File this one under "confusing plant terminology." Both a plant's stoma and its stroma are important in photosynthesis. What's the difference between stoma and stroma?
Stoma is the singular of stomata, the gas exchange pores in the leaf of the plant, while stroma is the fluid that fills the inner space of a chloroplast.
The three different known biochemical pathways organisms will use to photosynthesize include which of the following?
C3, C4, CAM
The rate-limiting step in a multi-step chemical reaction is defined as:
the slowest step of the reaction.
Which of the following is NOT a form of kinetic energy?
a covalent bond linking phosphate molecules
Which of the following statements most accurately depicts the relationship between the light reactions and the Calvin cycle in photosynthesis?
The Calvin cycle supplies ADP, NADP+, and a phosphate group to the light reactions, and the light reactions return ATP and NADPH to the Calvin cycle.
Life gains most of its energy from:
sunlight
The first law of thermodynamics states that energy is constant; it can ____________________, but not _______________.
be transferred and transformed; created or destroyed
The carbon dioxide needed for photosynthesis enters the plant through the:
stomata
Which of the following occurs in an oxidation-reduction reaction (a "redox" reation)?
One molecule gives up electrons and is oxidized, while the other molecule gains electrons and is reduced.
Desert plants reduce water loss by ____________.
closing stomatas
Glycolysis:
occurs in all cells
Which of the following environmental effects on human enzymatic activity is INCORRECT?
All of the above statements about human enzymes are correct.
Carotenoids:
are accessory pigments in chloroplasts that protect the chlorophyll by absorbing excessive light energy.
A molecule of glucose sugar is used by the cells of your body to make about 34-36 ATP. This means that:
glucose carries at least 30-40 times the energy of an ATP molecule.
During C4 photosynthesis:
plants are able to continue producing sugars even when they must close their stomata to reduce water loss during hot days.
According to the clip, what is the main function of chloroplasts?
harvest light energy to make sugars and other plant tissue
An anabolic process:
is one where simpler molecules are built up to from more complex molecules.
How do enzymes speed the conversion of a substrate into a product?
The enzyme binds to the substrate, inducing a slight conformational change in both the enzyme and the substrate that releases the product from the enzyme
Which by-product of photosynthesis was important in altering the atmosphere of the earth so that aerobic organisms could evolve?
oxygen
Chlorophyll b and the carotenoids are important as receptors of light energy because they:
respond to wavelengths different from the wavelengths that chlorophyll a responds to.
Which of the following energy-generating processes is the only one that occurs in all living organisms:
glycolysis.
According to the clip, what is the main function of photosynthesis?
make sugars for food
The energy transformation pathways of cellular respiration and photosynthesis are related in which of the following ways?
b), c), and d) are correct.
Which of the following statements about the light reactions of photosynthesis are correct?
a), b), and c) are all correct.
To synthesize 1 glucose molecule, the Calvin cycle uses _______ molecules of CO2, _______ molecules of ATP, and ________ molecules of NADPH.
6, 18, 12
ATP is an effective biological energy currency for several reasons. Which of the following is NOT one of them?
ATP's terminal phosphate bond is like the covalent bonds between carbon and hydrogen in organic molecules and is very stable.
When fermentation occurs in grapes left on the vine, the final product is the ethanol used to make wine. When fermentation occurs in our muscles, the final product is:
2 lactic acid molecules.
The reaction-center chlorophyll of photosystem I is known as P700 because:
this pigment optimally absorbs light of a 700 nm wavelength.
Energy derived from cellular respiration can originate from:
carbohydrates, proteins, and fats.
An inherited disease results from abnormal mitochondria passed from mother to child. Using your knowledge of mitochondria's function within human cells, which of the following is the most likely description of the symptoms of this disease?
extreme muscle weakness
The most abundant protein in the world is the enzyme that initiates the fixation of carbon in the Calvin cycle. This enzyme is called:
rubisco
The specialized cells that facilitate gas exchange in plants are known as:
guard cells.
What are the resulting products of the splitting of water in photosynthesis?
electrons, oxygen, and hydrogen ions
A molecule of chlorophyll increases in potential energy:
when one of its electrons is boosted to a higher-energy excited state after absorbing a photon of light.
Cellular respiration is the process by which:
energy from the chemical bonds of food molecules is captured by an organism.
During fermentation, yeast cells convert pyruvate to ethanol and CO2. Fermentation also occurs in human muscle cells when oxygen is depleted. In the case of muscle cells, what are the byproduct(s) of the fermentation of pyruvate?
lactic acid
The splitting of a mole (1023) of molecules of ATP to ADP and phosphate produces about:
7 kilocalories of energy.
Which of the following products of the light reactions of photosynthesis are later employed in the Calvin cycle?
NADPH and ATP
The light reactions of photosynthesis supply the Calvin cycle with:
ATP and NADPH & H+.
Because enzymes are proteins, they are sensitive to denaturing conditions that disrupt protein structure. Which of the following is NOT an example of a denaturing condition?
All of the above are examples of denaturing conditions.
In the Krebs cycle, the pieces of the starting glucose molecule (now pyruvate) are completely broken apart to produce carbon dioxide. What happened to all the energy that was contained in the bonds of the original glucose molecule?
It was transferred into NADH and FADH2 and some ATP.
When a photon strikes a molecule, the photon may
a) and c) are correct
Although the reactions of the Calvin cycle do not depend directly on light, they do not usually occur at night. Why?
The Calvin cycle depends on products of the light reactions which cannot occur at night.
Which of the following statements about glycolysis is INCORRECT?
It requires oxygen.
The number of photons striking a square meter surface each second is known as WHICH of the following?
photon flux density
Competitive inhibitors can prevent an enzyme from catalyzing a chemical reaction by binding to which of the following?
the enzyme's active site
Where does the Calvin cycle take place?
in the stroma of the chloroplast
Every time a source of energy is converted from one form to another:
some of the energy is converted to heat, which is not a very usable form of kinetic energy
What is the first step in CAM photosynthesis?
plants open their stomata at night to take in carbon dioxide
Biologically speaking, a pigment
is a molecule that absorbs a photon.
The three steps, in order, of the Calvin Cycle are:
fixation of CO2, sugar creation, regeneration
Mitochondria have a "bag within a bag" structure. This is necessary to:
create two distinct regions with a concentration differential, a form of potential energy.
Photosynthesis is the process by which plants, some bacteria, and some protistans, use the energy from sunlight to produce sugar, which _______________ converts to ATP, the "fuel" used by all living things.
cellular respiration
During photosynthesis, visible light has enough energy to:
excite electrons
Non-cyclic photophosphorylation produces:
both ATP and NADPH.
The leaf of a plant is the main place where photosynthesis takes place. Where are the photosynthetic cells located on a plant's leaf?
Only answers b) and c) are correct.
Which of the following statements about catalysts is INCORRECT?
A catalyst changes the amount of final net energy that is produced from a reaction.
Plants that carry out the Calvin cycle during the day when the stomata are closed and fix carbon dioxide into organic acids at night when the stomata are open are called:
CAM Plants
Which of the following half reactions is a part of the general equation for aerobic respiration?
6O2 + C6H12O6
Within the study of thermodynamics, a closed system is defined as system in which energy does not come in and energy does go out. Which of the following is considered a closed system?
the universe
Oxygen gas produced during photosynthesis originates as:
oxygen atoms contained in water molecules
Each ATP molecule is composed of three separate subunits. Which of the following is NOT a proper description of one of these subunits?
three carbon-nitrogen rings
Which of the following is NOT one of the major molecular changes that occurs in glycolysis?
Two molecules of pyruvate are converted into two molecules of Acetyl-CoA.
Which of the following equations properly represents the total production of energy, in kcal/mol, obtained from a single glucose molecule that has gone through substrate-level phosphorylation and oxidative respiration?
6 ATP + 32 ATP - 2 ATP = 36 ATP x 7.3 kcal/mol = 263 kcal/mol per glucose
A green plant can carry out photosynthesis if given nothing more than:
water, light, air
When electrons are exchanged in oxidation and reduction reactions, often they do not travel alone. Which of the following is an electron's most common partner in (energy) crime?
a proton
In the late summer, cooler temperatures have which of the following effects on some trees?
Chlorophyll production decreases.
In C4 photosynthesis, carbon is fixed in the ________ cells, and is then transported as aspartic or malic acid to ________ cells, where carbon dioxide is released for entry into the Calvin cycle.
mesophyll : bundle-sheath
Chloroplasts are most likely to be found in which type of cell?
plant mesophyll cells
In photosynthesis, both the first and the second photosystems:
generate energy-storage molecules.
Energized electrons from the water-splitting photosystem pass down an electron-transport chain to the ___________-producing photosystem
NADPH
What are the two major sources of electrons needed to drive the proton-pumping channels in chemiosmosis?
Both a) and b) are correct
In the lab, you measure the amount of ATP consumed by the Calvin cycle to be 14,000 molecules and the amount of NADPH consumed in the same cycle to be only 9,600 molecules. From where did the extra ATP molecules emerge?
cyclic electron flow
Which of the following is NOT a product of photosynthesis?
carbon dioxide
Substrate-level phosphorylation and oxidative respiration is only able to extract 38% of the total energy stored in the chemical bonds of one molecule of glucose. Using your knowing of net ATP production of these processes and the amount of energy in each
686 kcal/mol
Which of the statements below about the electron transport chain is INCORRECT?
Iron in the ferrous form gains an electron and become reduced to the ferric form.
All of the following are true about cyclic electron flow in photosynthesis BUT:
Cyclic electron flow only occurs in photosystem II.
Bubbles come from the leaves of an elodea plant when it is put under water because:
oxygen is a by-product of photosynthesis.
In photosynthesis, as electrons pass from carrier to carrier in redox reactions, hydrogen ions removed from ___________ are deposited in ______________.
the stroma; the thylakoid space
The energy released from the oxidation of a single mole of glucose:
All of the above are correct answers
Until very recently an enzyme was solely defined as "the catalysts of biological systems." Recent discoveries, however, has made it necessary to add a qualification. It is now known that RNA can act in place of an enzyme in certain reactions in a cell. In
RNA must display specificity to the substrates it acts on
Which of the following statements does NOT describe a specific action or function of oxygen during aerobic cellular respiration?
Oxygen physically removes ions from glucose, releasing energy.
Which of the following is another name for the light we can see?
photosynthetically active radiation
If a thylakoid were punctured so that its interior was no longer separated from the stroma, which of the following processes would be most directly affected?
the synthesis of ATP
In C4 plants, what is the purpose of mesophyll cells?
Both a) and b) are true.
Theodor Engelmann broadcast light that had been passed through a prism onto a mat of algae. This exposed different parts of the algae to different wavelengths of light. When he added aerobic bacteria to the system, he noted that the largest groups of bact
Bacteria aggregated in the area in which the most oxygen was being released.
The mitochondrial matrix:
None of the above is correct.