Deck 2: The Chemistry of the Cell

Question 1

The moon lacks life and varies dramatically in temperature.If we could keep a layer of water spread on the surface of the moon,what effect would it have?

A)Physical conditions would remain the same.
B)Because water has a high heat of vaporization,the temperatures would rise to the upper extremes.
C)The temperatures would drop to the lower extremes.
D)Water would absorb and hold heat and moderate the temperature extremes.
E)Life would be possible,but it would have to withstand these extremes in temperature.

Answer 1

D

Question 2

Which of the following is not a fundamental property of carbon?

A)Carbon-containing molecules are diverse.
B)Carbon-containing molecules may form stereoisomers.
C)Carbon-containing molecules are stable.
D)Carbon has a valence of 4.
E)Carbon atoms are most likely to form ionic bonds with one another.

Answer 2

E

Question 3

Biologically,which of the following is the least important characteristic of water?

A)Water molecules are polar.
B)Water molecules form numerous hydrogen bonds.
C)Water is a good solvent.
D)Water typically contains isotopes of hydrogen.
E)Water has a temperature-stabilizing capacity.

Answer 3

D

Question 4

How do large polar and charged molecules cross biological membranes?

A)Large polar and charged molecules can't cross biological membranes.
B)Large polar and charged molecules cross biological membranes via diffusion through the hydrophilic core of the membrane.
C)Large polar and charged molecules must be hydrolyzed before they can cross a biological membrane.
D)Large polar and charged molecules cross biological membranes via transport proteins that form hydrophilic channels through the membrane.
E)Both A and C

Question 5

Which of the following is false regarding water's specific heat?

A)The specific heat of water is 1.0 calorie per gram.
B)Heat applied to water must initially break a number of hydrogen bonds.
C)Water's high specific heat has a temperature-buffering effect.
D)Water gains and loses heat more slowly than most other liquids do.
E)The specific heat of water is similar to that of most liquids.

Question 6

The term amphipathic refers to those molecules that are

A)hydrophilic.
B)hydrophobic.
C)charged at both ends but with opposite charges.
D)nonpolar at both ends.
E)charged at one end and nonpolar at the other.

Question 7

The cell membrane can be described most accurately as

A)permeable to all small molecules and ions.
B)impermeable to larger molecules independent of their chemical characteristics.
C)permeable to some molecules and impermeable to others.
D)impermeable to all polar molecules.
E)permeable to all molecules except water.

Question 8

Why is a selectively permeable membrane so important to living things?

A)It allows cells to attach to adjacent tissues.
B)It provides a good barrier between the inside and outside of the cell.
C)Proteins will avoid a selectively permeable membrane.
D)The membrane may absorb several times its weight in cholesterol.
E)All of the above.

Question 9

Detergents are best able to dissolve oil from fabric or dishes during washing because

A)the positively charged end is associated with water molecules,while the negatively charged end interacts with the oil droplet.
B)the negatively charged end is associated with water molecules,while the positively charged end interacts with the oil droplet.
C)the nonpolar end is associated with water molecules,while the charged end interacts with the oil droplet.
D)the charged end is associated with water molecules,while the nonpolar end interacts with the oil droplet.
E)detergents are nonpolar,they increase the size of the oil droplet,allowing the water to be more effective at removing the oil.

Question 10

While synthesizing a new blue pigment,a chemist notices that the new compound accumulates between an aqueous (water)environment and a hydrophobic environment.When added to a mixture of oil and water,the pigment creates a blue ring around the droplets of oil.Which of the following statements best describes this new pigment?

A)The pigment is a polar molecule and is forming hydrogen bonds with both the water and oil molecules.
B)The pigment is hydrophilic and will not form hydrophobic bonds with the oil.
C)The pigment is amphipathic,having polar and nonpolar regions.
D)The pigment is neither polar nor nonpolar; it is apolar.
E)The pigment is probably hydrophobic and is attempting to bond with the oil.

Question 11

Ribose has five carbon atoms,of which three are asymmetric.What is the maximum number of stereoisomers that may exist for ribose?

A)2
B)4
C)6
D)8
E)10

Question 12

Carbon can form ________ covalent bonds.

A)single
B)double
C)triple
D)single and double
E)single,double,and triple

Question 13

Why do ionic substances such as NaCl dissolve so readily in water?

A)NaCl is a very dry powder,and the water is able to soak into the salt.
B)The sodium ions repel the negative end of the water molecule.
C)Water molecules form spheres of hydration around the sodium and chloride ions.
D)The charged ends of the water molecules are able to surround the oppositely charged salt ion.
E)Both C and D

Question 14

Which of the following is a unit of energy?

A)calorie
B)bond
C)watt
D)mole
E)both A and B

Question 15

While fishing,you make the following observations: a.Water spiders appear to be able walk on the surface of the water.
B)Flat rocks may be made to skip across the water.
Which of the following properties of water can explain these observations?

A)Water is an excellent solvent.
B)Water molecules are heavy.
C)Water molecules are cohesive.
D)Water molecules are polar.
E)Both B and C

Question 16

Which of the following statements concerning hydrocarbons is false?

A)Octane is a hydrocarbon.
B)Hydrocarbons are insoluble in water.
C)Hydrocarbons are the most abundant organic molecules in cells.
D)Only hydrogen atoms are used to complete the valence requirements of carbon in hydrocarbons.
E)Phospholipids have hydrocarbon tails.

Question 17

Which of the following is true of an asymmetric carbon atom?

A)Only amino acids have asymmetric carbon atoms.
B)A carbon with hydrogens attached at two locations is usually asymmetric.
C)A carbon with hydrogens attached at three locations is usually asymmetric.
D)Asymmetric carbon atoms create stereoisomers.
E)Molecules may have only one asymmetric carbon atom.

Question 18

In the lab,you choose to design a simple experiment to distinguish between hydrophilic and hydrophobic substances.You start by adding equal amounts of vinegar and oil to a container.After shaking,the vinegar and oil levels separate,based upon polarity and density.To this you add glucose and sodium citrate and shake again.Where do you expect to find the glucose and sodium citrate in greatest quantities?

A)Both will concentrate in the oil layer.
B)The glucose will concentrate in the vinegar,sodium citrate in the oil.
C)Both will concentrate in the vinegar layer.
D)Sodium citrate will concentrate in the vinegar,glucose in the oil.
E)Both will be uniform throughout both layers.

Question 19

Which of the following molecules is most likely to cross the cell membrane directly by passive diffusion?

A)Na⁺
B)fructose (a sugar)
C)a steroid hormone (a hydrocarbon)
D)insulin (a polypeptide)
E)fructose and insulin

Question 20

What atom forms the backbone of almost all biological molecules?

A)hydrogen
B)nitrogen
C)carbon
D)sulfur
E)phosphorus

Question 21

Which of the following is a structural polysaccharide?

A)glycogen
B)fructose
C)cellulose
D)starch
E)All of the above are structural polysaccharides.

Question 22

Which of the following is an informational macromolecule?

A)DNA
B)ATP
C)starch
D)glycogen
E)polypeptide

Question 23

Which of the following is not an activated monomer?

A)adenosine triphosphate
B)glucose-6-phosphate
C)aminoacyl tRNA
D)amino acid
E)uracil triphosphate

Question 24

A hypothetical automobile has 100 parts that are to be assembled by four workers.During the car's assembly,each worker constructs 25 parts individually,and then the 4 resulting components are assembled together.The manner in which the car was assembled is much like which cellular strategy?

A)hierarchical assembly
B)renaturation
C)electrostatic assembly
D)self-assembly
E)assisted self-assembly

Question 25

Which of the following statements about self-assembly is false?

A)The noncovalent interactions that drive supramolecular assembly processes are similar to those that dictate the folding of individual protein molecules.
B)Self-assembly only occurs in structures composed of protein.
C)Self-assembly requires specific chemical conditions.
D)Molecular chaperones are sometimes required for the proper folding and assembly of complex proteins.
E)All of the above.

Question 26

Which of the following sequences correctly lists the hierarchical nature of cellular structures,from smallest to largest?

A)organic molecules,supramolecular structures,macromolecules,organelles,cells
B)organelles,organic molecules,supramolecular structures,macromolecules,cells
C)organic molecules,macromolecules,organelles,supramolecular structures,cells
D)organic molecules,macromolecules,supramolecular structures,organelles,cells
E)macromolecules,organic molecules,supramolecular structures,organelles,cells

Question 27

Monomers are removed from polymers by ________ reactions.

A)condensation
B)hydrolysis
C)neutralization
D)substitution
E)redox

Question 28

Which one of the following biological polymers is mismatched with its monomer?

A)DNA - nucleotide
B)enzyme - amino acid
C)chitin - monosaccharide
D)protein - amino acid
E)cellulose - amino acid

Question 29

Which of the following is important in protein folding after the formation of a polypeptide?

A)hydrogen bonding
B)ionic bonding
C)van der Waals interactions
D)hydrophobic interactions
E)hydrogen bonding,ionic bonding,van de Waals interactions,and hydrophobic interactions.

Question 30

Which of the following biomolecules are long polymers of repeating monomers?

A)polysaccharides
B)nucleic acids
C)proteins
D)lipids
E)polysaccharides,nucleic acids,and proteins

Question 31

Which of the following molecules is involved with assisted assembly?

A)water molecules
B)helper proteins
C)molecular chaperones
D)tobacco mosaic viruses
E)none of the above

Question 32

Ionic bonds are important in biological structures.Which of the following pairs of molecules would form an ionic bond?

A)two water molecules
B)two amino acids with oppositely charged functional groups
C)two different stereoisomers of the same sugar
D)two phospholipids
E)a water molecule and a lipid

Question 33

What inorganic precursors are needed to synthesize proteins?

A)carbon,water,and oxygen
B)carbon,water,oxygen,and phosphate
C)carbon,water,oxygen,nitrogen,and phosphate
D)carbon,water,oxygen,nitrogen,and sulfur
E)carbon,water,oxygen,sodium,and phosphate

Question 34

Which of the following macromolecules is insoluble in water?

A)lipids
B)sugars
C)amino acids
D)disaccharides
E)nucleic acids

Question 35

Self-assembly can be used for which of the following applications?

A)nanotechnology
B)quantum computing
C)biosensors
D)drug delivery systems
E)all of these

Question 36

An enzyme synthesized in the laboratory is found to have little activity when compared to the enzyme extracted from cell culture.Both enzymes were examined and have identical amino acid composition.What is the best explanation for the lack of activity of the synthesized enzyme?

A)The van der Waals radius was altered during laboratory synthesis.
B)The synthetic enzyme was not made of amino acids.
C)The ATP required for self-assembly was present in the cell extract but not in the laboratory synthesis.
D)Denaturation of the synthesized enzyme was not complete.
E)The synthesized enzyme was not folded correctly because molecular chaperones were not present.

Question 37

All of the following are common functional groups found in biological molecules except

A)phosphate groups.
B)carbonyl groups.
C)amino groups.
D)sulfhydryl groups.
E)butyl groups.

Question 38

Which of the following statements about the polymerization of macromolecules is false?

A)Often the energy needed for polymerization is supplied by ATP.
B)The polymer chain usually has two different ends.
C)Water is added to join the monomers of the macromolecules.
D)A monomer is usually activated by the coupling of the monomer to a carrier.
E)Macromolecules are synthesized by the stepwise addition of monomers.

Question 39

Self-assembly of some structures may depend on

A)the size of the monomers.
B)the presence of lipids in the cytosol.
C)information supplied by preexisting structures.
D)the time associated with forming noncovalent interactions.
E)all of the above.

Question 40

The hierarchical nature of cellular structure is accurately illustrated in which of the following lists of substances (from smallest to largest)?

A)nucleotides,chromosome,DNA,nucleus,cell
B)cellulose,glucose,cell wall,cell
C)nucleotides,nucleus,DNA,chromosome,cell
D)nucleotides,DNA,chromosome,nucleus,cell
E)protein,membrane,amino acids,chloroplast,cell

Question 41

________ aid in the assembly of some biomolecules.

Question 42

As a protein is being synthesized,the correct folding of the protein is aided by the movement of nonpolar amino acids toward the inner areas of the protein.How can this phenomenon be explained?

Question 43

A selectively ________ membrane is one that allows some molecules to pass through but not others.

Question 44

________ is a method used to determine the chemical structure and measure the relative abundance of individual molecules in a sample based on their mass to charge ratio.

Question 45

Macromolecules can be assembled into ________ that are components of organelles and other subcellular organelles.

Question 46

For each of the three basic macromolecules (proteins,polysaccharides,and nucleic acids),identify the monomer,its activated/carrier form,and one or two basic functions.

Question 47

In order to facilitate polymerization,monomers must be ________.

Question 48

Although energy is ________ for polymerization,most macromolecules fold into their final three-dimensional conformations ________.

Question 49

The cell membrane is composed of a bilayer of ________.These molecules have regions that are polar and nonpolar and are therefore ________.

Question 50

________ and ________ groups are negatively charged functional groups of carbon,whereas the ________ group is a positively charged functional group.

Question 51

Single covalent carbon-carbon bonds have a bond energy of 83 kcal/mol while visible light from the sun has 40-70 kcal of energy per mole of photons.Why is this property of carbon-carbon bonds important for life on earth? Based on this observation,how could the degradation of the earth's atmosphere and an increase in high-energy ultraviolet radiation affect life on earth?

Question 52

Describe how the amphipathic nature of phospholipids leads to the formation of the phospholipid bilayer organization observed in membrane structure.Based upon this information,how would you design a drug delivery system to cross the cell membrane?

Question 53

TMV,or ________,is a rodlike particle with a genome of ________ and a ________ consisting of 2130 copies of a single polypeptide.

Question 54

Polymers are synthesized by ________ reactions and broken down into their constituent monomers by ________ reactions.

Question 55

Predict whether or not each of the following substances can cross a biological membrane directly.Give a reason for each prediction.
a.Nucleotides
b.Na⁺
c.Steroid hormones
d.Polar amino acids
e.Water
f.Oxygen
g.Cl^?

Question 56

________ carbon atoms allow for the formation of ________,which are mirror images of each other.

Question 57

The ________ of water is caused by the unequal sharing of electrons between oxygen and hydrogen atoms.