioxide. Carbon dioxide causes bread to rise and gives effervescent drinks their bubbles. This action of yeast on sugar is used to ‘carbonate’ beverages, as in the addition of bubbles to champagne).

We will set up a fermentation in a closed system and capture the generated carbon dioxide to carbonate root beer. You may of course adjust the quantities of sugar and/or extract  (Zatarain’s) to taste. 

EQUIPMENT
SUPPLIES
  • clean 2 liter plastic soft drink bottle with cap
  • funnel
  • 1 cup measuring cup
  • 1/4 tsp measuring spoon
  • 1 Tbl measuring spoon
  • Cane (table) sugar [sucrose] (1 cup)
  • Zatarain’s Root Beer Extract (1 tablespoon)
  • (When I could not find it locally, I ordered a case of 12 bottles for $18 from Zatarain’s, New Orleans, LA 70114
  • powdered baker’s yeast (1/4 teaspoon)  (Yeast for brewing would certainly work at least as well as baking yeast.)
  • cold fresh water

 

 

INSTRUCTIONS:

1) Assemble the necessary equipment and supplies
2) With a dry funnel, add in sequence:

1 level cup of table sugar (cane sugar) (You can adjust the amount to achieve the desired sweetness.)
3) Add: 1/4 teaspoon powdered baker’s yeast ( fresh and active)

(Fleischmann’s or other brand)
4) You can see the yeast granules on top of the sugar.
5) Shake to distribute the yeast grains into the sugar.
6) Swirl the sugar/yeast mixture in the bottom to make it concave (to catch the extract).
7) Add with funnel:

1 Tbl of root beer extract (I prefer Zatarain’s, but Hires, etc. will work.)

on top of the dry sugar
8) The extract sticks to the sugar which will help dissolve the extract in the next steps.
9) Half fill the bottle with fresh cool tap water (the less chlorine, the better).

Rinse in the extract which sticks to the tablespoon and funnel. Swirl to dissolve the ingredients.
10) Q.s. [fill up] to the neck of the bottle with fresh cool tap water, leaving about an inch of head space, securely screw cap down to seal. Invert repeatedly to thoroughly dissolve.

If you leave it in a warm temperature longer than two weeks, you risk an explosion…

11) Place at room temperature about three to four days until the bottle feels hard to a forceful squeeze. Move to a cool place (below 65 F). refrigerate overnight to thoroughly chill before serving. Crack the lid of the thoroughly chilled root beer just a little to release the pressure slowly.

NOTE: Do not leave the finished root beer in a warm place once the bottle feels hard. After a couple weeks or so at room temperature, especially in the summer when the temperature is high, enough pressure may build up to explode the bottle! There is no danger of this if the finished root beer is refrigerated.
12) Move to a refrigerator overnight before opening.

 

NOTE: There will be a sediment of yeast at the bottom of the bottle, so that the last bit of root beer will be turbid. Decant carefully if you wish to avoid this sediment.

A WORD ABOUT THE ALCOHOL IN HOME MADE ROOT BEER: The alcoholic content which results from the fermentation of this root beer and found it to be between 0.35 and 0.5 %. Comparing this to the 6% in many beers, it would require a person to drink about a gallon and a half of this root beer to be equivalent to one 12 ounce beer. I would call this amount of alcohol negligible, but for persons with metabolic problems who cannot metabolize alcohol properly, or religious prohibition against any alcohol,  consumption should be limited or avoided.

 

Food Chemistry

 

Food Chemistry

Introduction:

All living things are made up of one or more cells, and the cells in turn contain many kinds of molecules.  In this lab we will be looking at several different macromolecules (large molecules): proteins, carbohydrates, and lipids (specifically fats).  Various chemicals will be used in this laboratory to test for the presence of these molecules.  Most often, you will be looking for a particular color change.  If the change is observed, the test is said to be positive because it indicates that a particular molecule is present.  If the color change is not observed, the test is said to be negative because it indicates that a particular molecule is not present.

You will be using these tests to determine which of the macromolecules are present in various samples of food.

In all of the procedures, you will need to include a distilled water sample as a control.  Usually, a control goes through all the steps of the experiment but lacks one essential factor (the experimental variable).  This missing factor allows you to observe the difference between a positive result and a negative result.  If the control sample tests positive, you know your test is invalid.  Some tests may also contain other controls to make sure certain additives are not contaminated with the substance for which you are testing.

Proteins:

Protein molecules are long chains of amino acids joined by peptide bonds.

Biuret reagent, which is a blue color, contains a strong solution of sodium or potassium hydroxide (NaOH or KOH) and a very small amount of very dilute copper sulfate (CuSO4) solution.  The reagent changes color in the presence of proteins or peptides because the amino group (H2N-) of the protein or peptide chemically combines with the copper ions in biuret reagent.

Carbohydrates:

Carbohydrates include sugars and molecules that are chains of sugars.  Glucose is a simple sugar, also known as a monosaccharide.  Sucrose, or table sugar is a disaccharide, two sugar units bonded together.  Starch is a polysaccharide, a long chain of glucose units.

Benedict’s reagent reacts with many sugars (both mono- and disaccharides) after being heated in a boiling water bath.  Increasing concentrations of sugar give a continuum of colored products ranging from green through yellow and orange to orange red.

Iodine solution reacts with starch to produce colors ranging from a brownish to blue black.

Lipids:

Lipids are hydrophobic molecules which are insoluble in water and soluble in solvents such as alcohol and ether.  Lipids include fats, oils, and cholesterol.

Lipids do not evaporate from brown paper, instead leaving an oily spot.  Lipids also do not mix with water, forming a separate layer, usually on top of the water.  However, some molecules mix with both water and lipids, and can be used to mix the two.  These molecules are known as emulsifiers.  The liver produces bile salts which act as emulsifiers in the digestive tract.  Soaps and detergents also act as emulsifiers.

Summary of tests:

 

Biuret Reagent
Benedict’s Reagent
Iodine Solution
Brown Paper
Reacts with proteins or peptides, turns purple (protein) or pink (peptides) Reacts with sugars, turns green through yellow to orange (green, less sugar, orange, more sugar) Reacts with starch, turns dark brown to black Lipids leave oily spot

Procedure:

Take some time to plan with your lab partner what tests you will do, and in what order before beginning the procedures.

There are available in the lab a variety of different types of common food.  Choose at least 3 foods and test each for the presence of protein, carbohydrate (both starch and simple sugars), and fats.  Be sure to plan your experiments before starting.

Form a hypothesis for each sample you have chosen to test.

Samples will need to be suspended in water for most tests.  Using a mortar and pestle if necessary, break each sample to be tested into small pieces and suspend the pieces in a small amount of distilled water.

Also available are samples of each of the types of molecules for which you will be testing.  Use these samples to try out the tests so that you will know what a positive result looks like.

Be sure to include a blank control (distilled water) with each test so you know what a negative result looks like.  You may also include a positive control, a sample which you know contains the substance for which you are testing.

The procedures for testing for each type of molecule are given below.

Proteins and Peptides

Proteins:

  1. Use a separate test tube for each sample to be tested, as well as one for a control.
  2. Label each test tube.
  3. Place about 1 mL of each sample (and control) in its test tube.
  4. Add 5 drops of copper sulfate solution to each tube.
  5. Add 10 drops of potassium hydroxide solution to each tube and mix.
  6. Record the tube contents and final color in a data table.
  7. Conclusions: which tubes contained protein?

Carbohydrates: Sugars and starch

Starch

  1. Use a separate test tube for each sample to be tested, as well as one (or two) for a control.
  2. Label each test tube.
  3. Place about 1 mL of each sample (and control) in its test tube.
  4. Add 5 drops of iodine solution to each tube and mix.
  5. Record the tube contents and final color in a data table.
  6. Conclusions: which tubes contained starch?

Sugar

  1. Use a separate test tube for each sample to be tested, as well as one (or two) for a control.
  2. Label each test tube.
  3. Place about 1 mL of each sample (and control) in its test tube.
  4. Add about 2 mL of Benedict’s reagent to each tube and mix.
  5. Heat the tubes in a boiling water bath for 5-10 minutes.
  6. Record the tube contents and final color in a data table.
  7. Conclusions: which tubes contained sugar?

Lipids

  1. Place a small sample of the material to be tested on a square of brown paper.
  2. Place a small drop of water on the square of brown paper.
  3. Compare the drop of water to the sample.
  4. Wait at least 5 minutes.  Evaluate which substance impregnates the paper and which is subject to evaporation.  Record your results.
  5. Conclusions: which sample contained lipids?

Conclusion Questions:

  1. Why do experimental procedures include control samples?
  2. How would you test an unknown solution for each of the following:
    1. Sugars
    2. Fat
    3. Starch
    4. Protein
  3. Assume that you have tested an unknown sample with both biuret solution and Benedict’s solution and that both tests result in a blue color.  What have you learned?
  4. What purpose is served when a test is done using water instead of a sample substance?
  5. Compare your results.

Lab report:

Lab reports must include the following:

  1. A Title to the lab.  A Purpose: What was studied in this lab, and why did we study it?
  2. Procedure: a brief description of each type of test, what constitutes a positive test and what constitutes a negative test.
  3. All data tables.
  4. For each food sample, state your hypothesis and your conclusions.  Did your results confirm or refute your hypothesis?
  5. Answers to questions.
  6. A brief analysis of what worked in this lab and what didn’t work, and why.

 

Ecology Worksheet Bi

 

Ecology

 

 

Chapter 19 Ecology

 

1. What is ecology?

2.. What is the most significant environmental change that is taking place today?

3. What is the sixth mass extinction?

4. What is the ozone layer, what does it do for earth, & what is happening to this layer & why?

5. Explain the green house effect.

6. List in order the ecological levels of organization.

7. What is the biosphere, tell where it extends, & tell why it is so important?

8. Define ecosystems & give an example.

9. What is a community?

10. What is a population?

11. What is the simplest ecological level of organization?

12. Use figure 19-6 on page 364 & explain how Lyme disease affects organisms in an ecosystem.

13. What are biotic factors & list them?

14. What are abiotic factors & list them?

15. Are abiotic factors constant? Explain by giving an example.

16.Organisms are able to survive within a _____________ range of environmental conditions.

17. Graphing the range of conditions an organism can survive is called a __________________ Curve.

18.When organisms adjust their tolerance to abiotic factors, the process is called ___________.

19. Explain how dormancy & migration help organisms escape unsuitable environmental conditions.

20. Define niche

Chapter 20 Populations

21. What is meant by population size?

22. What is meant by population density?

23. Name the 4 processes that determine whether a population will grow, shrink, or remain the same size.

24. What are immigration & emigration & how do they affect population size?

25. What are limiting factors & give some examples?

26. What affect does inbreeding have on small populations?

Chapter 21 Community Ecology

27. Interactions among species are called ____________.

28. List the 5 types of symbioses.

29. Define predator & prey & give an example.

30. What is mimicry & give an example?

31. Define these terms — parasitism, parasite, host, ectoparasites, & endoparasites.

32. When niches overlap, _________________________ results so more than one species are using the limited resources.

33. What are mutualism & commensalism?

34. Define succession.

35. Name & describe the 2 types of succession.

36. What are pioneer species & why are they important?

37. What is a climax community?

Chapter 22 Ecosystems

38. What are producers & what is another name they may be called?

39. What is biomass, why is it important, how does it accumulate, & what is its rate of accumulation called?

40. What is gross primary productivity?

41. All heterotrophs would be ______________________.

42. Define & give an example of each of these consumers — herbivore, carnivore, omnivore, detritivores, & decomposer.

43. Whenever one organism eats another, ________________ is transferred.

44. What are trophic levels?

45. All _______________ belong to the first trophic level, _______________ belong to the
Second trophic level, and the _______________ of herbivores belong to the third trophic level.

46. How many trophic levels do most ecosystems contain?

47. What is a food chain & what always begins the chain?

48. Write an example of a food chain.

49. What is a food web?

50. Draw a diagram of a food web that has at least 4 food chains.

51. Approximately __________ percent of the total energy consumed at one trophic level is incorporated into the organisms in the next level.

52. In terms of energy passage, why will there be many more producers than herbivores and fewer large carnivores than small carnivores?

53. What are biogeochemical cycles, why are they important, & name three?

54. Draw & explain the water cycle. Be sure to color your diagram!

55. List & define the 3 important processes in the water cycle.

56. What is groundwater?

57. What 2 processes form the basis for the carbon cycle?

58. Draw & explain the carbon cycle. Be sure to color your diagram!

59. What purpose do decomposers have in the carbon cycle?

60. Why do organisms need nitrogen?

61. Draw & explain the nitrogen cycle. Be sure to color your diagram!

62. Organisms such as ________________ convert _________________ gas into compounds
Called __________________ during the process known as________________________.

63. Bodies of dead organisms contain mainly in _________________ & _________________.

64. Wastes such as __________________ & _______________ also contain nitrogen that must be recycled.

65. ________________ recycle nitrogen from dead organisms & wastes by changing it into
______________________. The process is called ________________________.

66. Explain nitrification & denitrification.

67. Plants can absorb ____________________ from the soil, but animals obtain nitrogen from
their ___________________.

68. Define biome.

69. List the 7 major biomes.

70. Why don’t mountains belong to any one biome?

71. What is a tundra, where are they found, & tell organisms that would be found tree?

72. What is permafrost & how does it control plant life in the tundra?

73. What are taigas, where would they be found, & what type of vegetation dominates this area?

74. Plants & animals in the taiga must be adapted for long __________________, short
_________________, & ________________________ soil.

75. List some typical animals of the taiga.

76. What characterizes a temperate deciduous forest?

77. Deciduous forests have 4 pronounced ____________________ with _________________
summers, _______________________ winters, and__________________________ than the
taiga.

78. Grasses dominate what biome?

79. Why aren’t there more trees on grassland?

80. What are grasslands called in each of these areas —– North America, Asia, South America, & southern Africa?

81. Describe the soil of grasslands. Because of the soil condition, how is much of the grassland used?

82.What type of animals would be found on grassland?

83. What periodically occurs across grasslands & why doesn’t it kill the grasses?

84. Approximately how much rainfall do deserts receive each year?

85. Are deserts always hot? Explain.

86. What adaptation must desert vegetation make to survive?

87. What types of adaptations must desert animals make to conserve water?

88. What are savannas & where are the best known savannas found?

89. Describe temperature & rainfall on savannas?

90. Name some herbivores & carnivores found on a savanna.

91. Describe the rainy season on a savanna & tell what special problem this poses for the animals & plants there?

92. What are tropical rain forests & where are they located?

93. Rain forests have stable, year-round ______________________ & abundant ____________.

94. Plants in the rainforest must constantly compete for what?

95. Explain the canopy & epiphytes in a rainforest.

96. Describe the plant & animal life in a rainforest.

97. Tropical rainforests are more commonly called _____________________.

98.Oceans cover what percent of the earth’s surface?

99. Draw, label, & color the zones found in the ocean (see figure 22-16). Define each term labeled on your drawing.

100. What are intertidal organisms exposed to & name some intertidal organisms.

101. Which zone in the ocean is the most productive & why?

102. What small organisms are found in the neritic zone & why are they important?

103. In tropical areas, what forms in the neritic zone & why are they important?

104. Which ocean zone has fewer species & why?

105. Where does most of the earth’s photosynthesis take place?

106. Animals in the aphotic zone feed on what?

107. Organisms living deep in the ocean must cope with what 2 problems? Give some examples of deep ocean animals & explain how they adapt to their environmental problems.

108. What are volcanic vents, when were they discovered, & describe the organisms found there?

109. What are estuaries & what special problem do estuary organisms face?

110. What characterizes freshwater zones & give several examples?

111. Name & describe the 2 categories into which ecologists divide lakes 7 ponds?

112. Define a river & describe organisms found there?

Chapter 23 Environmental Science

113. Where do upwellings occur & how are they helpful?

114. Describe the event known as El Nino & tell its effect.

115. Describe chlorofluorocarbons effect on the ozone layer & tell why we should be concerned?

116. Define biodiversity.

117. Define conservation biology & use migratory birds to explain an example of this new discipline?

118. Sometimes species are reintroduced into areas. Use the Gray wolf & describe its reintroduction in the United States.

119. Where are the Everglades located & what is being done to restore them?

BACK