Biology Ch 8 Photosynthesis Study Guide – Flashcards
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autotrophs
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organisms such as plants, which make their own food from sunlight or chemicals
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heterotrophs
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organisms, such as animals, that obtain energy from the foods they consume
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Where do plants get the energy they need to produce food?
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Plants and some other types of organisms are able to use light energy from the sun to produce food.
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What is the role of ATP (adenosine triphosphate) in cellular activities?
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ATP is used by all types of cells as their basic energy source.
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photosynthesis
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process by which plants and some other organisms use light energy to convert water and carbon dioxide into oxygen and high-energy carbohydrates such as sugars and starches
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What is the overall equation for photosynthesis?
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carbon dioxide + water —> sugars + oxygen
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What is the role of light and chlorophyll in photosynthesis?
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Light is a form of energy and chlorophyll absorbs light and the energy from the light.
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chlorophyll
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principal pigment of plants and other photosynthetic organisms; captures light energy
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Plants gather the sun's energy with light-absorbing molecules are called...
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pigments
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What happens in the light-dependent reactions?
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... use energy from sunlight to produce ATP, NADPH, and oxygen. It takes place within the thylakoid membranes of chloroplasts.
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What is the Calvin cycle?
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... uses ATP and NADPH from the light-dependent reations to produce high-energy sugars. It takes place in the stroma of chloroplasts and does NOT require light.
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thylakoid
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saclike photosynthetic membranes found in chloroplasts
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Proteins in the thylakoid membrane organize chlorophyll and other pigments into clusters known as...
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photosystems
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stroma
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the region outside the thylakoid membranes in chloroplasts
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NADP+
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(nicotinamide adenine dinucleotide phosphate) one of the carrier molecules that transfers high-energy electrons from chlorophyll to other molecules.
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light-dependent reactions
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reactions of photosynthesis that use energy from light to produce ATP and NADPH
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ATP synthase
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large protein that uses energy from H+ ions to bind ADP and a phosphate group together to produce ATP
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Which are autotrophs?
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plants, mushrooms
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One of the principal chemical compounds that living things use to store energy is...
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ATP
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In addition to light and chlorophyll, photosynthesis requires...
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water and carbon dioxide
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The leaves of a plant appear green because chlorophyll...
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reflects green light
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The products of photosynthesis are...
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sugars and oxygen
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The first process in the light-dependent reactions of photosynthesis is...
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Absorption of light
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Which substances from the light-dependent reactions of photosynthesis is a source of energy for the Calvin cycle?
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ATP ; NADPH
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The light independent reactions of photosynthesis are also known as the...
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Calvin cycle
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How do heterotrophs and autotrophs differ in the way they obtain energy?
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heterotrophs obtain energy from the food they eat. autotrophs obtain energy from the sunlight
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Describe the three parts of an ATP molecule.
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Adenine Ribose 3 Phosphate groups
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Use the analogy of battery to explain how energy is stored in and released from ATP.
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ATP can be compared to a fully charged battery because both contain stored energy.
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Compare the amounts of energy stored by ATP and glucose. Which compound is used by the cell as an immediate source of energy.
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- A single molecule of the sugar glucose stores more than 90 times the chemical energy of a molecule of ATP. - ATP is used as an immediate source of energy.
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How were Priestley's and Ingenhousz's discoveries about photosynthesis related?
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They both showed that light was necessary for plants to produce oxygen.
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Write the basic equation for photosynthesis using the names of the starting and final substances of the process.
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6CO2 + 6H20 —; C6H12O6 + 6O2 carbon dioxide + water —; sugars + oxygen (NOTE: —; is light)
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What role do plant pigments plan in the process of photosynthesis?
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They gather the sun's energy
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Explain the role of NADP+ as an energy carrier in photosynthesis.
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It transfers high-energy electrons from chlorophyll to other molecules.
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What is the role of ATP synthase? How does it work?
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they provide the energy to build energy - containing sugars from low - energy compounds. It allows hydrogen ions out of the thylakoid
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Summarize what happens during the Calvin cycle.
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plants use the energy that ATP and NADPH contain to build high-energy compounds that can be stored for a long time.
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How do the events in the Calvin cycle depend on the light-dependent reactions?
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The Calvin cycle uses ATP and NADPH from the light-dependent reactions to produce high-energy sugars.
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Describe three factors that affect the rate at which photosynthesis occurs.
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- water - temperature - intensity of light
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the ability to do work
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energy
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All living things require...
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energy
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Autotrophs are plants and some other types of organisms are able to use ________ from the sun to produce _________.
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- light energy - food
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autotrophs
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Plants and some other types of organisms are able to use light energy from the sun to produce food.
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heterotrophs
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organisms that obtain their energy from food they consume
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Energy comes in many different forms. Give examples.
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- light - heat - electrically - chemical compounds
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Living things use chemical compounds stored and released in cells called...
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ATP or adenosine triphosphate
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ATP (adenosine triphosphate) contains...
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a 5 carbon sugar (ribose) & 3 phosphates
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When the bond is broken between the 2nd and 3rd phosphate in ATP, ______ is released.
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energy
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The release of energy when the bond is broken between the 2nd and 3rd phosphate power these functions:
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- active transport - muscle contractions - protein synthesis
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The characteristics of ATP make it exceptionally useful as the basic _____ source of cells.
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energy
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When plants use the energy of sunlight to convert water and carbon dioxide into high-energy carbohydrates (sugar and starches) and a waste product (oxygen).
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photosynthesis
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Photosynthesis Equation
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- Reactants —> Products - Carbon Dioxide + water in the presence of light yields sugars & oxygen
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In addition to water and carbon dioxide, photosynthesis requires ________ and _________, a molecule in chloroplasts.
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light and chlorophyll
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Light is in ___________ form and creates a spectrum from ________ to ______.
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- wavelength form - violet to red
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pigments
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light absorbing molecules in plants
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chlorophyll
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the principle pigment in plants
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2 main types of chlorophyll:
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chlorophyll a & chlorophyll b
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Where does photosynthesis take place?
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in chloroplasts
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Chloroplasts contain tiny sacs like photosynthetic membranes called...
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thylakoids
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Thylakoids are arranged in stacks known as ...
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grana
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What are the 2 Photosynthesis reactions?
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- (1) light dependent (takes place in the thylakoids) - (2) light independent or Calvin cycle (takes place in the stroma - the region outside the thylakoid membranes)
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Sunlight excites the electrons in ________.
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chlorophyll
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The excited electrons and their energy must be transported by an electron carrier, like _______. This electron carrier can hold ______ electrons and an ion of _________. It is converted into _________ which is trapping sunlight energy into _______ energy. This is the electron ________ _______.
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- NADP+ - 2 electrons - hydrogen (H+) - NADPH - chemical energy - electron transport chain
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Light dependent reactions produce ________ and convert _____ and _______ into the energy carriers ______ and _______.
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... oxygen gas and convert ADP and NADP+ into the energy carriers ATP and NADPH.
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Light independent cycle
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takes in the stroma and outside the grana
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The Calvin cycle uses ______ and ______ from the light-dependent reactions to produce high energy sugars.
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ATP and NADPH
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3 factors that affect photosynthesis:
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- water supply - temperature - intensity of light
