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Biology Chapter 8

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What is the difference between ATP and ADP?
ATP has three phosphates; ADP has two
Organisms that make their own food are called
autotrophs
Energy is released upon the conversion of
ATP to ADP
One way cells use the energy provided by ATP is to
carry out active transport
Why are mushrooms considered heterotrophs?
Mushrooms feed by absorbing decomposing nutrients from organisms.
The reactants of photosynthesis are
CO2 and H2O
Chlorophyll molecules are located in the
thylakoid membranes
Photosynthesis takes place inside organelles called
chloroplasts
When chlorophyll absorbs light, the electrons produced are analogous to a hot potato in that both
have a lot of energy and require a carrier to be transported.
What would likely be the result of covering a healthy, green leaf with aluminum foil?
The leaf would lose its green color due to the breakdown of chlorophyll in the leaf.
The photosystems contain pigments that absorb light and pass the energy on to
electrons
The major products of the light-dependent reactions are
ATP and NADPH
In photosynthesis, carbon dioxide is used to make sugars during
the Calvin cycle
What is the function of NADPH and ATP in the Calvin cycle?
They provide the energy required to build high-energy sugars.
How do CAM plants photosynthesize under bright, hot conditions without drying out?
by sealing their leaves against water loss and trapping carbon as organic acids.
Which of the following are autotrophs?
deer
plants
leopards
mushrooms
plants
Which of the following is used by cells to store and release energy needed to power cellular processes?
DNA
ATP
H2O
CO2
ATP
The amount of energy stored in a molecule of ATP compared to the amount stored in a molecule of glucose is
less
When a candle burns, energy is released in the form of
light and heat
In addition to light and chlorophyll, photosynthesis requires
water and carbon dioxide
The leaves of a plant appear green because chlorophyll...
reflects green light
The first process in the light-dependent reactions of photosynthesis is
light absorbtion
Which substance from the light-dependent reactions of photosynthesis is a source of energy for the Calvin cycle?
NADPH
The light-independent reactions of photosynthesis are also known as the
Calvin cycle
ATP synthase in the chloroplast membranes makes ATP, utilizing the energy of highly concentrated
hydrogen ions
CAM plants are specialized to survive under what conditions that would harm most other kinds of plants?
hot, dry conditions
Autotrophs differ from heterotrophs because they
make their own food from carbon dioxide and water.
The principal pigment in plants is
chlorophyll
Which of the following is NOT produced in the light-dependent reactions of photosynthesis?
NADPH
sugars
hydrogen ions
ATP
sugars
The color of light that is least useful to a plant during photosynthesis is
green
The first step in photosynthesis is the
absorption of light energy
In a typical plant, all of the following factors are necessary for photosynthesis EXCEPT
chlorophyll
light
oxygen
water
oxygen
Why is ATP useful to cells?
ATP can easily release and store energy by breaking and re-forming the bonds between its phosphate groups.
What happens during the process of photosynthesis?
Plants convert the energy of sunlight into the chemical energy stored in the bonds of carbohydrates.
adenosine triphosphate (ATP)
Compound used to store and release energy.
heterotroph
Organism that obtains food by consuming other living things also called a consumer.
autotroph
Organism that is able to capture energy from sunlight or chemicals and use it to produce it's own food from inorganic compounds; also called a producer
photosynthesis
Process used by plants and other autotrophs to capture light energy and use it to power chemical reactions that convert carbon dioxide and water into oxygen and energy-rich carbohydrates such as sugars and starches.
What is ATP and what is its role in the cell?
Adenosine Triphosphate; one of the most important compounds that cells use to store and release energy
Explain how ATP and ADP are each like a battery. Which one is "partially" charged and which one is "fully" charged? Why?
ADP contains some energy but not as much as ATP. ADP is "partially" charged and ATP is "fully" charged. When you add an additional phosphate to ADP it becomes ATP (fully charged).
What is the ultimate source of energy for plants?
The sun
How do heterotrophs obtain energy? How is this different from how autotrophs obtain energy?
Heterotrophs obtain energy by consuming other living things. Autotrophs are able to use light energy from the sun to produce their own food.
Why are decomposers like mushrooms considered heterotrophs and not autotrophs?
Mushrooms cannot produce their own food. They obtain food from organisms in the environment that are decomposing.
What role do pigments play in the process of photosynthesis?
Pigments (chlorophyll) capture energy from sunlight. That light energy is transferred to the electrons in the chlorophyll molecule. Increasing energy levels in the electrons produces a steady supply of high-energy electrons and makes photosynthesis work.
What are electron carrying molecules?
A compound that can accept a pair of high-energy electrons and transfer them, along with most of their energy, to another molecule.
What are the reactants and the products of photosynthesis?
Water and carbon dioxide are the reactants and high-energy sugars and oxygen are the products.
Pigment
Light-absorbing molecule used by plants to gather the sun's energy.
Chlorophyll
Principal pigment of plants and other photosynthetic organisms.
Thylakoid
Saclike photosynthetic membranes found in chloroplasts.
stroma
Fluid portion of the chloroplast; outside of the thylakoids.
NADP+
Carrier molecule that transfers high-energy electrons from chlorophyll to other molecules.
light-dependent reactions
Set of reactions in photosynthesis that use energy from light to produce ATP and NADPH.
light-independent reactions
Set of reactions in photosynthesis that do not require light; energy from ATP and NADPH
Why are pigments such as chlorophyll needed for photosynthesis?
Chlorophyll absorbs light very well and a large fraction of that light is transferred directly to electrons.
How well would a plant grow under pure yellow light? Explain.
Plants tend not to absorb yellow light so photosynthesis will occur at a slower rate under pure yellow light.
What is the function of NADPH?
NADPH carries the high-energy electrons that were produced by light absorption in chlorophyll to chemical reactions elsewhere in the cell.
How is light energy converted into chemical energy during photosynthesis?
The conversion of NADP+ into NADPH. NADP+ accepts and holds 2 high-energy electrons, along with a hydrogen ion (H+)
How would photosynthesis be affected if there were a shortage of NADP+ in the cells of plants?
NADP+ is needed to pick up the hydrogen from the water to create NADPH. A shortage would cause photosynthesis to slow down or stop.
Describe the overall process of photosynthesis, including the reactants and products.
Photosynthesis uses the energy of sunlight to convert water and carbon dioxide (reactants) into high-energy sugars and oxygen (products).
What happens during the light-dependent reactions?
The light-dependent reactions use energy from sunlight to produce oxygen and convert ADP and NADP+ into the energy carriers ATP and NADPH.
What happens during the light-independent reactions?
ATP and NADPH from the light-dependent reactions are used to produce high-energy sugars.
photosystem
Cluster of chlorophyll and proteins found in thylakoids
electron transport chain
Series of electron carrier proteins that shuttle high-energy electrons during ATP-generating reactions.
ATP synthase
Cluster of proteins that span the cell membrane and allow hydrogen ions (H+) to pass through it.
Calvin cycle
Light-independent reactions of photosynthesis in which energy from ATP and NADPH is used to build high-energy compounds such as sugar.
Put the events of the light-dependent reaction in the order in which they occur and describe how each step is dependent on the step that comes before it.
Photosystem II, Electron Transport Chain, Photosystem I, Hydrogen Ion Movement, ATP Formation
List at least three differences between the light-dependent reactions and the light-independent reactions of photosynthesis.
Light-Dependent Reactions:
1. take place in the thylakoids
2. reactant is water
3. product is oxygen

Light Independent Reactions:
1. take place in the stroma of the chloroplast
2. reactant is carbon dioxide
3. product is high-energy sugars
What are the three primary factors that affect the rate of photosynthesis?
Temperature, light intensity and availability of water