WorksheetsBiology Midterm
Total questions: 126
Worksheet time: 3hrs 9mins
Which type of membrane receptor (B) is represented in the diagram?
G protein coupled receptor
Ligand gated ion channel receptor
Receptor Tyrosine Kinase
second messenger
What is Part 2 (second step) of the diagram showing?
A hormone passing through the plasma membrane via a G protein-coupled receptor
The dissociation of the receptor from the receptor protein, allowing the gate to close and prohibiting ions from entering
The channel receptor with a closed gate waiting for the signaling molecule to bind to the receptor
The signaling molecule binding to the receptor, allowing the gate to open for ions to flow through the channel
Many species of bacteria regulate gene expression using a cell signaling system known as quorum sensing (QS). In this system, bacteria synthesize QS signaling molecules and release them into the surrounding environment. The effects of these molecules on gene expression depend on the density of the bacterial population.
Which of the following best describes what occurs as the density of a QS bacterial population increases?
The concentration of QS signaling molecules decreases, eventually triggering a change in gene expression throughout the bacterial population.
The concentration of QS signaling molecules decreases, eventually triggering a change in gene expression in a few members of the bacterial population.
The concentration of QS signaling molecules increases, eventually triggering a change in gene expression throughout the bacterial population.
The concentration of QS signaling molecules increases, eventually triggering a change in gene expression in a few members of the bacterial population.
A mutation causes the extracellular domain of a G protein-coupled receptor (GPCR) to be misfolded. The misfolded GPCR is packaged into a vesicle that travels to the cell membrane. Upon reaching the cell membrane, the vesicle deposits the misfolded GPCR, which fuses with the cell membrane and functions as a membrane receptor.
Which of the following best predicts what will occur whenever the misfolded GPCR is in the presence of its specific ligand?
The ligand-binding domain of the misfolded GPCR will not bind with its specific ligand.
The intracellular domain of the misfolded GPCR will not bind with its specific ligand.
The extracellular domain of the misfolded GPCR will begin a signal transduction pathway.
The intracellular domain of the misfolded GPCR will change from an inactive to an active shape.
Enzymes often play a major role in signal transduction pathways. For example, enzymes can help convert an extracellular signal into an intracellular response. Specifically, adenylyl cyclase is an enzyme that catalyzes the conversion of ATP to cyclic AMP (cAMP).
One competitive inhibitor of adenylyl cyclase is called MANT-ITP.
Which of the following questions would best direct an investigation on how MANT-ITP impacts a signal transduction pathway?
How does MANT-ITP affect the shape of G protein-coupled receptors?
How does MANT-ITP affect the binding of ligands to G protein-coupled receptors?
How does MANT-ITP affect the recognition of an extracellular signal?
How does MANT-ITP affect the response to intracellular signals?
Thyroid-stimulating hormone (TSH) is a long-distance signaling molecule released by the anterior pituitary gland. Once released, TSH travels through the bloodstream to the thyroid gland, where it binds to G protein-coupled receptors called TSH receptors. This binding initiates signal transduction pathways that produce two thyroid hormones, T3 and T4.
In individuals with hypothyroidism, TSH is released by the pituitary gland normally, but these individuals have consistently low levels of T3 and T4.
Which of the following best explains why individuals with hypothyroidism have low levels of T3 and T4?
A mutation in their TSH receptors decreases TSH recognition, resulting in increased signal transduction.
A mutation in their TSH receptors increases TSH recognition, resulting in decreased signal transduction.
A mutation in their TSH receptors decreases TSH recognition, resulting in decreased signal transduction.
A mutation in their TSH receptors increases TSH recognition, resulting in increased signal transduction.
Which letter represents a signaling molecule coming from outside the cell?
B
C
A
D
Which letter represents the conversion of the signal to a form that brings about a cellular response?
B
C
A
D
During which process do cells enter into programmed cell death, during which time DNA is chopped up, organelles are fragmented, the cell shrinks and parts of the cell are packaged into vesicle and removed by scavenger cells?
Cell Transportation
Endocytosis
Apoptosis
Transduction
Which of the following observations could be best explained by water’s high surface tension?
A human sweats in order to cool down.
A leaf floats on the surface of a puddle.
A local pond is slow to freeze, despite low air temperature.
A tree takes up water from its roots.
Which of the following describes the most likely way in which two water molecules will interact?
A hydrogen bond will form between the hydrogen atom of one water molecule and the oxygen atom of the other water molecule.
An ionic bond will form between the oxygens in each water molecule.
A covalent bond will form between the hydrogen of one water molecule and the oxygen of the other water molecule.
A metallic bond will form between the hydrogens in each water molecule.
Water has a boiling point of 100.0 ∘C, which is unusually high compared to many other liquids.
Which of the following properties allows water to have a high boiling point?
It is a small, covalent molecule.
It contains oxygen.
It can form hydrogen bonds.
It contains only three atoms.
Bodies of water, such as ponds, freeze from top to bottom, forming a floating sheet of ice. This can help aquatic organisms survive during cold winter months.
Which of the following statements explains why the ice floats on the surface of the pond?
The ice molecules have higher kinetic energy than the liquid water molecules, causing them to float.
The increased number of hydrogen bonds in ice compared to liquid water causes the water molecules in ice to be further apart.
The crystalline structure of solid ice makes it more dense than liquid water.
As water freezes, ionic bonds form between water molecules, preventing the ice from sinking below the surface.
Which of the following best describes water's ability to dissolve certain substances such as glucose, but remain separate from other substances such as oils?
Water molecules can only form ionic bonds with polar molecules, such as glucose.
Due to hydrogen bonding, water is more dense as a liquid than a solid.
Water has an overall negative charge, which allows it to easily dissolve nonpolar substances like glucose.
Water molecules are polar, consisting of two partially positive hydrogen atoms, and one partially negative oxygen atom.
Given the structure of water, H2O which of the following must be true?
Each water molecule can form four hydrogen bonds.
Each water molecule will form covalent bonds with its neighbors.
Water has an overall negative charge.
Water is able to easily dissolve nonpolar substances.
Which of the following shows the most likely way that two water molecules will bond with each other?
Which of the following gives water its cohesive properties?
The overall negative charge of water molecules prevents attraction to other substances.
Hydrogen bonds between the hydrogens in one water molecule are attracted to the oxygens of other water molecules.
Water's polarity makes it attracted to other charged molecules.
Ionic bonds hold neighboring water molecules together.
The air temperature ranges of several Southern California cities in August are shown in the table below.
Which of the following best explains why coastal cities like San Diego often have a smaller air temperature range than inland cities?
The high heat capacity of water allows the ocean to moderate the temperature of nearby air and land.
The cohesive tendency of water molecules causes high surface tension, so heat is unable to penetrate the top layer of the ocean and escape into the air.
Because water is less dense as a solid than as a liquid, it easily vaporizes, causing excess heat to escape into the air near coastal cities.
The adhesive properties of ocean water allow the water molecules to stick to one another, preventing temperature change of the air above it.
A new dish soap claims that it is able to remove grease from pots and pans while still fully dissolving in the dishwasher water.
Which of the following best explains the ideal structure of the dish soap molecule?
The dish soap molecule must be polar at one end to dissolve grease, and nonpolar at the other end so it can dissolve in water.
The dish soap molecule must be nonpolar at one end to dissolve grease, and polar at the other end so it can dissolve in water.
The dish soap molecule must be polar so that it can dissolve both grease and water.
The dish soap molecule must be nonpolar so that it can dissolve in both grease and water.
Which statement best describes why water is an effective solvent?
Water is an ionic compound that attracts other like molecules.
Water’s hydrophobic nature separates polar and non-polar substances.
Water’s relatively small size allows it to fit between individual atoms, driving them apart.
Water’s polarity allows it to dissolve ionic and polar compounds.
Which of the following examples explains how a biological activity relies on water's adhesive properties?
Vacuoles swell as water dilutes the contents of the vacuole.
Feathers retain an oily coating that repels water droplets.
Water travels through vascular tissue from the roots to the leaves of a plant.
Stomata in leaves control transpiration of water out of the leaf as water vapor.
A team of virologists has isolated a nucleic acid sample from a newly discovered virus. In order to classify the virus, they need to figure out whether the viral nucleic acid is DNA or RNA.
Which of the the following characteristics of the nucleic acid sample would best help classify the viral nucleic acid as DNA or RNA?
The nucleotides of the virus contain a five-carbon sugar.
The nucleotides of the virus contain covalent bonds.
The nucleotides of the virus contain uracil.
The nucleotides of the virus contain phosphate groups.
Which of the following statements accurately describes a difference between DNA and RNA?
DNA is usually double-stranded, but RNA is usually single-stranded.
DNA has 3' hydroxyl and 5' phosphate ends, but RNA has 3' phosphate and 5' hydroxyl ends.
In DNA, the nitrogenous bases adenine and thymine are complementary, but in RNA, the nitrogenous bases adenine and guanine are complementary.
In DNA synthesis, nucleotides are added to the 3' end of the strand, but in RNA synthesis, nucleotides are added to 5' end of the strand.
The following excerpt describes a potential origin of the first living cells on earth.
We have proposed that a simple primitive cell, or protocell, would consist of two key components: a protocell membrane that defines a spatially localized compartment, and an informational polymer that allows for the replication and inheritance of functional information.
Schrum, J. P., Zhu, T. F., & Szostak, J. W. (2010). The Origins of Cellular Life. Cold Spring Harbor Perspectives in Biology, 2(9), a002212. http://doi.org/10.1101/cshperspect.a002212
Based on this excerpt, which of the following questions would best direct an investigation on whether the "informational polymer" is DNA or RNA?
Which functional group is located on the 5' end of the informational polymer?
Which functional group is located on the 3’3'end of the informational polymer?
Which types of bonds connect individual nucleotides in the sugar-phosphate backbone of the informational polymer?
Which nitrogenous bases are present in the structure of the informational polymer?
In order to develop antibiotics, scientists need to understand how bacteria grow, divide, and spread during an infection. An essential part of bacterial growth is RNA synthesis because RNA must be synthesized before proteins can be assembled. If RNA synthesis is blocked, bacteria will not be able to survive and reproduce.
Which of the following questions will best direct an investigation on how an antibiotic that inhibits RNA synthesis in bacteria can be developed?
Which chemical compounds block the 5' end of the growing RNA strand?
Which chemical compounds block the 3' end of a growing RNA strand?
Which chemical compounds add a hydroxyl (-OH) group to the growing RNA strand?
Which proteins are used to undergo cell division through binary fission?
Cowpox is classified as a DNA virus because its genome, or genetic material, consists of double-stranded DNA.
Which of the following claims is best supported by the information above?
Thymine nucleotides are not found in the cowpox genome.
Cowpox has a single-stranded nucleic acid structure.
Cowpox contains a five-carbon sugar called ribose in its nucleic acid structure.
Uracil nucleotides are not found in the cowpox genome.
A team of virologists has isolated a nucleic acid sample from a newly discovered virus. In order to classify the virus, they need to figure out whether the viral nucleic acid is DNA or RNA.
Which of the the following characteristics of the nucleic acid sample would best help classify the viral nucleic acid as DNA or RNA?
The nucleotides of the virus contain deoxyribose.
The nucleotides of the virus contain phosphate groups.
The nucleotides of the virus contain covalent bonds.
The nucleotides of the virus contain nitrogenous bases.
In the early 1950’s, a team of researchers led by Erwin Chargaff conducted a series of experiments related to deciphering the chemical composition of DNA. In one experiment, Chargaff’s team examined samples of DNA from different species of sea urchins. The results of this experiment are summarized in the table below. Which of the following results from the experiment is most consistent with the base-pairing rules of DNA?
The average molar ratio of adenine to guanine is greater than the average molar ratio of thymine to cytosine across all species in the experiment.
The percentage of adenine nucleotides is roughly equal to the percentage of thymine nucleotides across all species in the experiment.
The percentage of thymine nucleotides is roughly equal to the percentage of cytosine nucleotides across all species in the experiment.
The average molar ratio of guanine to cytosine is less than the average molar ratio of adenine to guanine across all species in the experiment.
In the image, a thymine nucleotide and cytosine nucleotide are connected together as a dinucleotide. A single guanine nucleotide is also shown.
Which of the following best predicts how the free guanine nucleotide will attach to the dinucleotide?
Through dehydration synthesis, the guanine nucleotide will form a covalent bond at the 3' hydroxyl (-OH) of the cytosine nucleotide.
Through dehydration synthesis, the guanine nucleotide will form a covalent bond at the 3' hydroxyl (-OH) of the thymine nucleotide.
Through hydrolysis, the guanine nucleotide will form a covalent bond at the the 3' hydroxyl (-OH) of the cytosine nucleotide.
Through hydrolysis, the guanine nucleotide will form a covalent bond at the the 3' hydroxyl (-OH) of the thymine nucleotide.
The image depicts how the bacterial protein barnase undergoes modifications that involve changing its conformation, or shape. In order to function in the cell, barnase has to be folded from a nonfunctional conformation into a functional conformation. Based on the information above, which of the following best describes the functional conformation of barnase?
The functional conformation of barnase has a quaternary structure because it consists of interactions between multiple polypeptide units.
The functional conformation of barnase has a primary structure because it consists of a linear chain of amino acids.
The functional conformation of barnase has a secondary structure because it consists of a single alpha-helix.
The functional conformation of barnase has a tertiary structure because it consists of a polypeptide chain folded into a three-dimensional shape.
Which of the following statements accurately describes a similarity between the nucleotides of DNA and RNA?
The nucleotides of DNA and RNA contain a five-carbon sugar bonded to a phosphate group and a nitrogenous base.
The nucleotides of DNA and RNA contain the same nitrogenous bases.
The nucleotides of DNA and RNA are connected through hydrogen bonds to form the sugar-phosphate backbone.
The nucleotides of DNA and RNA contain the same five-carbon sugar.
Human immunodeficiency virus (HIV) is classified as an RNA virus because its genome, or genetic material, consists of a single strand of RNA. Which of the following claims is best supported by the information above?
Uracil nucleotides are present in the HIV genome.
The structure of HIV forms a double-stranded nucleic acid.
The nucleotides of HIV form an antiparallel nucleic acid structure.
Deoxyribose is a five-carbon sugar within the nucleic acid structure of HIV.
Mutations within genes coding for G protein-coupled receptors (GPCRs) can lead to one of two major outcomes—a loss-of-function or a gain-of-function. Loss-of-function mutations prevent signaling in GPCR pathways, even in the presence of signaling molecules. Gain-of-function mutations activate signaling in GPCR pathways, even in the absence of signaling molecules.
Which of the following is most likely to result from a loss-of-function GPCR mutation?
Signal transduction pathways that are inactive only if ligand-to-receptor binding does not occur
Signal transduction pathways that are activated without ligand-to-receptor binding
Signal transduction pathways that are activated by multiple types of ligands
Signal transduction pathways that are inactive even if ligand-to-receptor binding occurs
The following is an excerpt from a scientific paper by Jean-Pierre Raufman.
Cholera, an infectious disease that can kill humans within a matter of hours, is a manifestation of a highly efficient and specific toxin delivery mechanism. This mechanism, which is shared by several bacteria, delivers a potent toxin to activate selectively the adenylyl cyclase system of human intestinal secretory cells. This increases production of the ‘‘second messenger’’ cyclic adenosine monophosphate (cAMP) that activates an intestinal crypt cell chloride ion channel, thereby resulting in massive fluid and electrolyte secretion into the lumen of the gut.
Raufman, J. P. (1998). Cholera. Am. J. Med. 104, 386–394.
Based on the information above, which of the following is most likely to be observed in the intestinal environment of a person infected with cholera?
Reduced levels of extracellular chloride ions
Elevated levels of intracellular ATP
Reduced levels of intracellular cAMP
Elevated levels of extracellular chloride ions
The information shows and describes the initial steps of the MAPK/ERK signaling cascade. When epidermal growth factor (EGF) ligands bind to their receptors, the receptors pair up and act as kinases, attaching phosphate groups to one another’s intracellular tails. The activated receptors then trigger a series of events that activate the kinase Raf.
Which of the following toxins will most likely inhibit the activation of MEK?
A toxin that prevents the dephosphorylation activity of Raf
A toxin that prevents the transfer of a phosphate group to Raf
A toxin that prevents the kinase activity of Raf
A toxin that prevents MEK from phosphorylating Raf
The information shows and describes the intermediate steps of the MAPK/ERK signaling cascade. After MEK is activated, it phosphorylates and activates ERK. ERK goes on to phosphorylate and activate a variety of target molecules, including transcription factors like c-Myc that promote cell growth and division.
Which of the following toxins will most likely inhibit the phosphorylation of c-Myc?
A toxin that prevents the phosphorylation of ERK
A toxin that prevents the removal of a phosphate group from ERK
A toxin that prevents c-Myc from activating ERK
A toxin that prevents the dephosphorylation activity of MEK
The following excerpt and image come from a scientific paper written by Ebrahimi & Chess. They discuss the role of G proteins in olfaction, or the sense of smell.
Each mammalian olfactory neuron appears to use the same machinery for transducing signals from its odorant receptor molecules. Upon odorant binding, the receptor is thought to activate Golf_\text{olf} start subscript, start text, o, l, f, end text, end subscript, a G protein. Golf m_\text{ol start subscript, start text, o, l, f, end text, mediated activation of adenylate cyclase III then raises intracellular cAMP levels, causing a cyclic-nucleotide-gated channel to open. The influx of cations through this channel ultimately leads to the formation of an action potential, which allows the primary neuron to signal to the brain. A mutation in a component of this signal transduction pathway prevents the cyclic-nucleotide-gated channel from opening.
Which of the following scientific questions would best help researchers understand how the mutation prevents the cyclic-nucleotide-gated channel from opening?
Does mutation stimulate the conversion of ATP to cAMP?
Does mutation cause intracellular cAMP level to rise?
Does the mutation block the activation of adenylate cyclase III?
Does mutation cause the influx of cations into the cell?
Which of the following correctly describes how positive and negative feedback are different?
Negative feedback reverses changes in a system, while positive feedback amplifies changes in a system.
Positive feedback occurs only in response to stimuli, while negative feedback can occur in the absence of stimuli.
Negative feedback requires the detection of stimuli, while positive feedback functions independently of stimuli.
Positive feedback moves a system closer to its set point, while negative feedback moves a system further from its set point.
Which of the following statements about feedback mechanisms is most accurate?
Positive feedback mechanisms bring a system closer to its set point.
Positive feedback mechanisms maintain a system at its set point.
Negative feedback mechanisms move a system further from its set point.
Negative feedback mechanisms return a system to its set point.
The endocrine system maintains homeostasis in the body through the release of various hormones. For example, the pancreas releases the hormone insulin to help regulate blood glucose homeostasis.
Which of the following best describes the role of insulin in regulating blood glucose homeostasis?
Insulin is released in response to high blood glucose levels. This release triggers a positive feedback loop that further increases blood glucose levels.
Insulin is released in response to high blood glucose levels. This release triggers a negative feedback loop that returns blood glucose levels back to normal.
Insulin is released in response to low blood glucose levels. This release triggers a negative feedback loop that returns blood glucose levels back to normal.
Insulin is released in response to low blood glucose levels. This release triggers a positive feedback loop that further decreases blood glucose levels.
Which of the following best explains how the light reactions of photosynthesis generate ATP?
As photosystem II (PSII) absorbs energy from light, electrons are excited to a higher energy level and accepted by ADP to form ATP.
A proton gradient drives the formation of ATP from ADP and inorganic phosphate via ATP synthase.
Energy from light excites ATP synthase, causing it to bind ADP with inorganic phosphate to form ATP.
ADP accepts excited electrons at the end of the electron transport chain (ETC) to form ATP.
Which of the following best indicates that the light reactions of photosynthesis have completed and that the Calvin cycle has begun?
An electrochemical gradient forms across the thylakoid membrane.
ATP and NADPH accumulate in the stroma.
Electrons are transferred across the electron transport chain (ETC) on the thylakoid membrane.
A high concentration of carbohydrates is found in the thylakoid lumen.
A group of students are conducting an experiment on Elodea canadensis, a species of aquatic plant. In order to test the effect of light intensity on the rate of photosynthesis, they place each Elodea canadensis plant into an aquarium tank and place each tank at a different distance from a light source.
After a few minutes, oxygen bubbles begin to form in each of the tanks. The students count the number of oxygen bubbles released during a 5 minute period for each tank. The results of their experiment are shown below.
A decrease in light intensity increases the rate of photosynthesis.
An increase in light intensity decreases the rate of photosynthesis.
Light intensity does not affect the rate of photosynthesis.
An increase in light intensity increases the rate of photosynthesis.
The cytochrome complex is an integral thylakoid membrane protein that forms an electrochemical gradient by pumping protons. In an experiment, researchers apply a toxin to a plant cell that inhibits the cytochrome complex.
Which of the following explains the most likely effect of this toxin on the light reactions of photosynthesis?
Hydrogen ions will move across the thylakoid membrane using simple diffusion.
NADP+ will not be reduced to NADPH
ATP synthesis will not occur.
Carbohydrates will not be produced in the stroma.
Which of the following best describes how the Calvin cycle and the light reactions of photosynthesis function together?
The Calvin cycle uses ATP and NADPH generated by the light reactions to synthesize carbohydrates.
The Calvin cycle uses ATP and NADPH generated by the light reactions to break down carbohydrates.
The Calvin cycle generates ATP and NADPH to excite electrons during the light reactions.
The Calvin cycle produces ATP and NADPH to drive the formation of an electrochemical gradient during the light reactions.
A researcher claims that increased atmospheric carbon dioxide levels cause increased growth rates in plants. Which of the following statements best supports the researcher’s claim?
Atmospheric carbon dioxide is produced by the burning of fossil fuels, which are formed from the remains of living organisms such as plants.
Atmospheric carbon dioxide is a byproduct of cellular respiration, which is a metabolic process that occurs in plants and other living organisms.
Atmospheric carbon dioxide typically enters plant leaves through stomata, which plants rely on for regulating gas exchange with the atmosphere.
Atmospheric carbon dioxide is the raw material for photosynthesis, which plants rely on for producing sugars and other organic compounds.
RuBisCO catalyzes the joining of carbon dioxide with RuBP during carbon fixation. In an experiment, researchers apply a toxin to a plant cell that inhibits RuBisCO.
Which of the following explains the most likely effect this toxin will have on the Calvin cycle?
Excited electrons will not be transferred across the electron transport chain.
Carbon and oxygen will not be released after the breakdown of carbon dioxide.
Carbon dioxide will not be converted into sugar.
ATP synthase will not catalyze the formation of ATP on the thylakoid membrane.
When light is absorbed by pigments in photosystem II (PSII), energy is passed inward from pigment to pigment until it reaches the reaction center. Electrons are then boosted to a high energy level and captured by the primary electron acceptor.
Which of the following occurs immediately after the electrons from PSII are captured by the primary electron acceptor?
Water is broken down.
The electrons return to PSII.
ADP is converted to ATP.
NADP+ accepts the electrons.
Pancreatic amylase is a digestive enzyme found in the small intestine. It helps break down large starch molecules later in the digestive process. Pancreatic amylase is unable to break down lipids.
Which of the following best explains why pancreatic amylase is able to break down starches, but not lipids?
Lipids are too small to bind to enzymes.
Lipids are too hydrophobic to be broken down by enzymes.
Enzymes denature in the presence of lipids.
Enzymes bind only to their specific substrates.
Acetylcholine (ACh) is an important signaling molecule in the nervous system. After it transmits a signal, ACh is broken down by the enzyme acetylcholinesterase (AChE) in a reaction known as ACh hydrolysis.
Which of the following best describes the effect AChE has on the hydrolysis of ACh?
AChE increases the activation energy of ACh hydrolysis, increasing the rate of this reaction.
AChE increases the activation energy of ACh hydrolysis, increasing its rate.
AChE decreases the activation energy of ACh hydrolysis, increasing the rate of this reaction.
AChE decreases the activation energy of ACh hydrolysis, decreasing the rate of this reaction.
Which of the following statements about letter B is true?
Letter B represents the energy difference between the reactants and products for the uncatalyzed pathway.
Letter B represents the energy difference between the reactants and products for the catalyzed pathway.
Letter B represents the activation energy of the catalyzed reaction pathway.
Letter B represents the activation energy of the uncatalyzed reaction pathway.
Which of the following statements about letter C is true?
Letter C represents the activation energy of the catalyzed reaction pathway.
Letter C represents the activation energy of the uncatalyzed reaction pathway.
Letter C represents the energy difference between the reactants and products for the uncatalyzed pathway.
Letter C represents the energy difference between the reactants and products for the catalyzed pathway.
Which of the following best describes the process of induced fit?
A substrate binds to the active site of an enzyme without either structure changing conformation.
A substrate binds to the active site of an enzyme, causing the conformation of the active site to change slightly.
A substrate binds to an allosteric site on an enzyme, causing the conformation of the allosteric site to change slightly.
A substrate changes conformation and then binds to the active site of an enzyme.
Which of the following best explains how the addition of an enzyme would affect the above reaction?
The enzyme would increase the activation energy of the reaction, increasing its rate.
The enzyme would decrease the activation energy of the reaction, increasing its rate.
The enzyme would increase the activation energy of the reaction, decreasing its rate.
The enzyme would decrease the activation energy of the reaction, decreasing its rate.
Maltase is an enzyme found in the small intestine. It helps break down maltose during the process of digestion.
Which of the following best describes what happens when maltose binds with maltase?
Maltose binds to the active site of maltase, causing the conformation of the active site to change slightly.
The conformation of maltose is already complementary to the active site of maltase, so maltose binds to the active site without either structure changing conformation.
The conformation of maltose changes, and then maltose binds to the active site of maltase.
Maltose binds to an allosteric site on maltase, causing the conformation of the allosteric site to change slightly.
The human body is capable of digesting the complex polymer starch into simpler subunits. This digestive process requires the presence of water and the enzyme amylase in order to break down starch into maltose. Which of the following statements best describes the digestion of starch into maltose?
This is a hydrolysis reaction that forms water by breaking down a complex polymer into simpler subunits.
This is a dehydration synthesis reaction that produces water when forming a complex polymer from simpler subunits.
This is a hydrolysis reaction that requires water to break down a complex polymer into simpler subunits.
This is a dehydration synthesis reaction that requires water to form a complex polymer from simpler subunits.
In the reaction depicted, two amino acids have combined to form a dipeptide.
Which of the following best explains the process occurring in this reaction?
Through hydrolysis, a covalent bond forms to connect the dipeptide together, and a water molecule forms as a product.
The dipeptide will immediately break back down into the two amino acid monomers.
Water is used to cleave the covalent bond between the two amino acid monomers.
Through dehydration synthesis, a covalent bond forms to connect the dipeptide together, and a water molecule forms as a product.
In the reaction depicted, two amino acids have combined to form a dipeptide.
Which of the following best describes the role of water in the reaction?
Water is a product that forms as a result of a dehydration synthesis reaction between the two amino acid monomers.
Water is a reactant that is added in order to drive the dehydration synthesis reaction between the amino acid monomers.
Waters forms as result of a combination between the amino group (-NH2) of one amino acid and the carboxyl group (-COOH) of the other amino acid.
Water is a product that forms as a result of the hydrolysis of the dipeptide.
Which of the following best describes the role that water plays in the reaction depicted above?
Water is a product of this dehydration synthesis reaction.
In the reverse of this reaction, water is used to promote hydrolysis.
When water is added, the two monomers form a covalent bond that holds the dimer together.
As a reactant, water cleaves the covalent bond that holds the dimer together.
What role do the highlighted hydroxyl group (-OH) and hydrogen atom (H) play in the depicted reaction above?
Through dehydration synthesis, a water molecule is added to those regions of the monomers to produce a covalent bond in the dimer.
Through hydrolysis, a water molecule is added to those regions of the monomers to produce a covalent bond in the dimer.
Through hydrolysis, they condense out of the reaction as a water molecule and a covalent bond forms in their place.
Through dehydration synthesis, they condense out of the reaction as a water molecule and a covalent bond forms in their place.
If water was removed from the reaction depicted above, which of the following describes the most likely outcome of this removal?
The covalent bond that holds the dimer together would not be cleaved because hydrolysis would not occur.
The reverse of the reaction would occur and a covalent bond would spontaneously form between the two monomers.
The covalent bond that holds the dimer together would not be cleaved because dehydration synthesis would not occur.
The reverse of the reaction would occur and the dimer would spontaneously form from the two monomers.
Which of the following best describes the role that water plays in the reaction depicted above?
Water catalyzes the formation of a covalent bond in the dimer through hydrolysis.
When water condenses out of the reaction, a dimer is created as a covalent bond forms between two monomers.
When water combines with the two monomers, a dimer forms.
Water is an input of the reaction, leading to the formation of a covalent bond in the dimer product.
Based on the reaction depicted above, which of the following statements is true?
The reverse of this reaction requires the removal of water from the reaction in order to break down the dimer.
The reverse of this reaction requires the addition of water in order to build the dimer.
If water is not added to the reaction, hydrolysis will not occur.
If water is not added to the reaction, dehydration synthesis will not occur.
In the reaction depicted above, maltose is broken down into two molecules of glucose.
Which of the following best explains the process of this reaction?
The reverse of this reaction would require the addition of water to build the maltose dimer from the glucose monomers.
The ionic bond of maltose is broken down through the addition of water in this hydrolysis reaction.
This breakdown process requires the release of water as a product of the reaction.
The addition of a water molecule cleaves the covalent bond holding maltose together.
In the reaction above, two glucose monomers combine to form the dimer maltose.
Which of the following best explains the process of this reaction?
To form a covalent bond, the monomers underwent a hydrolysis reaction.
A covalent bond forms through dehydration synthesis, which results in the formation of maltose and water.
An ionic bond forms through dehydration synthesis, which combines the two glucose monomers and forms the maltose dimer.
Water is added to the reaction to promote the formation of a covalent bond between the glucose monomers.
Lactose is a dimer sugar composed of two monomeric subunits (galactose and glucose). In an investigation, researchers placed intestinal cells in a nutrient medium containing lactose. The researchers determined that the lactose had broken down to galactose and glucose in the manner depicted in the reaction below. Which of the following conclusions best explains the outcome of this modification?
The cells were able to undergo a reverse reaction and build lactose.
The cells were unable to hydrolyze the lactose dimer into its monomeric subunits.
The cells were able to perform dehydration synthesis reactions in order to break down lactose into its monomeric subunits.
The cells were unable to hydrolyze lactose, resulting in the formation of a covalent bond between galactose and glucose.
Which of the following questions would a researcher most likely ask if they wanted to know whether a hydrolysis reaction or a dehydration synthesis reaction is occurring?
Are the monomers identical to one another?
Is an enzyme involved in the reaction?
Is water a reactant or product of the reaction?
Which polymer is involved in the reaction?
What is represented by the small dots found in each of the bacteria cells?
cell wall
free-floating DNA
cytoplasm
ribosomes
All the internal structures are suspended (floating) in what substance?
cytoplasm
free-floating DNA
cell membrane
cell wall
One of the bacteria has a tail-like structure. What is this structure called?
cytoplasm
cell wall
cell membrane
flagella
Based on the tail-like structure, what might you infer about the absence of this structure in the other two bacteria cells?
Since this structure is important for replication, the other two cells would replicate less frequently.
Since this structure is important for movement, the other two cells would lack locomotion abilities.
Since this structure is important for energy production, the other two cells would have limited energy availability.
Since this structure is important for protein synthesis, the other two cells would have limited proteins.
Where do you find the DNA in each cell?
Nucleus
Lysosome
Vesicle
Mitochondria
What is different about the outermost boundary in a plant cell compared to an animal cell?
Plants have a cell wall
Plants make protein exclusively using free ribosomes
Plants lack mitochondria because they have chloroplasts
Only animal cells have a nucleus to store DNA
Both cells have a nucleus.
True
False
Both cells have mitochondria.
True
False
Only animal cells have chloroplasts to generate energy for cellular respiration.
True
False
Which organelle has malfunctioned?
enzymes & chemical messengers won’t be ready to be used
Golgi apparatus
ribosomes
vacuole
nucleus
Which organelle has malfunctioned?
organism won’t have energy to perform everyday functions
nucleus
vacuole
mitochondria
lysosomes
Which organelle has malfunctioned?
the plant would not be able to stand up
chloroplasts
cell wall
vacuole
cell membrane
Which organelle has malfunctioned?
organism won’t be able to break down food it eats
vacuole
endoplasmic reticulum
lysosomes
Golgi apparatus
In order to develop antibiotics, scientists need to understand how bacteria grow and reproduce. One factor that is essential for bacterial growth and reproduction is protein synthesis. By understanding how bacteria synthesize proteins, scientists can then attempt to develop antibiotics that block bacterial protein synthesis during an infection.
Which of the following questions will best direct an investigation on how to develop an antibiotic that inhibits protein synthesis in bacteria?
How can the carboxyl (-COOH) terminus of a growing polypeptide chain be blocked?
How can the 5' end of the growing polypeptide chain be blocked?
How can the 3' end of the growing polypeptide chain be blocked?
How can the amino (-NH2) terminus of a growing polypeptide chain be blocked?
Glycogen is a highly branched macromolecule usually stored in liver and muscle cells. If blood glucose levels decrease, glycogen breaks down to release glucose in a process called glycogenolysis. In this process, the glycogen polysaccharide goes through hydrolysis and breaks down into glucose monosaccharides.
If a toxin were to inhibit glycogenolysis, which of the following statements best predicts a consequence of this inhibition?
In response to the detection of low glucose levels, glycogen will continuously be broken down to release glucose.
The covalent bonds between individual glucose monomers will not be cleaved.
The covalent bonds within an individual glucose monomer will not be cleaved.
In response to the detection of low glucose levels, more glucose will be released from stored glycogen.
In order to develop antibiotics, scientists need to understand how bacteria grow and reproduce. One factor that is essential for bacterial growth and reproduction is protein synthesis. By understanding how bacteria synthesize proteins, scientists can then attempt to develop antibiotics that block bacterial protein synthesis during an infection.
Which of the following questions will best direct an investigation on how to develop an antibiotic that inhibits protein synthesis in bacteria?
How can the formation of covalent bonds between amino acids be blocked?
How can the formation of hydrogen bonds between amino acids be blocked?
How can the hydroxyl end of the growing polypeptide chain be blocked?
How can the phosphate end of the growing polypeptide chain be blocked?
Most species of shark are strict carnivores. However, bonnethead sharks (Sphyrna tiburo) have been observed consuming seagrass within their natural habitat. Like other plants, seagrasses contain cellulose within their cell walls.
Based on the information above, which of the following best supports the claim that bonnethead sharks are capable of hydrolyzing cellulose during digestion?
Cellulose is consumed as a linear polysaccharide and remains as a linear polysaccharide during digestion.
Cellulose is consumed as glucose monosaccharides and is converted into a linear polysaccharide and during digestion.
Cellulose is consumed as a linear polysaccharide and is converted into branched glucose monosaccharides during digestion.
Cellulose is consumed as a linear polysaccharide and is broken down into glucose monosaccharides during digestion.
Match the monomers with the correct polymers. Which of the following is an incorrect pair?
nucleotide-nucleic acids
monosaccharides-charbohydrates
fatty acids-lipids
amino acids-proteins
Name the covalent bond that connects two amino acids.
glycosidic linkage
phosphodiester bond
peptide bond
ester linkage
Name the covalent bond that connects the glycerol and fatty acids
glycosidic linkage
phosphodiester bond
ester linkage
peptide bond
Name the covalent bond that connects the nucleotides in the DNA's sugar-phosphate backbone.
ester linkage
glycosidic linkage
peptide bond
phosphodiester bond
Name the covalent bond that connects two monosaccharides.
glycosidic linkage
peptide bond
ester linkage
phosphodiester bond
What is the solute potential of the potato cubes?
-1.9 bar
-13 bar
13 bar
1.9 bar
-17 bar
-1.2 bar
17 bar
1.2 bar
−22 bar; water will move into the cell
-8 bar; water will move into the cell
-8 bar; there will be no net movement of water
-22 bar; water will move out of the cell
The potato cube has a water potential of 0 bar and the distilled water has a water potential of -17 bar.
The potato cube has a water potential of -2.6 bar and the distilled water has a water potential of 0 bar.
The potato cube has a water potential of 0 bar and the distilled water has a water potential of -2.6 bar.
The potato cube has a water potential of -17 bar and the distilled water has a water potential of 0 bar.
-15 bar; water will move out of the cell
-9 bar; water will move into the cell
-15 bar; water will move into the cell
-9 bar; water will move out of the cell
A cell is treated with a toxin that prevents the synthesis of new lysosomes. However, the cell continues to produce the hydrolytic enzymes normally found in lysosomes.
In which of the following structures are the hydrolytic enzymes most likely to accumulate?
Mitochondria
Nucleus
Smooth ER
Golgi Apparatus
Tay-Sachs disease is a genetic disorder that causes certain lipids known as gangliosides to accumulate in the neurons of the brain and spinal cord. As the gangliosides build up, neurons rapidly degenerate.
Which of the following cell structures is most likely associated with the accumulation of gangliosides?
Nucleus
Mitochondria
ER
Lysosomes
Chlorophyll a is a pigment that absorbs light energy from the sun and gives plants their green color.
Which of the following plant cell structures is most likely to contain chlorophyll a?
Mitochondria
Ribosomes
Chloroplast
Vacuole
Which of the following statements is true for both prokaryotic and eukaryotic cells?
The rough endoplasmic reticulum synthesizes lipids and modifies proteins.
The Golgi complex packages and sorts proteins for transport throughout the cell.
Ribosomes synthesize proteins using mRNA sequences.
Mitochondria produce ATP through cellular respiration.
A lack of water can cause plant cells to become flaccid. This gives the plant a wilted appearance as shown in the figure below. Which of the following cell structures is most likely responsible for the plant’s wilted appearance?
Central Vacuole
Nucleus
Mitochondria
Lysosomes
A student uses a microscope to compare a human skeletal muscle cell and a human epithelial cell. The student observes that the muscle cell has more mitochondria than the epithelial cell.
Which of the following conclusions is best supported by this observation?
The muscle cell requires more ATP than the epithelial cell.
The epithelial cell does not require ATP to function.
The epithelial cell requires more ATP than the muscle cell.
The muscle cells do not require ATP to function.
Cell X has a surface are of 60μm2 and a volume of 15μm3. Cell Y has a surface area of 36μm2 and a volume of 12μm3. Using the information, determine the surface area to volume ratio of each cell. What is the SA:V ration of the cell that will exchange materials with its environment at the fastest rate of diffusion?
4μm
3μm
0.25μm
0.33μm
The physical characteristics of a cell influence how it functions. For example, the surface area and volume of a cell affect how efficiently waste is removed from the cell via diffusion. The table below shows data for four different cuboidal cells. Using the information from the table, which cell can remove waste via diffusion most efficiently?
A
B
C
D
Humans are made up of many types of cells, and these cells have a broad range of sizes. For example, a type of fat cell called an adipocyte has a radius of approximately 50μm, while a type of heart muscle cell called a cardiomyocyte has a radius of about 15μm.
Surface area of a sphere: A = 4πr^2
Assuming both cell types are perfectly spherical, approximately how many times larger is the surface area of an adipocyte compared to the surface area of a cardiomyocyte? Round your answer to the nearest integer.
0.09 times
11 times
100 times
1000 times
The figure above depicts an agar cube with a side length of 13mm. In an experiment, students submerged the cube in orange dye for 12 hours. The orange dye permeated 1mm on each side, as indicated by the shading in the figure.
Calculate the volume of the agar cube that remained unpenetrated by the orange dye.
1331 mm3
1728 mm3
1500 mm3
397mm3
Which of the following best describes what will result when a glucose-fed yeast cell is placed in an anaerobic environment?
Due to the presence of oxygen, the yeast cell will produce ATP through oxidative phosphorylation.
The yeast cell will produce ATP through fermentation, generating lactic acid as byproducts.
The yeast cell will produce ATP through fermentation, generating CO2 and ethanol as byproducts.
Due to a lack of oxygen, the yeast cell will no longer produce ATP, and its ATP stores will be depleted.
The human oral microbiota contains over 700 species of bacteria. One species often found in the oral cavity is Streptococcus mutans, an anaerobic bacterium strongly associated with the formation of dental cavities. S. mutans metabolizes glucose and other dietary sugars remaining in the mouth after a meal, producing lactic acid as a byproduct. Over time, high levels of lactic acid can erode tooth enamel, eventually leading to the formation of dental cavities.
Which of the following drugs would be most likely to prevent cavities caused by S. mutans?
A drug that inhibits the formation of a proton gradient across the cell membrane
A drug that prevents the conversion of glucose into pyruvate
A drug that inhibits the production of NADH and FADH2 during the Krebs cycle
A drug that prevents the movement of oxygen across the cell membrane
Cyanide poisoning is a type of poisoning caused by exposure to certain cyanide-containing compounds, such as hydrogen cyanide or cyanide salts. Inhalation or consumption of these compounds can cause histotoxic hypoxia, a condition in which cells are no longer able to take up or utilize oxygen during cellular respiration. As a result, ATP production during respiration is significantly reduced.
Based on the information above, which of the following is the most likely explanation for how cyanide causes histotoxic hypoxia?
Cyanide inhibits the transport of pyruvate across the mitochondrial membrane.
Cyanide inhibits the reduction of NAD+ and FAD during the Krebs cycle.
Cyanide inhibits the enzymatic breakdown of glucose during glycolysis.
Cyanide inhibits the transfer of electrons to the final acceptor in the electron transport chain.
In humans, red blood cells contain hemoglobin, which is an oxygen-binding protein. Hemoglobin helps provide oxygen to the body’s tissues. Each molecule of hemoglobin is made up of four subunits. The human genome encodes multiple variations of the hemoglobin subunit, including the alpha, beta, and gamma chains. The specific subunits that make up the dominant form of hemoglobin in a person’s body are determined by the person’s age and genetic background.
The hemoglobin that is present in a fetus, or fetal hemoglobin, has a different functional profile than the hemoglobin present after birth, which is called adult hemoglobin. This difference can be seen in Figure 1, which shows how strongly each type of hemoglobin binds to oxygen. Both adult and fetal hemoglobin contain alpha chain subunits. According to the information provided, which of the following diagrams is the most likely representation of fetal and adult hemoglobin?
Unlike most other cells in the human body, mature red blood cells (RBCs) do not contain a nucleus or mitochondria. This allows RBCs to carry more hemoglobin, and therefore oxygen, through the bloodstream.
Based on the information above, which of the following is most likely true about RBCs?
Due to a lack of mitochondria, RBCs do not produce ATP.
RBCs generate lactate as a waste product.
CO2 and ethanol are byproducts of ATP production in RBCs.
Oxygen is used as the terminal electron acceptor in RBCs.
Bacteroides is the predominant genus of bacteria found in the human gut microbiota. As anaerobic bacteria, Bacteroides undergo fermentation in the gut, converting otherwise nondigestible carbohydrates into fermentation products that are used by the host for energy.
Which of the following toxins would be most likely to disrupt carbohydrate metabolism in Bacteroides species?
A toxin that inhibits the function of ATP synthase
A toxin that prevents the formation of Krebs cycle products
A toxin that breaks down the membrane proteins of the electron transport chain
A toxin that inhibits the function of an enzyme during glycolysis
In mitochondria, the rate of ATP synthesis during oxidative phosphorylation is tightly coupled to the movement of electrons through the electron transport chain (ETC). When ADP levels rise and the demand for ATP synthesis increases, electron flow through the ETC also increases.
Based on the information above, which of the following best describes an effect of rising ADP levels in mitochondria?
Fewer protons will be pumped across the inner mitochondrial membrane.
Oxygen consumption will increase.
NADH and FADH2 will be oxidized to NAD+ and FAD less rapidly.
The flow of protons through ATP synthase will decrease.
During step 3 of the Krebs cycle, the enzyme isocitrate dehydrogenase (IDH) catalyzes the conversion of isocitrate α-ketoglutarate. IDH is allosterically activated by ADP at high concentrations. Which of the following best describes how this interaction helps regulate the Krebs cycle?
High levels of ADP inhibit the Krebs cycle because ADP prevents IDH from catalyzing the conversion of isocitrate to α-ketoglutarate.
Low levels of ADP stimulate the Krebs cycle, leading to the production of excess ATP that is stored for later use.
High levels of ADP stimulate the Krebs cycle, leading to the increased conversion of ADP to ATP during oxidative phosphorylation.
Low levels of ADP inhibit the Krebs cycle because IDH requires ADP as a substrate for the reaction it catalyzes.
Which of the following is true about the transportation of substances across the lipid region of the cell membrane?
Ions can freely dissolve across the lipid region of the cell membrane.
Gases such as N2, O2, and CO2 require embedded transport proteins to dissolve across the lipid region of the cell membrane.
Small nonpolar molecules can freely dissolve across the lipid region of the cell membrane.
Polysaccharides can freely dissolve across the lipid region of the cell membrane.
Which of the following best describes how substances move across the cell membrane?
Ions move across the cell membrane through embedded channel proteins.
Polar amino acids freely move across the cell membrane.
Hydrophilic amino acids freely move across the cell membrane.
Nucleic acids freely move across the cell membrane.
Which of the following best describes the permeability of the cell wall?
Only water passes across the cell wall because it is a semipermeable structural boundary.
Some substances pass across the cell wall because it is a semipermeable structural boundary.
All substances pass across the cell wall because it is a permeable structural boundary.
Substances cannot pass across the cell wall because it is an impermeable structural boundary.
Which of the following statements best describes the selective permeability of the cell membrane?
The cell membrane regulates the transport of intracellular substances out of, but not into the cell.
The cell membrane regulates the transport of extracellular substances into, but not out of the cell.
The cell membrane regulates the transport of all substances into and out of the cell.
The cell membrane regulates the transport of specific substances into and out of the cell.
Na+ moving out of a parietal cell into the blood
K+ moving out of the blood into a parietal cell
K+ moving out of a parietal cell into the gastric pit lumen
H+ moving out of a parietal cell into the gastric pit lumen
A neuron stimulates muscle contraction by sending signals across the neuromuscular junction, or the point of contact between a neuron and a muscle cell. The signaling process begins when membrane-bound structures inside the neuron fuse with the cell membrane, releasing signaling molecules into the neuromuscular junction. These molecules then diffuse through the junction and binds to receptors on the surface of the muscle cell, leading to muscle contraction.
Botulism is a rare illness caused by a toxin produced by the bacterium Clostridium botulinum. This toxin, called botulinum toxin, inhibits the process by which signaling molecules are released from neurons at the neuromuscular junction. This disrupts the neuron-muscle cell signaling pathway, resulting in temporary paralysis.
Based on the information above, which of the following cell processes does botulinum toxin most likely inhibit?
Facilitated diffusion through membrane channels
Membrane transport mediated by transmembrane ATPases
Vesicle fusion during exocytosis
Receptor-mediated endocytosis
Which of the following statements accurately describes one of the movements shown in the model?
K+ movement into the cell does not require an input of energy
Na+ moves out of the cell by passive transport
Na+ movement into the cell does not require an input of energy
H+ moves out of the cell by passive transport.
Which of the following statements accurately describes one of the movements shown in the model?
Cl- is transported out of the cell by active transport.
K+ movement into the cell requires ATP
K+ is transported out of the cell by active transport.
Fructose movement out of the cell requires ATP
Which of the following statements accurately describes an energy-releasing process that is coupled to an energy-requiring process in the cell?
The movement of motor proteins is powered by the formation of ADP and inorganic phosphate from ATP.
An exothermic chemical reaction is powered by ATP hydrolysis in the chloroplast
The transport of ions across a membrane is powered by the formation of ATP from ADP and inorganic phosphate.
An endothermic chemical reaction provides the energy for ATP hydrolysis in the mitochondria.
A group of biology students wants to study the effects of pH on enzyme activity. They measure the activity of enzymes A and B at various pHs and record their data in the graph below.
A solution of enzyme A has pH of 8. Based on the graph, which pH change would result a higher enzyme activity?
Decreasing the pH of the solution to 4
Increasing the pH of the solution to 10
Increasing the pH of the solution to 12
Decreasing the pH of the solution to 6
Which of the following best describes what happens to the rate of product formation at higher initial substrate concentrations?
The rate of product formation levels off because no substrate is available to bind with the enzyme.
The rate of product formation levels off because nearly all of the enzyme is bound to substrate.
The rate of product formation decreases because nearly all of the enzyme is bound to substrate.
The rate of product formation decreases because no substrate is available to bind with the enzyme.
Methotrexate is a drug that is commonly used to treat cancers and autoimmune diseases in humans. It functions by binding to the active site of the enzyme DHFR, preventing both DNA synthesis and excess cell proliferation.
Which of the following terms best describes methotrexate?
Noncompetitive inhibitor
Cofactor
Competitive inhibitor
Allosteric activator
Pepsin, a proteolytic enzyme found in the stomach, is essential for digestion. Pepsin functions optimally at approximately 37oC.
Which of the following would most likely result if pepsin’s environmental temperature was lowered from 37oC to 25oC?
Pepsin would catalyze reactions at a faster rate.
Pepsin would be less efficient at catalyzing reactions.
Pepsin would lose its three-dimensional shape.
Pepsin would more easily lower the activation energy of reactions.
The enzyme glutamine synthetase facilitates the use of energy to combine glutamate and ammonia (NH4), forming glutamine. This process occurs in two steps, as represented in the following diagram.
Which of the following statements best describes the process carried out by glutamine synthetase?
Glutamine synthetase uses energy to hydrolyze ATP, which then drives the formation of glutamine from glutamate and ammonia.
Glutamine synthetase forms glutamine by coupling two endothermic reactions, both of which occur in the enzyme’s active site.
Glutamine synthetase uses an exothermic reaction to drive an endothermic one by catalyzing the formation of a phosphorylated intermediate.
Glutamine synthetase forms a phosphorylated intermediate by attaching a molecule of ATP to glutamate
