HCS 215: The Cell

Which of the following ions is found in a higher concentration in the intracellular fluid (ICF) compartment? -K+ (potassium) -Na (sodium) -HCO3- (bicarbonate) -Cl- (chlorine)

K+ (potassium)

Which of the following statements best describes Lactate formation? -Lactate is formed inside the nucleus -Lactate is not formed in cells -Lactate is formed in mitochondria -Lactate is formed in the cytosol.

Lactate is formed in the cytosol.

Which of the following statements is true of lipids? -Lipids are hydrophobic molecules. -All steroid hormones are made from testosterone. -Triglycerides are formed from a glycerol backbone and two fatty acids. -If a molecule is amphipathic, it cannot be a lipid.

Lipids are hydrophobic molecules.

Which of the following statements best represents the second law of thermodynamics? -Stored energy can eventually be converted to kinetic energy. -Metabolic reactions are the sum of all the reactions in the body. -Energy is neither created nor destroyed. -Natural processes tend to proceed in the direction that expands the energy. -Energy is the capacity to do work.

Natural processes tend to proceed in the direction that expands the energy.

A college student had a very poor diet during her first semester away from home. She tried convincing her parents that her poor diet caused her to receive a failing grade in physiology due to the fact that her lack of nutrient intake caused her to run low on amino acid neurotransmitters--which, of course, hindered her ability to learn. Should her parents believe her? -No, they should not believe her. -Yes, they should believe her.

No, they should not believe her.

__________ is when the actions of the body's __________ overwhelm that of the __________. -Oxidative coincidence; antioxidants; antioxidants -Oxidative stress; antioxidants; oxidants -Emotional stress; oxidants; other oxidants -Oxidative stress; oxidants; antioxidants

Oxidative stress; oxidants; antioxidants

Given what you know about glycolysis and regulation of metabolism by PFK, what is the likely mechanism by which PFK activity differs depending on ATP concentration? -PFK is an allosteric enzyme that is stimulated by AMP, ADP, and ATP. -PFK is an allosteric enzyme that is inhibited by ATP and stimulated by AMP. -PFK is an allosteric enzyme that is inhibited by AMP, ADP, and ATP. -PFK is an allosteric enzyme that is inhibited by ADP and stimulated by ATP.

PFK is an allosteric enzyme that is inhibited by ATP and stimulated by AMP.

Which of the following experimental protocols would you use to determine whether two cells were joined together by desmosomes? -Inject dye into one of the cells and observe the spread of the dye. -At the junction of the two cells, place a drop of liquid and observe whether the liquid passes between the cells. -Pull the two cells in opposite directions.

Pull the two cells in opposite directions.

A woman has just consumed a very large piece of wedding cake, resulting in a large spike in plasma glucose concentration. Which of the following is true? -The blood plasma is isotonic. -The blood plasma is hypo-osmotic relative to the ICF of the blood cells. -The blood plasma is hypotonic. -The blood plasma is hyperosmotic relative to the ICF of the blood cells.

The blood plasma is hyperosmotic relative to the ICF of the blood cells.

If a cell's membrane potential (Vm) were equal to +100mV, what would this mean? -Positive ions are lined up along the outside edge of the cell's plasma membrane. -The cell's Vm was measured under normal, resting conditions. -The cell would attract negative ions. -The cell would attract positively charged ions.

The cell would attract negative ions.

Based on what you know about types of reactions and enzyme regulation, what can you conclude about the chemical reaction catalyzed by a protein kinase? -The chemical reaction catalyzed by a protein kinase is an endergonic reaction. -This reaction is common in allosteric regulation of enzymes. -The energy change in this reaction is negative. -The chemical reaction catalyzed by a protein kinase is a dephosphorylation reaction.

The chemical reaction catalyzed by a protein kinase is an endergonic reaction.

Which of the following statements is true of passive transport of solutes across the plasma membrane? -Some kind of membrane-bound protein is necessary for passive transport to take place. -The direction of solute movement is determined by the concentration gradient of the solute. -The energy spent to move the solutes across the plasma membrane is generated through oxidative phosphorylation. -The direction of movement is determined by the amount of phospholipids in the plasma membrane.

The direction of solute movement is determined by the concentration gradient of the solute.

Which of the following characteristics of active transport is INCORRECT? -The direction of the net flux is down the electrochemical gradient. -It requires the input of energy. -It is not spontaneous. -It involves a pump.

The direction of the net flux is down the electrochemical gradient.

If the equilibrium potential for K+ is -94mV, the Vm of a cell is -70mV, and K+ is more concentrated inside the cell, which of the following statements is true? -Since the Vm potential is normal, this means that there is no net movement of ions across the membrane. -The inside of the cell has more than enough negative charge to prevent the outward movement of K+, and K+ will be drawn into the cell. -The inside of the cell has enough negative charge to prevent the outward movement of K+ and there will be no net movement of K+ across the membrane. -The inside of the cell does not have enough negative charge to prevent the outward movement of K+, and K+ will leave the cell under these conditions.

The inside of the cell does not have enough negative charge to prevent the outward movement of K+, and K+ will leave the cell under these conditions.

A cell's membrane potential (Vm) is -70 mV, the concentration of K+ is greater inside the cell, and K+'s equilibrium potential (Ek) is -94 mV. Which of the following statements is FALSE? -The inside of the cell has enough negative charge to prevent K+ from following its chemical driving force. -The chemical driving force acting on K+ is stronger than the electrical driving force acting on K+. -The electrical driving force acting on K+ is to move it into the cell. -The electrochemical gradient for K+ in this situation follows the chemical driving force.

The inside of the cell has enough negative charge to prevent K+ from following its chemical driving force.

If a person had a disease in which carrier proteins were nonfunctional, what might happen? -The person's blood could not transport hydrophobic hormones but would still be able to transport all hydrophilic hormones. -The person's blood could not transport hydrophobic and some hydrophilic hormones. -All hormones would be preserved in the blood for much too long (their half-lives would be overly extended). -The blood could not transport any hormones at all.

The person's blood could not transport hydrophobic and some hydrophilic hormones.

When proteins need to be degraded, they are "marked" with a protein called ubiquitin. Multiple ubiquitin proteins on a protein cause binding of the protein with a proteasome, a structure containing proteases which hydrolyze proteins into their amino acid subunits. Ubiquitin proteins are then released to mark a new protein. Which of the following statements is true regarding this process? -This process requires water. -Proteases are nucleotides. -Water is formed by this process. -Ubiquitin is an enzyme.

This process requires water.

Which of the following best defines tonicity? -Tonicity is a hypothetical value for the membrane potential at which the electrical driving force is equal and opposite to the chemical driving force, resulting in an electrochemical driving force of zero. -Tonicity is the passive movement of water across a biological membrane. -Tonicity is a function of the concentration of impermeant solutes outside the cell relative to inside the cell, and it determines the structural behavior of a cell placed in the solution. -Tonicity is an indirect measure of the total solute particle concentration of a solution.

Tonicity is a function of the concentration of impermeant solutes outside the cell relative to inside the cell, and it determines the structural behavior of a cell placed in the solution.

Foods are broken down into their building blocks by adding water. This would be an example of which characteristic of water? -Water acts as a reactant. -Water acts as a lubricant. -Water acts as a cushion. -Water has a high heat of vaporization.

Water acts as a reactant.

Water acts to dissolve molecules in the body. How does water dissolve the salt (NaCl) in your mouth from a salty pretzel? -Water acts as a cofactor for enzymes that dissolve the salt. -When water is added to the NaCl, NaCl is broken down by adding OH- to one element and H+ to the other. This is known as hydrolysis. -Water acts as a solvent because the partial negative charge on the oxygen in water attracts sodium, while the partial positive charge on hydrogen attracts chloride. This results in the separation of sodium from chloride, thus breaking the ionic bond.

Water acts as a solvent because the partial negative charge on the oxygen in water attracts sodium, while the partial positive charge on hydrogen attracts chloride. This results in the separation of sodium from chloride, thus breaking the ionic bond.

Which of the following statements is FALSE regarding mechanisms of water transport? -Water molecules diffuse down their own concentration gradient, but up their osmotic pressure gradient. -Water molecules utilize transmembrane proteins to move into or out of cell. -Water is actively absorbed by the digestive system. -Tight junctions prevent the movement of water between epithelial cells lining hollow organs like the urinary bladder

Water is actively absorbed by the digestive system.

In plasma, a typical body fluid, protein floating around would be considered to be which of the following? -a solute, specifically both a colloid and an electrolyte -a solute, specifically both a colloid and a nonelectrolyte -a solvent

a solute, specifically both a colloid and an electrolyte

When you put lotion on dry skin, you are trying to __________ the waters and lipids present in the lotion across your skin (an epithelial membrane). -absorb -exchange -secrete -endocytose

absorb

Which is the correct order of events for hormones activating Gs proteins? -activation of a G protein, tyrosine kinase receptor, phosphorylation of intracellular proteins -activation of G protein, binding of GTP, activation of adenylate cyclase, conversion of ATP to cAMP -activation of G protein, binding of GTP, activation of phospholipase C, activation of DAG and IP3

activation of G protein, binding of GTP, activation of adenylate cyclase, conversion of ATP to cAMP

What is the mechanism of action of lipid-soluble hormones? -increasing protein kinases -phosphorylation of intracellular proteins -activation of genes, which increases protein synthesis in the cell

activation of genes, which increases protein synthesis in the cell

Sodium can be moved out of cells and potassium can be moved into cells by ____, which moves ions ___ their electrochemical gradients.

active transport, against

After a lipid-soluble hormone is bound to its intracellular receptor, what does the hormone complex do? -phosphorylates a protein -activates a protein kinase -acts as a transcription factor and binds to DNA, activating a gene -directly alters protein synthesis at the ribosome

acts as a transcription factor and binds to DNA, activating a gene

If a patient were experiencing a less than ideal reaction to a drug, you could try to treat the patient with another drug that interfered with the first drug. Which of the following types of drug would be your best option for this? -an agonist drug with greater affinity -an agonist drug with equal affinity -an antagonist drug with equal affinity -an antagonist drug with greater affinity

an antagonist drug with greater affinity

Which enzyme will become saturated more quickly? -an enzyme with low affinity for a substrate -an enzyme with high affinity for substrate

an enzyme with high affinity for substrate

Forming peptide bonds is an example of __________. -catabolic and endergonic -anabolism and hydrolysis -catabolic and exergonic -anabolism and condensation

anabolism and condensation

Neurohormones __________. -bind receptors located on neurons only -are exocytosed by neurons -travel a short distance to reach target cells -are produced by epithelial cells

are exocytosed by neurons

In an atom, electrons __________ in pairs. -are more stable -never occur -always occur -are less stable

are more stable

Fatty acids are catabolized to acetyl CoA by __________. -chemiosmotic coupling -lipolysis -beta oxidation -dephosphorylation

beta oxidation

What keeps intracellular receptors from binding to DNA before a hormone binds to the receptor? -transcription factors -Receptors can't enter the nucleus until the hormone is bound to it. -chaperone proteins (chaperonins)

chaperone proteins (chaperonins)

Electrolytes are charged particles called ions that are dissolved in body fluids. Which of the following ions would be considered a major anion in the body? -sodium -chloride -calcium -potassium

chloride

All EXCEPT which of the following are important coenzymes in energy metabolism? -coenzyme A -nicotinamide adenine dinucleotide (NAD) -flavin adenine dinucleotide (FAD) -coenzyme D

coenzyme D

Which of the following hormones has intracellular receptors? -epinephrine -cortisol -insulin

cortisol

Which of the following second messengers activates protein kinase A? -cyclic adenosine monophosphate (cAMP) -inositiol triphosphate (IP3) -diacylglicerol (DAG) -cyclic guanosine monophosphate (cGMP)

cyclic adenosine monophosphate (cAMP)

During ischemia, oxygen delivery to cells will ____. ATP production in these cells will then ____. Then, the ability of cells to pump sodium out of cells via the Na+/K+ pump will ____. This will cause the intracellular concentration of sodium to ____. The osmolarity of the intracellular fluid will ____. The extracellular fluid will be ____ compared to the intracellular fluid. Water will ____. And the cells will ____.

decrease, decrease, decrease, increase, increase, hypotonic, diffuse into cells, swell

A similarity between diabetes mellitus and familial hypercholesterolemia is __________ transport of substances into cells, resulting in increased __________ levels of these substances. -decreased, intracellular -increased, intracellular -increased, extracellular -decreased, extracellular

decreased, extracellular

Normally, between meals, blood glucose ____, insulin secretion (and blood insulin levels) ____, the number of glucose carriers in target cell plasma membranes ____, transport of glucose into cells ____, intracellular glucose ____, and extracellular glucose ____.

decreases, decreases, decreases, decreases, decreases, increases

Phospholipase C is an enzyme that functions to produce which of the following second messengers? -calcium -cyclic adenosine monophosphate (cAMP) -cyclic guanosine monophosphate (cGMP) -diacylglicerol (DAG)

diacylglicerol (DAG)

A prostaglandin is a type of ____________, which is a type of lipid. -eicosanoid -leukotrienes -steroids -protein

eicosanoid

Which of the following correctly pairs the organ system with its appropriate characteristic? -endocrine system; longer duration of effect -nervous system; secreted messenger = hormone -nervous system; secretory cell = endocrine cell -endocrine system; target cell = neuron, muscle, or gland

endocrine system; longer duration of effect

The __________ class of receptors uses enzymes directly to carry out its intracellular signaling. -gap junctions -G protein-coupled -channel-linked -enzyme-linked

enzyme-linked

A vesicle fuses with the plasma membrane and releases its contents to the extracellular fluid. This statement describes _____. -facilitated diffusion -exocytosis -endocytosis -simple diffusion -active transport

exocytosis

Sodium and calcium ions are higher in the _____.

extracellular fluid

Some transport processes use transport proteins in the plasma membrane, but do not require ATP. This type of transport is known as _____. -active transport -exocytosis -endocytosis -simple diffusion -facilitated diffusion

facilitated diffusion

The majority of water molecules moving across plasma membranes by osmosis do so via a process that is most similar to ____. -a process that requires energy from the cell -active transport -simple diffusion -cotransport -facilitated diffusion

facilitated diffusion

Lactate is formed from acetyl CoA in order to supply glycolysis with enough NAD+ to ensure that it can proceed in situations of limited oxygen availability. -True -False

false

Steroid hormones are are stored in vesicles and released by exocytosis from cells. -True -False

false

Which of the following refers to the number of molecules that cross the membrane in a given length of time? -permeability -concentration gradient -membrane potential -flux

flux

Which of the following processes describes the catabolism of glycogen? -glycolysis -glycogenesis -gluconeogenesis -glycogenolysis

glycogenolysis

Which stage of glucose oxidation begins with a six-carbon molecule, and splits it into two three-carbon molecules? -the Krebs cycle -glycolysis -the electron transport chain -the "linking step"

glycolysis

Which type of athlete would rely most heavily on anaerobic glycolysis for energy during their sporting event? -soccer player -long-distance cyclist -high jumper -ballroom dancer

high jumper

Ions diffuse from areas of ____ concentration to areas of ____ concentration.

higher, lower

There are different prostaglandins, some perform __________ functions and some perform __________ functions. -nerve; hormonal -homeostatic; inflammatory -no; homeostatic -enzyme; inflammatory

homeostatic; inflammatory

A 300 mOsm cell is placed in a 550 mOsm solution. The solute particles inside the cell are different from those outside the cell. None of the solute particles inside the cell are permeant to the membrane. All of the solute particles in the surrounding solution are permeant to the membrane. Describe the surrounding solution. -hyper-osmotic and hypertonic -hyper-osmotic and hypotonic -hypo-osmotic and hypertonic -hypo-osmotic and hypotonic

hyper-osmotic and hypotonic

Sometimes a free radical can be beneficial to the human body, as in its usefulness in the actions of the __________. -mitochondria -golgi -cell membrane -immune system

immune system

In type 1 diabetes, after eating, blood glucose ____, insulin secretion (and blood insulin levels) ____, the number of glucose carriers in target cell plasma membranes ____, transport of glucose into cells ____, intracellular glucose ____, and extracellular glucose ____.

increases, does not change, does not change, does not change, does not change, does not change

Normally, after eating, blood glucose ____, insulin secretion (and blood insulin levels) ____, the number of glucose carriers in target cell plasma membranes ____, transport of glucose into cells ____, intracellular glucose ____, and extracellular glucose ____.

increases, increases, increases, increases, increases, decreases

Sodium and calcium will diffuse ___ cells, and potassium will diffuse ___ cells.

into, out of

Potassium ions are higher in the ____.

intracellular fluid

The total number of positive charges in our ICF __________. -is greater than the number of positive charges in the ECF -is lower than the number of positive charges in our ECF -is equal to the number of positive charges in the ECF -is equal to the number of negative charges in our ICF

is lower than the number of positive charges in our ECF

Which type of receptor is also called a "fast channel"? -G protein-linked receptor that activates an enzyme -G protein-linked receptor that opens or closes an ion channel -ligand-gated ion channels -enzyme-linked receptor

ligand-gated ion channels

Which of the following correctly matches the stage of the glucose oxidation with the amount of ATP molecules produced from one molecule of glucose? -electron transport chain; 38 ATP synthesized per molecule of glucose -glycolysis; 2 ATP synthesized per molecule of glucose -linking step; 0 ATP synthesized per molecule of glucose -citric acid cycle; 1 ATP per molecule of glucose

linking step; 0 ATP synthesized per molecule of glucose

In addition to the fact that it stinks really badly, smoking cigarettes also damages the cilia located in the lumen of the upper respiratory structures. What part of the cytoskeleton is damaged by smoking cigarettes? -microfilaments -intermediate filaments -microvilli -microtubule

microtubule

A primary active transport process is one in which __________. -molecules pass directly through the phospholipid bilayer of the plasma membrane -molecules move through transport proteins that have been activated by ATP -an intracellular vesicle fuses with the plasma membrane and releases its contents to the extracellular fluid -molecules move across the plasma membrane without an input of energy -the plasma membrane folds inward to form a vesicle containing extracellular material

molecules move through transport proteins that have been activated by ATP

which of the following organelles is genomic material stored? -ribosome -rough endoplasmic reticulum -nucleus -lysosomes

nucleus

Which of the following correctly describes the quaternary structure of a protein? -beta pleated sheets or alpha helixes -a folded pattern formed by interactions between the R groups of amino acids -only in proteins containing more than one polypeptide chain -a simple chain of amino acids

only in proteins containing more than one polypeptide chain

The flow of water across a biological membrane down its concentration gradient is known as __________. -osmosis -simple diffusion -primary active transport -osmolarity

osmosis

A(n) ________ is a substance that can remove electrons from another substance. -oxidant -base -reductant -acid

oxidant

A free radical is considered to be a type of __________ that __________ removes electrons from another substance; it does this because it has one or more __________. -oxidant; inappropriately; unpaired electrons -acid; appropriately; paired electrons -oxidant; appropriately; unpaired electrons -base; appropriately; unpaired electrons

oxidant; inappropriately; unpaired electrons

Which of the following types of reactions is considered central to aerobic energy metabolism in mitochondria? -condensation -hydrolysis -oxidation-reduction reactions -phosphorylation

oxidation-reduction reactions

Which of the following choices best describes this equation? ADP + Pi = ATP -oxidative phosphorylation -substrate level phosphorylation -ATP hydrolysis -glycolysis

oxidative phosphorylation

The actions of prostaglandins are typically localized near where they are produced. What type of communication is this? -autocrine -hormone -gap junctional -paracrine

paracrine

The sodium-potassium pump __________. -binds three K+ ions and two Na+ ions -has a higher affinity for Na+ when it is open to the side of the membrane where Na+ is in greater concentration -participates in both primary active transport and secondary active transport -utilizes two molecules of ATP for a full cycle: One ATP is spent as Na+ is moved across the membrane and one ATP is spent as K+ is moved across the membrane

participates in both primary active transport and secondary active transport

Which intracellular substance degrades cAMP, thus inactivating the response to a hormone? -phosphodiesterase -phospholipase C -adenylate cyclase -protein kinase C

phosphodiesterase

Receptors for lipophobic messengers are typically located where in the cell? -cytosol -rough endoplasmic reticulum -plasma membrane -nucleus

plasma membrane

What chemical property is given to a biomolecule with a hydroxyl (--OH) functional group? -Amphipathic -base -polar -acid

polar

Most chemical messengers are __________. -polypeptides -amines -steroids -eicosanoids

polypeptides

Sodium, calcium, and potassium are _____.

positively-charged cations

Which of the following is NOT a form of endocytosis? -pressure-mediated endocytosis -phagocytosis -pinocytosis -receptor-mediated endocytosis

pressure-mediated endocytosis

The sodium-potassium pump uses ATP to move sodium and potassium ions across the plasma membrane. This statement describes _____. -secondary active transport -exocytosis -simple diffusion -primary active transport -facilitated diffusion

primary active transport

In which phase of mitosis do chromosomes become linked at their centromeres to spindle fibers? -anaphase -metaphase -telophase -prometaphase

prometaphase

Which of the following is NOT a function of exocytosis? -adding components to the plasma membrane -secreting specific substances out of the cell and into the extracellular fluid -providing resources for energy metabolism -recycling receptors that are removed from the membrane by endocytosis

providing resources for energy metabolism

Of the various forms of endocytosis which one is the most selective? -pinocytosis -receptor-mediated endocytosis -exocytosis -phagocytosis

receptor-mediated endocytosis

The enzyme phospholipase A2 is responsible for __________ the __________ acid from membrane phospholipids. This fatty acid acts as the precursor molecule to form prostaglandins. -releasing; arachidonic -attaching; arachidonic -releasing; leukotrienes

releasing; arachidonic

Which of the following organelles is classified as nonmembranous? -mitochondria -lysosomes -ribosomes -Golgi apparatus

ribosomes

In which of the following situations would exocytosis be the proper mechanism of membrane transport? -secretion of the neurotransmitter serotonin, which is a water-soluble amine molecule -secretion of water from a cell -secretion of a steroid hormone from a cell -secretion of Na+ from a cell

secretion of the neurotransmitter serotonin, which is a water-soluble amine molecule

One of the striking features of second messengers is the ability to elicit a marked response on a target cell by small changes in the concentration of a chemical messenger. This phenomenon is known a(n) __________. -signal transduction -signal amplification -up-regulation -down-regulation

signal amplification

If a person sprays air freshener into a room, the fragrance will eventually reach your nose, even in the absence of air currents. Which of the following best describes this process? -facilitated diffusion -primary active transport -flux -simple diffusion

simple diffusion

An atom's electrons are ___________ in pairs, and if there are ______ electrons for all the electrons to be paired, then the atom will ______ to obtain electrons from other atoms. -do not desire; not enough; want -stable; not enough; want -desire; not enough; not want -do not desire; enough; want

stable; not enough; want

Cortisol is a type of lipid hormone. Which type of lipid would cortisol be classified as? -steroid -triglyceride -phospholipid

steroid

If an atomic nucleus has a __________ pull (electronegativity/electron affinity) on electrons, it will have a(n) __________ ability to obtain its __________ number of electrons. -weak; minimal; incorrect -strong; enhanced; proper -strong; minimal; proper -weak; enhanced; incorrect

strong; enhanced; proper

Which of the following is an example of oxidative phosphorylation? -ATP formed in the cytoplasm -ATP generated in the fifth step of the TCA cycle -ATP generated at the immediate onset of exercise -the ATP synthesis that occurs at the inner mitochondrial membrane

the ATP synthesis that occurs at the inner mitochondrial membrane

The net direction of a chemical reaction is dictated by __________. -the temperature of the solvent in which the reaction is occurring -the pH of the solvent in which the reaction is occurring. -the difference in concentration between the reactants and the products -the difference in energy between the reactants and products

the difference in energy between the reactants and products

Communication in the nervous system generally involves __________, which is very fast and typically of short duration. -the opening and closing of ion channels -activation of second messengers like cAMP and cGMP -altering enzyme concentrations within neurons -altered mRNA transcription

the opening and closing of ion channels

Chose the option which correctly completes the sentence. The activation energy barrier arises because __________. -the reactants have more than sufficient potential energy to initiate the reaction -the transition state is sudden and immediate -the product of the reaction inhibits the enzyme involved -the potential energy of the transition state is greater than that of either of the reactants or products

the potential energy of the transition state is greater than that of either of the reactants or products

In primary active pumping of ions across the plasma membrane, __________. -the ion is moved down its electrochemical gradient -steady state occurs when there are equal numbers of an ion on either side of the membrane -once the pump has transported one ion across the membrane, it cannot be used again to pump another ion across the membrane -the system will approach steady state as the concentration of the ion increases on the side of the pump with lower affinity for the ion

the system will approach steady state as the concentration of the ion increases on the side of the pump with lower affinity for the ion

Which hormone's receptor is always bound to DNA, even when the receptor is empty? -cortisol -thyroid hormone -insulin

thyroid hormone

Which of the following is NOT one of the factors that affect the rate of chemical reactions? -temperature -height of the activation energy barrier -transition state -reactant and product concentration

transition state

Ricin is a toxic substance which damages ribosomes. Ricin causes cellular death by disrupting __________. -post-translational modification -post-transcriptional modification -transcription -translation

translation

The "heads" of the phospholipids forming the bilayer of the plasma membrane face both the extracellular fluid and the intracellular fluid. -true -false

true

There are __________ forms of cyclooxygenase (COX). -three -four -five -two

two

Growth factor hormones, such as insulin, bind to which type of receptor? -tyrosine kinase receptors -intracellular receptors -G proteins

tyrosine kinase receptors

Which of the following chemical messengers communicate with neighboring cells? -vasopressin -vascular endothelial growth factor -epinephrine -insulin

vascular endothelial growth factor

In which of the following hormones would signal transduction be impaired if there were an intracellular shortage of GTP? -insulin -thyroxine -vasopressin -estrogen

vasopressin

What type of hormones bind to receptors located on the cell membrane? -lipid-soluble hormones, such as thyroid hormones and cortisol -water-soluble hormones, such as insulin and epinephrine

water-soluble hormones, such as insulin and epinephrine

A reaction is said to be in equilibrium __________. -when the reactant is converted to product at the same rate that product is converted to reactant -when there is absolutely no conversion of reactants to products, or products to reactants -when the equilibrium constant is greater than one -when the concentration of reactants equals the concentration of products

when the reactant is converted to product at the same rate that product is converted to reactant

In facilitated diffusion, carrier proteins will be more likely to bind with solute molecules __________. -where they are in greatest concentration, regardless of which side of the membrane the concentration is highest -on the inside of the membrane (facing the ICF) -on the outside of the membrane (facing the ECF) -when they are less concentrated, regardless of which side of the membrane the concentration is lower

where they are in greatest concentration, regardless of which side of the membrane the concentration is highest

Which of the following adrenergic receptors increase cAMP levels? -α2 receptors -β receptors -α1 receptors

β receptors

A 300 mOsm cell is placed in a 200 mOsm solution. The solute particles inside the cell are the same as those outside the cell, all of which are permeant to the membrane. Determine the new osmolarity of the ICF. -150 mOsm -250 mOsm -400 mOsm -500 mOsm

250 mOsm

Humans are approximately __________ % efficient. -40 -50 -85 -100

40%

A 300 mOsm cell is placed in a 600 mOsm solution. The solute particles inside the cell are different from those outside the cell. None of the solute particles inside the cell are permeant to the membrane. All of the solute particles in the surrounding solution are permeant to the membrane. Determine the new osmolarity of the ICF. -150 mOsm -450 mOsm -600 mOsm -900 mOsm

600 mOsm

In translation, which of the following occurs last? -The large ribosomal subunit binds to the small subunit. -An anticodon aligns with a codon. -A peptide bond is formed. -A small ribosomal subunit aligns with an mRNA strand.

A peptide bond is formed.

Which of the following statements is FALSE regarding allosteric modulation? -Allosteric modulators can alter the rate of enzyme-catalyzed reactions by changing the active site conformation to be more or less affinitive for a substrate. -Allosteric activators increase enzyme reaction rates by binding to the active site of the enzyme molecule. -Modulator molecules bind reversibly to enzymes. -The relationship between substrate concentration and reaction rate of an allosteric-modulated enzyme is graphically represented with a sigmoidal curve.

Allosteric activators increase enzyme reaction rates by binding to the active site of the enzyme molecule.

Based on the energy requirements of catabolic and anabolic reactions, which of the statements is correct? -Anabolic reactions should occur spontaneously in cells. -Anabolic reactions are able to occur in cells because cellular mechanisms link these reactions with catabolic reactions. -Neither anabolic nor catabolic reactions can occur spontaneously in cells. -Catabolic reactions should not occur spontaneously in cells.

Anabolic reactions are able to occur in cells because cellular mechanisms link these reactions with catabolic reactions.

__________ is acted upon by the enzyme __________ to form __________. -Linoleic acid; cyclooxygenase; prostaglandins -Arachidonic acid; lipoxygenase; prostaglandins -Arachidonic acid; phospholipase A2; leukotrienes -Arachidonic acid; cyclooxygenase; prostaglandins

Arachidonic acid; cyclooxygenase; prostaglandins

Which of the following statements is FALSE about energy use and storage? -The glycerol backbone of a triglyceride can be used in glycolysis. -Glucose can be stored in liver cells as glycogen. -Glucose can be made from amino acids via gluconeogenesis. -Before glycogen can be used in glycolysis, it is first broken down into glucose molecules.

Before glycogen can be used in glycolysis, it is first broken down into glucose molecules.

Which of the following statements is true of carriers found in the plasma membrane? -Carriers are membrane-bound proteins that transport molecules across a membrane. -Carriers are typically nonspecific. For example, the same carrier that transports glucose would also transport ions and proteins -Carriers are also called channels or pores. -Carriers directly utilize ATP to move ions against their concentration gradient.

Carriers are membrane-bound proteins that transport molecules across a membrane.

The steroid hormones cortisol and aldosterone are almost identical structurally. What do you predict would happen if a person had a supraphysiological level of cortisol? ? -Cortisol would bind only to its own receptors. -Cortisol would bind to the aldosterone receptor. -Cortisol would show nonspecific binding with enzme-coupled receptors after saturation of its own receptors. -Cortisol would display nonspecific binding with G protein-coupled receptors.

Cortisol would bind to the aldosterone receptor.

Which of the following is true regarding the differences between RNA and DNA? -DNA consists of a single strand of nucleotides and RNA consists of two strands which form a double helix. -Adenine is present in DNA only. Uracil is present in RNA instead of adenine. -DNA is located in the nucleus of a cell, whereas RNA is located both in the nucleus and in the cytoplasm. -RNA functions in the storage of genetic information, whereas DNA functions in the expression of genetic information.

DNA is located in the nucleus of a cell, whereas RNA is located both in the nucleus and in the cytoplasm.

A neuroscientist was running an experiment to determine how much dopamine was present in a group of dopaminergic (dopamine secreting) neurons in a particular brain region. She knew that some of the cells in a nearby brain region secreted norepinephrine. She took a sample of cells from the dopaminergic region and a sample of cells from the region where the cells secreted norepinephrine, keeping them separate from one another. She put them into a solution that degraded the phospholipids of the cells in order to release the intracellular contents into the solution. When she tested each of the two solutions of cellular contents, what do you think she found? -Dopamine did not appear to be present in either of the solutions because all the dopamine was contained in vesicles, preventing it from being measured. -Dopamine was present in the dopaminergic cells but not in the cells that secrete norepinephrine. -Dopamine was present in the solution containing the dopaminergic cells and the cells that secreted norepinephrine.

Dopamine was present in the solution containing the dopaminergic cells and the cells that secreted norepinephrine.

Which of the following statements best describes a characteristic of enzymes? -Enzymes can be used only once in a chemical reaction. -Enzymes increase the rate of reactions by decreasing the amount of energy needed for the colliding reactant molecules to enter into a transitional state. -Enzymes are formed from cholesterol molecules. -Enzymes are relatively nonspecific (that is, they will bind multitude of ligands).

Enzymes increase the rate of reactions by decreasing the amount of energy needed for the colliding reactant molecules to enter into a transitional state.

All beta adrenergic receptors are __________. -nuclear receptors -cholinergic receptors -receptors with intrinsic tyrosine kinase activity -G protein-linked receptors

G protein-linked receptors

Once a cell has successfully undergone mitosis and cytokinesis, the two daughter cells immediately enter which state of interphase? -S -G1 -G0 -G2

G0

Part E Which second messenger causes the release of calcium from the endoplasmic reticulum? -DAG -cAMP -tyrosine kinase -IP3

IP3