study guide
In the equation 2 H2 + O2 -> 2 H2O, the H2 molecules are _______ and the H2O molecules are _____.
a. reactants... products
b. products... reactants
c. used... stored
d. destroyed... created
e. created... destroyed
A. Reactants... Products
Isotopes of the same element vary in their
a. number of protons and neutrons
b. atomic number
c. number of protons
d. number of neutrons
D. Number of neutrons
The four most common elements in living organisms like humans are
a. C, N, O, Na
b. C, H, O, Fe
c. C, H, O, Na
d. Fe, N, O, Ca
e. C, H, O, N
E. C, H, O, N
which of the following statements regarding a common cellular activity is false?
a. Cells develop and maintain complex organization.
b. cells take in and use energy.
c. cells respond to the environment
d. new cells derived from cellular components like organelles.
e. cells regulate their internal environment
D. new cells derived from cellular components like organelles.
A buffer
a. is an acid that is used to offset overly basic conditions in the body
b. is a base that used to offset overly acidic conditions in the body.
c. donates OH- ions when conditions become too basic and accepts OH- ions when conditions become too acidic
d. donates OH- ions when conditions become too acidic and accepts OH- ions when conditions become too basic
e. donates H+ ions when conditions become too basic and accepts H+ ions when conditions become to acidic.
E. donates H+ ions when conditions become too basic and accepts H+ ions when conditions become to acidic.
To be scientifically valid, a hypothesis must be
a. controlled
b. phrased as a question
c. reasonable
d. testable and falsifiable
D. testable and falsifiable
Which of the following statements regarding the oxygen atom of a water molecule is true?
a. oxygen attracts electrons less strongly than the hydrogen atoms
b. oxygen is more electro-negative than the hydrogen atoms
c. oxygen is more positively charged than the hydrogen atoms.
d. oxygen is attracted to the negatively charged atoms of the other molecules.
e. oxygen is electrically neutral.
B. oxygen is more electro-negative than the hydrogen atoms.
what happens to an atom if the electrons in the outer shell are altered?
a. the atom becomes radioactive
b. the atom will disintegrate
c.the atom will remain the same.
d. the atom's characteristics change and it becomes a different element.
e. the properties of the atom will change.
E. The properties of the atom will change
What is the fundamental difference between covalent and ionic bonding?
A) In a covalent bond, the partners share electrons; in an ionic bond, one partner accepts electrons from the other.
B) In covalent bonding, both partners end up with filled outer electron shells; in ionic bonding, one partner does and the other does not.
C) Covalent bonds form between atoms of the same element; ionic bonds form between atoms of different elements.
D) In a covalent bond, the partners have identical electro-negativity; in an ionic bond, one of them is more electronegative.
E) Covalent bonding involves only the outermost electron shell; ionic bonding also involves the next electron shell inside the outermost shell.
A. In a covalent bond, the partner accepts electrons from the other.
An oxygen atom has two unpaired electrons in its outer shell. How many covalent bonds can it form?
A) four
B) three
C) one
D) two
D. two
Acid-base reactions involve the transfer of _____; whereas, reduction-oxidation reactions involve the transfer of _____.
A) protons . . . neutrons
B) protons . . . electrons
C) electrons . . . protons
D) neutrons . . . protons
E) hydrogen ions . . . protons
B. Protons... electrons
Which of the following statements regarding a common cellular activity is false?
A) Cells take in and use energy.
B) New cells are derived from cellular components like organelles.
C) Cells develop and maintain complex organization.
D) Cells respond to the environment.
E) Cells regulate their internal environment.
B) New cells are derived from cellular components like organelles.
When full, the innermost electron shell of elements in the second row of the periodic table contains ________ electrons, and the outermost shell contains ________ electrons.
A) 2 . . . 2
B) 2 . . . 8
C) 8 . . . 2
D) 4 . . . 8
E) 8 . . . 8
B) 2 . . . 8
Water's surface tension and heat storage capacity is accounted for by its
A) mass.
B) orbitals.
C) hydrogen bonds.
D) size.
E) weight.
C) hydrogen bonds.
A pharmaceutical company hires a chemist to analyze the purity of the water being used in its drug preparations. If the water is pure, the chemist would expect to find
A) H2O molecules, H+ ions, and OH- ions.
B) H2O molecules and OH- ions.
C) only molecules of H2O.
D) H2O molecules and H+ ions.
E) only H+ ions and OH- ions.
A) H2O molecules, H+ ions, and OH- ions.
As ice melts,
A) covalent bonds form.
B) water molecules become less tightly packed.
C) hydrogen bonds are broken.
D) heat is released.
E) the water becomes less dense.
C) hydrogen bonds are broken.
A(n) ________ forms when two atoms share electrons.
A) covalent bond
B) hydrogen bond
C) element
D) ionic bond
E) ion
A) covalent bond
Which of the following is dependent on the ability of water molecules to form hydrogen bonds with other molecules besides water?
A) the milder temperatures of coastal regions compared to inland areas
B) the movement of water from the roots of a tree to its leaves
C) the ability of certain insects to walk on the surface of water
D) the evaporative cooling of skin surfaces
E) the universality of water as a solvent
E) the universality of water as a solvent
The most common base in biological and environmental systems is sodium hydroxide.
A) True
B) False
B. False
Household ammonia has a pH of 12; household bleach has a pH of 13. Which of the following statements about them is true?
A) The ammonia has 10 times as many OH- ions as the bleach.
B) The ammonia has twice the amount of H+ ions as the bleach.
C) Both of these substances are strong acids.
D) The ammonia has 10 times as many H+ ions as the bleach.
D) The ammonia has 10 times as many H+ ions as the bleach.
Peptide bonds
A) bind monosaccharides.
B) are formed by a hydrolysis reaction.
C) link amino acids.
D) form between fatty acids.
E) are used to form amino acids.
C) link amino acids.
Fatty acids with double bonds between some of their carbons are said to be
A) triglycerides.
B) saturated.
C) monoglycerides.
D) completely hydrogenated.
E) unsaturated.
E) unsaturated.
DNA differs from RNA because DNA
A) consists of a single rather than a double polynucleotide strand.
B) contains phosphate groups not found in RNA.
C) contains the sugar ribose rather than the sugar deoxyribose.
D) contains thymine in place of uracil.
D) contains thymine in place of uracil.
An oil may be converted into a substance that is solid at room temperature by
A) adding hydrogens, decreasing the number of double bonds in the molecules.
B) removing water, causing a dehydration synthesis reaction to occur.
C) removing hydrogens, increasing the number of double bonds.
D) cooling it, so that double bonds form and the fats solidify.
A) adding hydrogens, decreasing the number of double bonds in the molecules.
Which of the following contains a carboxyl and an amino group?
A) vinegar
B) amino acids
C) sugars
D) ATP
E) fats
B) amino acids
Amino acids can be distinguished from one another by
A) the chemical differences of their R groups.
B) the type of bond between the R group and the rest of the amino acid molecule.
C) the chemical properties of their amino and carboxyl groups.
D) the number of R groups found on the amino acid molecules.
A) the chemical differences of their R groups.
Which of the following statements about animal cell lipids is false?
A) Steroids are lipids that function as signaling molecules.
B) Many lipids function as enzymes.
C) Cholesterol is a type of lipid that is a component of cell membranes and steroid hormones.
D) Fats are a form of lipid that function to store energy.
E) Phospholipids are important components of cell membranes.
B) Many lipids function as enzymes.
Genetic information is encoded in the
A) linear sequence of amino acids in a polypeptide.
B) length of glycogen.
C) degree of saturation of fatty acids.
D) quaternary structure of a protein.
E) sequence of nucleotides in DNA.
E) sequence of nucleotides in DNA.
A hydroxyl group is
A) also called a carbonyl group.
B) characteristic of proteins.
C) characteristic of alcohols.
D) hydrophobic.
C) characteristic of alcohols.
.The storage form of carbohydrates is ________ in animals and ________ in plants.
A) glycogen . . . starch
B) chitin . . . glycogen
C) starch . . . glycogen
D) cellulose . . . glycogen
E) glycogen . . . cellulose
A) glycogen . . . starch
A phospholipid is composed of
A) one fatty acid molecule linked to three glycerol molecules.
B) one glycerol molecule linked to three fatty acids.
C) one fatty acid molecule linked to one glycerol molecule and two phosphate groups.
D) one glycerol molecule linked to one phosphate group and two fatty acids.
E) one glycerol molecule linked to three phosphate groups.
D) one glycerol molecule linked to one phosphate group and two fatty acids.
Carbohydrate isomers have
A) the same molecular formula, but often different chemical properties.
B) different molecular formulas, but the same chemical properties.
C) the same molecular formula and the same chemical properties.
D) the same number of carbon atoms, but different numbers of oxygen and hydrogen atoms.
A) the same molecular formula, but often different chemical properties.
Proteins differ from one another because
A) each protein contains its own unique sequence of sugar molecules.
B) the sequence of amino acids in the polypeptide chain differs from protein to protein.
C) the number of nucleotides found in each protein varies from molecule to molecule.
D) the number of nitrogen atoms in each amino acid varies.
E) the peptide bonds linking amino acids differ from protein to protein.
B) the sequence of amino acids in the polypeptide chain differs from protein to protein.
Which of the following statements regarding carbon is false?
A) Carbon has the ability to bond together to form extensive, branched, or unbranched "carbon skeletons."
B) Carbon has the ability to bond with up to four other atoms.
C) Carbon has the capacity to form polar bonds with hydrogen.
D) Carbon has a tendency to form covalent bonds.
E) Carbon has the capacity to form single and double bonds.
C) Carbon has the capacity to form polar bonds with hydrogen
Which of the following statements regarding nucleotides is false?
A) Nucleotides can be linked together to form nucleic acids.
B) Nucleotides contain nitrogenous bases.
C) Nucleotides contain sugar molecules.
D) Nucleotides have a nitrogenous base backbone.
E) Nucleotides contain phosphate groups.
D) Nucleotides have a nitrogenous base backbone.
A disaccharide forms when
A) two starches join by hydrolysis.
B) two monosaccharides join by hydrolysis.
C) a starch and a monosaccharide join by dehydration synthesis.
D) two starches join by dehydration synthesis.
E) two monosaccharides join by dehydration synthesis.
E) two monosaccharides join by dehydration synthesis.
Which of the following characteristics of protein will remain intact if the protein is denatured?
A) the shape of the protein
B) the solubility of the protein in water
C) the function of the protein
D) the primary structure
D) the primary structure
The tertiary structure of a polypeptide refers to
A) the number of R groups it contains.
B) its size.
C) the amino acids of which it is made.
D) the overall three-dimensional structure.
E) the presence of pleated sheets.
D) the overall three-dimensional structure.
A molecule with the formula C55H110O55 is probably a(n)
A) wax.
B) steroid.
C) protein.
D) polysaccharide.
E) oil.
D) polysaccharide.
Most animal cells are
A) embedded in a lipid matrix.
B) surrounded by a cell wall.
C) embedded in an extracellular matrix.
D) attached to each other via plasmodesmata.
E) embedded in an endomembrane system.
C) embedded in an extracellular matrix.
Cilia differ from flagella in that
A) cilia are anchored only in the proteins of the cell membrane, while flagella are anchored in a special structure called the basal body.
B) cilia contain nine microtubule doublets surrounding a central pair of microtubules, while flagella contain only nine microtubule doublets.
C) the protein filaments of cilia are "naked," while those of flagella are wrapped in an extension of the cell membrane.
D) cilia are typically more numerous and shorter than flagella.
E) cilia are composed of microfilaments and flagella are composed of intermediate filaments.
D) cilia are typically more numerous and shorter than flagella.
Which of the following types of cell lacks a membrane-enclosed nucleus?
A) Fungal
B) Animal
C) Prokaryotic
D) Eukaryotic
E) Plant
C) Prokaryotic
The function of mitochondria is
A) intracellular digestion.
B) lipid synthesis.
C) intracellular transport of proteins.
D) cellular respiration.
E) photosynthesis.
D) cellular respiration.
Mitochondria differ from chloroplasts in that mitochondria
A) convert solar energy to chemical energy, whereas chloroplasts convert one form of chemical energy to another.
B) contain membrane folds called cristae, whereas chloroplasts contain disk-like vesicles in stacks called grana.
C) produce glucose, whereas chloroplasts break glucose down.
D) contain three different membrane-bound compartments, whereas chloroplasts contain two.
B) contain membrane folds called cristae, whereas chloroplasts contain disk-like vesicles in stacks called grana
Unlike animal cells, plant cells have ________ and ________. Unlike plant cells, animal cells have ________.
A) chloroplasts . . . cell walls . . . centrioles
B) centrioles . . . cell walls . . . large central vacuoles
C) chloroplasts . . . cell walls . . . cell membranes
D) centrioles . . . chloroplasts . . . cell walls
E) chloroplasts . . . cell walls . . . a nucleus
A) chloroplasts . . . cell walls . . . centrioles
Which of the following statements about lysosomes is false?
A) Lysosomes synthesize proteins from the recycled amino acids.
B) Lysosomes recycle materials within the cell.
C) Lysosomes help to digest worn-out or damaged organelles.
D) Lysosomes destroy harmful bacteria engulfed by white blood cells.
E) Lysosomes fuse with food vacuoles to expose nutrients to lysosomal enzymes.
A) Lysosomes synthesize proteins from the recycled amino acids.
The cells that produce protein-rich hair contain a lot of ________, while the cells that produce the oils that coat the hair contain a lot of ________.
A) nuclei . . . chromatin
B) rough endoplasmic reticulum . . . smooth endoplasmic reticulum
C) smooth endoplasmic reticulum . . . lysosomes
D) smooth endoplasmic reticulum . . . rough endoplasmic reticulum
E) microbodies . . . lysosomes
B) rough endoplasmic reticulum . . . smooth endoplasmic reticulum
Which of the following statements regarding the Golgi apparatus is false?
A) The Golgi apparatus works closely with the endoplasmic reticulum.
B) The Golgi apparatus modifies chemicals received from the endoplasmic reticulum.
C) The Golgi apparatus decreases in size when a cell increases its protein production.
D) The Golgi apparatus sorts molecules according to their destination.
C) The Golgi apparatus decreases in size when a cell increases its protein production.
A bacterial cell's DNA is found in its
A) capsule.
B) nucleus.
C) nucleoid region.
D) peroxisome.
E) ribosomes.
C) nucleoid region.
The function of the nucleolus is
A) to manufacture polypeptides.
B) to manufacture ribosomal RNA.
C) to produce H2O2.
D) intracellular digestion.
E) to store chromatin.
B) to manufacture ribosomal RNA
Insulin is a protein that is produced by pancreatic cells and secreted into the bloodstream. Which of the following options correctly lists the order of the structures through which insulin passes from its production to its exit from the cell?
A) rough ER, lysosomes, transport vesicles, cell membrane
B) rough ER, transport vesicles, Golgi apparatus, transport vesicles, cell membrane
C) rough ER, Golgi apparatus, smooth ER, cell membrane
D) rough ER, transport vesicles, Golgi apparatus, vacuole, cell membrane
E) rough ER, transport vesicles, cell membrane
B) rough ER, transport vesicles, Golgi apparatus, transport vesicles, cell membrane
The two main functions of the rough endoplasmic reticulum are the production of
A) hydrogen peroxide and steroid hormones secreted by the cell.
B) mitochondria and proteins secreted by the cell.
C) membrane and proteins secreted by the cell.
D) chromatin and mitochondria.
E) ribosomes and steroid hormones.
C) membrane and proteins secreted by the cell.
The membranous compartmentalization of a cell
A) requires the presence of a large central vacuole.
B) is common in prokaryotes and eukaryotes.
C) allows different metabolic processes to occur simultaneously.
D) divides the cell into two equal-sized halves.
E) requires the presence of a cell wall.
C) allows different metabolic processes to occur simultaneously.
Which of the following statements regarding the endomembrane system is false?
A) The endomembrane system is a system of interrelated membranes that are all physically connected.
B) The endomembrane system is involved in the synthesis, storage, and export of important molecules.
C) The endomembrane system divides the cell into compartments.
D) The endomembrane system includes the rough and smooth endoplasmic reticulum.
E) The endomembrane system includes the nuclear envelope.
A) The endomembrane system is a system of interrelated membranes that are all physically connected.
Which of the following statements about the cytoskeleton is false?
A) The cytoskeleton is composed of three types of fibers: microfilaments, microtubules, and intermediate filaments.
B) Once laid down, the elements of the cytoskeleton are fixed and remain permanently in place.
C) The cytoskeleton plays an important role in amoeboid motion.
D) The cytoskeleton helps to support cells.
B) Once laid down, the elements of the cytoskeleton are fixed and remain permanently in place.
During cell reproduction, chromatin fibers coil up into structures called
A) peroxisomes.
B) nucleoli.
C) chromosomes.
D) ribosomes.
E) lysosomes.
C) chromosomes.
A drug that interferes with microtubule formation is likely to completely disrupt
A) the function of lysosomes.
B) contraction of muscle cells.
C) the movements of sperm cells.
D) the amoeboid motion of a cell.
E) the production of ribosomes.
C) the movements of sperm cells.
The function of chloroplasts is
A) lipid synthesis.
B) photosynthesis.
C) intracellular digestion.
D) intracellular transport of proteins.
E) cellular respiration.
B) photosynthesis.
The nucleus of a cell
A) is surrounded by a single layer of membrane.
B) is contained within the nucleolus.
C) contains DNA.
D) is the region of the cell where ribosomes are degraded.
E) is the primary location of protein synthesis.
C) contains DNA.
When an enzyme catalyzes a reaction,
A) it becomes a product.
B) it raises the activation energy of the reaction.
C) it lowers the activation energy of the reaction.
D) it is used once and discarded.
E) it acts as a reactant.
C) it lowers the activation energy of the reaction.
Glucose molecules provide energy to power the swimming motion of sperm. In this example, the sperm are changing
A) chemical energy into potential energy.
B) kinetic energy into potential energy.
C) chemical energy into kinetic energy.
D) kinetic energy into chemical energy.
C) chemical energy into kinetic energy.
Which of the following statements regarding active transport is false?
A) Active transport is necessary to allow nerves to function properly.
B) Active transport can move solutes against a concentration gradient.
C) Active transport requires the cell to expend energy.
D) Active transport is driven by the concentration gradient.
E) Active transport uses ATP as an energy source.
D) Active transport is driven by the concentration gradient.
Heating inactivates enzymes by
A) inducing the addition of amino acids.
B) causing enzyme molecules to stick together.
C) changing the enzyme's three-dimensional shape.
D) breaking the covalent bonds that hold the molecule together.
E) removing phosphate groups from the enzyme.
D) breaking the covalent bonds that hold the molecule together.
Which of the following processes is endergonic?
A) the release of heat from the breakdown of glucose
B) cellular respiration
C) the burning of wood
D) the breakdown of glucose
E) the synthesis of glucose from carbon dioxide and water
E) the synthesis of glucose from carbon dioxide and water
Which of the following statements regarding membrane function is false?
A) The plasma membrane plays a role in signal transduction.
B) The plasma membrane is the control center of the cell.
C) The plasma membrane is involved in self-recognition.
D) The plasma membrane forms a selective barrier around the cell.
E) The plasma membrane has receptors for chemical messages.
B) The plasma membrane is the control center of the cell.
How does inhibition of an enzyme-catalyzed reaction by a competitive inhibitor differ from inhibition by a noncompetitive inhibitor?
A) Competitive inhibitors are inorganic substances such as metal ions; noncompetitive inhibitors are vitamins or vitamin derivatives.
B) Competitive inhibitors bind to the enzyme reversibly; noncompetitive inhibitors bind to it irreversibly.
C) Competitive inhibitors bind to the active site of the enzyme; noncompetitive inhibitors bind to a different site.
D) Competitive inhibitors change the enzyme's tertiary structure; noncompetitive inhibitors cause polypeptide subunits to dissociate.
E) Competitive inhibitors interfere with the enzyme; noncompetitive inhibitors interfere with the reactants.
C) Competitive inhibitors bind to the active site of the enzyme; noncompetitive inhibitors bind to a different site.
In the lab, you use a special balloon that is permeable to water, but not sucrose, to make an "artificial cell." The balloon is filled with a solution of 20% sucrose and 80% water and is immersed in a beaker containing a solution of 40% sucrose and 60% water. Which of the following will occur?
A) Water will enter the balloon.
B) Sucrose will enter the balloon.
C) Sucrose will leave the balloon.
D) Water will leave the balloon.
E) Sucrose and water will pass across the balloon simultaneously.
D) Water will leave the balloon.
Which of the following statements is true among all types of passive diffusion?
A) Proteins are needed to transport molecules across the membrane.
B) Only small nonpolar molecules are able to cross the plasma membrane.
C) Only small polar molecules are able to cross the plasma membrane.
D) Ions never cross the plasma membrane by passive transport.
E) The concentration gradient is the driving force.
E) The concentration gradient is the driving force.
Which of the following statements regarding enzyme function is false?
A) Enzymes are very specific for certain substrates.
B) An enzyme binds to its substrate at the enzyme's active site.
C) Enzymes are used up in chemical reactions.
D) An enzyme's function depends on its three-dimensional shape.
E) Enzymes emerge unchanged from the reactions they catalyze.
C) Enzymes are used up in chemical reactions.
The fluid mosaic model describes the plasma membrane as consisting of
A) a phospholipid bilayer with embedded carbohydrates.
B) two layers of phospholipids with protein sandwiched between them.
C) individual proteins and phospholipids that can drift in a phospholipid bilayer.
D) a protein bilayer with embedded phospholipids.
C) individual proteins and phospholipids that can drift in a phospholipid bilayer.
Some protozoans have special organelles called contractile vacuoles that continually eliminate excess water from the cell. The presence of these organelles tells you that the environment
A) is hypertonic to the protozoan.
B) is hypotonic to the protozoan.
C) contains a higher concentration of solutes than the protozoan.
D) is isotonic to the protozoan.
B) is hypotonic to the protozoan.
Which of the following statements regarding diffusion is false?
A) Diffusion requires no input of energy into the system.
B) Diffusion is a result of the kinetic energy of atoms and molecules.
C) Diffusion occurs even after equilibrium is reached and no net change is apparent.
D) Diffusion occurs when particles spread from areas where they are less concentrated to areas where they are more concentrated.
E) Diffusion is driven by concentration gradients.
D) Diffusion occurs when particles spread from areas where they are less concentrated to areas where they are more concentrated.
Which of the following statements regarding membrane protein function is false?
A) Membrane proteins serve as enzymes.
B) Membrane proteins transfer genetic information to the cytoplasm.
C) Membrane proteins form junctions between cells.
D) Membrane proteins act as receptors to molecules like hormones.
E) Membrane proteins provide cellular identification tags.
B) Membrane proteins transfer genetic information to the cytoplasm.
ATP can be used as the cell's energy exchange mechanism because
A) ATP is the most energy-rich small molecule in the cell.
B) endergonic reactions can be fueled by coupling them with the hydrolysis of high-energy phosphate bonds in ATP.
C) endergonic reactions can be fueled by coupling them with the formation of ATP from ADP.
D) the regeneration of ATP from ADP can be fueled by coupling it with endergonic reactions.
E) ATP is a disposable form of chemical energy, used once and then discarded by the cell.
B) endergonic reactions can be fueled by coupling them with the hydrolysis of high-energy phosphate bonds in ATP.
Certain cells that line the stomach synthesize a digestive enzyme and secrete it into the stomach. This enzyme is a protein. Which of the following processes could be responsible for its secretion?
A) passive transport
B) pinocytosis
C) diffusion
D) exocytosis
E) endocytosis
D) exocytosis
Which of the following substances could be a cofactor?
A) a zinc atom
B) a protein
C) collagen
D) a polypeptide
E) a ribosome
A) a zinc atom
Facilitated diffusion across a biological membrane requires ________ and moves a substance ________ its concentration gradient.
A) transport proteins . . . against
B) energy and transport proteins . . . against
C) energy and transport proteins . . . down
D) energy . . . down
E) transport proteins . . . down
E) transport proteins . . . down
Relaying a message from a membrane receptor to a molecule that performs a specific function within a cell is called
A) self-recognition.
B) signal transduction.
C) competition.
D) inhibition.
E) selective permeability.
B) signal transduction.
In a hypotonic solution, an animal cell will
A) experience turgor.
B) neither gain nor lose water.
C) shrivel.
D) lyse.
E) lose water.
D) lyse.
The chloroplast ATP synthase
A) is a nucleic acid complex.
B) helps transport H+ against the concentration gradient.
C) is embedded in the inner membrane of the chloroplast.
D) transports H+ ions from the thylakoid space to the stroma.
E) couples the flow of H+ to the phosphorylation of NADP+.
D) transports H+ ions from the thylakoid space to the stroma.
Carbon fixation
A) occurs during the light reactions.
B) occurs when carbon and oxygen from CO2 are incorporated into an organic molecule.
C) provides the cell with a supply of NADPH molecules.
D) powers the process of glucose synthesis by supplying the cell with ATP.
B) occurs when carbon and oxygen from CO2 are incorporated into an organic molecule.
The electron transport chains of the light reactions
A) shuttle electrons along in a series of redox reactions.
B) are very different from those of cellular respiration.
C) provide energy for the Krebs cycle.
D) are located in the stroma.
A) shuttle electrons along in a series of redox reactions.
Photophosphorylation differs from oxidative phosphorylation in that
A) energy is stored in the form of a proton concentration difference.
B) the final electron acceptor is NADP+ and not oxygen.
C) regeneration of ATP is driven by a flow of protons through an ATP synthase.
D) it involves an electron transport chain.
B) the final electron acceptor is NADP+ and not oxygen.
Photosystem II
A) is reduced by NADPH.
B) does not have a reaction center.
C) releases CO2 as a by-product.
D) passes electrons to photosystem I.
E) has P700 at its reaction center.
D) passes electrons to photosystem I.
Which of the following molecules is both a reactant and a product of photosynthesis?
A) glucose
B) H2O
C) O2
D) CO2
E) chlorophyll
B) H2O
The ultimate source of all the food we eat and the oxygen we breathe is
A) anaerobic metabolism.
B) cellular respiration.
C) chemiosmosis.
D) glycolysis.
E) photosynthesis.
E) photosynthesis
In photosynthesis, the chemiosmotic production of ATP
A) requires oxygen.
B) requires the input of NADPH.
C) is a result of the oxidation of glucose.
D) is done by the Calvin cycle.
E) is analogous to the production of ATP in mitochondria.
E) is analogous to the production of ATP in mitochondria.
ATP and NADPH
A) play a role in glucose synthesis by plants.
B) are products of the Calvin cycle.
C) are inputs to the photosystems.
D) production is associated with events taking place on the inner mitochondrial membrane.
A) play a role in glucose synthesis by plants.
The light reactions occur in the ________, while the Calvin cycle occurs in the ________.
A) cytoplasm . . . thylakoid membrane
B) cytoplasm . . . stroma
C) thylakoid membranes . . . stroma
D) stroma . . . thylakoid membranes
C) thylakoid membranes . . . stroma
Photosynthetic organisms derive their carbon from
A) carbon dioxide.
B) hydrocarbons.
C) methane.
D) ribose.
E) carbon monoxide.
A) carbon dioxide.
Which of the following are produced during the Calvin cycle?
A) ADP, NADP+, O2
B) ATP, NADPH, O2
C) glucose, ADP, NADP+, CO2
D) glucose, ADP, NADP+
D) glucose, ADP, NADP+
Photoautotrophs
A) eat other organisms that use light energy to make food molecules.
B) produce organic molecules from inorganic molecules.
C) include only the green plants.
D) make sugar by using organic raw materials.
E) are only found on land.
B) produce organic molecules from inorganic molecules.
Which of the following statements concerning the role of redox reactions in photosynthesis and cellular respiration is true?
A) Photosynthesis involves only oxidations, while respiration involves only reductions.
B) In photosynthesis, carbon dioxide is reduced to form sugar, while in respiration, sugar is oxidized to form carbon dioxide.
C) Photosynthesis involves both reduction and oxidation, while respiration involves only oxidation.
D) In photosynthesis, carbon dioxide is oxidized to form sugar, while in respiration, sugar is reduced to form carbon dioxide.
E) Photosynthesis involves only reductions, while respiration involves only oxidations.
B) In photosynthesis, carbon dioxide is reduced to form sugar, while in respiration, sugar is oxidized to form carbon dioxide.
Mitochondria transfer ________ energy from ________ to ATP; chloroplasts transform ________ energy into the chemical energy of ATP.
A) food . . . light . . . chemical
B) food . . . light . . . nuclear
C) chemical . . . food . . . light
D) light . . . food . . . kinetic
E) nuclear . . . light . . . food
C) chemical . . . food . . . light
Which of the following are produced during the light reactions of photosynthesis?
A) glucose, ADP, NADP+, CO2
B) ATP, NADPH, O2
C) glucose, ADP, NADP+
D) ADP, NADP+, O2
B) ATP, NADPH, O2
Plant cells
A) have chloroplasts and vestigial mitochondria.
B) have mitochondria but do not have chloroplasts.
C) have mitochondria and chloroplasts.
D) lack mitochondria and chloroplasts.
E) lack mitochondria but have chloroplasts.
C) have mitochondria and chloroplasts.
Why are most plants green?
A) Chlorophyll b primarily uses green light as the source of energy for photosynthesis.
B) Chlorophyll a reflects green light.
C) Green helps plants blend into their environment as a sort of camouflage.
D) All photosynthetic pigments are colored green.
E) Chlorophyll a absorbs green light.
B) Chlorophyll a reflects green light.
Which of the following statements regarding photosynthesis is false?
A) ATP is not produced during photosynthesis, but only during respiration.
B) Photosynthesis consumes CO2; respiration consumes O2.
C) The principal electron carrier in photosynthesis is NADPH; the principal electron carrier in respiration is NADH.
D) Photosynthesis is ultimately powered by light energy and respiration by the chemical energy of fuel molecules.
E) Photosynthesis produces O2; respiration produces CO2.
A) ATP is not produced during photosynthesis, but only during respiration.
Where is chlorophyll found in a plant cell?
A) matrix
B) thylakoid membranes
C) cristae
D) stroma
E) cytoplasm
B) thylakoid membranes
During which phase of mitosis do the chromosomes line up on a plane equidistant from the two spindle poles?
A) interphase
B) metaphase
C) prophase
D) anaphase
E) telophase
B) metaphase
The roles of cell division in asexual reproduction include all of the following except one. Which one?
A) Repair and replacement of cells in an adult
B) Sperm and egg production
C) Growth of a multicellular organism
D) Reproduction of an entire single-celled organism
E) Growth from a fertilized egg into an adult
B) Sperm and egg production
Prior to mitosis, each chromosome of a eukaryotic cell consists of a pair of identical structures called
A) sister chromosomes.
B) DNA transcripts.
C) sister chromatids.
D) nucleoli.
E) chromatin.
C) sister chromatids.
Strictly speaking, the phrase "like begets like" refers to
A) sexual reproduction between different species.
B) sexual reproduction only.
C) asexual reproduction only.
D) all forms of reproduction.
C) asexual reproduction only.
Which of the following statements regarding the function of mitosis is false?
A) Mitosis allows organisms to regenerate lost parts.
B) Mitosis allows organisms to reproduce asexually.
C) Mitosis allows organisms to repair tissues.
D) Mitosis allows organisms to grow.
E) Mitosis allows organisms to generate genetic diversity.
E) Mitosis allows organisms to generate genetic diversity.
Which of the following helps maintain the structure of chromosomes and control the activity of genes?
A) centromeres
B) lipids
C) the nuclear membrane
D) ribosomes
E) proteins
E) proteins
The phase of mitosis during which the nuclear envelope fragments and the nucleoli disappear is called
A) anaphase.
B) prophase.
C) metaphase.
D) interphase.
E) telophase.
B) prophase.
At the start of mitotic anaphase,
A) the chromatid DNA replicates.
B) the centromeres of each chromosome come apart.
C) equivalent and complete collections of chromosomes have reached the two poles.
D) sister chromatids separate.
E) daughter chromosomes begin to move toward opposite poles of the cell.
B) the centromeres of each chromosome come apart.
With the exception of identical twins, siblings who have the same two biological parents are likely to look similar, but not identical, to each other because they have
A) the same combination of traits, but different genes.
B) identical chromosomes, but different genes.
C) a similar but not identical combination of genes.
D) identical genes but different chromosomes.
C) a similar but not identical combination of genes.
The process by which the cytoplasm of a eukaryotic cell divides to produce two cells is called
A) binary fission.
B) cytokinesis.
C) telophase.
D) mitosis.
E) spindle formation.
B) cytokinesis.
The genetic material is duplicated during
A) the S phase
B) the mitotic phase
C) G2
D) mitotic
E) G1
A) the S phase
Eukaryotic chromosomes differ from prokaryotic chromosomes in that they
A) are copied immediately after cell division.
B) include fewer proteins.
C) are housed in a membrane-enclosed nucleus.
D) are circular in structure.
C) are housed in a membrane-enclosed nucleus.
Sister chromatids are
A) tightly linked together at a centromere.
B) formed when chromatids separate during cell division.
C) made only of DNA.
D) found right after a cell divides.
E) unique to prokaryotes.
A) tightly linked together at a centromere.
Virchow's principle, stated formally in 1858, was that
A) all life evolves.
B) photosynthesis is the center of all life.
C) animals must always reproduce.
D) every cell comes from a cell.
E) animals must develop.
D) every cell comes from a cell.
Eukaryotic cells spend most of their cell cycle in which phase?
A) anaphase
B) interphase
C) metaphase
D) telophase
E) prophase
B) interphase
Which of the following features likely accounts for the difference between plant and animal cell cytokinesis?
A) Plant cells have two sets of chromosomes; animal cells have one set of chromosomes.
B) Animal cells lack chloroplasts.
C) Plant and animal cells do not have a common ancestor.
D) Plant cell division must maintain the integrity of the cell wall.
E) Animal cells lack the microfilaments required for forming a cleavage furrow.
D) Plant cell division must maintain the integrity of the cell wall.
Which of the following is a feature of plant cell division that distinguishes it from animal cell division?
A) disappearance and subsequent reappearance of the nucleolus
B) production of four (rather than two) new cells per mitotic division
C) formation of a cleavage furrow
D) formation of a cell plate
E) lack of cytokinesis
D) formation of a cell plate
Which of the following statements regarding prokaryotes is false?
A) Most prokaryotes reproduce by binary fission.
B) In prokaryotes, daughter chromosomes are separated by an active movement away from each other and the growth of a new plasma membrane between them.
C) Prokaryotic cells are generally smaller and simpler than eukaryotic cells.
D) Prokaryotic chromosomes are more complex than those of eukaryotes.
D) Prokaryotic chromosomes are more complex than those of eukaryotes.
During which phase of mitosis does the nuclear envelope re-form and the nucleoli reappear?
A) interphase
B) prophase
C) anaphase
D) metaphase
E) telophase
E) telophase
Which of the following options best depicts the flow of information when a gene directs the synthesis of a cellular component?
A) DNA → amino acid → RNA → protein
B) DNA → tRNA → mRNA → protein
C) DNA → RNA → protein
D) protein → RNA → DNA
E) RNA → DNA → RNA → protein
C) DNA → RNA → protein
Which of the following is a function of tRNA?
A) joining to only one specific type of amino acid
B) transferring nucleotides to rRNA
C) recognizing the appropriate anticodons in mRNA
D) helping to translate codons into nucleic acids
E) joining to several types of amino acid
A) joining to only one specific type of amino acid
Which of the following enzymes catalyzes the elongation of a new DNA strand?
A) primase
B) single-stranded binding protein
C) DNA polymerase
D) helicase
E) ligase
C) DNA polymerase
Which of the following statements about eukaryotic RNA is true?
A) A long tail of extra nucleotides is removed from the 5' end of the RNA.
B) The modified RNA molecule is transported into the nucleus.
C) Exons are spliced together.
D) Introns are added to the RNA.
E) A small cap of extra nucleotides is added to both ends of the RNA.
C) Exons are spliced together.
A physical or chemical agent that changes the nucleotide sequence of DNA is called a(n)
A) terminator.
B) anticodon.
C) reverse transcriptase.
D) mutagen.
D) mutagen.
Which of the following options most accurately lists the sequence of events in translation?
A) codon recognition → peptide bond formation → termination → translocation
B) codon recognition → peptide bond formation → translocation → termination
C) peptide bond formation → codon recognition → translocation → termination
D) codon recognition → translocation → peptide bond formation → termination
E) peptide bond formation → translocation → codon recognition → termination
B) codon recognition → peptide bond formation → translocation → termination
Which of the following changes in nucleotide sequence has the lowest risk of causing a non-functional protein to result?
A) Insertion of a transposon
B) Deletion of single nucleotide
C) Insertion of a single nucleotide
D) Substitution of a single nucleotide
D) Substitution of a single nucleotide
If one strand of DNA is CGGTAC, the corresponding strand would be
A) GCCAUC.
B) GCCTAG.
C) TAACGT.
D) GCCATG.
E) CGGTAC.
D) GCCATG.
We would expect that a 15-nucleotide sequence will direct the production of a polypeptide that consists of
A) 2 amino acids.
B) 6 amino acids.
C) 4 amino acids.
D) 3 amino acids.
E) 5 amino acids.
C) 4 amino acids.
Which of the following takes place during translation?
A) the addition of nucleotides to a DNA template
B) DNA replication
C) the conversion of genetic information from DNA nucleotides into RNA nucleotides
D) the conversion of genetic information from the language of nucleic acids to the language of proteins
E) the conversion of genetic information from the language of proteins to the language of enzymes
D) the conversion of genetic information from the language of nucleic acids to the language of proteins
Which of the following statements regarding the flow of genetic information is false?
A) The codons in a gene specify the amino acid sequence of a polypeptide.
B) Eukaryotic mRNA is processed in several ways before export out of the nucleus.
C) Ribosomes serve to coordinate the functioning of mRNA and tRNA.
D) Polypeptides form proteins that determine the appearance and function of the cell and organism.
E) Transcription occurs in the cytoplasm of eukaryotic cells.
E) Transcription occurs in the cytoplasm of eukaryotic cells.
The transfer of genetic information from DNA to RNA is called
A) transcription.
B) initiation.
C) translation.
D) promotion.
E) elongation.
A) transcription.
Which of the following statements regarding a DNA double helix is always true?
A) The amount of adenine is equal to the amount of guanine, and the amount of thymine is equal to the amount of cytosine.
B) The amount of adenine is equal to the amount of cytosine, and the amount of guanine is equal to the amount of thymine.
C) The amount of adenine is equal to the amount of thymine, and the amount of guanine is equal to the amount of cytosine.
D) The amount of adenine is equal to the amount of uracil, and the amount of guanine is equal to the amount of cytosine.
E) The amount of adenine is equal to the amount of thymine, and the amount of guanine is equal to the amount of uracil.
C) The amount of adenine is equal to the amount of thymine, and the amount of guanine is equal to the amount of cytosine.
Why does a DNA strand grow only in the 5' to 3' direction?
A) because DNA polymerases can only add nucleotides to the 5' end of the growing molecule
B) because mRNA can only read a DNA molecule in the 5' to 3' direction
C) because DNA polymerase requires the addition of a starter nucleotide at the 5' end
D) because DNA polymerases can only add nucleotides to the 3' end of the growing molecule
E) because the DNA molecule only unwinds in the 5' to 3' direction
D) because DNA polymerases can only add nucleotides to the 3' end of the growing molecule
When one DNA molecule is copied to make two DNA molecules, the new DNA contains
A) none of the parent DNA.
B) 100% of the parent DNA
C) 75% of the parent DNA.
D) 50% of the parent DNA.
E) 25% of the parent DNA.
D) 50% of the parent DNA.
A base substitution mutation in a gene does not always result in a different protein. Which of the following factors could account for this?
A) a correcting mechanism that is part of the mRNA molecule
B) the fact that such mutations are usually accompanied by a complementary deletion
C) the fact that some amino acids are specified from more than one codon
D) the fact that the mutation affects only the sequence of the protein's amino acids, so the protein stays the same
E) the double-ring structure of adenine and guanine
C) the fact that some amino acids are specified from more than one codon
How would the shape of a DNA molecule change if adenine paired with guanine and cytosine paired with thymine?
A) The DNA molecule would be shorter.
B) The DNA molecule would be longer.
C) The DNA molecule would have irregular widths along its length.
D) The DNA molecule would be circular.
E) The DNA molecule would have regions where no base-pairing would occur.
C) The DNA molecule would have irregular widths along its length.
Which of the following statements regarding DNA is false?
A) DNA uses the sugar deoxyribose.
B) One DNA molecule can include four different nucleotides in its structure.
C) DNA molecules have a sugar-phosphate backbone.
D) DNA uses the nitrogenous base uracil.
D) DNA uses the nitrogenous base uracil
DNA replication
A) results in the formation of four new DNA strands.
B) begins when two DNA molecules join together to exchange segments.
C) occurs through the addition of nucleotides to the end of the DNA molecule.
D) produces two daughter DNA molecules that are complementary to each other.
E) uses each strand of a DNA molecule as a template for the creation of a new strand.
E) uses each strand of a DNA molecule as a template for the creation of a new strand.
Which of the following occurs when RNA polymerase attaches to the promoter DNA?
A) addition of nucleotides to the DNA template
B) initiation of a new polypeptide chain
C) initiation of a new RNA molecule
D) elongation of the growing RNA molecule
E) termination of the RNA molecule
C) initiation of a new RNA molecule
RNA splicing involves the
A) removal of introns from the molecule.
B) addition of a nucleotide "tail" to the molecule.
C) removal of exons from the molecule.
D) addition of a nucleotide "cap" to the molecule.
E) addition of introns to the molecule.
A) removal of introns from the molecule.
All of the following mechanisms are used to regulate protein production except
A) the breakdown of mRNA.
B) DNA editing.
C) protein breakdown.
D) protein activation.
E) controlling the start of polypeptide synthesis.
B) DNA editing.
Small pieces of RNA that can regulate mRNA transcription are called
A) minorRNA.
B) miniRNA.
C) monoRNA.
D) microRNA.
E) minuteRNA.
D) microRNA.
Transcription factors attach to
A) proteins.
B) mRNA.
C) plasma membrane receptors.
D) DNA.
E) signal molecules.
D) DNA.
In female mammals, the inactive X chromosome in each cell
A) becomes a Barr body.
B) can be activated if mutations occur in the active X chromosome.
C) becomes a nucleotroph corpus.
D) is broken down, and its nucleotides are degraded and reused.
E) is absorbed and used in energy production.
A) becomes a Barr body.
Enhancers are
A) the site on DNA to which activators bind.
B) required to facilitate the binding of DNA polymerases.
C) required to turn on gene expression when transcription factors are in short supply.
D) adjacent to the gene that they regulate.
E) the products of transcription factors.
A) the site on DNA to which activators bind.
The lac operon in E. coli
A) prevents lactose-utilizing enzymes from being expressed when lactose is absent from the environment.
B) coordinates the production of tryptophan-utilizing enzymes when it is present.
C) regulates the rate of binary fission.
D) uses activators to initiate the production of enzymes that break down lactose.
E) allows the bacterium to resist antibiotics in the penicillin family.
A) prevents lactose-utilizing enzymes from being expressed when lactose is absent from the environment.
The coding regions of a gene (the portions that are expressed as polypeptide sequences) are called
A) nucleosomes.
B) introns.
C) proto-oncogenes.
D) exons.
E) redundant coding sections.
D) exons.
A gene operon consists of
A) a regulatory gene only.
B) a promoter only.
C) transcribed genes, an operator, and a promoter.
D) a transcribed gene only.
E) transcribed genes, a promoter, and a regulatory gene.
C) transcribed genes, an operator, and a promoter.
A homeotic gene
A) is found only in adult somatic cells.
B) represses gene transcription and promotes mRNA translation.
C) serves as a master control gene that functions during embryonic development by controlling the developmental fate of groups of cells.
D) produces a product that controls the transcription of other genes.
E) turns on the genes necessary for synthesis of proteins.
C) serves as a master control gene that functions during embryonic development by controlling the developmental fate of groups of cells.
Which of the following permits a single gene to code for more than one polypeptide?
A) alternative RNA splicing
B) protein degradation
C) retention of different introns in the final version of the different mRNA strands
D) genetic differentiation
E) addition of different types of caps and tails to the final version of the mRNA strands
A) alternative RNA splicing
The genes for the enzymes of glycolysis
A) and the genes for specialized proteins are expressed in all nonembryonic cell types.
B) and the genes for all specialized proteins are expressed in all metabolizing cells.
C) are inactive in all metabolizing cells, but the genes for specialized proteins are expressed in all cell types.
D) and the genes for all specialized proteins are expressed in all embryonic cells.
E) are active in all metabolizing cells, but the genes for specialized proteins are expressed only in particular cell types.
E) are active in all metabolizing cells, but the genes for specialized proteins are expressed only in particular cell types.
Which of the following statements regarding DNA packing is false?
A) Prokaryotes have proteins analogous to histones.
B) Highly compacted chromatin is generally not expressed at all.
C) DNA packing tends to promote gene expression.
D) Histones account for about half the mass of eukaryotic chromosomes.
E) A nucleosome consists of DNA wound around a protein core of eight histone molecules.
C) DNA packing tends to promote gene expression.
The expression of the tryptophan operon is controlled by
A) an activator that permanently deletes genes in the tryptophan operon.
B) a repressor that is active when it is alone.
C) an activator that turns the operon on by binding to DNA.
D) a repressor that is active when it binds to tryptophan.
E) a repressor that is inactive when it binds to lactose.
D) a repressor that is active when it binds to tryptophan.
Both prokaryotic and eukaryotic cells use ________ to turn certain genes on or off.
A) intron segments
B) DNA ligase
C) regulatory proteins
D) RNA transcriptase
E) nucleosome packing
C) regulatory proteins
The term "gene expression" refers to the
A) flow of information from parent to offspring.
B) fact that each individual of a species has a unique set of genes.
C) fact that individuals of the same species have different phenotypes.
D) fact that certain genes are visible as dark stripes on a chromosome.
E) process by which genetic information flows from genes to proteins.
E) process by which genetic information flows from genes to proteins.
A single cell, the zygote, can develop into an entirely new organism with many different specialized cells. Which of the following statements about this process is false?
A) Differentiation of the zygote into a multicellular organism results from selective gene expression.
B) Additional genetic information for the formation of specialized cells is passed on to the developing embryo via the placenta.
C) The descendant cells specialize by a process known as cellular differentiation.
D) Only some of the genes in the zygote are expressed in all of its descendant cells.
E) The zygote contains all of the genetic information required for the development of many different cell types.
B) Additional genetic information for the formation of specialized cells is passed on to the developing embryo via the placenta.
Animal development is directed by
A) cell-to-cell signaling.
B) the availability of certain "key" nutrients as cells divide.
C) cell-to-cell signaling and signal transduction pathways.
D) signal transduction pathways.
E) cell receptors that detect transcription factors.
C) cell-to-cell signaling and signal transduction pathways.
Which of the following mechanisms of controlling gene expression occurs outside of the nucleus?
A) translation
B) adding a cap and tail to RNA
C) DNA packing/unpacking
D) RNA splicing
E) transcription
A) translation