Ch2 and Ch3 test ( from hw)

Question 1

A substance that cannot be broken down into other substances by ordinary chemical procedures is a(n) _____.

isotope
proton
element
compound
molecule

Answer 1

Element

Question 2

About 20-25% of the 92 natural elements are known to be essential to life. Which four of these elements make up approximately 96% of living matter?

carbon, hydrogen, nitrogen, oxygen

oxygen, hydrogen, calcium, nitrogen

carbon, oxygen, nitrogen, calcium

carbon, oxygen, phosphorus, hydrogen

carbon, sodium, hydrogen, nitrogen

Answer 2

carbon, hydrogen, nitrogen, oxygen

Question 3

The atoms of different phosphorus isotopes __________.

have different numbers of neutrons
have different atomic numbers
have different numbers of protons
react differently with other atoms
have different numbers of electrons

Answer 3

have different numbers of neutrons

Question 3

Trace elements are those required by an organism in only minute quantities. Which of the following is a trace element that is required by all organisms?

iron
sodium
iodine
calcium
potassium

Answer 3

iron

Question 4

Which of the following subatomic particles always has a positive charge?

atom
electron
proton
neutron
element

Answer 4

proton

Question 5

In what way are elements in the same column of the periodic table the same?

They have the same number of protons.

They have the same number of electrons.

They have the same number of electrons in their valence shell.

They have the same number of electron shells.

They have the same number of neutrons.

Answer 5

They have the same number of electrons in their valence shell

Question 5

From the atomic mass, one can deduce the number of ________ in each atom of an element.

neutrons
protons
protons plus neutrons
electrons
protons plus electrons

Answer 5

protons plus neutrons

Question 6

In what way are elements in the same row of the periodic table the same?

They have the same number of neutrons.

They have the same number of electron shells.

They have the same number of protons.

They have the same number of electrons.

They have the same number of electrons in their valence shell.

Answer 6

They have the same number of electron shells

Question 7

The nucleus of a nitrogen atom contains 7 neutrons and 7 protons. Which of the following is a correct statement concerning nitrogen?

The nitrogen atom has a mass number of 14 and an atomic number of 14.

The nitrogen atom has a mass number of 7 and an atomic number of 14.

The nitrogen atom has a mass number of 14 and an atomic number of 7.

The nitrogen atom has a mass number of 14 and an atomic number of 21.

The nitrogen atom has a mass number of 7 and an atomic number of 21.

Answer 7

The nitrogen atoms has a mass number of 14 and an atomic number of 7.

Question 7

One difference between carbon-12 ( 126C ) and carbon-14 ( 146C) is that carbon-14 has

two more protons and two more neutrons than carbon-12.
two more electrons and two more protons than carbon-12.
two more electrons than carbon-12.
two more protons than carbon-12.
two more neutrons than carbon-12.

Answer 7

two more neutrons than carbon-12

Question 8

The type of bonding and the numbers of covalent bonds an atom can form with other atoms are determined by __________.

the number of protons

the number of neutrons

the number of unpaired electrons
in the valence shell

the size of the atom; smaller atoms are chemically more reactive

the nucleus

Answer 8

the number of unpaired electrons in the valence shell

Question 9

A carbon atom and a hydrogen atom form what type of bond in a molecule?

ionic bond
hydrogen bond
polar covalent bond
nonpolar covalent bond
Van der Waals interaction

Answer 9

nonpolar covalent bond

Question 10

What is the maximum number of covalent bonds an element with atomic number 8 can make with hydrogen?

6
4
3
1
2

Answer 10

2

Question 10

An ionic bond is formed when __________.

one atom transfers an electron to another atom

both atoms are nonpolar

both atoms are equally attractive to electrons

both atoms are electrically neutral
atoms are subjected to radioactive isotopes

Answer 10

one atom transfers an electron to another atom

Question 11

Hydrogen bonding is most often seen _____.

when the bonds within the molecule are nonpolar covalent bonds

if the molecule consists of three or fewer atoms

in molecules whose three-dimensional shape is tetrahedral

when hydrogen is covalently bonded to an electronegative atom

when multiple carbon atoms are present

Answer 11

when hydrogen is covalently bonded to an electronegative atom

Question 12

When two atoms are equally electronegative, they will interact to form

nonpolar covalent bonds.

van der Waals interactions.

hydrogen bonds.

polar covalent bonds.

ionic bonds.

Answer 12

nonpolar covalent bonds

Question 13

What results from an unequal sharing of electrons between atoms?

a hydrophobic interaction
an ionic bond
a polar covalent bond
a nonpolar covalent bond

Answer 13

a polar covalent bond

Question 14

A covalent bond is likely to be polar when

one of the atoms sharing electrons is much more electronegative than the other atom.

oxygen is one of the two atoms sharing electrons.

the two atoms sharing electrons are the same element.

the two atoms sharing electrons are different elements.

the two atoms sharing electrons are equally electronegative.

Answer 14

one of the atoms sharing electrons is much more electronegative than the other atom.

Question 15

Which of the following molecules contains the most polar covalent bond?

CO2
H2O
O2
H2
CH4

Answer 15

H20

Question 16

What is the difference between covalent bonds and ionic bonds?

Covalent bonds are formed between atoms to form molecules; ionic bonds are formed between atoms to form compounds.

Covalent bonds involve the sharing of electrons between atoms; ionic bonds involve the electrical attraction between atoms.

Covalent bonds involve the sharing of pairs of electrons between atoms; ionic bonds involve the sharing of single electrons between atoms.

Covalent bonds involve the sharing of electrons between atoms; ionic bonds involve the sharing of protons between atoms.

Covalent bonds involve the transfer of electrons between atoms; ionic bonds involve the sharing of electrons between atoms.

Answer 16

Covalent bonds involve the sharing of electrons between atoms; ionic bonds involve the electrical attraction between atoms.

Question 17

A covalent bond is formed by

sharing of a pair of electrons between two atoms.

sharing of a single electron between two atoms.

transfer of an electron from one atom to another.

sharing of a pair of protons between two atoms.

transfer of a proton from one atom to another.

Answer 17

sharing of a pair of electrons between two atoms

Question 18

An ionic bond is formed by

transfer of an electron from one atom to another.

sharing of a pair of electrons between two atoms.

sharing of a single electron between two atoms.

transfer of a proton from one atom to another.

sharing of a pair of protons between two atoms.

Answer 18

transfer of an electron from one atom to another

Question 19

Which of the following are the strongest molecular interactions?

hydrogen bonds

van der Waals interactions in a nonpolar environment

ionic bonds in an aqueous environment

van der Waals interactions

covalent bonds

Answer 19

covalent bonds

Question 20

Which of the following would be regarded as compounds?

O2 and CH4

H2O and CH4, but not O2

CH4 and O2, but not H2O

H2O, O2, and CH4

H2O and O2

Answer 20

H20 and CH4, but not O2

Question 20

What is the maximum number of hydrogen atoms that can be covalently bonded in a molecule containing two carbon atoms? 2 3 6 8 4

Answer 20

6

Question 21

The slight negative charge at one end of one water molecule is attracted to the slight positive charge of another water molecule. What is this attraction called? an ionic bond a hydrogen bond a hydrophilic bond a van der Waals interaction a covalent bond

Answer 21

a hydrogen bond

Question 21

Chemical equilibrium is reached when __________. matter is conserved the forward and reverse reactions occur at the same rate so that the concentrations of reactants and products remain the same the reverse reaction begins to occur all of the reactants are converted to products the rate at which matter is destroyed and the rate at which it is created offset each other

Answer 21

the forward and reverse reactions occur at the same rate so that teh concentrations of reactants and products remain the same

Question 22

Carbon dioxide (CO2) is readily soluble in water, according to the equation CO2 + H2O ↔ H2CO3. Carbonic acid (H2CO3) is a weak acid. If CO2 is bubbled into a beaker containing pure, freshly distilled water, which of the following graphs correctly describes the results?

Answer 22

the one sloping down

Question 22

Based on your knowledge of the polarity of water molecules, the solute molecule depicted in the figure is most likely without charge. nonpolar. positively charged. negatively charged. hydrophobic.

Answer 22

positively charged

Question 23

Many of water's emergent properties, such as its cohesion, its high specific heat, and its high heat of vaporization, result from the fact that water molecules _____. are very small tend to repel each other are extremely large are in constant motion are attracted to each other by partial negative and positive charges on the oxygen and hydrogen atoms, respectively

Answer 23

are attracted to each other by partial negative and positive charges on the oxygen and hydrogen atoms, respectively

Question 24

The amount of energy that must be absorbed or lost to raise or lower the temperature of 1 g of liquid water by 1°C _____. depends on the initial temperature of the water sample is 1 kilocalorie is 1,000 kilocalories is 1 calorie is 1,000 calories is 1,000 joules

Answer 24

is 1 calorie

Question 24

Water molecules have a polarity, which allows them to be electrically attracted to other water molecules and other polar molecules by weak chemical bonds known as _____. Van der Waals interactions hydrogen bonds polar covalent bonds nonpolar covalent bonds ionic bonds

Answer 24

hydrogen bonds

Question 25

Sodas typically contain sugar, flavorings, coloring agents, and carbon dioxide dissolved in water. The best term to describe this mixture would be _____. a solute an aqueous solution a solvent a suspension an aqueous solvent

Answer 25

an aqueous solution

Question 25

Because organisms are made primarily of water, they resist rapid temperature changes. This useful quality is based on water's _____. buffering activity solvation ability lower density in the solid phase cohesion high specific heat

Answer 25

high specific heat

Question 26

Most acid precipitation results from the combination of __________ with water in the atmosphere, which forms strong acids that fall with rain or snow. ozone carbon dioxide ammonium sulfur oxides and nitrogen oxides buffers

Answer 26

sulfur oxides and nitrogen oxides

Question 26

An acid is a substance that _____. reduces the hydrogen ion concentration of a solution contains hydrogen increases the hydrogen ion concentration of an aqueous solution is a versatile solvent forms covalent bonds with other substances

Answer 26

increases the hydrogen ion concentration of an aqueous solution

Question 27

A pH of 6 is how many times more acidic than a pH of 9? 3 30 100 300 1,000

Answer 27

1,000

Question 28

Water molecules are able to form hydrogen bonds with oxygen gas (O2) molecules. methane gas (CH4) molecules. compounds that have polar covalent bonds. compounds that are not soluble in water. compounds that have nonpolar covalent bonds.

Answer 28

compounds that have polar covalent bonds

Question 28

Which of the following effects is produced by the high surface tension of water? A water strider can walk across the surface of a small pond. Lakes don't freeze solid in winter, despite low temperatures. Evaporation of sweat from the skin helps to keep people from overheating. Water flows upward from the roots to the leaves in plants. Organisms resist temperature changes, although they give off heat due to chemical reactions.

Answer 28

A water strider can walk across teh surface of a small pond

Question 29

Which of the following takes place as an ice cube cools a drink? Molecular collisions in the drink increase. A calorie of heat energy is transferred from the ice to the water of the drink. The specific heat of the water in the drink decreases. Evaporation of the water in the drink increases. Kinetic energy in the drink decreases.

Answer 29

Kinetic energy in the drink decreases

Question 30

Which type of bond must be broken for water to vaporize? ionic bonds hydrogen bonds polar covalent bonds both hydrogen bonds and ionic bonds both polar covalent bonds and hydrogen bonds

Answer 30

hydrogen bonds

Question 31

Hydrophobic substances such as vegetable oil are polar substances that repel water molecules. nonpolar substances that have an attraction for water molecules. charged molecules that hydrogen-bond with water molecules. polar substances that have an affinity for water. nonpolar substances that repel water molecules.

Answer 31

Nonpolar substances that repel water molecules

Question 32

Why does ice float in liquid water? Hydrogen bonds stabilize and keep the molecules of ice farther apart than the water molecules of liquid water. The ionic bonds between the molecules in ice prevent the ice from sinking. The crystalline lattice of ice causes it to be denser than liquid water. Ice always has air bubbles that keep it afloat. The high surface tension of liquid water keeps the ice on top.

Answer 32

Hydrogen bonds stabilize and keep the molecules of ice farther apart than the water molecules of liquid water.

Question 33

A strong acid like HCl is a strong buffer at high pH. increases the pH when added to an aqueous solution. reacts with strong bases to create a buffered solution. dissociates completely in an aqueous solution. is a strong buffer at low pH.

Answer 33

dissociates completely in an aqueous solution

Question 34

Which of the following dissociates completely in aqueous solution and is therefore considered to be a strong base (alkali)? NaOH HCl NH3 NaCl H2CO3

Answer 34

NaOH

Question 35

One of the buffers that contributes to pH stability in human blood is carbonic acid (H2CO3). Carbonic acid is a weak acid that, when placed in an aqueous solution, dissociates into a bicarbonate ion (HCO3-) and a hydrogen ion (H+). Thus, H2CO3 ↔ HCO3- + H+ If the pH of the blood increases, one would expect an increase in the concentration of HCO3- and a decrease in the concentration of OH-. a decrease in the concentration of HCO3- and an increase in the concentration of both H2CO3 and H+. a decrease in the concentration of H2CO3 and an increase in the concentration of HCO3-. an increase in the concentration of H2CO3 and a decrease in the concentration of HCO3-. a decrease in the concentration of HCO3- and an increase in the concentration of H+.

Answer 35

a decrease in the concentration of H2CO3 and an increase in the concentration of HCO3-.

Question 35

If acid rain has lowered the pH of a particular lake to pH 4.0, which of the following statements about this lake is true? The hydroxyl ion concentration is 1 × 10-4 moles per liter of lake water. The hydroxyl ion concentration is 1 × 10-10 moles per liter of lake water. The hydrogen ion concentration is 1 × 10-10 moles per liter of lake water. The hydrogen ion concentration is 1 × 104 moles per liter of lake water. The hydrogen ion concentration is 4.0 moles per liter of lake water.

Answer 35

The hydroxyl ion concentration is 1 × 10-10 moles per liter of lake water.

Question 35

If the pH of a solution is decreased from pH 8 to pH 6, it means that the concentration of H+ is twice (2×) what it was at pH 8. concentration of OH- is 100 times greater than what it was at pH 8. concentration of H+ is one-half (1/2) what it was at pH 8. concentration of OH- is one-hundredth (0.01×) what it was at pH 8. concentration of H+ is one-hundredth (0.01×) what it was at pH 8.

Answer 35

Concentration of OH- is one-hundredth (0.01x) what it was at pH 8

Question 36

Buffers are substances that help resist shifts in pH by accepting OH- to a solution when bases are added. releasing OH- to a solution when bases are added. accepting H+ from a solution when acids are added. accepting OH- from a solution when acids are added. releasing H+ to a solution when acids are added.

Answer 36

Accepting H+ from a solution when acids are added

Question 37

Carbonic acid (H2CO3) serves as a buffer in human blood. Carbonic acid is a weak acid that dissociates into a bicarbonate ion (HCO3-) and a hydrogen ion (H+). Thus, H2CO3 ↔ HCO3- + H+ A decrease in blood pH would result in a decrease in the concentration of H2CO3 and an increase in the concentration of HCO3-. a decrease in the concentrations of H2CO3 and HCO3-. an increase in the concentrations of H2CO3 and HCO3-. an increase in the concentrations of H2CO3, HCO3-, and OH-. an increase in the concentration of H2CO3 and a decrease in the concentration of HCO3-.

Answer 37

an increase in the concentration of H2CO3 and a decrease in the concentration of HCO3-.

Question 37

If the cytoplasm of a cell is at pH 7, and the mitochondrial matrix is at pH 8, this means that the concentration of H+ ions in the cytoplasm is 7/8 the concentration in the mitochondrial matrix. the concentration of H+ ions is tenfold higher in the cytoplasm than in the mitochondrial matrix. the concentration of H+ ions is tenfold higher in the mitochondrial matrix than in the cytoplasm. the concentration of H+ ions in the cytoplasm is 8/7 the concentration in the mitochondrial matrix. the mitochondrial matrix is more acidic than the cytoplasm.

Answer 37

the concentration of H+ ions is tenfold higher in the cytoplasm than in the mitochondrial matrix.

Question 38

You have two beakers. One contains pure water; the other contains pure methanol (wood alcohol). The covalent bonds of methanol molecules are nonpolar, so there are no hydrogen bonds among methanol molecules. You pour crystals of table salt (NaCl) into each beaker. Predict what will happen. NaCl crystals will dissolve readily in methanol but will not dissolve in water. Equal amounts of NaCl crystals will dissolve in both water and methanol. NaCl crystals will not dissolve in either water or methanol. NaCl crystals will dissolve readily in water but will not dissolve in methanol.

Answer 38

NaCl crystals will dissolve readily in water but will not dissolve in methanol.

Question 38

Increased atmospheric CO2 concentrations might have what effect on seawater? Seawater will become more acidic, and bicarbonate concentrations will decrease. Seawater will become more alkaline, and carbonate concentrations will decrease. Seawater will become more acidic, and carbonate concentrations will increase. There will be no change in the pH of seawater, because carbonate will turn to bicarbonate. Seawater will become more acidic, and carbonate concentrations will decrease.

Answer 38

Seawater will become more acidic, and carbonate concentrations will decrease

Question 39

Many mammals control their body temperature by sweating. Which property of water is most directly responsible for the ability of sweat to lower body temperature? water's ability to dissolve molecules in the air the release of heat by the formation of hydrogen bonds water's change in density when it condenses the absorption of heat by the breaking of hydrogen bonds

Answer 39

the absorption of heat by the breaking of hydrogen bonds

Question 40

Which property of water allows dogs to cool themselves by panting? water’s high surface tension water’s high heat of vaporization the formation of covalent bonds between water molecules

Answer 40

water's high heat of vaporization

Question 41

Which property of water allows a water strider to walk on water? water’s high surface tension adhesion of water molecules to other kinds of molecules the formation of covalent bonds between water molecules

Answer 41

water's high surface tension

Question 42

Which property of water allows a paper towel to pick up a puddle of water? water’s high heat of vaporization water’s high surface tension adhesion of water molecules to other kinds of molecules

Answer 42

adhesion of water molecules to other kinds of molecules

Question 43

Identify all correct statements about the ionization of water. Check all that apply. Dissociation of water produces equal numbers of OH- and H+. Water ionizes to form peroxide and hydronium ions. Water ionizes to form hydroxide and hydronium ions. Dissociation of water is reversible. Dissociation of water is not reversible. Dissociation of water produces equal masses of OH- and H+.

Answer 43

Dissociation of water produces equal numbers of OH- and H+ Water ionizes to form hydroxide and hydronium ions Dissociation of water is reversible

Question 44

Most organic compounds contain carbon and _____. nitrogen oxygen sulfur phosphate hydrogen

Answer 44

hydrogen

Question 45

Which of the following is a hydrocarbon? CO2 H2CO3 C6H12O6 C3H8 CCl2F2

Answer 45

C3H8

Question 46

The large diversity of shapes of biological molecules is possible because of the extensive presence of _____ in the molecules. carbon nitrogen sulfur hydrogen oxygen

Answer 46

carbon

Question 47

Molecules that have the same chemical formula (same numbers of each atom) but different three-dimensional shapes are called __________. isomers isotopes functional groups enantiomers hydrocarbons

Answer 47

isomers

Question 47

Which of the following best describes cis-trans isomers? They have the same number of atoms of the same elements but different structures. They are long chains of hydrogen and carbon atoms. They differ in their spatial arrangement around inflexible double bonds. They are mirror images of each other. They differ in the arrangement of covalent bonds and in covalent partners.

Answer 47

They differ in their spatial arrangement around inflexible double bonds

Question 47

Variations in the reactive properties of different organic molecules are most closely associated with __________. the orientation of the carbon skeleton, as either ringed or linear the presence or absence of functional groups the presence or absence of double bonds the number of carbon atoms composing the molecule's skeleton

Answer 47

the presence or absence of functional groups

Question 48

When carbon forms single covalent bonds with four other atoms, the atoms joined to the carbon form a plane. sphere. tetrahedron. line. cube.

Answer 48

tetrahedron

Question 49

How many electron pairs does carbon share in order to complete its valence shell? 4 2 8 3 1

Answer 49

4

Question 50

When two carbon atoms are joined by a double bond, how many electron pairs are shared between the two carbons? 1 2 3 4

Answer 50

2

Question 51

A carbon atom is most likely to form which of the following bonds with other atoms? ionic bonds covalent bonds hydrogen bonds covalent bonds and hydrogen bonds

Answer 51

covalent bonds

Question 52

The primary functional groups in a common macromolecule are hydroxyl groups. Which of the following statements regarding this macromolecule is true? It will dissolve in a nonpolar solvent. It will form hydrogen bonds with water. It will not dissolve in water. It lacks an asymmetric carbon, and it is probably a fat or lipid.

Answer 52

It will form hydrogen bonds with water

Question 52

Research indicates that ibuprofen, a drug used to relieve inflammation and pain, is a mixture of two enantiomers, that is, molecules that differ in the arrangement of atoms around their double bonds. are mirror images of one another. have identical chemical formulas but differ in the branching of their carbon skeletons. exist in either linear chain or ring forms.

Answer 52

are mirror images of one another

Question 53

Which of the following chemical equations describes a dehydration reaction? disaccharide + H2O → monosaccharide + monosaccharide monosaccharide + monosaccharide → disaccharide + H2O disaccharide → monosaccharide + monosaccharide + H2O monosaccharide + monosaccharide + H2O → disaccharide

Answer 53

monosaccharide + monosaccharide → disaccharide + H2O

Question 53

Which two functional groups are always found in amino acids? carbonyl and amino carboxyl and amino hydroxyl and carboxyl ketone and amino

Answer 53

Carboxyl and amino

Question 54

Which of the following will dissolve in water? organic hydrocarbons organic molecules with hydroxyl groups carbon skeletons bound to hydrogen fats

Answer 54

organic molecules with hydroxyl groups

Question 55

Amino acids are acids because they always possess which functional group? carbonyl hydroxyl phosphate carboxyl amino

Answer 55

carboxyl

Question 56

A dehydration reaction (or condensation reaction) is the process in which __________. View Available Hint(s)for Part A the bonds between the individual monomers of a polymer are broken by the addition of water molecules water molecules are used as a source of raw material to break down polymers to monomers water molecules are attracted to each other water molecules are produced as a polymer is formed from monomers None of the listed choices is correct.

Answer 56

water molecules are produces as a polymer is formed with monomers

Question 57

The four main categories of large biological molecules present in living systems are __________. RNA, DNA, proteins, and carbohydrates monosaccharides, lipids, polysaccharides, and proteins proteins, nucleic acids, polysaccharides, and lipids proteins, DNA, RNA, and steroids nucleic acids, carbohydrates, monosaccharides, and proteins

Answer 57

proteins, nucleic acids, polysaccharides, and lipids

Question 58

Which of the following best summarizes the relationship between dehydration reactions and hydrolysis? Dehydration reactions split water molecules and add hydroxyl groups to polymers, and hydrolysis reactions remove hydroxyl groups from polymers. Dehydration reactions break down polymers, and hydrolysis reactions create monomers. Dehydration reactions assemble polymers, and hydrolysis reactions break down polymers. Dehydration reactions create monomers, and hydrolysis reactions assemble polymers.

Answer 58

Dehydration reactions assemble polymers, and hydrolysis reactions break down polymers

Question 58

What is a common chemical reaction mechanism by which cells make polymers from monomers? the formation of disulfide bridges between monomers decreasing the pH dehydration reactions hydrolysis reactions

Answer 58

dehydration reactions

Question 59

Which of the following is true of both starch and cellulose? They are both structural components of the plant cell wall. They can both be digested by humans. They are both polymers of glucose. They are both used for energy storage in plants.

Answer 59

They are both polymers of glucose

Question 59

The biochemical reaction that joins two amino acids to form a dipeptide is accompanied by the release of a carbon dioxide molecule. the addition of a water molecule. the release of a water molecule. the addition of a nitrogen atom.

Answer 59

The relase of a water molecule

Question 60

Humans can digest starch but not cellulose because the monomer of starch is glucose, whereas the monomer of cellulose is glucose modified by the addition of a nitrogen-containing group. humans harbor starch-digesting bacteria in the digestive tract, but not cellulose-digesting bacteria. humans have enzymes that can hydrolyze the α glycosidic linkages of starch but not the β glycosidic linkages of cellulose. humans have enzymes that can hydrolyze the β glycosidic linkages of starch but not the α glycosidic linkages of cellulose.

Answer 60

humans have enzymes that can hydrolyze the α glycosidic linkages of starch but not the β glycosidic linkages of cellulose.

Question 61

Polysaccharides, triacylglycerols, and proteins are similar in that they are synthesized from subunits by dehydration reactions. are synthesized through the formation of peptide bonds between monomers. are broken down into their subunits by dehydration reactions. are synthesized from monomers by hydrolysis reactions.

Answer 61

Are synthesized from subunits by dehydration reactions

Question 62

Plant cell walls consist mainly of _____. peptidoglycan chlorophyll chitin cellulose None of the listed choices is correct.

Answer 62

Cellulose

Question 63

Which of the following is true of cellulose? It is a polymer of glucose joined by α glycosidic linkages. It is a polymer composed of enantiomers of glucose. It is a storage polysaccharide for energy in plant cells. It is a primary structural component of plant cell walls. It is digestible by bacteria in the human gut.

Answer 63

It is a primary structural component of plant cell walls

Question 64

Which of the following polymers contains nitrogen? glycogen cellulose starch chitin

Answer 64

chitlin

Question 65

The enzyme amylase can break glycosidic linkages between glucose monomers only if the monomers are the α form. Which of the following could amylase break down? cellulose chitin starch starch and chitin

Answer 65

Starch

Question 66

Lactose, a sugar in milk, is composed of one glucose molecule joined by a glycosidic linkage to one galactose molecule. How is lactose classified? as a hexose as a disaccharide as a polysaccharide as a monosaccharide as a pentose

Answer 66

As a disaccharide

Question 67

Structure of a molecule. The molecule is H3CCH2CHCHCH2CH2CH2CHCHCH2COOH with double bonds between the third (from left to right) and the fourth carbons and between the eighth and the ninth carbons. The molecule shown in the figure is a(n) saturated fatty acid. polysaccharide. unsaturated fatty acid. triacylglycerol.

Answer 67

Unsaturated fatty acid

Question 67

Structure of a molecule. The molecule is HOOCCH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH3. Which of the following statements regarding the molecule illustrated in the figure is true? Molecules of this type are usually liquid at room temperature. It would be highly soluble in water. It is an entirely nonpolar molecule. It is a saturated fatty acid.

Answer 67

It is a saturated fatty acid

Question 68

Structure of a molecule. It consists of five six-membered carbon rings successively fused together. The second and the third (clockwise) carbons of the first ring are the fifth and the sixth carbons of the second one. The first and the second carbons of the second ring are the fourth and the fifth carbons of the third one. The second and the third carbons of the third ring are the fifth and the sixth carbons of the fourth one. The first and the second carbons of the fourth ring are the fourth and the fifth carbons of the fifth one. There is an OH group attached to the fifth carbon of the first ring, one CH3 group attached to the second carbon of the first and the third rings, a CH3 group attached to the sixth carbon of the fifth ring, and a CH2CH2CH2C left parenthesis CH3 right parenthesis 2 group attached to the second carbon of the fifth ring. There is also a double bond between the fourth and the fifth carbons of the second ring. What is the structure shown in the figure? triacylglycerol molecule phospholipid molecule fatty acid molecule steroid molecule

Answer 68

Steroid molecule

Question 69

Some regions of a polypeptide may coil or fold back on themselves. This is called __________, and the coils or folds are held in place by __________. primary structure ... covalent bonds secondary structure ... hydrogen bonds tertiary structure ... hydrogen bonds secondary structure ... peptide bonds tertiary structure ... covalent bonds

Answer 69

secondary structure.... hydrogen bonds

Question 69

Which of the following statements regarding lipids is true? They are made from glycerol and amino acids. They generally contain nitrogen. A gram of lipid stores less energy than a gram of carbohydrate. They are insoluble in water.

Answer 69

They are insoluble in water

Question 70

Which of the following is true regarding saturated fatty acids? They have double bonds between the carbon atoms of the fatty acids. They are the principal molecules in lard and butter. They are the predominant fatty acid in corn oil. They are usually produced by plants. They are usually liquid at room temperature.

Answer 70

They are the principal molecules in lard and butter

Question 70

The tertiary structure of a polypeptide is the localized region of a polypeptide chain that forms an α helix or β pleated sheet. overall three-dimensional shape of a protein composed of more than one polypeptide. overall three-dimensional shape of a fully folded polypeptide. linear sequence of amino acids in a polypeptide.

Answer 70

Overall three-dimensional shape of a fully folded polypeptide

Question 71

Which bonds maintain the primary structure of a protein? ionic bonds peptide bonds hydrogen bonds disulfide bonds

Answer 71

peptide bonds

Question 72

Interactions between the side chains (R groups) in a polypeptide are most important in stabilizing which of the following? secondary structure quaternary structure primary structure tertiary structure

Answer 72

Tertiary structure

Question 73

The flow of genetic information in a cell goes from __________. DNA to lipid to protein protein to RNA to DNA DNA to RNA to glucose DNA to ribosomes to RNA DNA to RNA to protein

Answer 73

DNA to RNA to protein

Question 74

One of the primary functions of RNA molecules is to transmit genetic information to offspring. function in the synthesis of proteins. act as a pattern or blueprint to form DNA. make a copy of itself, thus ensuring genetic continuity.

Answer 74

function in the synthesis of proteins

Question 75

If one strand of a DNA molecule has the sequence of bases 5'-ATTGCA-3', the other complementary strand would have the sequence 3'-UAACGU-5'. 5'-UAACGU-3'. 5'-TGCAAT-3'. 5-'TAACGT-3'.

Answer 75

5'-TGCAAT-3'.

Question 76

Which molecule is a nucleotide? Deoxyribose ATP The amino acid glycine

Answer 76

ATP

Question 78

Which of the following statements concerning unsaturated fats is true? They have double bonds in their fatty acid chains. They contain more hydrogen than do saturated fats having the same number of carbon atoms. They are more common in animals than in plants. They generally solidify at room temperature.

Answer 78

They have double bonds in the ir fatty acid chains

Question 79

Which polymers are composed of amino acids? Nucleic acids Proteins Carbohydrates Monomers

Answer 79

Proteins

Question 80

Which of the following is not attached to the central carbon atom in an amino acid? An oxygen An amino functional group A side chain ("R group") A carboxyl functional group

Answer 80

An oxygen

Question 81

Which part of an amino acid is always acidic? Carboxyl functional group Amino functional group Side chain ("R group") None of the above

Answer 81

Carboxyl functional group

Question 82

Which monomers make up RNA? View Available Hint(s)for Part D Amino acids Nucleotides Simple sugars Polymers

Answer 82

Nucleotides

Question 83

Which of the following statements about the formation of polypeptides from amino acids is true? Polypeptides form by condensation or hydrolysis reactions. A bond can form between any carbon and nitrogen atom in the two amino acids being joined. The reaction occurs through the addition of a water molecule to the amino acids. A bond forms between the carboxyl functional group of one amino acid and the amino functional group of the other amino acid.

Answer 83

A bond forms between the carboxyl functional group of one amino acid and the amino functional group of the other amino acid.

Question 84

True or false? Enzymes in the digestive tract catalyze hydrolysis reactions. True False

Answer 84

True

Question 85

How many molecules of water are needed to completely hydrolyze a polysaccharide that is 10 monomers long? 9 11 10 12

Answer 85

9

Question 86

Sucrose is formed when glucose is joined to fructose by a(n) __________. View Available Hint(s)for Part A ionic bond ester linkage glycosidic linkage peptide linkage phosphodiester linkage

Answer 86

Glycosidic linkage

Question 87

On food packages, to what does the term insoluble fiber refer? cellulose starch polypeptides glycogen

Answer 87

Cellulose

Question 88

Changing a single amino acid in a protein consisting of 433 amino acids would always alter the primary structure of the protein but never alter its tertiary structure or function. always alter the primary structure of the protein and sometimes alter its tertiary structure or function. always alter the primary and tertiary structure of the protein but never alter its function. sometimes alter the primary and tertiary structure of the protein but always alter its function.

Answer 88

always alter the primary structure of the protein and sometimes alter its tertiary structure or function

Question 88

Which of the following statements concerning saturated fats is true? They have multiple double bonds in the carbon chains of their fatty acids. They contain fewer hydrogen atoms than unsaturated fats having the same number of carbon atoms. They are generally solid at room temperature. They are more common in plants than in animals.

Answer 88

They are generally solid at room temperature

Question 89

There are 20 different amino acids. What makes one amino acid different from another? different side chains (R groups) attached to the carboxyl carbon different side chains (R groups) attached to an α carbon different asymmetric carbons different side chains (R groups) attached to the amino groups

Answer 89

different side chains ( R groups) attatched to an a carbon

Question 90

What maintains the secondary structure of a protein? hydrogen bonds between the carboxyl group of one peptide bond and the R group of another amino acid disulfide bonds between the amino group of one peptide bond and the R group of another amino acid peptide bonds between adjacent amino acids hydrogen bonds between the amino group of one peptide bond and the carboxyl group of another peptide bond

Answer 90

hydrogen bonds between the amino group of one peptide bond and the carboxyl group of another peptide bond

Question 91

The building blocks, or monomers, of nucleic acid molecules are called __________. fatty acids nucleotides polysaccharides pyrimidines and purines DNA and RNA

Answer 91

nucleotides

Question 92

Which of the following is a correct monomer/polymer pairing? monosaccharide/polypeptide amino acid/polypeptide glycerol/triglyceride amino acid/polysaccharide

Answer 92

amino acid/ polypeptide

Question 93

Which of the following is an example of a hydrolysis reaction? the reaction of two monosaccharides, forming a disaccharide with the release of water the reaction of a fat with glycerol, forming fatty acids with the release of water the synthesis of two amino acids, forming a peptide bond with the release of water the reaction of a fat, forming glycerol and fatty acids with the consumption of water

Answer 93

the reaction of a fat, forming glycerol and fatty acids with the consumption of water

Question 94

Which of the following large biological molecules will self-assemble into a bilayer when mixed with water? cellulose triacylglycerols proteins phospholipids

Answer 94

Phospholipids

Question 95

How will brief heating (to 95°C) affect macromolecular structures in aqueous solution? Unsaturated fatty acid tails will become saturated. Proteins will unfold (denature). Proteins will hydrolyze into amino acids. Starch will hydrolyze into monomeric sugars.

Answer 95

Proteins will unfold ( denature)

Question 96

A nucleotide is composed of a nitrogenous base and a pentose sugar. a nitrogenous base, a phosphate group, and a pentose sugar. a nitrogenous base and a phosphate group. a nitrogenous base, a phosphate group, a pentose sugar, and an amino acid.

Answer 96

a nitrogenous base, a phosphate group, and a pentose sugar

Question 97

If a DNA sample were composed of 15% adenine, what would be the percentage of guanine? 15 30 35 50

Answer 97

35

Question 98

The difference between the sugar in DNA and the sugar in RNA is that the sugar in DNA is in the α configuration and the sugar in RNA is in the β configuration. is a six-carbon sugar and the sugar in RNA is a five-carbon sugar. contains one less oxygen atom than the sugar in RNA. is a five-carbon sugar and the sugar in RNA is a six-carbon sugar.

Answer 98

contains one less oxygen atom than the sugar in RNA

Question 99

There are four levels of protein structure. These figures show primary, secondary, tertiary, and quaternary protein structure. Which level(s) of protein structure may be stabilized by covalent bonds? None of the levels of protein structure is stabilized by covalent bonds. Primary, tertiary and quaternary levels of protein structure Secondary level of protein structure

Answer 99

Primary, tertiary and quaternary levels of protein structure