Resources 55 - BIOLOGY JUNCTION

Chlorophyll Fluorescence

Chlorophyll Fluorescence

INTRODUCTION

When a pigment absorbs light, electrons of certain atoms in the pigment molecules are boosted to a higher energy level. The energy of an absorbed photon is converted to the potential energy of the electron that has been raised to an excited state. In most pigments, the excited electron drops back to its ground-state, or normal orbit, and releases the excess energy as heat. Some pigments, including chlorophyll, emit light as well as heat after absorbing photons.
In the chloroplast, these excited electrons jump from the chlorophyll molecule to a protein molecule in the thylakoid membrane, and are replaced by electrons from the splitting of water. The energy thus transferred, is used in carbohydrate production.
This release of light is called fluorescence. Chlorophyll will fluoresce in the red part of the spectrum, and also give off heat. In this lab, you will observe this fluorescence by separating the chlorophyll from the thylakoid membrane.

MATERIALS

Spinach leaves	Flashlight or small lab light
Mortar and pestle	Test tube
Acetone	Filter paper
25-mL graduated cylinder	Funnel
Ring stand or funnel rack	Safety goggles

PROCEDURE

1. Grind the spinach leaves using a mortar and pestle.

2. Add acetone to the ground leaves, using enough acetone and spinach leaves to get between 10 and 15 mL of extract.

3. Set up your filtering apparatus, and using proper filtering technique, filter the extract to a test tube. NOTE: Use a small amount of acetone to wet the filter paper, to hold it into place, instead of water.

4. Shine a flashlight, or other similar light source, through the test tube and extract.

5. Observe the fluorescence of the chlorophyll at a 90 degree angle to the flashlight.

Chloroplast Diagram

Chloroplast

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Ecosystem Quiz

Name:

Ecosystem Interactions

True/False

Indicate whether the sentence or statement is true or false.

Freshwater habitats are independent of terrestrial habitats.

An ecosystem consists of biotic and abiotic factors.

Clearing a forest would reduce the amount of energy available to the consumers.

While an understanding of the interactions between organisms and their environment was very important to early hunter and gatherer humans, it is even more important today because humans are having significant effects on the environment.

Cutting down trees in a forest alters the habitat of the organisms living in the forest.

An organism’s niche includes its habitat.

Multiple Choice

Identify the letter of the choice that best completes the statement or answers the question.

Abiotic factors affect an ecosystem by all of these except the

a.	quantity and quality of water	c.	nitrogen-fixing bacteria
b.	amount of light available	d.	quantity of minerals

The most important single factor affecting the biosphere is

a.	solar radiation	c.	precipitation
b.	the biotic community	d.	wind

Which of the following is the smallest ecological unit?

a.	a community	c.	a population
b.	a biome	d.	an ecosystem

10.

Collectively, physical factors such as light, temperature, and moisture that affect an organism’s life and survival are called the

a.	biotic environment	c.	ecosystem
b.	abiotic environment	d.	niche

11.

The rate of photosynthesis carried on by plants living in a body of water depends upon the

a.	oxygen content of the water	c.	amount of light that penetrates the water
b.	nitrogen content of the water	d.	elevation of the body of water

12.

Which of the following would not be included in a description of an organism’s niche?

a.	its trophic level	c.	its color
b.	the humidity it prefers	d.	when it reproduces

13.

Ecology is the study of the interaction of living organisms

a.	with each other and their habitat.
b.	and their communities.
c.	with each other and their physical environment.
d.	and the food they eat.

14.

The destruction of the ozone layer may be responsible for an increase in

a.	cataracts.	c.	cancer of the retina.
b.	melanoma.	d.	All of the above

15.

Ozone in the atmosphere

a.	leads to formation of acid precipitation.
b.	combines readily with water vapor.
c.	absorbs harmful radiation from the sun.
d.	All of the above

16.

Ecological models are useful for

a.	making predictions about future ecological changes.
b.	testing predictions about future ecological changes.
c.	evaluating proposed solutions to environmental problems.
d.	All of the above

17.

The physical location of an ecosystem in which a given species lives is called a

a.	habitat.	c.	community.
b.	tropical level.	d.	food zone.

18.

Which of the following is not an adaptation for avoiding unfavorable conditions?

a.	acclimation	c.	dormancy
b.	body temperature regulation	d.	migration

19.

Which of the following would not be included in a description of an organism’s niche?

a.	its trophic level
b.	the humidity and temperature it prefers
c.	its number of chromosomes
d.	when it reproduces

Chapter 1 Worksheet BI

Biology – Science of Life

Section 1-1 Themes of Biology

1. How many species of organisms are estimated to inhabit the Earth?

2. About how many species have actually been identified?

3. When did the first life forms probably arise on Earth?

4. What was the first organism like?

5. What is an organism?

6. Most unicellular organisms can only be seen with a __________________________.

7. Where did these first cells live?

8. Over time, organisms _____________ and new kinds of _______________ arose from ___________ of organisms and came to inhabit every _______________ of the Earth.

9. Define biology.

10. Name several things that the study of biology would include.

11. The study of biology is unified by ___________________________.

12. Name 6 unifying themes of biology.

13. What is a cell? Where are they found?

14. What is the difference between a unicellular & a multicellular organism?

15. Cells are ___________________ but highly _______________________.

16. Are all cells alike? Explain.

17. All cells are surrounded by a ____________ & contain _____________ instructions.

18. Genetic instructions are used by cells to make new __________ and new cell ________________.

19. How do new cells produced by unicellular organisms compare to the parent unicellular organism?

20. How do mature multicellular organisms begin their life?

21. If multicellular organisms begin their life as one cell, how do they have so many cells? Explain.

22. Give an example of an organism maintaining a stable internal environment.

23. Define homeostasis and tell whether it occurs in unicellular&/or multicellular organisms.

24. Genetic information is passed to offspring during _______________________.

25. What molecule contains the cell’s hereditary information?

26. How does DNA exist in multicellular organisms? In unicellular organisms?

27. What is a gene?

28. In multicellular organisms, each body cell has an _____________ copy of its DNA.

29. Does each cell in a multicellular organism use all the genes on its DNA? Explain.

30. Explain sexual reproduction.

31. When a sperm joins with an egg to make a fertilized cell, what happens next to this cell?

32. New organisms from sexual reproduction have _______________ material from both parents.

33. Explain asexual reproduction.

34. Name a unicellular organism that reproduces by asexual reproduction.

35. New cells or organisms from asexual reproduction have ____________ genetic information.

36. What is evolution?

37. Do individuals or populations evolve?

38. What is the driving force for evolution?

39. Explain natural selection and give an example.

40. Competition for what types of resources drives natural selection?

41. Why is it so important to a species for members to survive?

42. Organisms that survive and reproduce are ones with ________________ traits.

43. Define ecology.

44. What are ecosystems and give an example?

45. Name 3 things organisms must get from the environment to survive.

46. What has been the effect of man’s activities on many ecosystems?

47. Living things are _______________ and need a constant supply of _________________.

48. What process supplies energy for organisms on Earth?

49. Define autotroph.

50. Autotrophs trap _________ and use this energy to combine __________ and _________ into__________ and starches.

51. Define heterotrophs.

52. Give an example of an autotroph.

53. Give several examples of heterotrophs.

54. How do heterotrophs get their food?

Section 1-2 World of Biology

55. List 6 characteristics shared by all living things.

56. All living things composed of _________________.

57. Cells may be specialized in _________________ organisms. What does this mean?

58. What is always true about cell size?

59. Living things are organized at what 2 levels?

60. How are cells organized in multicellular organisms?

61. Define metabolism.

62. The energy from metabolism is used for ___________, ___________, and _______________ of organisms.

63. What is homeostasis and give an example?

64. Is growth a characteristic of living and nonliving things? Explain.

65. What 2 things must occur for living things to grow?

66. Define cell division.

67. Define development.

68. Explain why development is necessary for multicellular organisms?

69. Is reproduction essential to the survival of a species? Explain.

70. Sexual reproduction produces offspring ______________________ to the parents.

71. Have all organisms been identified? Explain.

Section 1-3 Scientific Method

72. Scientists solve problems using the ___________________________.

73. The first step of the scientific method is when scientists make ___________________ of the natural world.

74. Define data.

75. What does a scientist usually employ in making their observations?

76. What is quantitative data?

77. What is sampling & why is it used by scientists?

78. What 2 things must be true for samples to be useful?

79. To be useful, data must be _____________________ into ____________________,

______________________, and _____________________, or maps.

80. Once an observation is made, the second thing a scientist must do is to develop a(n) ___________________________.

81. Define hypothesis.

82. All hypotheses must be __________________ to give supporting evidence.

83. What is a prediction & how are they usually written?

84. What is an experiment?

85. Name the 2 groups in a controlled experiment.

86. Both groups in an experiment are identical except for ___________ factor called the

___________________.

87. Name the 2 types of variables in a controlled experiment.

88. After data is collected and organized, it must be __________________ to tell if it is reliable.

89. If experimental data does not support the hypothesis, what should be done?

90. What is a scientific model?

91. What is an inference?

92. How is a theory formed?

93. Define theory.

94. What is the difference between a field biologist and a laboratory biologist? Do they both use the scientific method?

95. What do scientists do with the results of their scientific studies?

Section 1-4 Microscopes & Measurement

96. What is a microscope?

97. What is the difference between resolution & magnification?

98. When would a microscope be used?

99. Do all microscopes have the same magnification & resolution?

100. Draw and label the parts of a light (LM) microscope.

101. Tell the function of each of these parts of an LM — stage, light source, objective lens, ocular lens, & nosepiece.

102. To view specimens with a light microscope, they must be placed on a _______________

and be ________________ so light will pass through to the lenses & your eyes.

103. What is the power of magnification & explain how it is determined?

104. Light microscopes can only magnify up to ______________ before the image becomes blurry.

105. What type of scope is used to view viruses & cell parts?

106. What produces an image with the electron microscope?

107. Name the 2 main types of electron microscopes.

108. What is the highest magnification for the TEM? For the SEM?

109. Can electron microscopes be used to view living cells?

110. What type of scope gives a magnified view of an object’s surface?

111. What is the standard unit of measurement used by scientists?

112. Name the SI base units, what they measure, & give their abbreviations (table 1-1, page 23)

113. The SI system is based on units of __________ with designated _________________.

114. Give the SI prefix for these base units — 1000, .01, .001, .000001, .000000001, & .000000000001.

115. Give the SI unit for area, volume, and time.

Chapter 2 Worksheet BI – Chemistry

Chemistry Worksheet

Section 2-1 Composition of Matter

1. Define matter.

2. Define mass.

3. Explain the difference between mass & weight.

4. Why do biologists study chemistry?

5. Define element.

6. Name the 4 elements that make up 90% of the mass of living things. Give the symbol for each of these elements.

7. Explain why some elements such as sodium have odd symbols.

8. Sketch a block from the periodic table and label the atomic number, atomic mass, & symbol for the element.

9. Define atom and tell whether they can be seen.

10. What is the center of an atom called & what 2 subatomic particles are found there?

11. How does the charge of a proton differ from the charge of a neutron?

12. Where is most of the mass of an atom concentrated?

13. How is the atomic number of an element determined?

14. What is the charge on an electron?

15. Explain why the overall or net charge on an atom is zero.

16. Where are electrons found in an atom & describe their movement?

17. In which energy levels do the electrons have more energy?

18. How many electrons can these energy levels hold — a. first? b. second?

19. Define compound and write a formula for water, carbon dioxide, & sodium chloride (table salt).

20. Do compounds have the same chemical properties as the elements that compose them?

21. When would an atom be chemically stable (not react)?

22. What occurs in a chemical reaction?

23. What is a covalent bond?

24. Define molecule.

25. Give an example of a gas that exists as a molecule.

26. Define ionic bond.

27. What is an ion?

28. Name a compound formed from — a. covalent bonding? b. ionic bonding?

29. If electrons are shared, a(n) ______________ compound forms.

30. If electrons are transferred, a(n) _____________ compound forms.

31. Forming ionic or covalent bonds helps make atoms more ________________.

Section 2-2 Energy

32. All living things require _____________ to do work.

33. Energy can’t be created or _____________ in a chemical reaction, but it can be _____________ from one form into another.

34. Name 4 forms of energy important to living things.

35. What is free energy?

36. Give an example of energy changing form in an organism.

37. Atoms & molecules are in constant _______________.

38. Name the 3 main states of matter.

39. Explain how the shape and volume of a solid, liquid, and gas differ.

40. Organisms undergo thousands of ____________ as part of their life processes.

41. Where are the reactants and products in a chemical equation?

42. What does a two-direction arrow mean in a chemical equation?

43. _______________ are broken down in chemical reactions in your body to release ___________ and produce _______________ and ______________.

44. What is the difference between an endergonic & exergonic reaction?

45. What is activation energy?

46. What effect does a catalyst have on activation energy?

47. What are biological catalysts called?

48. Redox is the abbreviation for what type of reaction?

49. Redox reactions involve the transfer of energy and _________ between atoms.

50. What happens during oxidation?

51. What happens during reduction?

52. Give an example of oxidation.

53. Give an example of reduction.

Section 2-3 Solutions

54. Many of the chemical reactions in organisms take place in __________.

55. What is a solution?

56. Give an example of a complex solution in your body.

57. Name & describe the 2 parts of a solution.

58. What is meant by concentration of the solution?

59. How do you get a saturated solution?

60. What are aqueous solutions?

61. Explain dissociation of water molecules.

62. Name and give the charge for the 2 ions formed whenever water dissociates.

63. Write the final equation for the dissociation of water.

64. What is the hydronium ion?

65. How are acidity and alkalinity measured?

66. When would a solution be neutral? Give an example of a neutral solution.

67. When would solutions be considered as acidic?

68. Acids have what taste?

69. Acids form what ion in water?

70. Give an example of an acid in your stomach.

71. When would solutions be considered as a base?

72. What adjective refers to basic solutions?

73. Give an example of a base.

74. What ion forms whenever a base is dissolved in water?

75. How does a base taste and feel?

76. How is soap made?

77. What is the pH scale used for?

78. What is the range for the pH scale?

79. At what pH would you find each of these solutions on a pH scale: a. acids? b. Bases? c. neutral?

80. How many times stronger is a pH of 3 than a pH of 5?

81. A change of one pH unit reflects a __________ change.

82. Why is controlling the pH range important to organisms?

83. How do organisms control their pH levels?

84. What is a buffer?

85. Give an example of a human body fluid that is: a. acidic? b. alkaline?

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