Bio Ch 6 Photosynthesis Notes

Transcription

1 Bio Ch 6 Photosynthesis Notes

2 I. Photosynthesis Basics A. What is photosynthesis? 1. Photosynthesis is a chemical reaction in which light energy is converted to chemical energy in glucose.

3 2. It is the means by which the energy in sunlight becomes usable to living things. 3. Living things can eat glucose, we can't eat sunlight.

4 Which of the following are not necessary to be present in order for photosynthesis to occur? A. carbon dioxide B. water C. oxygen D. light 0% 0% 0% 0% carbon dioxide water oxygen light Answer Now 15

5 B. Why is photosynthesis so important? 1. Two big reasons. One product of photosynthesis is glucose (sugar), which provides the basis for most food chains.

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7 2. The second product of photosynthesis is oxygen, which is necessary for an aerobic organism that requires oxygen for survival.

8 C. Where does photosynthesis occur? (This question can be answered on various levels.) 1. On the planetary level, most photosynthesis occurs in the oceans, because the oceans occupy the vast majority (70%) of the earth's surface.

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10 Organisms, such as plants, that make their own food are called A. autotrophs. B. heterotrophs. C. thylakoids. D. pigments. 0% 0% 0% 0% Answer Now 15

11 2. In terms of organisms, photosynthesis occurs in autotrophs that contain the green pigment chlorophyll. This would include the entire plant kingdom, "half" of the Protista (the algae-seaweeds, & diatoms), & "half" the Eubacteria Kingdom (the blue-green algae). Phytoplankton os/bios104/mike/bacteria01.ht m

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13 Which of the following is an autotroph? A. mushroom B. impala C. leopard D. tree 0% 0% 0% 0% mushroom impala leopard tree Answer Now 15

14 3. On the multicellular level, photosynthesis occurs in the leaves of plants.

15 4. On the cellular level, the reactions for photosynthesis occur in organelles called chloroplasts (in eukaryotic cells). Blue-green algae (which are prokaryotic) carry-out the photosynthesis reactions in the cytoplasm.

16 D. What raw materials are needed for the process of photosynthesis? 1. Chlorophyll must be present. (Chlorophyll pigment absorbs solar energy).

17 2. Sunlight is necessary. That's why we call it PHOTOsynthesis. 3. And from the environment, photosynthetic organisms must get water & carbon dioxide.

18 E. To which "life function" is photosynthesis related? 1. Photosynthesis falls under nutrition, autotrophic nutrition to be exact. 2. Nutrition has to do with how organisms obtain the materials necessary for energy, growth, etc. a. We call these necessary materials nutrients.

19 3. Autotrophs are organisms that are able to use the source of energy, such as sunlight, to produce food directly from simple inorganic molecules in the environment. a. Other organisms, such as animals, cannot use the sun s energy directly.

20 b. These organisms known as heterotrophs obtain energy from the food they eat. c. Heterotrophs may eat autotrophs or other heterotrophs or both.

21 Organisms that cannot make their own food and must obtain energy from the foods they eat are called A. autotrophs. B. heterotrophs. C. thylakoids. D. plants. 0% 0% 0% 0% Answer Now 15

22 F. How can we summarize photosynthesis? 1. In words, remember this: carbon dioxide + water + light energy glucose + oxygen + water

23 2. As a chemical reaction it's like so: 6CO H 2 O + light energy C 6 H 12 O 6 + 6O 2 + 6H 2 O

24 3. The process of photosynthesis is divided into two parts: the light reactions (photolysis or photochemical) and the dark reactions (carbon fixation).

25 a. As their names implies, the light reactions require light. b. In the light reactions, the energy of sunlight is captured and used to make energy-storing compounds.

26 Which one is not a product of the lightdependent reactions? A. ATP B. NADPH C. oxygen D. carbon dioxide 0% 0% 0% 0% ATP NADPH oxygen carbon dioxide Answer Now 15

27 c. The dark reactions do not require light and thus are called non-light or light-independent reactions. i. However the dark can and do occur in the light.

28 ii. The dark reactions use the energy stored by the light reactions to make glucose.

29 What is the end product of photosynthesis for plants? A. high-energy carbohydrates. B. light energy. 0% 0% 0% 0% C. ATP. D. carbon dioxide. Answer Now 15

30 G. What else should we remember about photosynthesis? 1. It's an important component of the Oxygen- Carbon Dioxide Cycle. (Carbon Cycle)

31 2. Organisms that carry-out photosynthesis are like oxygen factories. a. At the same time they are removing CO 2 from the atmosphere.

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33 3. Damaging the ecosystems where photosynthesis occurs (i.e. the rainforests, the oceans) reduces the amount of oxygen being pumped into the air & slows the rate at which carbon dioxide is removed from the atmosphere.

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35 II. Plants & how they are adapted for photosynthesis. The leaves of plants are the photosynthesis factories. The structure of a "typical" leaf is illustrated below. A. Leaf Layers

36 1. This diagram shows a leaf cross section with only the layers labeled.

37 2. Note that each roundish shape is a single plant cell. So each layer is a plant tissue (a group of cells). 3. The top & bottom layers are both referred to as an epidermis (outer layer). The upper epidermis & the lower epidermis basically are protective layers.

38 4. They are coated with a waxy surface, the cuticle, which further protects the leaf & prevents excess water loss.

39 5. The area sandwiched in the middle of the leaf is referred to as "mesophyll". There are two layers in the mesophyll: a. The palisade layer - packed tight w/ oval cells b. The spongy layer - this area contains circular cells that are spread out --- allowing gases to circulate within the leaf

40 B. The Vascular Bundle (Vein) 1. If you've ever looked closely at a leaf you've noticed some pattern of lines running through it. a. These lines are veins, or "vascular bundles"

41 2. Inside the vascular bundle are tubes that transport materials from place to place in the plant. 3. The xylem transports water & minerals from the roots, through the stem, & into the leaves (remember... we need water for photosynthesis).

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43 4. Phloem are tubes that transport "food" through the plant. a. This "food" is basically sugary water (sap). b. The sugars are synthesized (made) during photosynthesis.

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45 Water vapor, carbon dioxide, and oxygen enter and leave a plant through microscopic openings called A. pores. B. stomata. C. stroma. D. chloroplasts. 0% 0% 0% 0% Answer Now 15

46 C. Stomates & Guard Cells 1. Scattered about the lower epidermis are small openings called stomata. a. It is through these holes that carbon dioxide enters the leaf, & oxygen & water vapor exit.

47 2. Each stomate is surrounded by a pair of guard cells. a. When guard cells swell, the stomates open, when the guard cells shrink, the stomates are closed.

48 ree/ /58644/0021.swf::stomata 3. Plants respond to changes in temperature & humidity by opening or closing their stomata (an example of maintaining... homeostasis).

49 Which of the graphs represents the effect of temperature on the rate of photosynthesis? A. A B. B C. C 0% 0% 0% 0% A B C D D. D 15 Answer Now

50 Which organelle is involved in photosynthesis? A. mitochondria B. golgi apparatus C. chloroplast D. nucleus 0% 0% 0% 0% Answer Now 15

51 D. Chloroplasts 1. All of the "black dots" in the picture represent chloroplasts, which are the cell organelles in plant cells where the chemical reactions of photosynthesis take place.

52 2. Notice that the vast majority of chloroplasts are found in the cells of the mesophyll. a. Even more specifically, the palisade layer has the most chloroplasts b. Therefore, the greatest amount of photosynthesis occurs in that leaf layer.

53 3. Within the chloroplast are like saclike photosyntheic membranes that contain chlorophyll called thylakoids. a. When the thylokoids are stacked on top of each other they are called grana b. The solution surrounding the thylakoids is called stroma.

54 A granum is a A. stack of chloroplasts. B. stack of thylakoids. C. membrane enclosing a thylakoid. 0% 0% 0% 0% D. photosynthetic pigment molecule. Answer Now 15

55 The stroma is the region outside the A. thylakoids. B. chloroplasts. C. plant cells. D. all of the above 0% 0% 0% 0% Answer Now 15

56 c. The light reactions occur in the photosynthic membranes (thylakoids), whereas the dark reactions occur outside the photosynthic membranes (stroma).

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58 Where do the light-dependent reactions A. in the stroma of chloroplasts. take place in plants? B. outside the chloroplasts. C. in the thylakoid membranes of chloroplasts. D. in the cytoplasm of plant 0% 0% 0% 0% cells. 15 Answer Now

59 4. 2 types of chlorophyll: chlorophyll a (directly involved in light reactions) & chlorophyll b.

60 Which part of the electromagnetic spectrum do we see? A. ultraviolet B. infrared C. visible light D. microwaves 0% 0% 0% 0% Answer Now 15

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62 a. They are slightly different chemically, but similar in that they like to absorb blue, violet, orange, & red wavelengths of light, & tend to REFLECT (not absorb) yellow & green wavelengths.

63 Plants gather the sun s energy with lightabsorbing molecules called A. pigments. B. thylakoids. C. chloroplasts. D. glucose. 0% 0% 0% 0% Answer Now 15

64 i. Accessory pigments include chlorophyll b and carotenoids.

65 The color of light that is least useful to plants is A. violet. B. green. C. blue. D. red. 0% 0% 0% 0% violet. green. blue. red. Answer Now 15

66 b. Plants can't use light energy that they reflect. c. So, since plants reflect yellows & greens, that energy cannot be used for photosynthesis.

67 d. Plants under yellow & green light will carry out photosynthesis at a lower rate than the same type of plant under other colors (blue, violet, red).

68 Where in the chloroplast is chlorophyll found? A. in the stroma B. in the thylakoid C. in the ATP D. in the glucose 0% 0% 0% 0% in the stroma in the thylakoid in the ATP in the glucose Answer Now 15

69 Most plants appear green because chlorophyll A. does not absorb green light. B. reflects violet light. C. absorbs green light. D. none of the above 0% 0% 0% 0% does not absorb green light. reflects violet light. absorbs green light. none of the above Answer Now 15

70 III. Light & Dark Reactions A. The light reactions absorb the energy of the sunlight and convert it to the energy that is stored in chemical bonds. 1. This process occurs very rapidly.

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72 2. The light reactions can be divided into four basic processes: a. Light absorption b. Electron transport

73 c. Oxygen production - the light energy is used to split the water molecule, which produces H + & O - ions (O 2 is released by the plant to the air). d.atp & NADPH formation energy molecules used up during the dark reactions (as will the H + ions).

74 ATP - Adenosine-5'-triphosphate NADPH - Nicotinamide adenine dinucleotide phosphate ATP NADPH

75 What are the three parts of an ATP molecule? A. adenine, thylakoids, stroma B. stroma, grana, chlorophyll 0% 0% 0% 0% C. adenine, ribose, phosphate groups D. NADH, NADPH, and FADH 2 15 Answer Now

76 Between which parts of the molecule must the bonds be broken to form an ADP molecule? A. A and B B. B and C C. C and D D. all of the above 0% 0% 0% 0% A and B B and C C and D all of the above Answer Now 15

77 3. These processes are closely linked and are dependent on one another.

78 Which of the following is NOT a step in the light-dependent reactions? A. High-energy electrons move through the electron transport chain. B. Pigments in photosystem II absorb light. C. ATP synthase allows H+ ions to pass through the thylakoid membrane. D. ATP and NADPH are used to produce high-energy sugars. Answer Now 0% 0% 0% 0% 15

79 Which step is the beginning of photosynthesis? A. Pigments in photosystem I absorb light. B. Pigments in photosystem II absorb light. C. High-energy electrons move through the electron transport chain. D. ATP synthase allows H + ions to pass through the thylakoid membrane. Answer Now 0% 0% 0% 0% 15

80 Why does the inside of the thylakoid membrane become positively charged during the light-dependent reactions? A. H + ions are released as water splits. B. ATP synthase allows H + ions to pass through the membrane. C. ATP synthase produces ATP from ADP. D. Carbon dioxide builds up in the stroma. 0% 0% 0% 0% TP + ions synthase ATP are released allows synthase Carbon H+ dioxide produces water ions to splits. builds pass ATP through up from in the ADP. the strom membrane. Answer Now 15

81 B. The dark reactions generally take place in the sunlight. 1. However, light does not play a role in the dark reactions.

82 2. The series of chemical changes that make up the dark reactions is particularly critical to living things.

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85 The Calvin cycle takes place in the A. stroma. B. photosystems. C. thylakoid membranes. D. chlorophyll molecules. 0% 0% 0% 0% Answer Now 15

86 3. In this part of photosynthesis, the simple inorganic molecule, carbon dioxide, is used to make a complex organic molecule (PGAL/G3P phosphoglyceraldehyde)

87 a. PGAL can be thought of as a building block that can be used to make other biologically important molecules, including glucose.

88 Energy is released from ATP when A. a phosphate group is added. B. adenine bonds to ribose. C. ATP is exposed to sunlight. D. a phosphate group is removed. 0% 0% 0% 0% a phosphate group is added. Answer Now adenine bonds to ribose. ATP is exposed to sunlight. a phosphate group is removed. 15

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91 Another name for the light-independent cycle of photosynthesis is A. the Krebs cycle. B. the light-dependent cycle. C. the Calvin cycle. D. the electron transport chain. 0% 0% 0% 0% Answer Now 15

92 IV. Summary of Photosynthesis A. Overall Summary Split in light reactions Used in light reactions to split water & form ATP & NADPH Released into the air Combined during dark reactions to form PGAL waste Formed from 2 PGAL s during dark reactions

93 What is the first step in photosynthesis? A. production of oxygen. B. breakdown of CO 2. C. formation of ATP. D. absorption of light energy. 0% 0% 0% 0% Answer Now 15

94 B. Summary of how each of the raw materials end up in the chloroplasts.

95 C. Summary of what happens to the products of photosynthesis

96 Which chemical equation illustrates photosynthesis? 0% 0% 0% 0% A. 6 CO 2 + H 2 O + light C 6 H 12 O O 2 +6 H 2 O B. 6 CO H 2 O + light C 6 H 12 O O 2 +6 H 2 O C. HCO 2 + H 2 O + light H 2 O + O 2 + energy D. 6 CO H 2 O + light C 6 H 12 O 6 + 6O 2 +6 H 2 O Answer Now 15

97 A student is collecting the gas given off from a plant in bright sunlight at a temperature of 27 C. The gas being collected is probably A. oxygen. B. carbon dioxide. C. ATP. D. vaporized water. 0% 0% 0% 0% oxygen. carbon dioxide. ATP. vaporized water. Answer Now 15

98 1. Glucose may be used for things other than energy. a. For example, a whole bunch of glucoses could be combined (by dehydration synthesis) to form cellulose, which is the structural material of the cell wall surrounding plant cells.

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100 b. It could also be converted to starch (again by dehydration synthesis) & stored by the plant for future use.

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102 If carbon dioxide is completely removed from a plant s environment, what would you expect to happen to the plant s production of high-energy sugars? A. More sugars will be produced. B. No sugars will be produced. C. The same number of sugars will be produced but without carbon dioxide. D. Carbon dioxide does not affect the production of high-energy sugars in plants. 0% 0% 0% 0% Answer Now 15

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104 Photosynthesis uses sunlight to convert water and carbon dioxide into A. oxygen. B. high-energy sugars and starches. C. ATP and oxygen. 0% 0% 0% 0% D. oxygen and high-energy sugars and starches. Answer Now 15

105 Which of the following affects the rate of photosynthesis? A. water B. temperature C. light intensity D. all of the above 0% 0% 0% 0% Answer Now 15

106 If you continue to increase the intensity of light that a plant receives, what happens? A. The rate of photosynthesis increases with light intensity. B. The rate of photosynthesis decreases with light intensity. C. The rate of photosynthesis increases and then levels off. D. The rate of photosynthesis does not change. 0% 0% 0% 0% Answer Now 15

107 Which of the graphs represents the effect of light intensity on the rate of photosynthesis? A. A B. B C. C 0% 0% 0% 0% A B C D D. D 15 Answer Now

108 Crash Course: k Photosynthesis Summary: 0w Photosynthesis Song: Nw

109 Which pathway represents the flow of electrons during photosynthesis? A. H 2 O Photosystem I Photosystem II B. O 2 ADP Calvin cycle C. Photosystem I Calvin cycle NADPH D. H 2 O NADPH Calvin cycle 0% 0% 0% 0% Answer Now 15