BIO 110 - EXAM 2
Exergonic
(of a metabolic or chemical process) accompanied by the release of energy.
How many NADH are produced by glycolysis?
2
In glycolysis there is a net gain of ______ ATP.
2
Starting with one molecule of glucose, the energy-containing products of glycolysis are
2 NADH, 2 pyruvate, and 2 ATP
Which of these equations best summarizes photosynthesis?
6 CO2 + 6 H2O → C6H12O6 + 6 O2
In cellular respiration, the energy for most ATP synthesis is supplied by
A proton gradient across a membrane
A series of enzymes catalyze the reaction X → Y → Z → A. Product A binds to the enzyme that converts X to Y at a position remote from its active site. This binding decreases the activity of the enzyme. What is substance X?
A substrate
In glycolysis, what starts the process of glucose oxidation?
ATP
Which of the following are products of the light reactions of photosynthesis that are utilized in the Calvin cycle?
ATP and NADPH
The energy required to run the calvin cycle comes from ______ and ______.
ATP, NADPH
The oxygen consumed during cellular respiration is involved directly in which process or event?
Accepting electrons at the end of the electron transport chain
Which of these enters the citric acid cycle?
Acetyl CoA
Which of these is NOT a product of the citric acid cycle?
Acetyl CoA
The primary role of oxygen in cellular respiration is to
Act as an acceptor for electrons and hydrogen, forming water
Reactants capable of interacting to form products in a chemical reaction must first overcome a thermodynamic barrier known as the reaction's
Activation Energy
How does an enzyme increase the rate of the chemical reaction it catalyzes?
An enzyme reduces the free energy of activation of the reaction it catalyzes
Generation of proton gradients across membranes occurs during
Both photosynthesis and respiration
The energy-carrying products of the light reactions, NADPH and ATP, are used by the ______ ________.
Calvin Cycle
Into which molecule are all the carbon atoms in glucose ultimately incorporated during cellular respiration?
Carbon Dioxide
Carbon from the carbon dioxide is attatched to a 5-carbon molecule called RuBP
Carbon Fixation
What is the term for metabolic pathways that release stored energy by breaking down complex molecules?
Catabolic pathways
Increasing the substrate concentration in an enzymatic reaction could overcome which of the following?
Competitive Inhibition
What is an heterotroph?
Consume organic carbon
What is an autotroph?
Converting inorganic carbon into organic carbon
Which stage of glucose metabolism produces the most ATP?
Electron transport and chemiosmosis
What is the overall reaction for photosynthesis?
Energy + 6 CO2 + 6 H2O ---> C6H12O6 + 6 O2
Which of the following statements regarding enzymes is true?
Enzymes increase the rate of a reaction by lowering the activation energy barrier
Which of these is NOT a product of glycolysis?
FADH2
The mechanism in which the end product of a metabolic pathway inhibits an earlier step in the pathway is most precisely described as
Feedback Inhibition
Which process is not part of the cellular respiration pathway that produces large amounts of ATP in a cell?
Fermentation
Which molecule is metabolized in a cell to produce energy for performing work?
Glucose
Net input of Glycolysis
Glucose, NAD+, ADP
Which process in eukaryotic cells will proceed normally whether oxygen (O2) is present or absent?
Glycolysis
Which step of the cellular respiration pathway can take place in the absence of oxygen?
Glycolysis
Spontaneous
If it occurs without being driven by some outside force
Where is ATP synthase located in the mitochondrion?
Inner Membrane
Nonspontaneous/Endergonic
Is a chemical reaction in which the standard change in free energy is positive and energy is absorbed.
The active site of an enzyme is the region that
Is involved in the catalytic reaction of the enzyme
What happened to most of the energy that the cell obtains from the oxidation of glucose?
It is stored in NADH and FADH2
What happens to the lactate in skeletal muscle cells?
It is taken to the liver and converted back to pyruvate
Why does the process of photosynthesis require an input of energy?
It takes more energy to break 6 CO2 bonds and energy 6 H2O bonds than formed
Why is glycolysis described as having an investment phase and a payoff phase?
It uses stored ATP and then forms a net increase in ATP
Photosynthesis converts __________ energy to ________ energy.
Kinetic, Potential
In muscle cells, fermentation produces _______.
Lactate and NAD+
Which of the following events occurs in the light reactions of photosynthesis?
Light is absorbed and funneled to reaction-center chlorophyll a
Besides turning enzymes on or off, what other means does a cell use to control enzymatic activity?
Localization of enzymes into specific organelles or membranes
The overall function of the calvin cycle is ________.
Making sugar
Energy released by the electron transport chain is used to pump H+ into which location in eukaryotic cells?
Mitochondrial intermembrane space
Where are the proteins of the electron transport chain located?
Mitochondrial intermembrane space
Which of the following statements describes NAD+?
NAD+ is reduced to NADH during glycolysis, pyruvate oxidation, and the citric acid cycle
Which of the following statements about the electron transport chain is true?
NADH and FADH2 donate their electrons to the chain
Which of the following products of the light reactions of photosynthesis is consumed during the calvin cycle?
NADPH
The splitting of carbon dioxide to from oxygen gas and carbon compounds occurs during
Neither photosynthesis nor respiration
One function of both alcohol fermentation and lactic acid fermentation is to
Oxidize NADH to NAD+
Is oxygen oxidized or reduced?
Oxidized
Which of the following is a product of the light reactions of photosynthesis?
Oxygen, ATP, and NADPH
Reduction of NADP+ occurs during
Photosynthesis
Which of the following statements best describes the relationship between photosynthesis and respiration?
Photosynthesis stores energy in complex organic molecules, whereas respiration releases it
Net output of Glycolysis
Pyruvate, NADH, ATP
In fermentation _______ is reduced and _________ is oxidized.
Pyruvate... NADH
The NADPH required for the calvin cycle comes from
Reactions initiated in photosystem I
Which of the following are directly associated with photosystem I?
Receiving electrons from the thylakoid membrane electron transport chain
Is carbon oxidized or reduced?
Reduced
When a molecule of NAD+ (nicotinamide adenine dinucleotide) gains a hydrogen atom (not a proton), the molecule becomes
Reduced
Reduction of oxygen to form water occurs during
Respiration only
What is carbon fixation catalyzed by?
Rubisco
What is the role in the light reactions?
Splits into electrons
When oxygen is released as a result of photosynthesis, it is a direct by-product of
Splitting water molecules
Where in the chloroplast do the reactions of the calvin cycle occur?
Stroma
Where do the enzymatic reactions of the calvin cycle take place?
Stroma of the chlorplast
In glycolysis, ATP molecules are produced by ___________.
Substrate-level phosphorylation
In the citric acid cycle, ATP molecules are produced by _________.
Substrate-level phosphorylation
The ATP made during fermentation is generated by which of the following?
Substrate-level phosphorylation
The ATP made during glycolysis is generated by
Substrate-level phosphorylation
What is the primary function of the calvin cycle?
Synthesize simple sugars from carbon dioxide
Where does the energy from to drive the process of photosynthesis?
The Sun
According to the induced fit hypothesis of enzyme catalysis, which of the following is correct?
The binding of the substrate changes the shape of the enzyme's active site
Which of the following statements best represents the relationships between the light reactions and the calvin cycle?
The light reactions provide ATP and NADPH to the Calvin cycle, and the cycle returns ADP, Pi, and NADP+ to the light reactions.
When electrons move closer to a more electronegative atom, what happens?
The more electronegative atom is reduced, and energy is released
Where in the chloroplast do the light reactions occur?
Thylakoid discs
In a plant cell, where are the ATP synthase complexes located?
Thylakoid membrane and inner mitochondrial membrane
Where are the molecules of the electron transport chain found in plant cells?
Thylakoid membranes of chloroplasts
True or false? The potential energy in an ATP molecule is derived mainly from its three phosphate groups.
True
True or false? The reactions that generate the largest amounts of ATP during cellular respiration take place in the mitochondria
True
In the absence of oxygen, what is the net gain of ATP for each glucose molecule that enters glycolysis?
Two ATP
Which statement about the binding of enzymes and substrates is correct?
When substrate molecules bind to the active site of the enzyme, the enzyme undergoes a slight change in shape
In photosynthetic cells, synthesis of ATP by the chemiosmotic mechanism occurs during
both photosynthesis and respiration
The light reactions of photosynthesis use _____ and produce _______.
water...NADPH