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Chapter 2 Review Questions
Your Results:The correct answer for each question is indicated by a .
1 INCORRECTChemistry is the discipline that studies
A)various forces of the physical world.
B)electrical charges.
C)the composition of matter and how it changes.
D)the interaction of elements and living organisms.
Feedback: Incorrect: Chemistry studies the atomic and molecular composition of changing matter
2 INCORRECT The smallest complete units of elements are
A)neutrons
B)electrons
C)atoms
D)protons
Feedback: Incorrect: Neutrons are subatomic particles
3 INCORRECTWhat are the components of an atom that determine its electrical charge?
A)protons and neutrons
B)electrons
C)electrons and protons
D)neutrons
Feedback: Incorrect: Electrons are negative and protons positive
4 INCORRECT
The number of protons in the nucleus of an atom ___________ the number of electrons in its outer rings.
A)equals
B) is less than
C)is more than
D)has no relationship to
Feedback: Incorrect: In a neutral atom, the protons equal the electrons.
5 INCORRECTThe defining characteristic of stable elements is
A)a high atomic weight
B)a low atomic number
C)the maximum number of electrons in its outer shell
D)a positive electrical charge
Feedback: Incorrect: Atomic weight is independent of chemical reactivity
6 INCORRECT When atoms combine with other atoms, they
A)share an electron with
another atom
B) lose an electron
C)gain an electron
D)all of the above
Feedback: Incorrect: Bonds can be formed by sharing, gaining, or losing electrons
7 INCORRECTAtoms that have gained an electrical charge by gaining or losing electrons are called
A)elements
B)molecules
C)compounds
D) ions
Feedback: Incorrect: Ions are atoms or molecules with a charge
8 CORRECT Hydrogen bonds are found in
A)protein molecules
B)gaseous oxygen
C)carbohydrate molecules
D) inorganic molecules exclusively
Feedback: Correct Answer: Hydrogen bonds between H and O or N give proteins their three-dimensional form
9 INCORRECTTable sugar, baking soda, natural gas, and alcoholic beverages are examples of
A)natural substances
B)elements
C)compounds
D)particles
Feedback: Incorrect: Compounds are new combinations of elements
10 INCORRECT Chemical reactions may
A)form new bonds between atoms
B)break existing bonds between atoms
C)combine atoms in new combinations to make new compounds
D)accomplish all of the above
Feedback: Incorrect: Chemical reactions always result in new combinations; bonds are broken and new ones formed.
11 INCORRECT
When two or more atoms or reactants bond to form a new, more complex structure, the reaction is called
A)creation
B)synthesis
C)recombination
D)hydration
Feedback: Incorrect: Synthesis is the creation of a new molecule from reactants
12 INCORRECT The acidity of a solution is determined by
A)a high hydrogen ion concentration
B)a pH below 7
C)a low hydroxyl concentration
D)all of the above
Feedback: Incorrect: pH is a relative measure of H+ or hydrogen ion concentration relative to OH-
13 CORRECTWhat is the pH of a solution whose H+ concentration is 0.0001?
A)4
B)-3
C)3
D)2
Feedback: Correct Answer: pH is the logarithm to the base 10
14 INCORRECTWhich of the following substances is most acidic?
A)cow's milk - pH 6.6
B)apple juice - pH 3.0
C)cabbage - pH 5.3
D)distilled water - pH 7.0
Feedback: Incorrect: A pH below 7 is considered acidic
15 CORRECT Organic substances are least likely to dissolve in
A)water
B)alcohol
C)ether
D) lipids
Feedback: Correct Answer: Organic compounds are usually not very soluble in water
16 INCORRECTIn the human body, water plays an important role in
A)dissolving solid substances
B)moving chemicals around the body
C)absorbing and moving heat
D)all of the above
Feedback: Incorrect: The polar nature of water allows living reactions to take place
17 INCORRECTWhich of the following inorganic substances is a metabolic waste product?
A)oxygen
B)carbon dioxide
C) inorganic salts
D)all of the above
Feedback: Incorrect: Oxygen is an essential compound
18 INCORRECTMost of the energy needed by cells is supplied by
A)protein
B)carbohydrates
C) lipids
D) inorganic salts
Feedback: Incorrect: Proteins are not as commonly used for energy as carbohydrates
19 CORRECT The structure of plant starch is chains of
A)monosaccharides
B)disaccharides
C)glycogen
D)none of the above
Feedback: Correct Answer: Monosaccharides such as glucose comprise large polysaccharides called starches
20 INCORRECT Lipids include all of the substances below except
A)fats
B)steroids
C)phospholipids
D)amino acids
Feedback: Incorrect: Proteins are comprised of amino acids
21 CORRECTA fat that has all of its carbon atoms joined by single carbon to carbon bonds is said to be
A)saturated
B)unsaturated
C)polyunsaturated
D)complete
Feedback: Correct Answer: The presence of double bonds indicates a degree of unsaturation
22 INCORRECT A phospholipid typically has
A)phosphorus atoms substituted for carbon atoms
B)no glycerol portion
C)two fatty acid chains and a phosphate group
D)three fatty acids each of which
contain phosphate groups
Feedback: Incorrect: Phospholipids such as myelin contain fatty acids and a phosphate group
23 INCORRECT Which of the following are steroids?
A)cholesterol
B)estrogens
C)testosterone
D)all of the above
Feedback: Incorrect: Steroids are lipids derived from the parent cholesterol
24 INCORRECTWhich of the following is not a function of proteins?
A)control of the speed of chemical reactions
B)combine with carbohydrates to form receptors on cell surfaces
C)serve as structural materials
D)provide insulation to conserve heat
Feedback: Incorrect: Enzymes are protein derivatives that control rates
25 INCORRECTThe element sulfur is sometimes found in which one of the following molecules.
A)carbohydrate
B) lipid
C)protein
D)nucleic acid
Feedback: Incorrect: Proteins contain C, H, O, N and sometimes sulfur.
26 CORRECTThe bond that contributes to maintaining the special shape of a protein is a(n)
A)hydrogen bond
B)electrovalent bond
C) ionic bond
D)peptide bond
Feedback: Correct Answer: It is usually the H-N or H-O bonds that allow proteins to have complex three-dimensional forms
27 INCORRECTWhen hydrogen bonds within a protein break, the protein is said to be
A)dehydrated
B)denatured
C)both
D)neither
Feedback: Incorrect: Denaturation is a process that destroys
the functional form of a protein
28 INCORRECT Protein synthesis rate is controlled by
A)nucleotides
B)nitrogen atoms
C)genes
D)enzymes
Feedback: Incorrect: Enzymes control the rate of all reactions
29 CORRECTSome forms of Alzheimer disease may be caused by protein misfolding.
A)True
B)False
Feedback: Correct Answer: Some diseases may be caused by misfolded proteins that are not infectious.
30 CORRECTMatter is found in various forms, gases, liquids, and solids.
A)True
B)False
Feedback: Correct Answer: The classic forms of matter are solid, liquid, and gas
31 CORRECTThe atomic weight of an atom is determined by the sum of its protons and neutrons.
A)True
B)False
Feedback: Correct Answer: Atomic weight is protons plus neutrons
32 CORRECT
The protons carry a positive electrical charge and electrons carry a negative electrical charge.
A)True
B)False
Feedback: Correct Answer: Protons are positive and electrons, negative
33 CORRECT
Unstable elements achieve stable structures by gaining, losing, or sharing electrons in their outer shells.
A)True
B)False
Feedback: Correct Answer: Chemicals react to gain electrical stability
34 CORRECTA ion is an atom that has developed an electrical charge by losing or gaining an electron.
A)True
B)False
Feedback: Correct Answer: Ions are either positive cations or negative, anions
35 CORRECT One pair of shared electrons forms a single
covalent bond; two pair of shared electrons form a double covalent bond.
A)True
B)False
Feedback: Correct Answer: Covalent bonds may involve 2, 4, or 6 electrons and be single, double, or triple
36 INCORRECTA molecular formula depicts how atoms are joined and arranged in molecules.
A)True
B)False
Feedback: Incorrect: A molecular formula may only show the relative numbers of atoms, not the structures
37 CORRECTSynthesis requires energy and is important to the growth of body parts.
A)True
B)False
Feedback: Correct Answer: Syntheses in the body, such as proteins, always requires some form of energy
38 CORRECT
A catalyst affects the speed with which a chemical reaction takes place but is not consumed by the reaction.
A)True
B)False
Feedback: Correct Answer: The most common catalysts are the enzymes
39 INCORRECTElectrolytes that release hydrogen ions in water are called bases.
A)True
B)False
Feedback: Incorrect: Acids release hydrogen atoms or H+
40 CORRECT
When electrically charged ions disassociate in water, the solution will conduct electricity.
A)True
B)False
Feedback: Correct Answer: Ions always conduct electricity
1 INCORRECT Which of these is a measurement of gravitational force?
A)mass
B)matter
C)weight
D)valance
E)electronegativity
Feedback: Incorrect Answer: weight is the gravitational force acting on an object of a given mass.
2 CORRECT Neutrons are subatomic particles that
A)are located in the nucleus and have a positive charge.
B)are located in the nucleus and have no charge.
C)are located in the nucleus and have a negative charge.
D)are located around the nucleus and have a positive charge.
E)are located around the nucleus and have a negative charge.
Feedback: Correct Answer
3 INCORRECT Most of the volume of an atom is occupied by the
A)electrons.
B)neutrons.
C)protons.
D)protons and neutrons.
Feedback: Incorrect Answer: Most of the volume of an atom is occupied by the electrons.
4 INCORRECT The simplest type of matter with unique chemical properties is
A)an electron.
B)an element.
C)a neutron.
D)a proton.
E)an isotope.
Feedback: Incorrect Answer: An element is the simplest type of matter with unique chemical properties.
5 INCORRECTThe atomic number of an element is equal to the number of
A)electrons in each atom.
B)neutrons in each atom.
C)protons in each atom.
D)protons plus electrons in each atom.
E)neutrons plus electrons in each atom.
Feedback: Incorrect Answer: The atomic number of an element is equal to the number of protons in each atom.
6 INCORRECT Which of the pairs below are equal to each other in an atom?
A)neutrons and protons
B)protons and electrons
C)neutrons and electrons
D)atomic number and mass number
E)mass number and electrons
Feedback: Incorrect Answer: The number of positively charged protons equals the number of negatively charged electrons in an
atom.
7 INCORRECTGiven that manganese (Mn) has an atomic number of 25 and a mass number of 55, an atom of manganese has
A)25 neutrons.
B)25 electrons.
C)30 electrons.
D)55 protons.
E)80 neutrons.
Feedback: Incorrect Answer: The atomic number is equal to the number of protons in the atom.
8 CORRECT
Selenium (Se) has 34 protons and 46 neutrons in each atom, therefore its atomic number is __________ and its mass number is __________.
A)12, 46
B)34, 46
C)12, 34
D)34, 80
E)46, 80
Feedback: Correct Answer: The number of protons is equal to the atomic number, and the mass number is equal to the number of protons plus neutrons.
9 INCORRECT 14N and 15N are
A)different elements.
B)atoms with different atomic numbers.
C)isotopes of the same element.
D) identical except for different numbers of electrons.
E) identical except for different numbers of protons.
Feedback: Incorrect Answer: 14N and 15N are isotopes, elements with the same number of protons and electrons, but different numbers of neutrons.
10 INCORRECTIn the human body, which element makes up the largest percentage of atoms by number?
A)carbon
B)fluorine
C)hydrogen
D)nitrogen
E)oxygen
Feedback: Incorrect Answer: Hydrogen atoms make up the largest percentage of atoms by number in the body.
11 INCORRECTGiven that the atomic mass of magnesium is 24.31, which of these statements is true?
A)24.31g of magnesium contains 1 mol of magnesium atoms.
B)24.31g of magnesium contains Avogadro's number of magnesium atoms.
C)24.31g of magnesium
contains 6.022 x 1023 magnesium atoms.
D)24.31g of magnesium has the same number of atoms as 12.01 g of carbon..
E)All of these are true.
Feedback: Incorrect Answer: All of the statements concerning magnesium are correct.
12 INCORRECT The chemical behavior of an atom is determined largely by
A) its number of protons.
B) its outermost electrons.
C)the size of the electron cloud.
D) its mass.
E) its weight.
Feedback: Incorrect Answer: The outermost electrons of an atom determine its chemical behavior since those electrons will be shared with or transferred to other atoms, resulting in chemical bonding.
13 INCORRECTChemical bonding occurs when the __________ are transferred or shared between atoms.
A)outer protons
B) largest neutrons
C)outermost electrons
D) innermost electrons
E)outermost protons
Feedback: Incorrect Answer: The outermost electrons of an atom will be shared with or transferred to other atoms, resulting in chemical bonding.
14 INCORRECT Ionic bonding occurs when
A)a cation and an anion are attracted to each other.
B)two cations are attracted to each other.
C)two anions are attracted to each other.
D)two atoms lose protons.
E)two atoms lose neutrons.
Feedback: Incorrect Answer: The attraction of positively charged cations and negatively charged anions results in ionic bonding.
15 CORRECT An atom that gains an electron
A)becomes a cation.
B)becomes a different isotope of the same element.
C)has a different atomic number.
D)becomes an anion.
E)explodes.
Feedback: Correct Answer
16 INCORRECT A calcium ion (Ca2+)
A)has lost two electrons.
B)has gained two electrons.
C)has gained two protons.
D)has lost two protons.
E)has gained two neutrons.
Feedback: Incorrect Answer: A calcium ion has lost two electrons as noted by the 2+ charge.
17 INCORRECTWhen two hydrogen atoms each share an electron with an oxygen atom (H2O),
A)polar covalent bonding occurs.
B)nonpolar covalent bonding occurs.
C)ionic bonding occurs.
D)metallic bonding occurs.
E) it is called a james bond.
Feedback: Incorrect Answer: Because oxygen does not share electrons equally with hydrogen atoms when covalently bound with them, we describe the bond as a polar covalent bond.
18 INCORRECT
When a positively charged hydrogen atom of one water molecule is attracted to a negatively charged oxygen atom of another water molecule,
A)covalent bonding occurs.
B)hydrogen bonding occurs.
C)ionic bonding occurs.
D)metallic bonding occurs.
Feedback: Incorrect Answer: hydrogen bonding results from the attraction of the positive end of a polar molecule to the negative end of another polar molecule.
19 INCORRECTPotassium chloride is formed when a potassium ion (K+) is attracted to a chloride ion (Cl-). Therefore, potassium chloride is
A)an atom.
B)a molecule.
C)a compound.
D)a metal.
E)all of these
Feedback: Incorrect Answer: Potassium chloride is a compound since it is composed of two different ions held together by the force of attraction between their opposite charges.
20 INCORRECT If potassium chloride is placed in water, it will
A)form strong covalent bonds with the water molecules.
B)dissociate into separate ions.
C)not mix with the water.
D)become nonpolar.
E)form covalent potassium chloride molecules.
Feedback: Incorrect Answer:
Potassium chloride will dissociate into separate ions in water, positively charged potassium ions and negatively charged chloride ions.
21 INCORRECT Which of these substances is nonpolar?
A)canola oil
B)glucose
C)potassium chloride
D)sodium chloride (table salt)
E)sucrose (table sugar)
Feedback: Incorrect Answer: Canola oil is a lipid and nonpolar. Sodium chloride is an ionic compound that is polar.
22 CORRECT Which of these substances is an electrolyte?
A)canola oil
B)glucose
C)fructose
D)sodium chloride
E)sucrose
Feedback: Correct Answer: Because sodium chloride can dissociate in water and can conduct electrical current, it is known as an electrolyte.
23 INCORRECT A synthesis reaction
A)may be a dehydration
reaction.
B)results in catabolism.
C)may be a hydrolysis reaction.
D)breaks down a larger reactant into two or more smaller products.
E)all of these
Feedback: Incorrect Answer: A synthesis reaction takes two or more smaller reactants and combines them to make a larger product.
24 INCORRECTAll of the synthesis and decomposition reactions that take place in the body are collectively referred to as
A)anabolism.
B)catabolism.
C)dissociation.
D)electrolytes.
E)metabolism.
Feedback: Incorrect Answer: Metabolism refers to all the synthesis and decomposition reactions that take place in the body.
25 CORRECT The gain of an electron by an atom is called
A)anabolism.
B)catabolism.
C)oxidation.
D)reduction.
E)synthesis.
Feedback: Correct Answer: Reduction refers to an atom gaining an electron.
26 CORRECTIn which of these types of reactions does an equilibrium occur?
A)decomposition reaction
B)synthesis reaction
C)exchange reaction
D)reversible reaction
Feedback: Correct Answer
27 INCORRECT
Chemical events in cells are regulated primarily by mechanisms that control either the concentration or the activity of
A)acids.
B)bases.
C)enzymes.
D) lipids.
E)sugars.
Feedback: Incorrect Answer: Because enzyme function is so essential to cell function, mechanisms that control enzyme concentration or activity regulate cellular chemical events.
28 INCORRECT
__________ energy results from the relative positions and interactions among the charged subatomic particles of a substance.
A)Chemical
B)Electric
C)Electromagnetic
D)Heat
E)Mechanical
Feedback: Incorrect Answer: Chemical energy (a form of potential energy) results from the relative positions and interactions among the charged subatomic particles of a substance.
29 INCORRECT Ultraviolet light is an example of
A)chemical energy.
B)electric energy.
C)electromagnetic energy.
D)heat energy.
E)mechanical energy.
Feedback: Incorrect Answer: Ultraviolet light is an example of electromagnetic energy.
30 INCORRECT In which of these reactions is energy released?
A)hydrolysis of ATP to ADP
B)production of ATP from ADP
C)photosynthesis
D)production of glucose from CO2 and H2O
E)all of these
Feedback: Incorrect Answer: The production of glucose from CO2 and H2O requires energy.
31 INCORRECT Osmolality
A)reflects the number of atoms in a solution.
B)of normal body fluid is about 300 osmoles.
C)influences the movement of water into and out of cells.
D) indicates the percent of solute by weight per volume of solution.
E)reflects the percent of solvent in a solution.
Feedback: Incorrect Answer: Osmolality reflects the number of particles in a solution.
32 INCORRECT If the number of hydrogen ions in a solution is increased, the
A)solution becomes more acidic.
B)solution becomes more alkaline (basic).
C)pH of the solution will be increased.
D)solution is a buffer.
E)pH of the solution remains unchanged.
Feedback: Incorrect Answer: A buffer refers to a weak acid or base that functions to prevent fluctuations in pH.
33 INCORRECTPotassium hydroxide (KOH) dissociates in solution to produce K+ and OH-; therefore it is classified as
A)an acid.
B)a base.
C)a buffer.
D)a neutral substance.
Feedback: Incorrect Answer: Because potassium hydroxide dissociates into K+ and OH- ions, it is a base. The OH- ions can bind with the H+ ion in a solution, increasing the pH.
34 CORRECT Which of these is a monosaccharide?
A)sucrose
B)starch
C)glycogen
D)glucose
E)cellulose
Feedback: Correct Answer
35 CORRECTWhich of these molecules does NOT consist of glucose molecules joined together?
A)cellulose
B)glycogen
C)maltose
D)sucrose
E)starch
Feedback: Correct Answer: Sucrose consists of a glucose molecule joined to a fructose molecule.
36 CORRECT __________ constitute 95% of the fats in the human body.
A)Phospholipids
B)Prostaglandins, thromboxanes, and leukotrienes
C)Steroids
D)Triglycerides
E)Vitamins
Feedback: Correct Answer:
37 INCORRECT __________ are the building blocks for proteins.
A)Amino acids
B)Fatty acids and glycerol
C)Monosaccharides
D)Disaccharides
E)Nucleic acids
Feedback: Incorrect Answer: The building blocks for proteins are amino acids.
38 INCORRECTThe __________ structure of a protein results from the folding of the helices or pleated sheets.
A)primary
B)penitentiary
C)quaternary
D)secondary
E)tertiary
Feedback: Incorrect Answer: The tertiary structure of a protein results from the folding of the helices or pleated sheets.
39 INCORRECT Enzymes
A)are always composed of monosaccharides.
B)function by raising the activation energy required for a reaction.
C)can control many different reactions.
D)generally decrease the rate of chemical reactions.
E)sometimes require cofactors to be functional.
Feedback: Incorrect Answer: Sometimes require cofactors in order to be functional.
40 INCORRECT Which of these are NOT a part of nucleotide molecules?
A)ribose or deoxyribose
B)nitrogenous organic bases
C)phosphate groups
D)purines and pyrimidines
E)peptides
Chapter 3 Review Questions
Your Results:The correct answer for each question is indicated by a .
1 INCORRECT The shape of cells in the body vary based on their
A)maturity
B)function
C)location of reproduction
D)ability to reproduce
Feedback: Incorrect: The morphology or shape of cells correlates directly with their functionality
2 CORRECT The organelles are found in the
A)cytoplasm of the cell
B)nucleus of the cell
C)both cytoplasm and nucleus
D)neither cytoplasm nor nucleus
Feedback: Correct Answer: Organelles such as lysosomes are usually found within the cytosol or cytoplasm
3 INCORRECTWhich of the following statements about the cell membrane in the bilayer model is incorrect?
A)The membrane forms a boundary around the cellular contents.
B)The membrane allows some substances to enter and leave the cell but not others.
C)The basic structure of the cell membrane is a lipid-protein bilayer.
D)The interior of the cell membrane allows water soluble substances to pass through it.
Feedback: Incorrect: In this model, the inside is not water soluble
4 INCORRECTCarbohydrate molecules bound to proteins on the surface of the cell membrane function in
A)controlling substances entry and exit from the cell
B)providing a reservoir of energy for intracellular functions
C)recognition of self versus non-self
D)as hormone receptors
Feedback: Incorrect: Glycoproteins are recognized by the immune system
5 CORRECTFlattened sacs and elongated canals that may contain ribosomes are part of
A)endoplasmic reticulum
B)Golgi apparatus
C)mitochondria
D) lysosomes
Feedback: Correct Answer: The rough endoplasmic reticulum contains the ribosomes for protein synthesis
6 INCORRECTThe organelle that plays a central role in the transport of new molecules from inside to outside the cell is the
A)endoplasmic reticulum
B)Golgi apparatus
C)mitochondria
D) lysosome
Feedback: Incorrect: The endoplasmic reticulum is an internal transport system
7 INCORRECTEnergy released from glucose and other nutrients is made useful to cells by the
A)endoplasmic reticulum
B)Golgi apparatus
C)mitochondria
D) lysosome
Feedback: Incorrect: The main usable form of energy is mitochondrial ATP
8 INCORRECT The "garbage disposals of the cell" are the
A)endoplasmic reticulum
B)Golgi apparatus
C)mitochondria
D) lysosomes
Feedback: Incorrect: Lysosomes contain enzymes that break down substances
9 CORRECT The organelle essential to reproduction is the
A)centrosome
B)celium
C)microtubule
D)vesicle
Feedback: Correct Answer: The centrosome form the spindle fibers in division
10 INCORRECT Vesicles that have a role in secretion are formed by the
A)Golgi apparatus
B)endoplasmic reticulum
C)both
D)neither
Feedback: Incorrect: The Golgi apparatus and reticulum function in secretion and transport
11 CORRECTThin, threadlike processes within the cytoplasm that function in various kinds of cell movement are
A)microfilaments and microtubules
B)cilia and
flagella
C)both
D)neither
Feedback: Correct Answer: Examples of microfilaments are the actin and myosin proteins essential to muscle contraction
12 CORRECT The nucleolus is a small, dense body composed mainly of
A)RNA
B)DNA
C)invaginated cytoplasm
D)chromatin
Feedback: Correct Answer: The nucleolus produces the rRNA molecules
13 INCORRECT Chromatin fibers coil into rod-like structures known as
A)ribosomes
B) lysosomes
C)chromosomes
D)all of the above
Feedback: Incorrect: Chromosomes are the visible, condensed form of chromatin
14 INCORRECTPassive mechanisms that transport materials across the cell membrane are all of the following except
A)diffusion
B)filtratio
n
C)osmosis
D)endocytosis
Feedback: Incorrect: Diffusion requires no ATP
15 INCORRECT
The mechanism in which molecules or ions spread randomly from areas of higher concentration to areas of lower concentration is
A)filtration
B)osmosis
C)exocytosis
D)diffusion
Feedback: Incorrect: Filtration occurs through a membrane because of gravity or pressure
16 INCORRECTSubstances such as which of these can diffuse readily through the cell membrane?
A)oxygen
B)carbon dioxide
C)both
D)neither
Feedback: Incorrect: Oxygen and carbon dioxide are small enough to diffuse across membranes
17 INCORRECT
Molecules that are too large to pass through the membrane pores, such as glucose, and are insoluble in lipids enter the cell using
A)active transport
B)filtration
C)endocytosis
D)facilitated transport
Feedback: Incorrect: Facilitated transport uses a carrier molecule to transport molecules such as glucose into a cell
18 INCORRECTThe substance that moves through the cell membrane during osmosis is
A)glucose
B)oxygen
C)sodium
D)water
Feedback: Incorrect: Osmosis is the movement of water from hypotonic areas to hypertonic areas
19 INCORRECT Osmosis is a special case of
A)filtration
B)diffusion
C)facilitated transport
D)pinocytosis
Feedback: Incorrect: Osmosis is just the same as diffusion, but only for water
20 INCORRECTSolutions with a higher osmotic pressure than body fluids are called
A) isotonic
B)hypertonic
C)hypotonic
D)supersaturated
Feedback: Incorrect: Hypertonic fluids have a higher concentration relative to what they are being compared with, which are consequently considered hypotonic
21 CORRECTWhen fluid is forced through a membrane by hydrostatic or blood pressure, the mechanism is called
A)filtration
B)facilitated diffusion
C)controlled by electrically gated channels
D)hormone mediated
Feedback: Correct Answer: Filtration is the movement of particles through a membrane or filter, because of gravity or pressure
22 INCORRECTProcesses that require energy to move substances into and out of the cell without crossing through the cell membrane include
A)endocytosis
B)pinocytosis
C)phagocytosis
D)all of the above
Feedback: Incorrect: All of these are processes of membrane changes that engulf particles; all of these require ATP energy.
23 CORRECTThe phase of the cell cycle in which cell contents grow and duplicate is
A) interphase
B)metaphase
C)prophase
D)telophase
Feedback: Correct Answer: In traditional cell division, the DNA and contents double during the interphase
24 CORRECT Chromosomes first appear during
A)prophase
B)metaphase
C)anaphase
D)telophase
Feedback: Correct Answer: During prophase, the chromatin threads are condensed and become visible bodies called chromosomes
25 INCORRECTWhich of the following series of events of mitosis is in the correct sequence?
A)telophase, anaphase, metaphase, prophase
B)prophase, telophase, metaphase, anaphase
C)anaphase, prophase, metaphase, telophase
D)prophase, metaphase, anaphase, telophase
Feedback: Incorrect: Mitosis and meiosis proceed from interphase, prophase, metaphase, anaphase and telophase
26 INCORRECTThe process by which cells develop different characteristics in structure and function is called
A)maturation
B)specialization
C)hybridization
D)differentiation
Feedback: Incorrect: Differentiation is the process in which a single cell will produce many diverse populations such as muscle and bone
27 INCORRECT Which of the following are characteristic of cancer?
A)hyperplasia
B)dedifferentiation
C)metastasis
D)all of the above
Feedback: Incorrect: Cancer cells spread to distant areas
(metastasize), display excessive growth (hyperplasia), and exhibit properties found in earlier stages (de-differentiation)
28 CORRECT
A defect in an individual's response to infection, because disease fighting cells do not stay in the injured area, can be due to a problem with cell adhesion.
A)True
B)False
Feedback: Correct Answer: Cells have chemicals in their membranes that tends to help keep their proper integrity and function
29 INCORRECTAll of the structures described in the composite cell can be found in every cell regardless of function.
A)True
B)False
Feedback: Incorrect: Not all cells have all features, such as the mature erythrocyte which has lost its nucleus
30 INCORRECTThe cell membrane is an inert structure that separates one cell from another.
A)True
B)False
Feedback: Incorrect: The cell membrane is a living, vital part of a cell
31 CORRECTThe cell membrane contains many kinds of proteins, each with a special function.
A)True
B)False
Feedback: Correct Answer: Membranes contain enzymes, structural proteins and receptor proteins
32 CORRECTProteins that traverse the cell membrane serve as "channels" that permit entry of specific ions into the cell.
A)True
B)False
Feedback: Correct Answer: The movement of substances through a membrane occur aided by membrane channel proteins
33 CORRECTNutrients are received, processed, and used in the cytoplasm of the cell.
A)True
B)False
Feedback: Correct Answer: Nutrients such as glucose and amino acids are actively metabolized within a cell
34 INCORRECTFlagella are found on the free surfaces of epithelial cells; cilia are longer, more abundant, and move cells within the body.
A)True
B)False
Feedback: Incorrect: Cilia do not move cells but move particles on their surfaces
35 CORRECT Microtubules are composed of a globular protein, tubulin.
A)True
B)False
Feedback: Correct Answer: Tubulin is a name of a protein found in structures such as the microfilaments
36 INCORRECT The cytoplasm is the site of ribosome production.
A)True
B)False
Feedback: Incorrect: The ribosome is the site of protein synthesis
37 CORRECTThe cell membrane is a selective barrier that controls which substances enter and leave the cell.
A)True
B)False
Feedback: Correct Answer: The membrane uses energy to selectively move molecules in or out
38 CORRECTDiffusion continues when the concentrations of a molecule or ion are the same on both sides of a membrane.
A)True
B)False
Feedback: Correct Answer: Diffusion occurs until the forward and reverse rates are equal
39 INCORRECTGlucose passes easily through the cell membrane by simple diffusion.
A)True
B)Fals
e
Feedback: Incorrect: Glucose enters a cell by facilitated diffusion
Your Results:The correct answer for each question is indicated by a .
1 INCORRECTThe largest percentage of molecules that make up the cell membrane are
A)carbohydrates, nucleic acids, and proteins.
B)carbohydrates, water, and nucleic acids.
C)phospholipids, cholesterol, and proteins.
D)nucleic acids, amino acids, and fatty acids.
E)water, carbohydrates and cholesterol.
Feedback: Incorrect Answer: Phospholipids, cholesterol, and proteins make up the largest percentage of molecules in cell membranes.
2 INCORRECTIn the fluid mosaic model, the double layer (bilayer) of molecules found in the cell membrane is made up of
A)cholesterol.
B)phospholipids.
C)carbohydrates.
D)nucleic acids.
E)proteins.
Feedback: Incorrect Answer: Phospholipids make up the bilayer of cell membranes. Cholesterol is embedded within the bilayer.
3 INCORRECT
Although the basic structure of the plasma membrane is determined mainly by its __________ , the functions of the plasma membrane are determined mainly by its __________ .
A)carbohydrates, lipids
B)carbohydrates, proteins
C)lipids, proteins
D)nucleic acids, lipids
E)proteins, lipids
Feedback: Incorrect Answer: Lipids determine basic structure, and proteins determine many functions of plasma membranes.
4 INCORRECTWhich molecules in the cell membrane are mostly glycoproteins?
A)carrier molecules
B)channel proteins
C)marker molecules
D)receptor molecules
E)enzymes
Feedback: Incorrect Answer: Marker molecules are mostly glycoproteins.
5 INCORRECT Which of these conditions decreases the rate of diffusion?
A) increased concentration gradient
B) increased viscosity
C)increased temperature
D)decreased size of solute particles
E)all of these
Feedback: Incorrect Answer: An increased concentration gradient would increase, not decrease, the rate of diffusion.
6 INCORRECTWhich of these substances diffuse directly through the lipid bilayer of the cell membrane?
A)glucose and amino acids
B)Na+ and Cl-
C)O2 and CO2
D)whole cells
Feedback: Incorrect Answer: Because O2 and CO2 are soluble in lipids, they can diffuse directly through the phospholipid bilayer of the cell membrane. Glucose and amino acids, because of size and polarity cannot diffuse directly through the lipid bilayer of the cell membrane.
7 INCORRECT A 10% salt solution is __________ to distilled water.
A) isosmotic
B)hyperosmotic
C)hyposmotic
Feedback: Incorrect Answer: A 10% salt solution is
hyperosmotic to distilled water since it contains a higher concentration of solute particles than the distilled water and therefore it has a greater osmotic pressure.
8 INCORRECT
You place blood cells in an unknown solution and observe them with a microscope; you notice that most of the cells have crenated. Therefore, you conclude that the unknown solution is
A) isosmotic to the cells.
B)hyperosmotic to the cells.
C)isotonic to the cells.
D)hypertonic to the cells.
E)hypotonic to the cells.
Feedback: Incorrect Answer: The unknown solution has to be hypertonic to the cells since water moved out of the cells via osmosis, causing them to crenate. Water moves from a high concentration to a low concentration, across a semipermeable membrane, towards the hypertonic solution.
9 INCORRECT
Solution A has a greater osmotic pressure that solution B. Therefore, solution A contains __________ solutes and __________ water than solution B.
A)fewer, less
B)fewer, more
C)more, less
D)more, more
Feedback: Incorrect Answer: Solution A contains more solutes and less water than
solution B because the greater the concentration of solutes in a solution, the greater the osmotic pressure of that solution.
10 INCORRECT
In question 18 above, if the containers for solution A and solution B are connected, with a selectively permeable membrane between them, water moves
A)from solution A to solution B.
B)from solution B to solution A.
C)equally in both directions.
Feedback: Incorrect Answer: Because water moves from a high concentration to a low concentration through a selectively permeable membrane in osmosis, water will move from solution B to solution A.
11 INCORRECT__________ depends upon a pressure difference on either side of a partition.
A)Active transport
B)Endocytosis
C)Facilitated diffusion
D)Filtration
E)Secondary active transport
Feedback: Incorrect Answer: Filtration depends upon a pressure difference on either side of a partition, liquid moves from the side with the greatest pressure to the side with the lower pressure.
12 INCORRECT Which of these transport processes does NOT require ATP?
A)active transport
B)endocytosis
C)exocytosis
D)diffusion
E)secondary active transport
Feedback: Incorrect Answer: Of the choices, diffusion is the only transport process that does not require ATP. Active transport, endocytosis, exocytosis, and secondary active transport are all transport processes requiring ATP.
13 INCORRECT
Given these observations concerning a transport process into a cell: 1. ATP is required 2. does not exhibit saturation 3. solid particles are transported
The transport process involved is
A)active transport.
B)facilitated diffusion.
C)secondary active transport.
D)phagocytosis.
E)pinocytosis.
Feedback: Incorrect Answer: The transport process involved is phagocytosis, it requires ATP, does not exhibit saturation, and involves the transport of solid particles. Active transport does exhibit saturation.
14 INCORRECT Given these characteristics of a transport process:
1. moves with the concentration
gradient2. does not require energy3. requires carrier molecules
Which of these processes is described?
A)diffusion
B)facilitated diffusion
C)active transport
D)exocytosis
E)phagocytosis
Feedback: Incorrect Answer: Facilitated diffusion moves with the concentration gradient, does not require energy, and does require carrier molecules. Diffusion also moves with the concentration gradient and does not require energy, but it does not require carrier molecules.
15 INCORRECT
Formation of a secretory vesicle, fusion of the secretory vesicle to the cell membrane, and release of the contents of the secretory vesicles outside the cell describes
A)diffusion.
B)facilitated diffusion.
C)active transport.
D)phagocytosis.
E)exocytosis.
Feedback: Incorrect Answer: Exocytosis is the membrane transport mechanism involving the formation of a secretory vesicle, fusion of the secretory vesicle to the cell membrane, and release of the contents of the secretory vesicles outside
the cell.
16 INCORRECTWhich of these processes involves a sodium-potassium exchange pump and two carrier molecules?
A)active transport
B)cotransport
C)diffusion
D)endocytosis
E)facilitated diffusion
Feedback: Incorrect Answer: Cotransport is the process that involves a sodium-potassium exchange pump and two carrier molecules.
17 INCORRECT Microtubules are
A)composed of actin filaments.
B)essential components of cilia, flagella, centrioles, and spindle fibers.
C)responsible for changes in cell shape.
D)smaller in diameter than other cytoskeleton components.
E)all of these
Feedback: Incorrect Answer: Microtubules are composed of protein tubulin and are essential components of cilia, flagella, centrioles and spindle fibers.
18 CORRECTWhich of these organelles function as intracellular digestive systems and contain enzymes?
A) lysosomes
B)rough endoplasmic reticulum
C)Golgi apparatus
D)nucleus
E)secretory vesicles
Feedback: Correct Answer
19 INCORRECTThe production and export of milk from mammary gland cells involves which of these cell organelles?
A)Golgi apparatus
B)rough endoplasmic reticulum
C)smooth endoplasmic reticulum
D)vesicles
E)all of these
Feedback: Incorrect Answer: The production and export of milk from the mammary glands would involve the Golgi apparatus, the rough and smooth endoplasmic reticulum, and vesicles.
20 INCORRECT
During embryonic development, some structures are formed and then degenerate; the cell organelles responsible for the breakdown of these structures are the
A)Golgi apparatuses.
B) lysosomes.
C)mitochondria.
D)rough endoplasmic reticulum.
E)smooth endoplasmic reticulum.
Feedback: Incorrect Answer: The lysosomes, organelles containing hydrolytic enzymes, function as intracellular digestive systems able to break down cellular structures.
21 INCORRECTAs a result of exercise, there is an increase in the number of __________ in muscle cells.
A)nuclei
B)mitochondria
C) lysosomes
D)Golgi apparatus
E)smooth endoplasmic reticulum
Feedback: Incorrect Answer: There is an increase in the number of mitochondria with exercise due to increased ATP demand.
22 CORRECTWhich of these organelles is surrounded by a double membrane layer that contains many pores?
A)nucleus
B)rough endoplasmic reticulum
C)Golgi apparatus
D) lysosomes
E)both a and d
Feedback: Correct Answer
23 INCORRECT In which of these organelles is chromatin found?
A) lysosomes
B)rough endoplasmic reticulum
C)Golgi apparatus
D)secretory vesicles
E)nucleus
Feedback: Incorrect Answer: Chromatin, which consists of dispersed thin strands of DNA, histones and other proteins, is found in the nucleus of cells.
24 INCORRECT Subunits of ribosomes are manufactured in the
A)cytoskeleton.
B)endoplasmic reticulum.
C)Golgi apparatus.
D) lysosomes.
E)nucleolus.
Feedback: Incorrect Answer: The nucleolus is the structure in the nucleus of cells where subunits of ribosomes are produced.
25 INCORRECT Which of these organelles contains DNA?
A)Golgi apparatus
B) lysosomes
C)mitochondria
D)rough endoplasmic reticulum
E)smooth endoplasmic reticulum
Feedback: Incorrect Answer: Besides in the nucleus of a cell, DNA can be found in mitochondria.
26 INCORRECT
Aerobic respiration produces __________ ATP molecules, __________ require oxygen to be available, and produces __________ as end product(s).
A)2, does not, CO2 and water
B)2, does, lactic acid
C)36-38, does not, lactic acid
D)36-38, does, CO2 and water
Feedback: Incorrect Answer: Aerobic respiration produces 36-38 ATP molecules, requires oxygen, and produces CO2 and water as end products.
27 INCORRECTChemical reactions that convert glucose to pyruvic acid in the cell are called
A)aerobic respiration.
B)anaerobic respiration.
C)the citric acid
cycle.
D)the electron transport system.
E)glycolysis.
Feedback: Incorrect Answer: Glycolysis is the set of chemical reactions that convert glucose to pyruvic acid. Aerobic respiration is the breakdown of organic molecules to form ATP in the presence of oxygen.
28 INCORRECTA sequence of nucleotides in DNA that provides a chemical set of instructions for making a functional protein is called a
A)codon.
B)anticodon.
C)peptide bond.
D)mRNA.
E)gene.
Feedback: Incorrect Answer: A gene is the sequence of nucleotides in DNA that code for a functional protein. A codon is the triplet nucleotide sequence on mRNA that codes for a particular amino acid.
29 INCORRECT Transcription takes place in the __________ of the cell.
A)cytosol
B)Golgi apparatus
C)mitochondria
D)nucleus
E)ribosomes
Feedback: Incorrect Answer: Transcription takes place in the nucleus of the cell in eukaryotes.
30 CORRECT mRNA is copied from
A)DNA.
B)tRNA.
C)ribosomes.
D)polypeptide chains.
E)rRNA.
Feedback: Correct Answer: mRNA is the complementary copy of DNA formed during transcription.
31 INCORRECT In the DNA molecule, adenine always pairs with
A)cytosine.
B)guanine.
C)uracil.
D)thymine.
Feedback: Incorrect Answer: Adenine always pairs with thymine, and cytosine always pairs with guanine in the DNA molecule.
32 CORRECTThe __________ on a tRNA molecule pairs with three nucleotides on a mRNA molecule.
A)anticodon
B)codon
C)exon
D) intron
E)gene
Feedback: Correct Answer: The anticodon is the triplet nucleotide sequence on tRNA that is complementary to a codon sequence on mRNA.
33 INCORRECTRegions of DNA that do not code for portions of a protein are called
A)anticodons.
B)codons.
C)exons.
D) introns.
E)genes.
Feedback: Incorrect Answer: Introns are the sequences of DNA that do not code for portions of a protein. An anticodon is the triplet nucleotide sequence on tRNA that is complementary to a codon sequence on mRNA.
34 INCORRECTDuring the process of translation, __________ tRNA molecule(s) occupies the tRNA binding site(s) on a ribosome.
A)one
B)two
C)three
D)six
E)hundreds of
Feedback: Incorrect Answer: Two tRNA molecules occupy the tRNA binding sites on a ribosome.
35 INCORRECTPart of a proprotein is cleaved off to make a functional protein. This describes
A)posttranscriptional processing.
B)posttranslational processing.
C)transcription.
D)translation.
E)mitosis.
Feedback: Incorrect Answer: The cleavage of a proprotein, forming a functional protein, is an example of posttranslational processing.
36 INCORRECT Replication of DNA takes place during the
A)G0 phase.
B)G1 phase.
C)G2 phase.
D)S phase.
E)M phase (mitosis).
Feedback: Incorrect Answer: DNA replication takes place during the S phase of interphase. The G0 phase is the phase that cells enter when they exit the cell cycle.
37 INCORRECT During the process of DNA replication,
A)one new DNA strand is formed.
B)the production of new nucleotide strands is catalyzed by DNA ligase.
C)short segments are spliced together by DNA
polymerase.
D)each new DNA molecule has one strand of nucleotides from the original DNA and one newly synthesized strand.
E)all of these
Feedback: Incorrect Answer: During the process of DNA replication, two new strands are produced. Each new DNA molecule has one strand of nucleotides from the original DNA and one newly synthesized strand.
38 CORRECTBy the process of mitosis in a human cell, __________ daughter cells are produced, each of which has __________ chromosomes.
A)2, 46
B)2, 23
C)4, 46
D)4, 23
E)8, 23
Feedback: Correct Answer: In human cells, mitosis produces 2 daughter cells each with 46 chromosomes.
39 INCORRECTWhich of these processes is associated with meiosis, but not mitosis?
A)DNA replication prior to division
B)cytokinesis
C)crossing over
D)prophase-metaphase-anaphase-telophase sequence
E)all of these
Feedback: Incorrect Answer: DNA replication prior to division occurs in both mitosis and meiosis. Crossing over occurs only in meiosis, not mitosis.
40 INCORRECT The process of meiosis
A) includes meiosis I, II, and III.
B)results in the production of sperm cells or oocytes.
C)produces 4 diploid cells.
D)produces gametes that are identical to the parent cell.
E)produces new cells for growth or tissue repair.
Feedback: Incorrect Answer: The process of meiosis results in the production of sperm cells or oocytes and includes meiosis I and II, there is no meiosis III.
Chapter 4 Review Questions
Your Results:The correct answer for each question is indicated by a .
1 INCORRECT The proteins that control the reactions of metabolism are
A)amino acids
B)catalysts
C)enzymes
D)substrates
Feedback: Incorrect: Enzymes are protein catalysts that increase reaction rates; proteins are comprised of amino acids
2 INCORRECTThe process that provides the biochemicals required for cell growth and repair is
A)anabolism
B)catabolism
C)metabolism
D)synthesis
Feedback: Incorrect: Metabolism is a combined term for synthesis (anabolism) and break down (catabolism)
3 INCORRECT A by-product of dehydration synthesis is
A)carbon dioxide
B)oxygen
C)water
D)amino acids
Feedback: Incorrect: Dehydration is the removal of water from a molecule
4 INCORRECTEnzymes are needed to promote metabolic reactions in the body because
A)there is inadequate oxygen to promote the chemical reactions
B)the temperature in cells is not high enough to promote the increase in chemical reaction rates
C)both of the above
D)neither of the above
Feedback: Incorrect: Normal cells are assumed to have sufficient oxygen
5 INCORRECT Very small quantities of enzymes are needed because
A)they are very large protein molecules
B)a phospholipid layer provides insulation
C)very rapid production of enzymes is possible when they are needed
D)they are not consumed in the metabolic reaction they facilitate
Feedback: Incorrect: Enzymes are re-used in reactions
6 INCORRECT Enzymes can be denatured (destroyed) by
A)heat and radiation
B)chemicals and extremes of pH
C)electricity
D)all of the above
Feedback: Incorrect: Since enzymes are proteins, they
can be denatured by factors such as abnormal pH, electricity, chemicals, radiation and heat
7 INCORRECTThe form of energy most often used by the body's metabolic processes is
A)chemical
B) light
C)mechanical
D)electrical
Feedback: Incorrect: Energy reactions are chemical in nature
8 INCORRECTThe first stage of cellular respiration is ___________ and occurs in the __________________ .
A)aerobic, cytosol
B)anaerobic, Golgi apparatus
C)aerobic, cell membrane
D)anaerobic, cytosol
Feedback: Incorrect: The first series of reactions is anaerobic and does not require oxygen (glycolysis)
9 CORRECTThe second phase of cellular respiration is __________ and occurs in the ____________.
A)aerobic, mitochondria
B)aerobic, cytosol
C)anaerobic, Golgi apparatus
D)anaerobic, cell membrane
Feedback: Correct Answer: Following glycolysis, glucose end products enter the mitochondria if oxygen is available (Kreb cycle)
10 INCORRECTThe final products of glucose oxidation are all of the following except
A)water
B)carbon dioxide
C)energy
D)oxygen
Feedback: Incorrect: Glucose oxidation ends with carbon dioxide, water and ATP energy
11 INCORRECT The average human diet should consist largely of
A)protein
B)carbohydrates
C)saturated fats
D)unsaturated fats
Feedback: Incorrect: Carbohydrates are commonly required for energy
12 CORRECTThe initial phase of the metabolic pathway of carbohydrates produces
A)2 pyruvic acid molecules
B)36 citric acid molecules
C)acetyl coenzyme A
D)4 fumaric acid molecules
Feedback: Correct Answer: Pyruvic acid is the end product of glycolysis
13 CORRECT The most important product of the citric acid cycle is
A)hydrogen
B)oxygen
C)carbon dioxide
D)glycogen
Feedback: Correct Answer: Hydrogen is used by the electron transport chain to produce most of the ATP
14 INCORRECT A triglyceride molecule consists of
A)cholesterol and oxygen
B)glycerol and three fatty acids
C)ketones and water
D)phosphorus and lipids
Feedback: Incorrect: There are many triglycerides, but they all have one glycerol and three fatty acids
15 INCORRECTWhen protein is used as an energy source, protein molecules first undergo a process called
A)dehydration
B)deamination
C) lysis
D)none of the above
Feedback: Incorrect: Deamination is the removal of a NH2 group (amino) from an amino acid
16 CORRECTProtein is needed primarily to accomplish all of the following except
A)supply energy
B)create new cell parts
C)make enzymes
D)create hormones
Feedback: Correct Answer: Although proteins are used somewhat for energy, that is not their main function
17 INCORRECT The rate of an enzyme-controlled pathway is determined by a
A)chemical on-off switch
B)regulatory enzyme
C)rate-setting hormone
D)substrate-lysing substance
Feedback: Incorrect: Enzymes control all reaction rates
18 INCORRECT We inherit traits from both our parents because
A)DNA contains genes that are the carriers of inheritance
B)the sex cells from each parent join at conception to bring together genetic information unique for the new individual
C)messenger RNA carries the genetic code
D)our species, Homo sapiens, reproduces sexually
Feedback: Incorrect: We are all hybrids of our parents
19 INCORRECT The "backbone" of DNA is composed of alternating
A)strands of thymine and cytosine
B)phosphate and sugar molecule
C)nucleotides joined so that phosphate and sugar portions alternate
D)alternating organic bases and nucleotides
Feedback: Incorrect: The basic DNA chain is comprised of phosphates and the sugar deoxyribose, with bases attached to the sides
20 INCORRECT Which of the following base pairs of DNA is correct?
A)thymine and cytosine
B)guanine and adenine
C)guanine and thymine
D)adenine and thymine
Feedback: Incorrect: Adenine can base pair with thymine and guanine with cytosine
21 INCORRECT Genetic information must tell cells
A)what elements to combine in synthesizing protein
B)the kinds of bonds between elements that must be formed
C)how to position amino acids correctly in polypeptide chains
D)the position of phosphate and sugar molecules in the DNA "backbone"
Feedback: Incorrect: Genes become expressed as the proteins that are produced; proteins are amino acid chains
22 INCORRECTRNA molecules differ from DNA molecules in all of the following ways except
A)RNA molecules are single rather than double stranded
B)RNA molecules are found in both the nucleus and in cytoplasm
C)there are two forms of RNA
D)RNA molecules contain thymine and uracil
Feedback: Incorrect: RNA cannot contain the base
thymine
23 INCORRECTWhich of the following statements about RNA is (are) true?
A)RNA polymerase moves along a DNA molecule and separates the DNA strand exposing the nucleotides.
B)A triplet of nucleotides in mRNA that specifies the amino acid to be formed is a codon.
C)both
D)neither
Feedback: Incorrect: Both statements are true about the RNA polymerase and codon
24 INCORRECT The function of DNA is to
A)direct the activities of the cell
B)direct the synthesis of protein by the cell
C)both
D)neither
Feedback: Incorrect: DNA regulates division and metabolism
25 INCORRECTDNA molecules are replicated during what phase of the cell cycle?
A)prophase
B)anaphase
C)interphase
D)metaphase
Feedback: Incorrect: Replication is completed in interphase before any visible activity occurs
26 INCORRECTDNA of the parent cell must be replicated accurately so that the new cell can
A)maintain life functions
B)build cell parts
C)metabolize nutrients
D)all of the above
Feedback: Incorrect: DNA controls all cell activities
27 INCORRECT The occurrence of mutations may be
A)spontaneous
B)a result of exposure to ionizing radiation and toxic chemicals
C)both
D)neither
Feedback: Incorrect: Mutations are changes in the base sequences and may either be induced or random
28 CORRECT Enzymes are specialized proteins that control each of the interrelated reactions of
metabolism.
A)True
B)False
Feedback: Correct Answer: Enzymes are catalysts that are necessary to make all reactions proceed at a normal rate
29 INCORRECT A protein is a chain of less than 50 amino acids.
A)True
B)False
Feedback: Incorrect: Usually proteins have 50 amino acids or more
30 CORRECT Hydrolysis occurs during digestion.
A)True
B)False
Feedback: Correct Answer: Hydrolysis is the breaking of food bonds by the addition of water
31 CORRECTEnzymes recognize the specific shape of the substrate with which they react.
A)True
B)False
Feedback: Correct Answer: Enzymes form a lock-and-key fit with specific substrates
32 CORRECT Energy can be mechanical, chemical, and thermal.
A)True
B)False
Feedback: Correct Answer: Although energy has many forms, the usable ATP energy in cells is chemical in nature
33 INCORRECT
The major difference between burning substances outside cells and oxidation of substances inside cells is in the amount of heat produced.
A)True
B)False
Feedback: Incorrect: The main difference is the rate of the reaction
34 INCORRECT Anaerobic respiration requires oxygen.
A)True
B)False
Feedback: Incorrect: By definition, anaerobic means without oxygen
35 CORRECTThe function of ATP is to store energy in its terminal phosphate bond.
A)True
B)False
Feedback: Correct Answer: The last phosphate bond is the one broken when energy is utilized
36 INCORRECT The end product of carbohydrate digestion is glycogen.
A)True
B)False
Feedback: Incorrect: The end product of carbohydrate digestion is glucose
37 CORRECTThe primary use of carbohydrates is as energy sources.
A)True
B)False
Feedback: Correct Answer: Although other molecules are used for energy, carbohydrates are preferred
38 CORRECTProduction of the high energy terminal phosphate bond of ATP depends on oxygen.
A)True
B)False
Feedback: Incorrect: ATP can be produced anaerobically, such as in glycolysis
39 INCORRECT Ketone bodies are a product of glucose metabolism.
A)True
B)False
Feedback: Incorrect: Ketone bodies such as acetone are products of lipid metabolism
40 CORRECTGram for gram, fats contain more energy than either proteins or carbohydrates.
A)True
B)False
Feedback: Correct Answer: Fats have potentially more energy than other molecules