WorksheetsChapter 4 Review Assignment
Total questions: 90
Worksheet time: 1hrs 29mins
What is the study of how life harnesses and uses energy at the cellular level called?
Which of the following is NOT explored in Chapter 4?
The origin and forms of cellular energy
The biochemical processes that extract, store, and use energy
The structure of DNA
The efficiency of energy use in cells
Identify TWO biochemical processes mentioned in the overview that are involved in extracting, storing, and using energy in cells.
Photosynthesis
Cellular respiration
Fermentation
Osmosis
Even at rest, cells are actively using energy to maintain internal balance and perform necessary functions.
True
False
What is the sum of all chemical reactions that take place inside cells called?
Catabolism
Anabolism
Metabolism
Photosynthesis
Some chemical reactions in cells are spontaneous and release energy, while others require an input of energy.
True
False
What is the primary source of energy for most life forms on Earth?
Heat
Light energy from the sun
Producers
Decomposers
Fill in the blank: The sum of all chemical reactions that take place inside cells is referred to as the cell's (a) .
According to the diagram, which group is responsible for breaking down dead plant and animal material and contributing to the nutrient pool?
Producers
Consumers
Decomposers
Herbivores
What is energy?
The study of energy transformations
The capacity to perform work or cause change, existing in various forms such as light, heat, and chemical energy
The process of photosynthesis
The increase of disorder in a system
What does thermodynamics study?
The process of photosynthesis
The study of energy transformations
The creation of energy
The destruction of energy
The first law of thermodynamics states that energy cannot be ______ or destroyed, only transformed.
The second law of thermodynamics indicates that energy transformations increase ______ in a system.
entropy (disorder)
Living organisms are ______ systems, exchanging energy with their surroundings through processes like photosynthesis and cellular respiration.
Closed
Isolated
Open
Insulated
Which type of system exchanges both energy and matter with its surroundings?
Isolated system
Closed system
Open system
Refer to the diagram showing different forms of energy. Which of the following is NOT shown as a form of energy in the diagram?
Nuclear energy
Magnetic energy
Sound energy
Chemical energy
What type of energy is stored in food or fuel?
(a)
What type of energy is shown when a person is riding a bicycle?
(a)
Which type of energy is stored energy that an object has because of its position or condition?
Kinetic energy
Thermal energy
Potential energy
Chemical energy
Which of the following is an example of kinetic energy?
A rock at the edge of a cliff
A stretched rubber band
A rolling ball
Chemical energy stored in food
Light energy can be transformed into chemical energy in plants.
True
False
Fill in the blank: (a) energy is the energy of an object in motion.
Fill in the blank: (a) energy is stored energy that an object has because of its position or condition.
Refer to the diagram of metabolic pathways. Which of the following statements is true about anabolic pathways?
Large molecules are broken down into small ones. Energy is released.
Small molecules are built into large ones. Energy is required.
Small molecules are broken down into large ones. Energy is released.
Large molecules are built into small ones. Energy is required.
Metabolism encompasses all chemical reactions within a cell and is divided into two main pathways. Catabolic pathways ______ complex molecules to release energy.
Metabolism encompasses all chemical reactions within a cell and is divided into two main pathways. Anabolic pathways use energy to ______ complex molecules from simpler ones.
Which of the following best describes the relationship between catabolic and anabolic pathways?
They are completely independent of each other.
Energy released from catabolic reactions fuels anabolic processes.
Anabolic pathways release energy for catabolic reactions.
Both pathways only break down molecules.
Catabolic pathways use energy to synthesize complex molecules from simpler ones.
True
False
What is free energy (ΔG)?
The total energy in a system
The usable energy available to do work after accounting for energy lost (like heat) during a chemical reaction
The energy stored in products only
The energy released as heat only
Exergonic reactions (ΔG < 0) are called ______ reactions because they release energy and products have less free energy than reactants.
Endergonic reactions (ΔG > 0) are called ______ reactions because they require input of energy to occur.
nonspontaneous
Which of the following best describes an exergonic reaction?
It requires an input of energy
It results in a net release of free energy
The reactants have less free energy than the products
It cannot occur spontaneously
Which of the following best describes an endergonic reaction?
Energy is released to the surroundings
Requires an input of energy
Occurs without energy input
Products have less energy than reactants
What happens to energy during an endergonic reaction?
Energy is absorbed
Energy is released
No energy change
Energy is stored in products
What happens to energy during an exergonic reaction?
Energy is released
Energy is absorbed
No energy change
Energy is lost as heat
What are catalysts?
Substances that slow down chemical reactions
Substances that speed up chemical reactions without being consumed in the process
Proteins that are consumed in reactions
Substances that stop reactions completely
Enzymes make reactions occur faster at normal temperatures, enabling life processes to function efficiently.
True
False
Refer to the diagram of activation energy. Which line represents the reaction with an enzyme?
Solid purple line
Dashed red line
What is the role of substrates in enzyme-catalyzed reactions?
They are the products of the reaction
They are the reactant molecules that enzymes bind to in order to catalyze a reaction
They are the enzymes themselves
They are inhibitors of the reaction
The specificity of an enzyme for its substrate is determined by the arrangement of amino acid side chains in the ________.
active site
entire protein
cell membrane
nucleus
What is formed when an enzyme binds to its substrate?
Enzyme-substrate complex
Substrate-enzyme bond
Enzyme-product complex
Substrate complex
The enzyme-substrate complex (a) the activation energy of the reaction, speeding it up.
Which of the following is NOT a way enzymes work?
Bring substrates together
Create the right environment
Weaken bonds
Are denatured in the reaction
What feature of enzymes determine their "specificity" to a particular substrate molecule?
Which enzyme-substrate binding model is now widely accepted?
Lock-and-key model
Induced fit model
Substrate fit model
Enzyme lock model
The lock-and-key model suggests that enzyme-substrate binding is a perfect fit.
True
False
Fill in the blank: According to the induced fit model, an enzyme changes its (a) slightly when binding to a substrate to enhance interaction.
Which of the following factors can affect enzyme activity in cells?
pH
Temperature
Salt concentration
All of the above
What factors affect the rate of enzyme activity?
enzyme size and shape
presence of oxygen
temperature, pH, substrate concentration, enzyme concentration, inhibitors, and activators
enzyme and substrate concentration only
How does a competitive inhibitor affect enzyme activity?
It binds to the enzyme’s active site, preventing the substrate from binding.
It binds to a site other than the active site, changing the enzyme’s shape.
It increases the enzyme’s affinity for the substrate.
How does a noncompetitive inhibitor affect enzyme activity?
It binds to an allosteric site, altering the enzyme's shape and decreasing its catalytic efficiency.
It binds directly to the active site, blocking the substrate from binding.
It increases the enzyme's affinity for the substrate by binding to the active site.
What is the role of an allosteric activator in enzyme regulation?
It binds to the active site and blocks substrate binding.
It binds to a site other than the active site and enhances enzyme activity.
It permanently deactivates the enzyme.
What is the role of an inhibitor in allosteric inhibition?
It increases the affinity of the substrate for the active site
It binds to the allosteric site and alters the active site, preventing substrate binding
It acts as a substrate
It activates the enzyme
Refer to the diagram on 'Regulation of Enzyme Activity.' In allosteric activation, the activator binds to the enzyme and causes the active site to become (a) , allowing the substrate to bind.
The induced-fit model of enzyme activity suggests that:
The enzyme's active site changes shape to fit the substrate upon binding, unlike the lock-and-key model where the active site is a perfect fit from the start.
The enzyme's active site is always rigid and does not change shape when the substrate binds.
The substrate changes its shape to fit the enzyme's active site, but the enzyme remains unchanged.
Both the enzyme and substrate do not change shape during binding.
Refer to the diagram of feedback inhibition in metabolic pathways. What is the role of the end product in this process?
It acts as a substrate for Enzyme 1
It inhibits the activity of Enzyme 1
It is converted into the 1st intermediate substrate
It activates Enzyme 3
Cofactors and _______ are enzyme regulators, but cellular metabolic products are key players in feedback inhibition.
In competitive inhibition, the inhibitor binds to the enzyme's active site.
True
False
Molecules can regulate enzyme activity in various ways, such as allosteric modulation and competitive or non-competitive inhibition. Which of the following is NOT a way molecules regulate enzyme activity?
Allosteric modulation
Competitive inhibition
Non-competitive inhibition
Photosynthesis
What does ATP stand for?
Adenosine triphosphate
Adenosine diphosphate
Adenosine monophosphate
Adenine triphosphate
Which of the following is NOT a component of ATP as shown in the diagram?
Adenine
Ribose
Glucose
Phosphate groups
The energy stored in ATP is released when the bond between the _______ and third phosphate group is broken.
fourth
adenine base
Which of the following is formed when ATP releases energy?
ADP and an inorganic phosphate
AMP and glucose
Ribose and adenine
Protein and water
Glycolysis is the first step in glucose metabolism, breaking down one molecule of glucose (C6H12O6) into two molecules of (a) (C3H4O3).
Where does glycolysis occur in the cell?
Nucleus
Cytoplasm
Mitochondria
Endoplasmic reticulum
Glycolysis is an aerobic process that requires oxygen to occur.
True
False
In glycolysis, a glucose molecule (C6H12O6) is converted into two molecules of pyruvate (C3H4O3).
True
False
During glycolysis, how many molecules of ATP are produced from one molecule of glucose?
2 ATP
4 ATP
6 ATP
8 ATP
According to the Glycolysis Overview, how many ATP molecules are used in the energy investment phase?
1
2
4
0
How many ATP molecules are produced in the energy payoff phase of glycolysis?
2
3
4
6
What is the net gain of ATP molecules after glycolysis?
1
2
3
4
How many NADH molecules are produced during glycolysis?
What are the final products of glycolysis?
2 pyruvate, 2 ATP, 2 NADH
Glycolysis occurs in the mitochondrion.
True
False
In eukaryotic cells, pyruvate from glycolysis is transported into ________, when oxygen is available.
What is the molecule that enters the citric acid cycle after pyruvate is converted?
(a)
The citric acid cycle is also known as the:
Calvin cycle
Krebs cycle
Glycolysis cycle
Electron transport chain
Where does the citric acid cycle occur in eukaryotic cells?
Coenzyme A is added to pyruvate to form Acetyl CoA before entering the citric acid cycle.
True
False
What is the final stage of aerobic respiration that produces the majority of ATP during glucose breakdown?
Glycolysis
Citric acid cycle
Oxidative phosphorylation
Fermentation
Where does oxidative phosphorylation occur in eukaryotic cells?
Cytoplasm
Outer mitochondrial membrane
Inner mitochondrial membrane
Nucleus
Oxidative phosphorylation involves two key processes: the ________ and chemiosmosis.
The electron transport chain (ETC) and chemiosmosis together transform the energy from glucose's electrons into large amounts of ATP.
True
False
What molecule is produced by ATP synthase using an H+ gradient?
(a)
What is the main function of the Electron Transport Chain (ETC) in oxidative phosphorylation?
To break down glucose into pyruvate
To pump hydrogen ions (H⁺) and create an electrochemical gradient
To directly produce ATP from ADP
To convert oxygen into carbon dioxide
Fill in the blank: Oxygen is the final electron acceptor in the Electron Transport Chain, forming (a) by combining with electrons and H⁺.
Which enzyme uses the energy from the H⁺ gradient to convert ADP to ATP during chemiosmosis?
ATP synthase
NADH dehydrogenase
Cytochrome c oxidase
Pyruvate kinase
Without oxygen, the Electron Transport Chain (ETC) stops, and ATP production halts, leading to cell death.
True
False
What percentage of ATP generated in aerobic respiration is produced by the process of chemiosmosis?
10%
25%
50%
90%
Environmental factors may cause enzymes to ______, an irreversible change in the shape which can affect the function of the enzyme.
