Cell Exam 2
The sequential process of fatty acid catabolism to acetyl CoA is called
β-oxidation.
Oxidation/Reduction
Removal/Addition of electrons, OIL RIG
dendrite
Sends electrical signal toward cell body
Oxidation in biological systems is usually accompanied by -dehydrogenation. -hydrogenation. -resonance stabilization. -repulsion. -all of the above
dehydrogenation
The form of fatty acid that is transported into the mitochondrion is
fatty acyl CoA
In a cell, the concentration of glucose-6-phosphate is 83 μM and of fructose-6-phosphate is 14 μM. The ΔG°' = 410 cal/mol for the conversion of glucose-6-phosphate to fructose-6-phosphate. Based upon this information, the ΔG' for this reaction (in cal/mol) is
-644
Thermodynamic spontaneity can be measured by changes in __________. The reference point for whether a process will proceed in the forward or reverse direction is __________. -the rate of a reaction; equilibrium -entropy of the universe and free energy of the system; equilibrium -enthalpy; work -entropy of the system; enthalpy
-entropy of the universe and free energy of the system; equilibrium
From the equation ΔG = ΔH − TΔS, it can be concluded that __________. -increasing the change in entropy of a system will increase the probability of spontaneous change -increasing the temperature of a system will increase the probability of spontaneous change -the capacity of a system to perform useful work is related to the total free energy of the system -all of the other answer choices are true
-increasing the change in entropy of a system will increase the probability of spontaneous change -increasing the temperature of a system will increase the probability of spontaneous change -the capacity of a system to perform useful work is related to the total free energy of the system
A phosphoanhydride bond Check all that apply. -is broken by hydrolysis. -is a high-energy bond. -has a standard free energy of hydrolysis of -7.3 kcal/mol.
-is broken by hydrolysis. -is a high-energy bond. -has a standard free energy of hydrolysis of -7.3 kcal/mol.
The resting potential of a particular nerve cell is -66 mV. Depolarization of the membrane will shift the membrane potential toward
0 mV
Autophosphorylation
2 of the same molecules phosphorylate eachother
Net Na/K yield
3 Na out 2 K in
In a reversible chemical reaction at equilibrium, the concentration of X (the reactant) is 0.75 mol/L, and the concentration of Y (the product) is 2.25 mol/L. At 25°C, what would be the Keq?
3.0
The gross output of ATP from glycolysis is ________, whereas the net output of ATP is ________.
4, 2
The overall efficiency of aerobic respiration in eukaryotes is about
55%
A) Complex I: B) Complex II: C) Complex III: D) Complex IV:
A) NADH B) succinate C) coenzyme Q D) cytochrome C
ABC-type protein
ATB binding, transport sugars/amino acids
Which of the following events marks the transition to the uncoating phase for clathrin-coated vesicles? -a lowering of pH -the binding of v-SNAREs to t-SNAREs -ATP hydrolysis -calcium release from the endoplasmic reticulum
ATP hydrolysis
GTP bound GPCR
Active (activated by ligand)
G protein activation involves:
Adenylyl Cyclase or PLC
A nerve cell membrane exhibits an all-or-none response to excitation; that is, the magnitude of the response is independent of the magnitude of the stimulus, once a threshold value is exceeded.
At least some of the sodium channels in the membrane will open in response to a stimulus that depolarizes the membrane by about 20 mV.
Base your answer to the following question on the graph below, depicting an action potential. https://session.masteringbiology.com/problemAsset/1947508/1/0906.jpg In the graph above, the point at which the potassium channels open is indicated by the letter -A. -B. -C. -D. -E.
C
Reduction involves the -loss of neutrons. -increase in oxidation state. -gain of electrons. -gain of electrons; increase in oxidation state. -all of the above
gain of electrons
Pyruvate dehydrogenase is regulated by all of the following except -NADH. -CO2. -ATP. -AMP. -acetyl CoA.
CO2
The ER and Golgi work together to package and glycosylate proteins for secretion, incorporation into the plasma membrane, or deposition in other organelles of the endomembrane system. If a researcher were to add a nonhydrolyzable analog of GTP (cannot be hydrolyzed to GDP) intracellularly, which of the following processes would most likely be impacted?
COPI- and COPII-dependent transport between the ER and Golgi
All of the following statements about cellular trafficking are true except -tethering proteins mediate docking between target and vesicle. -COPII-coated vesicles move materials from ER to Golgi. -movement may be mediated by microtubules. -COPI-coated vesicles move materials from Golgi to the secretory vesicle. -v-SNAREs occur in vesicles; t-SNAREs occur on target sites.
COPI-coated vesicles move materials from Golgi to the secretory vesicle.
What binds to calcium when levels are elevated?
Calmodulin
What is the role of calcium at the synaptic terminal?
Depolarization of the synaptic terminals by an invading action potential releases intracellular calcium stores or allows calcium channels to open to allow calcium to enter the synaptic terminal from the extracellular environment, thus permitting neurotransmitter release.
Trans-Golgi
Distribution
IP3 receptors are associated with -lysosomes. -mitochondrial membranes. -intracellular membranes. -ER membranes. -plasma membranes.
ER Membranes
Pyruvate is the end-product of glycolysis. Many organisms, such as anaerobic bacteria, can only produce energy by glycolysis; therefore, pyruvate has no more potential for ATP generation for these organisms. Rather than simply excrete pyruvate, this molecule is changed to another molecule such as lactate. In these organisms, why is pyruvate changed to lactate and excreted, rather than simply excreted? -pyruvate export requires more energy than lactate. -Electrons (and protons) are added to pyruvate to make lactate. -NAD+ is regenerated as pyruvate is changed to lactate. -Substrate level phosphorylation changes pyruvate to lactate. -Electrons (and protons) are added to pyruvate to make lactate and NAD+ is regenerated as pyruvate is changed to lactate.
Electrons and protons are added to pyruvate to make lactate and NAD+ is regenerated as pyruvate is changed to lactate
Resting membrane potential
Excess negative charge within the cell, positive outside
The number of ATPs per NADH generated by the electron transport system is higher than the number generated per FADH2 because __________.
FADH2 has a lower (less negative) redox potential than NADH does
Disorder associated with 4 classes of mutations in the LDL receptor protein
Familial hypercholesterolemia
A researcher generates a mutant cell line in a laboratory culture in which the mutants have an RGS-GAP that is increased in activity. What is the likely outcome of this mutation?
G protein-mediated cellular signaling will terminate faster.
test for TCA cycle enzymes
mitochondria
A protein is destined to be secreted from a cell. In which of the following organelles would you expect to find the protein first? -lysosome -endosome -secretory vesicle -Golgi apparatus
Golgi apparatus
The gene for the glycolytic enzyme hexokinase is genetically altered so that it contains an SH2 domain at the C-terminus and then is expressed in yeast cells. Which of the following is the most likely outcome of this experiment?
Hexokinase will bind to and interact with activated receptor tyrosine kinases.
Pyruvate dehydrogenase is allosterically inhibited by ATP.
High ATP levels indicate adequate energy supply, so it makes sense that the enzyme responsible for providing the TCA cycle with more acetyl CoA substrate is shut down.
The dehydrogenases that oxidize isocitrate, α-ketoglutarate, and malate (reactions TCA-3, TCA-4, and TCA-8) are all allosterically inhibited by NADH.
High NADH levels mean adequate reduced coenzyme for the generation of more ATP, so it makes sense to shut down the catabolic machinery of the cell.
Phosphofructokinase (Reaction Gly-3) is allosterically inhibited by citrate.
High citrate levels are indicative of a sufficient supply of acetyl CoA, so it is reasonable that the key regulatory enzyme of the pathway leading to pyruvate and acetyl CoA is decreased in activity.
Isocitrate dehydrogenase (Reaction TCA-3) is allosterically activated by ADP.
High levels of ADP mean low levels of ATP, so it is to the advantage of the cell to activate the metabolic pathway responsible for coenzyme reduction, which can in turn give rise to ATP synthesis by electron transport.
Pyruvate dehydrogenase kinase is allosterically activated by NADH.
High levels of NADH mean adequate reduced coenzyme for the generation of ATP, so it makes sense to convert PDH to the inactive form, which is what PDH kinase does
α-ketoglutarate dehydrogenase (Reaction TCA-4) is allosterically inhibited by succinyl CoA.
High levels of succinyl CoA signal adequate levels of TCA-cycle intermediates, so it seems reasonable to shut down further TCA cycle activity.
GDP bound GPCR
Inactive
Pain suppression and anesthesia can be accomplished by inhibiting the initiation of a nervous signal in sensory neurons that respond to the pain stimulus. Which of the following strategies would be the most effective in inhibiting the initiation of a nervous signal in a sensory neuron that responds to a pain stimulus?
Inhibit sodium channels on the neuron responding to the pain stimulus to prevent sodium entry.
If every neuron exhibits an all-or-none response, how do you suppose the nervous system of an animal can distinguish different intensities of stimulation? How do you think your own nervous system can tell the difference between a warm iron and a hot iron or between a chamber orchestra and a rock band?
Intensity of stimulus is detected as the frequency with which individual neurons respond. Intensity of stimulus is detected as the difference in the number of separate neurons that respond.
Sorting of lysosomal proteins from secretory proteins
It is associated with Golgi.
Degradation of damaged organelles
It is associated with lysosome.
β oxidation of long-chain fatty acids
It is associated with peroxisomes and mitochondria.
Biosynthesis of insulin
It is associated with rough endoplasmic reticulum and Golgi.
Glycosylation of membrane proteins
It is associated with rough endoplasmic reticulum and Golgi.
Biosynthesis of cholesterol
It is associated with smooth endoplasmic reticulum.
Biosynthesis of testosterone or estrogen
It is associated with smooth endoplasmic reticulum.
Hydroxylation of phenobarbital
It is associated with smooth endoplasmic reticulum.
Which of the following statements is false regarding phagocytosis? -In vertebrates, macrophages and neutrophils possess this ability. -It is mediated by clathrin at the plasma membrane. -It involves the projection of pseudopodia. -It involves ingestion of large particles by the cell. -It is a method used predominantly by amoeba to obtain food.
It is mediated by clathrin at the plasma membrane.
You have isolated a factor from the blood of a space alien and named it XFF (for X-files factor). Based on preliminary data, you think that XFF could be one of three compounds normally found in human blood: epidermal growth factor (EGF), epinephrine, or estrogen. You obtain two different preparations of XFF, one of which contains the receptors for XFF. You perform a binding assay and obtain a standard curve. Based upon this data, what value would reflect the affinity of the receptor for the ligand? (Assume a 1 XFF-to-1 receptor interaction.) -Kd -Bmax -Kd - Bmax -1/Bmax -The affinity cannot be detertmined from the information available
Kd
RTK's are formed by:
Ligand binding and dimerization (2 molecules moving together)
Hyperpolarization
More negative than at rest, prevents a second immediate action potential
The endoplasmic reticulum is a site for
N-linked glycosylation of polypeptides.
test for presence of cytochromes
mitochondria
MAPKs are activated by
mitogens
Which of the following statements best describes the role of NAD+/NADH in glycolysis? -NAD+ is used to carry electrons. -NADH is used to produce energy by directly creating the phosphoanhydride bonds in ATP. -NADH is capable of pumping ions during glycolysis. -NADH is used primarily in substrate-level phosphorylation. -all of the above
NAD+ is used to carry electrons.
An action potential can always be initiated specifically at which of the following locations associated with a neuron?
Node of Ranvier
What is true about a process that is spontaneous at all temperatures? -One possibility is that ΔH will be positive and the TΔS term will be positive. -One possibility is that ΔH will be positive and the TΔS term will be negative. -One possibility is that ΔH will be negative and the TΔS term will be positive. -The reaction is at equilibrium.
One possibility is that ΔH will be negative and the TΔS term will be positive.
Vesicle contents are equivalent to
Outside of the plasma membrane (orientation of proteins - red/green dot picture)
The chemiosmotic model of ATP synthesis is based on several lines of experimental evidence. Which of the following statements is NOT correct experimental evidence to support the chemiosmotic model? -Artificial proton gradients established by addition of acid can drive ATP synthesis in the absence of electron transport. -Electron transport causes protons to be pumped out of the mitochondrial matrix. -Oxidative phosphorylation does not require a membrane-enclosed compartment. -Uncoupling agents abolish both the proton gradient and ATP synthesis. -The proton gradient established by electron transport has enough energy to drive ATP synthesis.
Oxidative phosphorylation does not require a membrane-enclosed compartment.
Phosphocreatine is used by your muscle cells to store energy. The dephosphorylation of phosphocreatine, like that of ATP, is a highly exergonic reaction with ΔG∘′=−10.3kcal/mol: Phosphocreatine+H2O⇌creatine+Pi ATP+H2O→ADP+Pi Choose a reaction for the transfer of phosphate from phosphocreatine to ADP to generate creatine and ATP. -P-creatine+ATP→creatine+H2O -P-creatine+ADP→creatine+ATP -P-creatine+ATP→creatine+Pi -P-creatine+ATP→creatine+ADP -P-creatine+ADP→creatine+H2O -P-creatine+ADP→creatine+Pi
P-creatine+ADP→creatine+ATP
Which of the following accurately summarizes the substrate-level phosphorylation strategy of ATP synthesis in glycolysis? -Phosphate groups are transferred exergonically from high-energy phosphorylated intermediates to ADP to make ATP. -Electrons are transported through a series of carriers to reduce substrates and drive the phosphorylation of ADP to ATP. -Energy from the sun is used to create a proton gradient that is used by an ATP synthase to phosphorylate ADP to ATP. -Electrons and hydrogen atoms are transferred to NAD+, which then transfers a phosphate to ADP to make ATP.
Phosphate groups are transferred exergonically from high-energy phosphorylated intermediates to ADP to make ATP.
__________ trap solar energy by pigment systems and convert __________ into more complex cellular materials via __________ chemistry. -Chemotrophs; oxygen; oxidation -Phototrophs; oxygen; isomerization -Phototrophs; carbon dioxide and water; reduction -Chemotrophs; carbon dioxide and water; hydrolysis
Phototrophs; carbon dioxide and water; reduction
Medial Golgi
Processing
RTK activation involves:
RAS activation anf PLC(gamma)
Cis-Golgi
Receives
Lysosomal storage diseases are the result of deficiencies in lysosomal proteins. An example of one such disorder is
Tay-Sachs disease
__________ results from the rapid summation of __________ over time, bringing the postsynaptic neuron to its threshold. __________ occurs at the postsynaptic neuron when multiple action potentials from several presynaptic neurons result in a large depolarization by the postsynaptic neuron.
Temporal summation; EPSPs; Spatial summation
Many biochemical reactions that occur in the cell are non-spontaneous when measured at the biochemical standard state, but are spontaneous inside of the cell. What is the most likely explanation for this difference in spontaneity for the same reaction measured under different conditions? -The concentrations of reactants inside the cell are lower than the concentration of the products. -Cells are closed thermodynamic systems. -The concentrations of reactants and products inside the cell favor the reactants. -Cells violate the second law of thermodynamics.
The concentrations of reactants and products inside the cell favor the reactants.
A particular interneuron is designed to receive a stimulus from other neurons in the form of the neurotransmitter GABA. Which of the following is an accurate description of the dendrites of this interneuron?
The dendrites of this interneuron will contain large quantities of GABA receptors.
With respect to an action potential, which of these statements is the most relevant regarding its direction of propagation?
The neuronal voltage-sodium channel has a refractory period following activation.
Which of the following is NOT a thermodynamic reason a process or reaction (reactant → product) could be endergonic? -The free energy of the products is higher than the free energy of the reactants. -The concentration of reactants and products favors too much product relative to the equilibrium ratio for the process. -The process is characterized by a significant loss of entropy. -The process or reaction liberates free energy.
The process or reaction liberates free energy.
The fourth reaction of glycolysis is the aldol cleavage of fructose-1,6-bisphosphate (F-1,6-BP) to dihydroxyacetone phosphate (DHAP) and glyceraldehyde-3-phosphate (GAP): F-1,6-BP → DHAP + GAP What about this process suggests that the forward reaction can be expected to occur based on the second law of thermodynamics? The fourth reaction of glycolysis is the aldol cleavage of fructose-1,6-bisphosphate (F-1,6-BP) to dihydroxyacetone phosphate (DHAP) and glyceraldehyde-3-phosphate (GAP): F-1,6-BP → DHAP + GAP What about this process suggests that the forward reaction can be expected to occur based on the second law of thermodynamics? -The reaction is endergonic. -The process results in an increase in entropy. -The process is characterized by a negative ΔH. -The process is at equilibrium.
The process results in an increase in entropy.
In a chemical reaction, the standard free energy change (ΔG°') is calculated to be 3.67 cal/mol. What can be said of the chemical reaction? -The reaction is not spontaneous under standard conditions. -The reaction is at equilibrium under standard conditions. -Products predominate over reactants at equilibrium under standard conditions. -There can be no reaction. -The reaction goes spontaneously to the right under standard conditions.
The reaction is not spontaneous under standard conditions.
Why are mitochondria so prevalent in skeletal muscle?
They are needed to provide energy for muscle contraction.
Which of these structures transmit signals from the central nervous system to muscles?
motor neurons
mechanical work
muscle contraction
Vytorin is a relatively new drug used to treat hypercholesterolemia, and it actually contains two active, efficacious ingredients. Vytorin contains a statin drug that inhibits a crucial enzyme in cholesterol biosynthesis, but it also contains a compound that inhibits the intestinal absorption of cholesterol from the diet. Which of the following is an accurate assessment of whether this drug can or cannot be used to treat familial hypercholesterolemia (FH)?
Vytorin can be used to treat FH patients, because it is not targeting the missing receptor in FH patients.
Which of the following statements is not true of the value ΔH? -ΔH = ΔE + Δ(PV) -ΔH is the change in enthalpy. -In biology, ΔH is basically the same as ΔE. -A reaction with a positive ΔH value is exothermic. -ΔH is the change in heat content.
a reaction with a positive ΔH value is exothermic.
concentration work
accumulation of substances in a cell
Which of the following is not a product of the TCA cycle? -NADH -CO2 -acetyl CoA -FADH2 -ATP
acetyl CoA
Which neurotransmitter is not an amino acid derivative? -dopamine -serotonin -acetylcholine -GABA -histamine
acetylcholine
Kinases are enzymes that
add phosphate groups
Which of the following experimental strategies could be used to block the IP3 branch but not the DAG branch of the IP3 pathway?
adding an antagonist of the IP3 receptor
Which term best describes the nitrogenous base adenine plus the sugar ribose? -adenosine diphosphate -adenosine -adenosine triphosphate -adenine -adenosine diphosphate followed by adenine or adenosine
adenosine
Which of the following pairings is not correct? -adenylyl cyclase-ATP -phospholipase C-diacylglycerol (DAG) -phospholipase C-inositol triphosphate -calmodulin-calcium ions
adenylyl cyclase- ATP
Cyclic AMP is __________.
an allosteric regulator of protein kinase A
Because NADH generated in the cytosol cannot enter the mitochondrion, electrons and protons from NADH are transferred in by __________.
an electron shuttle system
Synthetic compounds that inhibit receptors by preventing the natural messenger from binding are known as -antagonists. -syndecans. -specific proteoglycans. -receptor upregulators. -agonists.
antagonists
Which of the following would induce synaptic release of neurotransmitter in the absence of an action potential in a neuron?
application of a calcium ionophore that equilibrated calcium between the cytoplasm of the synaptic terminal and the extracellular space
Peroxisomes
are not derived from the endoplasmic reticulum.
The portion of the nervous system that is associated with the control of involuntary activities is the
autonomic nervous system.
Compared with the trans-Golgi proteins, the cis-Golgi proteins would
be glycosylated only.
A protein that is N-glycosylated is expected to
be secreted from the cell.
In comparing beta -oxidation to glycolysis, it can be said that __________. -beta-oxidation releases carbon dioxide and glycolysis does not -beta-oxidation produces more energy per carbon because all carbons go through the TCA cycle, whereas only two-thirds of carbons from glucose do -beta-oxidation bypasses acetyl co-A -both occur in the cytosol
beta-oxidation produces more energy per carbon because all carbons go through the TCA cycle, whereas only two-thirds of carbons from glucose do
The axon branches of a typical neuron terminate at structures called
boutons
cAMP activates:
cAMP gated ions and Protein Kinase A (PKA)
The stimulus for secretion of neurotransmitters into the synaptic cleft is an increase in -calcium levels -potassium levels -sodium levels. -chloride levels. -neurotransmitter levels.
calcium levels
In the Golgi complex, __________. -the anterograde transport system is used to move vesicles back to the ER -proteins are synthesized -proteins are N-glycosylated -carbohydrate side chains of glycoproteins are modified
carbohydrate side chains of glycoproteins are modified
synthetic work
carbon fixation
An energy-liberating pathway is considered to be
catabolic
The breakdown of glucose to pyruvate by a cell is an example of a(n) ________ reaction.
catabolic
A researcher is attempting to isolate rough ER microsomes using ultracentrifugation. Which of the following would indicate contamination of the rough ER with another organelle?
catalase
You are isolating cell fractions using a variety of centrifuge techniques. You have two very similar fractions but at this point are unable to discern which fraction is peroxisomes and which is lysosomes. As a result, you need to test the fractions for unique enzyme activities. If you are looking for peroxisomes, one enzyme activity you can test for is
catalase
Calcium ionophores __________.
cause membranes to become permeable to calcium, allowing entry to the cytosol from ER and extracellular stores and mimicking the effect of IP3
The form of energy that is available to living organisms is in the form of -nuclear energy. -radiation. -chemical bonds. -heat. -sunlight.
chemical bonds
Aerobic refers to what property of chemotrophs? -Chemotrophs use, but do not require oxygen. -Heat losses occur in the presence of oxygen. -Chemotrophs require oxygen to produce energy. -Chemotrophs remove carbon dioxide from the air. -Fermentation releases great amounts of gas but only in chemotrophs.
chemotrophs require oxygen to produce energy
Of the following electron carriers of the electron transport system, which transfers protons in addition to electrons?
coenzyme Q
Which process involves an increase in entropy of the system? -synthesis of cellulose -freezing of ice -combustion of paper -formation of raindrops -any spontaneous process
combustion of paper
In electron transport, which respiratory complex is not involved in the flow of electrons from FADH2?
complex I
Of the following sequences, which shows the correct molecules through which electrons flow when delivered to the electron transport system by NADH?
complex I, coenzyme Q, complex III, cytochrome c, complex IV, oxygen
In electron transport, which respiratory complex is not involved in the flow of electrons from NADH?
complex II
Proton gradients are generated by all of the following complexes except -complex I. -complex III. -complex II. -complex IV. -coenzyme Q.
complex II
Nerve impulses travel along the neurons by the opening of channels that allow sodium ions to flow inward, followed by an outward flow of potassium ions. In order to ensure that the impulse may be produced at any time, sodium is actively transported out of the cell, and potassium is transported into the cell by the sodium/potassium pump. Which of the following types of work is performed by the sodium/potassium pump? -electrical -concentration -bioluminescent -synthetic -mechanical
concentration
The continuous release of mucus by the epithelial cells lining the respiratory tract is an example of
constitutive secretion.
A spontaneous reaction -will never occur. -could occur but might take a very long time. -is associated exclusively with homeothermic organisms. -has to occur immediately. -has an overall positive free energy change.
could occur but might take a very long time.
adeynalate cyclase creates:
creates cAMP
Hyperpolarization of the postsynaptic nerve terminal
decrease the chance that an action potential will be initiated
Desensitization of a cell to a ligand may involve all of the following except -receptor down-regulation. -lowered affinity of a receptor for the ligand. -destruction of the ligand. -receptor-mediated endocytosis. -a lessened response to the ligand.
destruction of the ligand
Which of the following statements about action potentials is false? -Due to leaking, membranes are subject to subthreshold depolarization, which is insufficient to produce the action potential. -A refractory period is always necessary following an action potential. -At the end of the action potential, most neurons show a transient hyperpolarization. -Electrical signals are propagated along a dendrite. -They require rapid changes in membrane potential.
electrical signals are propagated along a dendrite
Chemiosmotic coupling
electron transfer generates a proton gradient which provides energy for ATP synthesis
Which of the following is defined as "heat content"? -enthalpy -energy output -solar radiation -entropy -heat loss
enthalpy
Which of the following ligands would not have an intracellular receptor?
epinepherine
All of the following are second messengers, except -cyclic adenosine monophosphate. -inositol trisphosphate. -epinephrine. -diacylglycerol. -calcium ions.
epinephrine
Which of the following represents a "molecular switch" that activates Gα proteins?
exchange of GDP for GTP on Gα
To have a hormone receptor system that is responsive to changes in hormone concentration, it is useful if the concentration of the hormone is
far below the Kd before the stimulation of hormone secretion.
Cells maintain themselves in a steady state, with most of their reactions __________. Cells accomplish this by __________. -far from thermodynamic equilibrium; having a continuous input of matter and energy from their surroundings -relying on an increase in entropy to create a negative ΔG; maintaining a constant temperature -having K′eq near 1; doing no useful work -having products and reactants that are the same; violating the second law of thermodynamics
far from thermodynamic equilibrium; having a continuous input of matter and energy from their surroundings
Cells maintain themselves in a steady state, with most of their reactions __________. Cells accomplish this by __________. -having products and reactants that are the same; violating the second law of thermodynamics -having K′eq near 1; doing no useful work -relying on an increase in entropy to create a negative ΔG; maintaining a constant temperature -far from thermodynamic equilibrium; having a continuous input of matter and energy from their surroundings
far from thermodynamic equilibrium; having a continuous input of matter and energy from their surroundings
Glucose is transported in the bloodstream to cells in all parts of your body. In cells, glucose has four main fates. Which of the following is not one of those fates? -Glucose is catabolized to carbon dioxide and water. -Glucose is used to synthesize glycogen. -Glucose is transformed into sucrose. -Glucose is converted to lactate. -Glucose is converted to acetyl CoA to make body fat.
glucose is transformed into sucrose
The phosphorylation of glucose using inorganic phosphate (abbreviated Pi) is endergonic (ΔG∘′=+3.3kcal/mol), whereas the dephosphorylation (hydrolysis) of ATP is exergonic (ΔG∘′=−7.3kcal/mol): glucose+Pi⇌glucose-6-phosphate+H2O ATP+H2O→ADP+Pi Choose a reaction for the phosphorylation of glucose by the transfer of a phosphate group from ATP. -glucose+ATP→G6P+ADP -glucose+ATP→Pi+H2O -glucose+ATP→Pi+ADP -glucose+ATP→G6P+Pi -glucose+ATP→G6P+H2O
glucose+ATP→G6P+ADP
You have isolated a factor from the blood of a space alien and named it XFF (for X-files factor). Based on preliminary data, you think that XFF could be one of three compounds normally found in human blood: epidermal growth factor (EGF), epinephrine, or estrogen. You add a large amount of XFF to cultured liver cells. Which of the following might you observe if XFF can bind to human epinephrine receptors?
glycogen breakdown
Animals that regulate their body temperature independently of the environment are called -biotherms. -homeotherms. -heterotherms. -poikilotherms. -abiotherms.
homeotherms
In an experiment, mice were fed glucose containing a radioactive carbon atom at position 1. This atom was found in __________.
in all TCA intermediates then CO2
In eukaryotes, pyruvate is converted to acetyl CoA -in the cellular cytosol. -in the intermembrane space. -in the mitochondrial matrix. -when passing through the mitochondrial outer membrane. -when passing the mitochondrial cristae.
in the mitochondrial matrix
In eukaryotes, pyruvate is converted to acetyl CoA
in the mitochondrial matrix.
Electron transport and oxidative phosphorylation are metabolic functions of the __________ of the mitochondrion. -inner membrane -matrix -outer membrane -intermembrane space
inner membrane
All of the following are glial cells except
interneurons.
In a lysosomal storage disease, the hydrolases of lysosomes are released from the cells, rather than being isolated into vesicles. What is one possible mechanism for this result?
lack of mannos-6-phosphatase activity
Which of the following would be most consistent with mammalian cells in culture that are primarily using glycolysis to make ATP and have a ratio of NADH/NAD+ that is higher than normal? -Lactate dehydrogenase is being inhibited under anaerobic conditions. -ADP is being phosphorylated to ATP too quickly. -ATP is being depleted rapidly. -Ethanol is being converted back to pyruvate.
lactate dehydrogenase is being inhibited under anaerobic conditions
bio- luminescence
luminous toadstools
presence of acid hydrolase
lysosome
heat
maintaining body temperature
Muscle contraction is an example of which of the following types of work? -bioluminescent -heat -mechanical -electrical -concentration
mechanical
Muscle contraction is an example of which of the following types of work? -electrical -bioluminescent -concentration -heat -mechanical
mechanical
electrical work
nerve impulse conduction
Oxidation -occurs when an atom accepts electrons. -is endothermic. -occurs when oxygen is added and energy released. -involves the removal of oxygen atoms. -is endothermic; occurs when an atom accepts electrons.
occurs when oxygen is added and energy released
As pyruvate is prepared for the TCA cycle, it undergoes a process of
oxidative decarboxylation
If a eukaryotic organism does not depend on fatty acids as an energy source, one would expect to find β-oxidation activity associated with which of the following organelles?
peroxisomes
Oxidation of very long fatty acids occurs in the
peroxisomes
Which of the following organelles are not part of the endomembrane system? -smooth endoplasmic reticulum -rough endoplasmic reticulum -peroxisomes -Golgi complexes -endosomes
peroxisomes
Which of the following organelles is associated with the ability to catabolize alkanes found in oil and petroleum products?
peroxisomes
test for catalase activity
peroxisomes
Which of the following statements is false with regard to G-protein coupled receptors (GPCRs)? -Protein Kinase A is activated by cAMP. -GPCRs can interact with specific receptor interacting proteins to modify ligand affinity. -Adenylate cyclase is activated. -Phosphodiesterase creates v cAMP molecules in response to moderate cAMP levels. -cAMP signals for its own degradation indirectly.
phosphodiesterase creates v cAMP molecules in response to moderate cAMP levels.
It would be useful to determine if the mechanism of action for the XFF-XFF receptor is similar to that of estrogen or epinephrine. To test this, you use a nonhydrolyzable analogue of GTP in the reaction mixture. If the mechanism is still similar to that of epinephrine, you would expect the cellular responses would be
prolonged
Which hormone is not an amino acid derivative?
prostaglandin
The kinase central to second messenger signalling based cAMP is -protein kinase A. -ATPase. -RNase PH. -Avastin kinase. -phosphorylase A.
protein kinase A
A radioactively labeled protein is made by cells and followed through the various organelles in the secretory pathway. After six hours, all of the radioactivity is still primarily in the Golgi apparatus. This suggests that the
protein possesses a signal for localization within the Golgi apparatus.
Which of the following is not a final electron acceptor in anaerobic respiration? -pyruvate -iron -hydrogen -nitrate -sulfur
pyruvate
Pyruvate is converted to acetyl CoA by a unique enzyme known as
pyruvate dehydrogenase complex
When ΔG' = 0 in a chemical reaction, under standard conditions, -no work can be done; no energy is required. -work can be done; energy is required. -the reaction is spontaneous to the left. -reactants and products are at equilibrium. -reactants and products are at equilibrium; no work can be done; no energy is required.
reactants and products are at equilibrium; no work can be done; no energy is required.
When the ΔG°' of a chemical reaction is positive (K'eq < 1.0) under standard conditions, -the reaction is exothermic. -reactants predominate over products. -work can be done under these conditions. -reactants and products are at equilibrium. -the reaction is spontaneous to the right.
reactants predominate over products
Uptake of low-density lipoproteins (LDLs) occurs by
receptor-mediated endocytosis.
The purpose of the fermentation process is the
regeneration of NAD+
Phosphatases are enzymes that
remove phosphate groups.
Which answer shows the correct order of occurrence during an action potential? -resting state, depolarizing phase, repolarizing phase, hyperpolarizing phase -depolarizing phase, hyperpolarizing phase, repolarizing phase, resting state -hyperpolarizing phase, depolarizing phase, repolarizing phase, resting state -resting state, hyperpolarizing phase, depolarizing phase, repolarizing phase
resting state, depolarizing phase, repolarizing phase, hyperpolarizing phase
All of the following are directly used as alternative substrates for glycolysis except -galactose. -ribose. -fructose. -mannose. -galactose and ribose.
ribose
The somatic nervous system controls
skeletal muscles
hydroxylation of compounds including phenobarbitals
smooth ER
Both the phosphorylation of intermediates and the formation of ATP in glycolysis are examples of
substrate level phosphorylation
Which of the following is not a product of fermentation? -CO2 -sucrose -lactate -NAD+ -ethanol
sucrose
Statins are drugs that are administered to inhibit the biosynthesis of cholesterol in the liver, and thus are used to lower blood plasma cholesterol levels in order to decrease patient risk of atherosclerosis and associated diseases such as myocardial infarction (heart attack). Which of the following components of the endomembrane system is the site of action of statin drugs?
the ER
Which of the following would NOT necessarily affect the rate of cellular respiration and oxidative phosphorylation? -the availability of ADP -the availability of fatty acids -the availability of reduced coenzymes -an intact inner mitochondrial membrane
the availability of fatty acids
The steady state so vital to life is possible because -all reactions are at equilibrium. -all cells are autotrophic. -all reactions are exothermic. -the cell cannot convert energy from one form to another. -the cell continually takes up energy from the environment.
the cell continually takes up energy from the enviornment
The statement, "The total amount of energy in the universe is constant," is a tenet of -the first law of thermodynamics. -entropy. -the second law of thermodynamics. -enthalpy. -thermodynamic spontaneity.
the first law of thermodynamics
Which of the following statements regarding the Ras protein is false? -Ras activates a cascade of phosphorylation events. -It is regulated by Sos, a guanine nucleotide exchange factor. -Ras is monomeric. -The ligands are largely steroid hormones. -It is regulated by GTPase activating proteins.
the ligands are largely steroid hormones
Much of the suitability of ATP as an energy intermediary is related to the instability of the bonds between the phosphate groups. These bonds are unstable because __________. -the phosphate groups are polar and are attracted to the water in the interior of a cell -the negatively charged phosphate groups vigorously repel one another -the valence electrons in the phosphorus atom have less energy on average than those of other atoms -they are hydrogen bonds, which are only about 10% as strong as covalent bonds
the negatively electrons in the phosphorus atom have less energy on average than those of other atoms.
A patient was diagnosed to possess a mutation in an ER-resident protein in which the ER-signal sequences of the protein were inappropriately deleted and instead replaced with a mannose-6-phosphate during protein synthesis and posttranslational modification. What is the likely fate of this mutant protein? -The protein would be secreted by exocytosis. -The protein would not be glycosylated. -The protein would be targeted to the lysosomes. -The protein never enters the Golgi complex.
the protein would be targeted to the lysosomes
A negative free energy change indicates that -energy must be added to the reaction before it can proceed. -the reaction is exothermic. -the reactant is predominant at equilibrium. -the reaction is at equilibrium. -the reaction is not possible.
the reaction is exothermic.
Under the conditions of a given reaction, a positive ΔG' means -the reaction is spontaneous. -no energy needs to be added. -the reaction is at equilibrium. -the reaction will not occur. -work can be done.
the reaction will not occur
Alpha- and beta-adrenergic receptors can bind epinephrine and norepinephrine, yet they trigger different signal transduction pathways. This is because __________.
the receptors activate different G proteins
In the first step of glycolysis, glucose can be phosphorylated because
the transfer of a phosphate from ATP to glucose is exergonic and a phosphoanhydride bond has higher energy than a phosphoester bond.
In brown fat, ________ present in the inner mitochondrial membrane uncouples ATP synthesis from electron transport in infants and other newborn mammals.
thermogenin
Which is true of heterotrophs? -They can obtain energy from consuming phototrophs. -They cannot be unicellular. -They can function as autotrophs in an emergency. -They store energy in the form of heat. -They capture light energy.
they can obtain energy from consuming phototrophs
Which is not true of phototrophs? -They store energy as glucose. -They capture light energy. -They can be bacteria. -They never function as autotrophs. -They provide energy for chemotrophs.
they never function as aut0trophs
If you were looking within a cell for organized clathrin structures, you would find them associated with which of the following structures?
trans golgi complex
he mannose-6-phosphate receptor would have what type of protein tag?
trans-Golgi retention tag
During receptor-mediated endocytosis, the ultimate fate of the vesicle and/or its contents include(s)
transcytosis, transport to late endosome for digestion, and recycling of receptors.
When one pyruvate is oxidized, the products created specifically by the TCA cycle are __________. -oxygen, ATP, NADH, and FADH2 -oxygen, ATP, NAD+, and FAD -two carbon dioxide, one ATP, three NADH, and one FADH2 -three carbon dioxide, one ATP, four NADH, and one FADH2
two carbon dioxide, one ATP, three NADH, and one FADH2
Photosynthesis is an important process that -uses water and carbon dioxide as reactants. -is performed by heterotrophs. -only plants can perform. -is performed by organisms living near deep-ocean thermal vents. -produces oxidized products.
uses water and carboon dioxide as reactants
The organelle of plant cells that is analogous to the lysosome in animal cells is the
vacuole
In the electron transport system, hydrogen atoms removed from NADH ultimately end up as part of __________. -ATP -NADH -carbon dioxide -water
water because oxygen is electronegative
During strenuous exercise, you may notice that your muscles burn. Which of the following statements best explains this phenomenon? -Without oxygen, pyruvate is being converted to lactic acid. -ADP is accumulating, which produces a burning sensation. -Proteins are being digested to provide energy. -Carbon dioxide is building up in muscle and changing the pH. -Pyruvic acid causes muscle pain.
without oxygen pyruvate is being converted to lactic acid
Calculate ΔG∘′ for this reaction.
ΔG∘′ = -4.0 kcal/mol
The conversion of glucose-6-phosphate to fructose-6-phosphate has a K′eq of 0.5. Based on that information, which of the following sets of changes in the terms of the Gibbs equation is correct? -ΔH°′ positive ΔS°′ negative ΔG°′ positive -ΔH°′ negative ΔS°′ positive ΔG°′ positive -ΔH°′ negative ΔS°′ positive ΔG°′ negative -ΔH°′ positive ΔS°′ positive ΔG°′ negative
ΔH°′ positive ΔS°′ negative ΔG°′ positive
