Question 1

The changing of an enzyme's shape as the substrate binds to the active site is called the
A) substrate binding theory.
B) induced fit model.
C) metabolic pathway.
D) energy of activation.
E) enzyme binding theory.

Accepted Answer

The changing of an enzyme's shape as the substrate binds to the active site is called the induced fit model. This model states that the active site of an enzyme is not a rigid structure, but rather it can change its shape slightly to accommodate the substrate, resulting in a more optimal fit between the two.

Question 2

A patient who is admitted to the hospital shares that she has been taking a series of "water pills" to help her lose weight.Her skin and mucous membranes are dry,and she is complaining of a headache.The physician on call asks for an IV treatment to be promptly administered.Based on the information given,what would likely be the type of IV solution given to this patient?
A) hypotonic
B) isotonic
C) osmotic
D) hypertonic
E) saturated

Accepted Answer

In medical settings, intravenous solutions IV) can be used to treat varied conditions. In the situation described here, the symptoms seen suggest that the individual is dehydrated. A solution that is hypotonic to the patient's cells will provide the greatest uptake of water to the dehydrated cells.

Question 3

The second law of thermodynamics states that all energy transformations result in more disordered energy.How does this relate to energy transformation in a living organism?
A) the energy taken in as food is eventually converted into kinetic energy
B) the energy taken in as food is eventually converted into heat energy
C) the energy taken in as kinetic energy is eventually converted into heat energy
D) the energy taken in as heat energy is eventually converted into kinetic energy
E) no energy in a living organism can undergo more than one transformation

Accepted Answer

In living organisms, the energy taken in as food is eventually converted into heat energy, which is a more disordered form of energy according to the second law of thermodynamics. Some of the energy is also used to carry out other functions such as movement and growth, but ultimately, a significant portion is lost as heat. This process contributes to the overall increase in entropy, or disorder, in the universe.

Question 4

Which of the following enables a cell to pick up and concentrate a specific type of molecule?
A) passive transport
B) receptor-mediated endocytosis
C) osmosis
D) exocytosis
E) facilitated diffusion

Accepted Answer

Receptor-mediated endocytosis is a process by which the cell uses specific receptors on its membrane to pick up and concentrate a particular type of molecule, such as a hormone or growth factor. The molecule binds to the receptor on the cell surface, triggering the formation of a vesicle that brings the molecule into the cell. This process is different from passive transport (A), osmosis (C), exocytosis (D), and facilitated diffusion (E), which do not involve specific receptors for particular types of molecules.

Question 5

Which of the areas shown in the figure below indicates the presence of an enzyme in the movement of reactant over to product? 
A) a
B) b
C) c
D) d
E) Both a & d

Accepted Answer

The answer of Which of the areas shown in the...

Question 6

Once the substrate moves into the active site of the enzyme
A) the enzyme breaks the substrate into three products.
B) the two molecules fuse together to form the product.
C) the enzyme alters in shape to more closely fit the substrate.
D) the substrate alters shape to more closely fit the active site.
E) the substrate and enzyme both alter shape to fit together.

Accepted Answer

The enzyme alters its shape to more closely fit the substrate in the active site, which promotes the reaction between the substrate molecules and allows for the formation of the product.

Question 7

The second law of thermodynamics states that all energy transformations result in more disordered energy.How do living organisms,which depend on chemical potential converting to kinetic energy to fuel their function,continue to live?
A) they must constantly take in chemical potential energy for fuel and excrete waste
B) living things do not obey the laws of thermodynamics
C) they must constantly take in chemical potential energy for fuel
D) they excrete the disordered molecules and lose the disordered energy as heat
E) they take the disordered molecules and heat energy and use them to create new fuel

Accepted Answer

The answer of The second law of thermodynamics states that...

Question 8

Which of the following is not a type of potential energy?
A) the energy in a glucose molecule
B) the energy contained in an rock sitting at the top of a cliff
C) the energy of a ball rolling down a hill
D) the energy contained in a hamburger
E) the energy of a diver standing on a diving board

Accepted Answer

The energy of a ball rolling down a hill is kinetic energy, not potential energy. Potential energy is stored energy, while kinetic energy is the energy of motion.

Question 9

Both starch and cellulose are made by stringing together many glucose molecules,but starch is easily digested by humans while cellulose is indigestible.The starch polysaccharide has every bond occurring below the sugar rings while the bonds in cellulose alternate between one bond above the ring and the next below the ring.How can you explain the human's inability to digest cellulose?
A) The enzyme that breaks down starch can only fit the specific bond configuration of bonds below the ring.
B) Humans do not eat cellulose.
C) The acidic molecules found in stomach acid cannot act on the bonds that are above the sugar rings in cellulose.
D) The alternating bonds make the cellulose molecule too large and bulk to enter cells for digestion.
E) Cellular respiration is only capable of breaking down specific bonds.

Accepted Answer

The enzyme that breaks down starch, amylase, can only fit and break the specific bond configuration of bonds occurring below the sugar rings. The alternating bond configuration in cellulose makes it resistant to amylase digestion.

Question 10

Why do metabolic pathways require tens to hundreds of different enzymes?
A) The enzymes are used up after one reaction and the molecules have to undergo multiple rearrangements.
B) The enzyme is deformed by the interaction with the substrate and needs a period of time to return to its original reactive form so many enzymes are needed to keep the pathway going.
C) Each enzyme has a specific substrate and produces a specific product.
D) Multiple enzymes are not required for the pathway but having them speed up the production of the final product.
E) The enzymes are attached to a membrane and cannot move to the location of the new intermediate so having a long line of enzymes to carry out the reaction allows the reaction to occur faster.

Accepted Answer

Each enzyme has a specific substrate and function in the metabolic pathway. The pathway requires different enzymes to ensure that each reaction occurs efficiently and in a specific order to produce the desired product.

Question 11

The second law of thermodynamics states that all energy transformations result in more disordered energy.How can photosynthesis take more disordered carbon dioxide and water and convert them into glucose which is more ordered?
A) living things do not obey the laws of thermodynamics
B) this is an illusion, it only appears that glucose is more ordered
C) photosynthesis is an exception to the second law of thermodynamics
D) solar energy is being added to the reaction to create glucose
E) plants are able to harness entropy and use it to carry out photosynthesis

Accepted Answer

The second law of thermodynamics applies to energy transformation within a closed system. In photosynthesis, solar energy is being added to the system, which is not considered in the law. The energy from sunlight allows the carbon dioxide and water molecules to become more ordered, resulting in the production of glucose. Therefore, choice D is correct.

Question 12

Which of the following statements reflects what occurs in the flow of energy conversions through living systems? A) Chloroplasts convert solar energy to the chemical energy of nutrient molecules. B) Mitochondria convert ATP molecules into glucose. C) Chloroplasts produce CO₂ and H₂O during photosynthesis. D) Mitochondria capture solar energy and convert it to oxygen. E) Chloroplasts burn glucose into ATP molecules during cell respiration.

Accepted Answer

Chloroplasts convert solar energy into the chemical energy of nutrient molecules during photosynthesis. This energy is then passed on to other organisms in the food chain through eating and digestion. Mitochondria are responsible for converting the chemical energy stored in nutrient molecules (such as glucose) into ATP, which can be used by cells for energy. The other options given do not accurately reflect the flow of energy conversions through living systems.

Question 13

Enzymes are able to speed up the rate of a reaction by
A) carrying substrates closer together.
B) binding substrates to a membrane.
C) producing more enzymes.
D) lowering the energy needed for the reaction to proceed.
E) producing more substrate.

Accepted Answer

Enzymes lower the activation energy required for a reaction to occur, which accelerates the reaction rate. They do this by stabilizing the transition state of the reaction, allowing it to proceed more quickly. Enzymes do not typically carry substrates closer together or produce more substrate or enzymes, and they do not bind substrates to a membrane.

Question 14

Pickles are often preserved in a 20-30% salt solution called brine.How does this method prevent contamination by microorganisms?
A) Bacteria can't survive in a hypertonic solution because they lose water.
B) Bacteria can't survive in hypotonic solutions because of the added pressure of the water they take in.
C) Bacteria cells are unable to digest the salt, thus killing the cells by starvation.
D) The high salt concentration increases the pH of the environment, making it unfavorable for bacteria to live there.
E) The high salt concentration creates an isotonic environment that the bacteria cannot live in.

Accepted Answer

The high salt concentration in the brine creates a hypertonic environment, meaning that there is a higher concentration of solutes (salt) outside of the bacterial cells than inside. This causes the bacterial cells to lose water, shrivel up, and ultimately die. Therefore, option A is the most accurate choice.

Question 15

ATP is a good source of energy for a cell because
A) it is able to be used in only one type of reaction.
B) its breakdown is coupled with energy-requiring reactions.
C) it provides excess energy for cellular reactions.
D) it is not reusable.
E) it takes no energy to make it.

Accepted Answer

The breakdown of ATP is coupled with energy-requiring reactions, meaning that the energy released from ATP hydrolysis can be used to power other cellular processes that require energy. This makes ATP an efficient source of energy for the cell. Choices A, C, D, and E are incorrect because ATP can be used in a variety of cellular reactions, provides just enough energy for cellular processes (not excess), is reusable, and actually requires energy to be made in the first place.

Question 16

Enzymes are named based on the substrate that they bind; this is possible because
A) enzymes all have the same shape.
B) an enzyme binds one specific substrate.
C) enzymes are used up in the reaction.
D) an enzyme is only associated with one metabolic pathway.
E) enzymes speed up the rate of a reaction.

Accepted Answer

Enzymes are highly specific in their function and only bind to one particular substrate or a group of related substrates. Therefore, enzymes can be named based on the substrate they bind. For example, lactase is an enzyme that specifically binds and breaks down lactose, while proteases are enzymes that catalyze the breakdown of proteins.

Question 17

Which of the following statements most accurately describes the first law of thermodynamics?
A) energy can be neither created nor destroyed but it can be changed from one form to another.
B) one usable form of energy cannot be completely converted into another usable form.
C) one usable form of energy can be completely converted into another usable form.
D) energy cannot be created or destroyed.
E) energy cannot be transformed.

Accepted Answer

The first law of thermodynamics, also known as the law of conservation of energy, states that energy can neither be created nor destroyed, but it can be changed from one form to another (such as from chemical energy to thermal energy). This statement is accurately represented in option A. Option B is incorrect as it suggests that one form of energy cannot be converted into another, which is not true. Option C is incorrect as it suggests complete conversion between certain types of energy, which is not always possible. Options D and E are partially correct but do not provide a complete explanation of the first law.

Question 18

Which energy association is correct?
A) Kinetic energy is energy of motion.
B) Water stored behind a dam is an example of kinetic energy.
C) Energy in the chemical bonds of a molecule is kinetic energy.
D) Potential energy must be used immediately or it is lost.
E) Light energy is a form of chemical energy.

Accepted Answer

Kinetic energy is defined as energy of motion, while potential energy is defined as energy that is stored due to an object's position or condition.

Answer: D
 Potential energy can be stored and used at a later time, such as water stored behind a dam that can be released to generate hydroelectric power.

Answer: E
 Light energy is a form of electromagnetic energy, not chemical energy, which is stored in the chemical bonds of molecules.

Question 19

Which of the types of cellular activities listed below would not use ATP?
A) active transport
B) muscular contraction
C) flagella movement
D) passive transport
E) protein synthesis

Accepted Answer

Passive transport does not require energy and thus does not use ATP. The other activities listed all require ATP to occur.

Question 20

Which of the following is a byproduct of photosynthesis that is used during cellular respiration? A) oxygen B) NADH C) carbon dioxide D) ATP E) FADH₂

Accepted Answer

Oxygen is produced by photosynthesis and used in cellular respiration as the final electron acceptor in the electron transport chain, creating a proton gradient that drives ATP synthesis.

Quiz 5: The Dynamic Cell

The changing of an enzyme's shape as the substrate binds to the active site is called the

The second law of thermodynamics states that all energy transformations result in more disordered energy.How does this relate to energy transformation in a living organism?

Which of the following enables a cell to pick up and concentrate a specific type of molecule?

Which of the areas shown in the figure below indicates the presence of an enzyme in the movement of reactant over to product?

Once the substrate moves into the active site of the enzyme

The second law of thermodynamics states that all energy transformations result in more disordered energy.How do living organisms,which depend on chemical potential converting to kinetic energy to fuel their function,continue to live?

Which of the following is not a type of potential energy?

Why do metabolic pathways require tens to hundreds of different enzymes?

The second law of thermodynamics states that all energy transformations result in more disordered energy.How can photosynthesis take more disordered carbon dioxide and water and convert them into glucose which is more ordered?

Which of the following statements reflects what occurs in the flow of energy conversions through living systems?

Enzymes are able to speed up the rate of a reaction by

Pickles are often preserved in a 20-30% salt solution called brine.How does this method prevent contamination by microorganisms?

ATP is a good source of energy for a cell because

Enzymes are named based on the substrate that they bind; this is possible because

Which of the following statements most accurately describes the first law of thermodynamics?

Which energy association is correct?

Which of the types of cellular activities listed below would not use ATP?

Which of the following is a byproduct of photosynthesis that is used during cellular respiration?