Studied by 5 people
Chapters: 8, 9, 10
The process of stabilizing the structure of an enzyme in its active form by the binding of a molecule is an example of __________.
allosteric regulation
How does ATP drive mechanical work inside a cell?
By binding to motor proteins
Which of the following statements about the active site of an enzyme is correct?
a) The active site has a fixed structure (shape).
b) Coenzymes are rarely found in the active site of an enzyme.
c) The active site may resemble a groove or pocket in the surface of a protein into which the substrate fits.
d) The structure of the active site is not affected by changes in temperature.
e) The active site allows the reaction to occur under the same environmental conditions as the reaction without the enzyme.
c
If the entropy of a living organism is decreasing, which of the following is most likely to be occurring simultaneously?
a) Energy input into the organism must be occurring to drive the decrease in entropy.
b) The entropy of the organism's environment must also be decreasing.
c) Heat is being used by the organism as a source of energy.
d) The first law of thermodynamics is being violated.
a
Which of the following is a correct description of the events of cellular respiration and the sequence of events in cellular respiration?
a) Oxidation of glucose to pyruvate; reduction of pyruvate; TCA cycle; oxidative phosphorylation
b) Glycolysis; reduction of pyruvate; TCA cycle; oxidative phosphorylation
c) Glycolysis; oxidative phosphorylation; TCA cycle; oxidation of pyruvate
d) Oxidation of pyruvate; TCA cycle; oxidation of glucose to pyruvate; oxidative phosphorylation
e) Oxidation of glucose to pyruvate; oxidation of pyruvate; oxidation of acetyl-coA; oxidative phosphorylation
e
In which process is glucose oxidized to form two molecules of pyruvate?
Glycolysis
The energy from the electrons in NADH and FADH2 fuel what process in the electron transport chain?
The pumping of H+ ions across the membrane of the mitocondria
A small amount of ATP is made in glycolysis by which of the following processes?
Transfer of a phosphate group from a fragment of glucose to ADP by substrate-level phosphorylation
Most of the NADH that delivers electrons to the electron transport chain comes from which of the following processes?
The citric acid cycle
Fermentation by itself produces no ATP but keeps glycolysis going, which produces a small amount of ATP. How does fermentation do this?
Fermentation oxidizes NADH to NAD+, which facilitates the production of ATP in glycolysis.
In what molecule(s) is the majority of the chemical energy from pyruvate transferred during the citric acid cycle?
NADH and FADH2
What is the role of oxygen in the electron transport chain?
It is reduced to form water with H+ ions as they cross the membrane, final proton acceptors
In the overall process of glycolysis and cellular respiration, __________ is oxidized and __________ is reduced.
glucose;oxygen
Which of the following processes occurs during the second phase, the reduction phase, of the Calvin cycle?
G3P Production
Metabolic pathways are typically redox processes. In photosynthesis, what molecule is oxidized and what molecule is reduced?
Water is oxidized and carbon dioxide is reduced.
Of the following, which occurs during the Calvin cycle?
a) Photons are absorbed.
b) CO2 is reduced.
c) Light energy is converted to chemical energy.
d) ATP and NADPH are synthesized.
e) Excited electrons are conveyed from chlorophyll to an electron acceptor.
b
During which process is molecular oxygen produced in photosynthesis?
a) The light reactions by linear electron flow
b) The light reactions by the excitation of electrons in chlorophyll
c) The Calvin cycle during carbon fixation
d) The Calvin cycle during G3P production
a
The light reactions of photosynthesis generate high-energy electrons, which end up in __________. The light reactions also produce __________ and __________.
NADPH; ATP; oxygen
Explain the 1st and 2nd Laws of Thermodynamics.
the first law of thermodynamics states that energy cannot be created or destroyed, energy can only be transferred or transformed. The second law of thermodynamics states that every energy transformation increases the entropy of the universe. entropy is the measure of molecular disorder/randomness
What happens when ATP is converted to ADP and is energy absorbed or released? What needs to occur to go back to ATP and does the reaction require energy or give it off?
when ATP is converted to ADP energy is released. To convert it back an inorganic phosphate is added to ADP through a process called phosphorylation which requires energy.
What is a redox reaction and what happens to electrons during reduction and during oxidation?
oxidation is losing electrons, reduction is gaining electrons.
What is produced in the following stages of cellular respiration and where does each take place?
Glycolysis:
Pyruvate oxidation:
Citric Acid Cycle:
Oxidative phosphorylation:
Glycolysis: 2 pyruvate, 2 ATP, 2 NADH, and water. Occurs in the cytoplasm
Pyruvate oxidation: acetyl CoA, NADH, carbon dioxide. occurs in mitochondria
Citric Acid Cycle: NADH, FADH2, ATP, carbon dioxide. occurs in mitochondria
Oxidative phosphorylation: ATP and water. occurs in membrane of mitochondria
How are photosynthesis and cellular respiration connected to one another? Include the products and reactants of each in your answer.
Sugar and oxygen made in photosynthesis is used in cellular respiration, which generates carbon dioxide and water in photosynthesis.
What is the chemical reaction of cellular respiration and what molecules are being reduced and oxidized?
glucose is oxidized and oxygen is reduced.
How do temperate and pH affect enzyme activity? What happens if an enzyme is heated to an extreme temperature and what term describes this?
lowering the temp decreases an enzymes function and increasing the temp to a certain extent increasing an enzymes function, however, in extremely high temps an enzyme denatures, loses its shape and therefore its function.
Compare and contrast competitive and noncompetitive inhibitors.
competitive inhibitors directly compete with substrate to fit in the active site to block the substrate from binding. Noncompetitive inhibitors attach away from the active site and change its shape to prevent substrate from binding
What is the main pigment involved in photosynthesis and what makes plants green?
the main pigment is chlorophyll, this pigment absorbs all colors except for green which is reflected, giving plants their color.
Explain what happens in a photosystem (make sure to mention sunlight, photons, pigments, and electrons).
in a photosystem pigments collect photons, energy from sunlight, that is then used to excite electrons
How are electrons replaced in each of the photosystems?
In PS II the electrons are replaced by the splitting of water and in PS I electrons are replaced by electrons from the main ETC
In the electron transport chain, how are electrons used to produce ATP?
NADH and FADH2 donate electrons to the ETC, which powers ATP synthesis via oxidative phosphorylation.
What is the use for ATP in the Calvin Cycle? What about NADPH?
ATP and NADPH are used for their stored energy to convert PGA to G3P (sugar), reduction rxn
In cellular respiration, where do electrons come from to fuel the Electron Transport Chain and where do those electrons ultimately end up?
The electrons from the ETC come from glucose and ultimately end up in ATP and with oxygen to form H2O
Why does fermentation occur? What is the difference between lactic acid fermentation and alcohol fermentation (what is produced in each)?
Fermentation occurs when glucose needs to be broken down, but when oxygen is not available. Lactic acid fermentation produces lactic acid and alcohol fermentation produces ethanol and carbon dioxide.
In which type of cellular respiration (aerobic respiration, lactic acid fermentation or alcohol fermentation) is the most ATP produced? Which step is it produced in?
aerobic respiration produces the most ATP with 32. 28 in oxidative phosphorylation, 2 in citric acid cycle, and 2 in glycolysis.
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