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Herr's Test Bank Q's #8 (BIO 171) Exam 2; Spring 2016

Terms in this set (84)

During the light reactions of photosynthesis, the synthesis of ________ is coupled to the diffusion of protons.
ATP
Atmospheric carbon dioxide enters plant leaves through openings called ________.
stomata
In the 1800s, the summarized chemical reaction for photosynthesis was incorrect because it left out ________as a product.
water
In noncyclic photophosphorylation, the electrons for the reduction of chlorophyll in photosystem II come from ________.
water
When ________ are exposed to light and CO2, four-carbon compounds are the first carbon-containing products.
C4 plants
During the process of ________ rubisco catalyzes the reaction of RuBP with oxygen.
photorespiration
A group of scientists led by ________ conducted experiments demonstrating that RuBP is the CO2 acceptor in the dark reactions of photosynthesis.
Calvin
When isolated chloroplasts are shifted from a low pH solution to a more alkaline solution, ATP synthesis occurs, even in the absence of light. This experiment was used to support the ________ mechanism of ATP formation in chloroplasts.
Chemiosmotic
During cyclic photophosphorylation, the energy of photons is converted to the chemical energy of the product, ________.
ATP
In C3 plants, the Calvin-Benson cycle occurs in the chloroplasts of ________ cells, but in C4 plants the cycle occurs in the ________ cells.
mesophyll; bundle sheath
In both photosynthesis and respiration, ________ synthesis is coupled to the diffusion of protons across a membrane.
ATP
The dark reactions take place in the ________.
stroma
NADP is the abbreviation for ________
Nicotinaminde adenine dinucleotide phosphate
The Calvin-Benson cycle is sometimes called the ________.
dark reactions
The oxygen found in Earth's atmosphere is generated from the photosystem ________ of noncyclic photophosphorylation.
II
________ instead of NADP+ receives the electron from ferredoxin during cyclic photophosphorylation.
plastoquinone (PQ)
The most abundant enzyme in the biosphere is ________.
rubisco
To obtain free energy, heterotrophs require a source of
partially reduced organic compounds.
How do red and blue light differ from one another?
Their wavelengths are different
The wavelength of X rays is shorter than the wavelength of infrared rays. Which of the following is true?
X rays have more energy per photon than infrared rays.
Brightness of light is a function of
the photons striking an area per unit time.
A molecule has an absorption spectrum that shows maximum absorption within the wavelengths of visible light. This molecule is
a pigment.
When white light strikes a blue pigment, blue light is
reflected or transmitted.
A graph that plots the rate at which carbon dioxide is converted to glucose versus the wavelength of light illuminating a leaf is called
an action spectrum
The photosynthetic pigment chlorophyll a absorbs
red and blue light.
Accessory pigments
allow plants to harvest visible light of intermediate wavelengths.
Why are the absorption spectrum of chlorophyll a and the action spectrum of photosynthesis not identical?
Accessory pigments contribute energy to drive photosynthesis.
Excited chlorophyll is a better reducing agent than ground-state chlorophyll because
one of the electrons is farther from the atomic nucleus.
In cyclic photophosphorylation, chlorophyll is reduced by
hydrogens liberated by the splitting of a water molecule.
The energy difference between an electron excited by a photon and its ground state is
the same as what was in the photon.
The precise moment when light energy is captured in chemical energy is when
chlorophyll is oxidized.
Free energy is released in cyclic photophosphorylation
during each of the redox reactions of the electron transport chain
During cyclic photophosphorylation, the energy to produce ATP is provided by
the redox reactions of the electron transport chain.
In noncyclic photophosphorylation, water is used for the
reduction of chlorophyll.
Photophosphorylation provides the CalvinñBenson cycle with
ATP and NADPH.
In noncyclic photophosphorylation, the chlorophyll in photosystem I is reduced by
an electron from the transport chain of photosystem II.
The enzyme ATP synthase couples the synthesis of ATP to
the diffusion of protons.
Why does this reaction stop when the algae are placed in the dark?
It requires ATP and NADPH + H+.
When the reduction of 3-phosphoglycerate to glyceraldehyde 3-phosphate is blocked, the concentration of ribulose bisphosphate declines. Why?
a and c
Ribulose bisphosphate is synthesized from glyceraldehyde 3-phosphate. & Ribulose bisphosphate is used to synthesize 3-phosphoglycerate.
The enzyme rubisco is found in
chloroplasts.
During carbon dioxide fixation, carbon dioxide combines with
ribulose bisphosphate.
__________ mole(s) of carbon dioxide must enter the CalvinñBenson cycle for the synthesis of one mole of glucose.
Six
The NADPH required for the reduction of 3PG to G3P comes from
the light reactions.
In C4 plants, the function of the four-carbon compound that is synthesized in the mesophyll cells is to
carry CO2 to the bundle sheath cells.
In the mesophyll layer of C4 plants, light energy is used to synthesize
oxaloacetate.
In C4 plants, starch grains are found in the chloroplasts of
bundle sheath cells.
During photorespiration, rubisco uses __________as a substrate.
oxygen
Photorespiration starts
in chloroplasts.
In plants, the reactions of glycolysis occur
in the cytosol.
In both photosynthesis and respiration, protons are pumped across a membrane during
electron transport.
The enzyme PEP carboxylase
can trap CO2 even at relatively low CO2 concentrations.
The function of photorespiration is
unknown.
The NADPH required for CO2 fixation is formed
during the light reactions.
The O2 gas produced during photosynthesis is derived from
water.
Photosynthesis and respiration have which of the following in common?
a, b, and c

A) In eukaryotes, both processes reside in specialized organelles.
B) ATP synthesis in both processes relies on the chemiosmotic mechanism.
C) Both use electron transport.
The expression "We are creatures of the chloroplasts" means that
all life depends ultimately on photosynthesis.
When a photon interacts with molecules such as those within chloroplasts, the photons may
A) bounce off the molecules, having no effect.
B) pass through the molecules, having no effect.
C) be absorbed by the molecules.
D) a and c
E) a, b, and c
a, b, and c
A) bounce off the molecules, having no effect.
B) pass through the molecules, having no effect.
C) be absorbed by the molecules.
Which of the following scientific tools "cracked" the CalvinñBenson cycle?
a and b
A) Isotopes
B) Paper chromatography
In noncyclic photophosphorylation, electrons from which source replenish chlorophyll molecules that have given up electrons?
Water
In our past evolutionary history, noncyclic photophos- phorylation by cyanobacteria, algae, and plants poured enough gas into the atmosphere to make possible the evolution of cellular respiration. That gas was
oxygen
After World War II, the Berkeley group (Calvin et al.) made progress in understanding the dark reactions when these researchers devised a way to grow dense quantities of algae in a flask that looked like a
lollipop.
Which of the following biological groups is dependent on photosynthesis for its survival?
a, b, and c
A) Vertebrates
B) Class Mammalia
C) Fish
Photosynthesis is divided into two main phases, the first of which is a series of reactions that requires the absorption of photons. This phase is referred to as the
light reactions phase, or photophosphorylation.
Based on its electronic structure, a molecule has a range of photon energies. These photon energies are known as the molecule's
absorption spectrum.
The energy to hydrolyze water comes from
oxidized chlorophyll.
Heterotrophs are dependent on autotrophs for their food supply. Autotrophs can make their own food by
using light and an inorganic carbon source to make reduced carbon compounds.
Photosynthesis is the process that uses light energy to extract H atoms from which of the following sources?
Water
Which of the following occurs during the dark reactions of photosynthesis?
Carbon dioxide is converted into sugars.
In bright light, the pH of the thylakoid space
can become more acidic.
When a photon is absorbed by a molecule, what exactly happens to the photon?
It raises the molecule from a ground state of low energy to an excited state.
A range of energy that cannot be seen by human eyes, but has slightly more energy per photon than visible light, is
ultraviolet radiation
The main photosynthetic pigments in plants are
chlorophyll a and chlorophyll b.
If one were to compare long wavelengths to short wavelengths, it would be evident that short-wavelength photons have
more energy.
The chemiosmotic hypothesis states that the energy for the production of ATP comes from
a proton gradient set up across the thylakoid membrane.
When carbon dioxide is added to RuBP, the first stable product synthesized is
phosphoglycerate.
Photosynthesis takes place in plants only in the light. Respiration takes place
both with and without light.
The revised, balanced equation for the generation of sugar from sunlight, water, and carbon dioxide is
6 CO2 + 12 H2O AE C6H12O6 + 6 O2 + 6 H2O.
After removal of the carbon, the oxygen in the carbon dioxide ends up in
water molecules.
The net energy outcome of cyclic photophosphory-lation is
ATP.
The air contains around ___________ carbon dioxide.
0.036%
The concentration of oxygen in the air is
21%.
In C4 plants, CO2 is first fixed into a compound called
oxaloacetate.
In cacti, CO2 is stored for use in the CalvinñBenson cycle
during the evening
Plants classified as CAM store CO2
a and c.
A) by making oxaloacetate.
B) by making PEP carboxylase.
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