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WorksheetsMHS Cellular Energetics
Total questions: 133
Worksheet time: 2hrs 35mins
A researcher proposes a model of an enzyme-catalyzed reaction in which a reactant is converted to a product. The model is based on the idea that the reactant passes through a transition state within the enzyme-substrate complex before the reactant is converted to the product.
Which of the following statements best helps explain how the enzyme speeds up the reaction?
The enzyme’s active site binds to and stabilizes the reactant, which decreases the free-energy change of the reaction.
The enzyme’s active site binds to and stabilizes the transition state, which decreases the activation energy of the reaction.
The enzyme’s active site binds to and stabilizes the product, which increases the amount of energy released by the reaction.
The enzyme’s active site binds to and stabilizes both the reactant and the product at the same time, which increases the reaction’s equilibrium constant.
If a mutation occurs in a DNA sequence that codes for an enzyme, what is the most likely result?
There will likely be no change in the shape and function of the enzyme.
The enzyme will most likely fold in a way that makes its shape incompatible with the substrate and the enzyme will not function correctly.
The enzyme will not be produced at all.
The enzyme will have an enhanced ability to bind with the substrate.
Which of the following correctly describes enzyme structure and function?
The shape of an enzyme is responsible for its function.
All enzymes can bind to all substrates.
The substrate is responsible for the shape of the enzyme.
The location of an enzyme determines its function.
The induced fit model of enzyme activity is best described by which of the following?
the binding of substrate depends on the conformation of the active site
the binding of an activator alters the active site to enable binding of products more tightly
binding of substrate changes the conformation of the active site to bind substrate more tightly
binging of competitive inhibitors changes the shape of the active site to bind substrate less tightly
What was the substrate in our enzyme lab?
Hydrogen peroxide
Catalase
The potato
Oxygen gas
A weightlifter is using heavy weights in short bursts for a competition. Because his muscle cells are not able to take in enough oxygen to make very much ATP the weightlifter begins to get fatigue in his muscles. Which of the following processes is most likely going on in the muscles of the weightlifter as he competes in his event?
As the cells run out of oxygen they switch to anaerobic respiration (fermentation), which allows the cell to make small amounts of ATP in the absence of oxygen.
As the cells run out of oxygen, they die off gradually and the weightlifter's muscles have fewer contracting muscle cells.
The cells will never run out of oxygen if the weightlifter is breathing.
As the cells run out of oxygen, they will continue to make the same amount of ATP, since oxygen is not required to make ATP.
A researcher claims that a certain herbicide suppresses plant growth by inhibiting chloroplast function. To test the claim, the researcher treats isolated chloroplasts with increasing concentrations of the herbicide. The data from the experiment are presented in Table 1.
Which of the following statements best clarifies how the data support the researcher’s claim?
The thylakoid membrane is more permeable to carbon dioxide than to polar molecules.
ATP synthase activity depends on a proton gradient across the thylakoid membrane.
Some enzymes embedded in the thylakoid membrane catalyze the hydrolysis of ATP.
Carbon fixation in the Calvin-Benson cycle takes place in the stroma of chloroplasts.
What is the main purpose of the Krebs cycle?
to produce ATP
to load up electron carriers
to produce water
to produce carbon dioxide
What is the primary function of the light reactions of photosynthesis?
To produce glucose
To produce NADPH and ATP
To use ATP
To produce RuBP
Where does carbon dioxide enter plants?
Flowers
Stomata
Roots
Stem
Carbon fixation
is part of the Krebs Cycle
is part of the Calvin Cycle
is part of the ETC
is part of the Light Reactions
A. Chemiosmosis
B. Pyruvate Oxidation
C. Electron Transport Chain
D. Glycolysis
E. Citric Acid Cycle
List the stages of Cellular Respiration in order
D, B, E, C, A
D, E, B, A, C
E, B, C, D, A
A, B, D, C, E
The light reaction occurs in the ________ and the Calvin Cycle (light-independent) take place in the ________.
Chloroplast / thylakoid membrane
stroma / thylakoid
mesophyl / stomata
thylakoid membrane / stroma
What are the roles of ATP and NADPH in photosynthesis?
ATP and NADPH are forms of chemical energy produced from the light-dependent reactions to be used in the light independent reactions that produce sugars
ATP and NADPH are forms of chemical energy produced from the light independent reactions, to be used in the light dependent reactions that produce sugars.
ATP and NADPH are forms of chemical energy produced from the light-dependent reactions to be used in the light independent reactions that produce proteins.
ATP and NADPH are forms of light energy produced from the light-dependent reactions to be used in the light independent reactions that use sugars.
If glucose is broken down through aerobic respiration, a number of ATP can be made from the energy extracted. How many ATP are possible?
2 to 4
38 to 42
10 to 12
26 to 38
1. How many NADH molecules are produced on each turn of the Kreb’s cycle (Citric Acid Cycle) per one Acetyl CoA molecule?
One
Two
Three
Six
Which molecules are produced in glycolysis and used in fermentation?
Acetyl-CoA and NADH
Lactate, ATP, and CO2
Glucose, ATP, and NAD+
Pyruvate and NADH
Enzymes ___________________ activation energy to speed up chemical reactions.
increase
decrease
What is the relationship between an enzymes active site and its substrate?
The active site has the right polarity to interact with the substrate.
The active site is hydrophobic and interacts with other hydrophobic amino acids on the substrate
The active site has a specific shape that fits the shape of the substrate
The active site uses energy to form covalent bonds with the substrate
How does a competitive inhibitor affect an enzymes function?
It binds to an allosteric site that alters the shape of the enzyme
It changes the polarity of the enzyme, decreasing the rate of reaction
It denatures the enzyme which increases the activation energy for the reaction.
It binds to the active site, preventing the enzyme from catalyzing the reaction
Which of these factors can affect the initial rate of an enzyme reaction?
Enzyme concentration
Substrate concentration
Temperature
pH
All of the above
What effect does high temperature have on most enzymes reaction rates?
High temperatures will speed up the enzyme's reaction rate
High temperatures will stabilize the enzyme's reaction rate
High temperatures will decrease enzyme reaction rates due to denaturation
High temperatures do not affect enzyme reaction rates
How does initial substrate concentration affect enzyme reaction rates?
High concentration of substrates will inhibit enzyme reaction rates
Low concentration of substrate will increase enzyme reaction rates
High initial concentrations of substrate will increase the enzyme reaction rate
Enzyme reaction rates are independent of substrate concentration
In scientific experiments what is a control?
The variable that is manipulated by the researcher
A test that does not have the independent variable, to show a baseline with no reaction
A test where the researcher does not know which sample contains which variable
The variable that changes based on the experimental conditions
What is chemiosmosis?
The diffusion of electrons through the electron transport chain
The breakdown of a glucose molecule
The diffusion of protons down their concentration gradient
The active transport of NADH into the mitochondria
Why is chemiosmosis important to cellular respiration?
It provides the energy needed to catabolize glucose
It is the force that powers ATP synthase
It provides the energy needed to breakdown pyruvate into carbon dioxide
It generates the electrons needed for the electron transport chain
Why is the hydrolysis of ATP important to a cells function?
It provides a source of phosphate for the cell.
It releases energy that can be used to power cellular processes
It absorbs excess hydrogen ions in the cell to regulate the internal pH
It acts as a catalyst for chemical reactions in the cell.
Why do plants not store 100% of the light energy absorbed by chlorophyll in glucose molecules?
Most of the energy is used to power the reaction or is lost as heat
Plants do not have a high energy requirement, so they do not need to convert 100% of the energy
The energy is used to power ATP synthase proteins on the thylakoid membrane
The remaining energy is used actively transport oxygen out of the cell.
What is the best reason that plants do not perform photosynthesis at night?
They close their stomata at night to rest
They do not have an energy source to power the light reactions
Only a few types of plants are nocturnal
There is less carbon dioxide released into the air at night
What are the net products of photosynthesis?
6 CO2, 6 H2O, Energy
6 O2 and 6 H2O
C6H12O6 and 6 O2
6 CO2 and C6H12O6
What factors affect the rate of photosynthesis?
CO2 concentration
H2O available
Temperature
Light intensity
All of the above
What powers the rotation of ATP synthase enzymes in mitochondria and chloroplasts?
The energy absorbed during the light reactions.
The electronegativity of oxygen
Energy released by breaking the chemical bonds in glucose
The diffusion of hydrogen
How does a plant obtain the carbon necessary to form glucose?
Through the light reactions
From stored sugars in the roots of the plant
From the catabolic breakdown of water
Through CO2 absorbed from the atmosphere
What products of the light reaction are directly needed by the Calvin cycle in photosynthesis?
H ions and carbon dioxide
Photons absorbed by chlorophyll
FADH2 and Oxygen
ATP and NADPH
Which phase of photosynthesis produces organic sugars?
The light reactions
The Calvin cycle
The link reaction
Electron transport chain
What are the products of the Krebs Cycle?
Pyruvate, water, ATP, NADH
Acetyl CoA, NADH
NADH, FADH2, carbon dioxide, ATP
ATP, glucose
What are the products of glycolysis?
Pyruvate, ATP, water, NADH
Carbon dioxide, FADH2, NADH, ATP
32 ATP
NADPH and ATP
What are the products of the light reaction of photosynthesis?
Oxygen, NADPH, ATP
Glucose, NADP, ADP
Carbon dioxide, water, ATP
Oxygen, FADH2, ATP
What process creates the proton motive force in cellular respiration?
The electron transport chain
The hydrolysis of ATP
Chemiosmosis
The Citric Acid cycle
What is the function of NAD in cellular respiration?
It catalyzes the conversion of glucose into ATP
It provides inorganic phosphate needed by ATP synthase
It acts as an electron and proton acceptor to carry energy to the electron transport chain
It is the coenzyme needed to convert glucose into pyruvate
How are the ATP synthase enzymes in photosynthesis and cellular respiration similar?
They both rely on chemiosmosis of hydrogens down a gradient to power phosphorylation
They are both located in the cytoplasm of the cell
They both use oxygen to create a concentration gradient
They both receive hydrogen ions from FADH2
When will lactic acid build up in animal cells?
When there is excess carbon dioxide
When the cells produce too much ATP
When there is not enough oxygen to fuel the mitochondria
When the cells need to remove excess oxygen to avoid damaging their components.
Based on this graph, which enzyme would function best in a basic environment?
A
B
Enzymes ___________________ activation energy to speed up chemical reactions.
increase
decrease
How does the active site of an enzyme determine the substrate for that enzyme?
The active site has the right polarity to interact with the substrate.
The active site is hydrophobic and interacts with other hydrophobic amino acids on the substrate
The active site has a specific shape that fits the shape of the substrate
The active site uses energy to form covalent bonds with the substrate
How does a competitive inhibitor affect an enzymes function?
It binds to an allosteric site that alters the shape of the enzyme
It changes the polarity of the enzyme, decreasing the rate of reaction
It denatures the enzyme which increases the activation energy for the reaction.
It binds to the active site, preventing the enzyme from catalyzing the reaction
Which of these factors can affect the initial rate of an enzyme reaction?
Enzyme concentration
Substrate concentration
Temperature
pH
All of the above
Based on this graph, which enzyme would function best in a basic environment?
A
B
Why is the hydrolysis of ATP important to a cells function?
It provides a source of phosphate for the cell.
It releases energy that can be used to power cellular processes
It absorbs excess hydrogen ions in the cell to regulate the internal pH
It acts as a catalyst for chemical reactions in the cell.
What is the best reason that plants do not perform photosynthesis at night?
They close their stomata at night to rest
They do not have an energy source to power the light reactions
Only a few types of plants are nocturnal
There is less carbon dioxide released into the air at night
What are the net products of photosynthesis?
6 CO2, 6 H2O, Energy
6 O2 and 6 H2O
C6H12O6 and 6 O2
6 CO2 and C6H12O6
What factors affect the rate of photosynthesis?
CO2 concentration
H2O available
Temperature
Light intensity
All of the above
How does a plant obtain the carbon necessary to form glucose?
Through the light reactions
From stored sugars in the roots of the plant
From the catabolic breakdown of water
Through CO2 absorbed from the atmosphere
What are the products of the light reaction directly needed by the Calvin cycle in photosynthesis?
H ions and carbon dioxide
Photons absorbed by chlorophyll
FADH2 and Oxygen
ATP and NADPH
Which phase of photosynthesis produces organic sugars?
The light reactions
The Calvin cycle
The link reaction
Electron transport chain
What are the products of the Krebs Cycle?
Pyruvate, water, ATP, NADH
Acetyl CoA, NADH
NADH, FADH2, carbon dioxide, ATP
ATP, glucose
What are the products of glycolysis?
Pyruvate, ATP, water, NADH
Carbon dioxide, FADH2, NADH, ATP
32 ATP
NADPH and ATP
What are the products of the light reaction of photosynthesis?
Oxygen, NADPH, ATP
Glucose, NADP, ADP
Carbon dioxide, water, ATP
Oxygen, FADH2, ATP
What is the function of NAD in cellular respiration?
It catalyzes the conversion of glucose into ATP
It provides inorganic phosphate needed by ATP synthase
It acts as an electron and proton acceptor to carry energy to the electron transport chain
It is the coenzyme needed to convert glucose into pyruvate
What powers the ATP synthase enzymes in mitochondria and chloroplasts?
The energy absorbed during the light reactions.
The electronegativity of oxygen
Energy released by breaking the chemical bonds in glucose
The diffusion of hydrogen
How are the ATP synthase enzymes in photosynthesis and cellular respiration similar?
They both rely on chemiosmosis of hydrogens down a gradient to power phosphorylation
They are both located in the cytoplasm of the cell
They both use oxygen to create a concentration gradient
They both receive hydrogen ions from FADH2
When will lactic acid build up in animal cells?
When there is excess carbon dioxide
When the cells produce too much ATP
When there is not enough oxygen to fuel the mitochondria
When the cells need to remove excess oxygen to avoid damaging their components.
An enzyme's shape determines its
function
substrate
product
activation energy
An enzyme's active site
is determined by the proteins primary, secondary, tertiary and quaternary structure.
is specific to a particular substrate
may be blocked by a competitive inhibitor
all of the above
The light dependent reactions make the following products
ATP and NADH
ATP and NADPH
ATP and FADH2
all of the above
During the Calvin Cycle
ATP from the light dependent reactions is used to make glucose
NADH from the light dependent reaction is used to make glucose
1 ATP molecule is generated by one turn
extra ATP is used to regenrate CO2
Which process is the first step of all energy producing metabolic pathways?
Glycolysis
Krebs Cycle
Calvin Cycle
ETC
Which of the following is the correct order for aerobic cell respiration?
Glycolysis, Krebs Cycle, Pyruvate Oxidation and ETC
Glycolysis, Pyruvate Oxidation, Krebs Cycle and ETC
Pyruvate Oxidation, Krebs Cycle, ETC and Glycolysis
ETC, Pyruvate Oxidation, Glycolysis, and Krebs Cycle
Which stage of Aerobic Cell Respiration produces the most ATP?
Glycolysis
Pyruvate Oxidation
Krebs Cycle
ETC and oxidative phosphorilation
Which is the final electron acceptor in aerobic cellular respiration?
Carbon Dioxide
Oxygen
Rubisco
Glucose
An enzyme's shape determines its
function
substrate
product
activation energy
An enzyme works by
decreasing the activation energy
Adding energy during induced fit
Breaking or making new bonds during induced fit
All of the above
The light dependent reactions make the following products
ATP and NADH
ATP and NADPH
ATP and FADH2
all of the above
The enzyme rubisco can
use carbon dioxide to make glucose
use oxygen to make glucose
use both gases to make glucose
none of the above
During the Calvin Cycle
ATP from the light dependent reactions is used to make glucose
NADH from the light dependent reaction is used to make glucose
1 ATP molecule is generated by one turn
extra ATP is used to regenrate CO2
