Cell Bio test 1

The primary structure of a protein is important for determining the secondary and tertiary structure of a protein. is the linear sequence of amino acids that are linked together by peptide bonds. is simply the order of amino acids from one end of the protein to another. is important both genetically and structurally. All of these statements are true.

All of these statements are true.

Trans fats are unsaturated fatty acids. are associated with an increased risk of heart disease. resemble saturated fatty acids in shape. are present in small amounts in meat and dairy products. All of these statements are true.

All of these statements are true.

Which of these is a difference between a DNA and an RNA molecule? DNA contains uracil, whereas RNA contains thymine. DNA is a polymer composed of nucleotides, whereas RNA is a polymer composed of nucleic acids. DNA is double-stranded, whereas RNA is single-stranded. DNA contains five-carbon sugars, whereas RNA contains six-carbon sugars. DNA contains nitrogenous bases, whereas RNA contains phosphate groups.

DNA is double-stranded, whereas RNA is single-stranded.

Suggest one advantage that DNA sequencing has over nucleic acid hybridization. -DNA sequencing makes it possible to identify species present in a sample of water, sewage, dirt, debris filtered from the air, or swab samples of organisms. -DNA sequencing makes it possible to determine the tertiary and quaternary structure of a DNA strand. -DNA sequencing can assess whether there is enough sequence complementarity to allow two strands to adhere to one another under specified conditions. -DNA sequencing makes it possible to determine the order of individual nucleotides along a DNA strand.

DNA sequencing makes it possible to determine the order of individual nucleotides along a DNA strand.

Cytological strand

Light microscopy/electron microscopy Transmission electron microscopy/scanning electron microscopy

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

True

The chemical nature of each amino acid is determined by which of the following groups? hydrogen R hydroxyl carboxyl amino

R

The term amphipathic refers to those molecules that are -hydrophobic. -hydrophilic. -nonpolar at both ends. -charged at one end and nonpolar at the other. -charged at both ends but with opposite charges.

charged at one end and nonpolar at the other.

What form of energy do all living organisms use? chemical bonds sunlight nuclear energy heat radiation

chemical bonds

Which process involves an increase in entropy of the system? formation of raindrops any spontaneous process combustion of paper freezing of ice synthesis of cellulose

combustion of paper

A spontaneous reaction will never occur. has an overall positive free energy change. is associated exclusively with homeothermic organisms. has to occur immediately. could occur but might take a very long time.

could occur but might take a very long time.

What strategy can you design to get this new drug into the cancer cells? Select all that apply. -adding nonpolar functional groups -linking with receptors of signal transduction pathway molecules -encase the drug in a lipid-soluble vesicle (liposome) -absorbtion on the surface of gold nanoparticles -attach functional groups to the drugs that have known transporters in the cell membrane -attaching cellular enzymes to the drug -attaching trans-activating transcriptional activator from RNA virus (Tobacco ringspot virus), that can translate through cellular membrane -linking with the drug inhibitors of cytoplasmic second messengers

adding nonpolar functional groups encase the drug in a lipid-soluble vesicle (liposome) attach functional groups to the drugs that have known transporters in the cell membrane

A student drops his notes, and his papers scatter. The fact that the papers scatter and do not remain neatly stacked is an illustration of an increase in entropy as predicted by the second law of thermodynamics. an increase in entropy. both the first and second laws of thermodynamics. the second law of thermodynamics. the first law of thermodynamics.

an increase in entropy as predicted by the second law of thermodynamics.

The term amphipathic describes the characteristic of some molecules that have ________. two polar regions both a polar and a nonpolar region no polar regions two nonpolar regions only a single polar region

both a polar and a nonpolar region

In eukaryotic cells DNA has the appearance of a _____. single strand letter U double helix triple helix circle

double helix

hermodynamic spontaneity can be measured by changes in __________. The reference point for whether a process will proceed in the forward or reverse direction is __________. the rate of a reaction; equilibrium entropy of the system; enthalpy entropy of the universe and free energy of the system; equilibrium enthalpy; work

entropy of the universe and free energy of the system; equilibrium

Each water molecule is joined to _____ other water molecules by ____ bonds. two ... polar covalent four ... polar covalent three ... ionic two ... hydrogen four ... hydrogen

four ... hydrogen

Reduction involves the loss of neutrons. loss of neutrons, gain of electrons, and an increase in oxidation state. gain of electrons and an increase in oxidation state. increase in oxidation state. gain of electrons.

gain of electrons.

Which of these are by-products of cellular respiration? carbon dioxide and water ATP, carbon dioxide, and water glucose, carbon dioxide, and water ATP and carbon dioxide heat, carbon dioxide, and water

heat, carbon dioxide, and water

Which of the following is not a major functional class of proteins? hereditary proteins structural proteins regulatory proteins enzymes motility proteins

hereditary proteins

To which of the following classes of sugars does glucose belong? heptose triose pentose tetrose hexose

hexose

A peptide bond is a covalent bond between the functional R groups of adjacent amino acids. is a covalent bond between the NH group of one polypeptide and the CO group of an adjacent polypeptide that holds together multimeric proteins. is a noncovalent bond that dictates the tertiary structure of a protein. is a covalent bond between adjacent glucose molecules in a peptide. is a covalent bond between the carboxyl carbon of one amino acid and the amino nitrogen of a second amino acid.

is a covalent bond between the carboxyl carbon of one amino acid and the amino nitrogen of a second amino acid.

Disulfide bonds are often found to stabilize which of the following levels of protein structure? primary, secondary, and tertiary primary secondary tertiary None of these structures involve disulfide bonds.

tertiary

Hydrogen bonding is most important in stabilizing the ________ structure of many proteins. quaternary secondary tertiary primary primary, secondary, tertiary, and quaternary

tertiary

A scientific hypothesis is __________. -the same as a theory -a test in which only specific conditions are allowed to vary -a theory that has been confirmed -a testable explanation of a natural phenomenon

testable explanation of a natural phenomenon

The steady state vital to life is possible because all cells are autotrophic. the cell continually takes up energy from the environment. all reactions are exothermic. the cell cannot convert energy from one form to another. all reactions are at equilibrium.

the cell continually takes up energy from the environment.

Fatty acids are ________; they function in the cell as ________. short chains of double-bonded carbon molecules; vitamins, cofactors, and storage lipids short chains of double-bonded carbon molecules; vitamins and cofactors four-ringed hydrocarbon molecules; key components of membranes long, unbranched hydrocarbon chains with a carboxyl group at one end; building blocks for other lipids short chains of double-bonded carbon molecules; storage lipids

long, unbranched hydrocarbon chains with a carboxyl group at one end; building blocks for other lipids

Muscle contraction is an example of which of the following types of work? concentration bioluminescent mechanical heat electrical

mechanical

Which of the following types of work involves a change in position of the cell or a cell structure? concentration bioluminescent electrical synthetic mechanical

mechanical

Which type of microscope can detect density differences and thereby see organelles in living cells? -SEM -fluorescence -TEM -phase contrast

phase contrast

Which of the following is not a steroid? estradiol aldosterone cortisol testosterone phenylalanine

phenylalanine

The nucleoside triphosphate molecules in DNA are linked together in the 5'→3' by a(n) ________ bridge. peptide phosphodiester covalent phosphate phosphatidyl

phosphodiester

Which of the following is not a polymer of numerous monomer units? an RNA molecule cellulose a polypeptide starch a phospholipid

phospholipid

The flow of energy in the biosphere begins primarily with chemotrophs. phototrophs. high-energy electrons. lightning. oxidized chemicals.

phototrophs

The unequal sharing of electrons within a water molecule makes the water molecule _____. polar hydrophobic ionic change easily from a liquid to gaseous form have a low surface tension

polar

Chemical energy is a form of _____ energy. entropic heat motion potential kinetic

potential

A negative free energy change indicates that the reactant is predominant at equilibrium. the reaction is exothermic. the reaction is not possible. the reaction is at equilibrium. energy must be added to the reaction before it can proceed.

the reaction is exothermic

You are working on a project that involves the direct observation of DNA molecules. The microscope that would give you the best information at this time would be the -digital video microscope. -fluorescent microscope. -transmission electron microscope. -light microscope. -phase-contrast microscope.

transmission electron microscope.

Photosynthesis is an important process that is performed by heterotrophs. produces oxidized products. only plants can perform. is performed by organisms living near deep-ocean thermal vents. uses water and carbon dioxide as reactants.

uses water and carbon dioxide as reactants.

In a biochemical reaction, reactants may be converted into products. The extent to which this occurs spontaneously is expressed as which of the following? Keq ΔS ΔG TΔS temperature

ΔG

If ln K′eq is positive, __________. ΔG°′ will be negative and the reaction will not proceed. ΔG°′ will be negative and the reaction will be at equilibrium. ΔG°′ will be negative and the reaction will be spontaneous. ΔG°′ will be positive and the reaction will be at equilibrium.

ΔG°′ will be negative and the reaction will be spontaneous.

Which of the following statements about the formation of polypeptides from amino acids is true? -A bond forms between the carboxyl functional group of one amino acid and the amino functional group of the other amino acid. -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. -Polypeptides form by condensation or hydrolysis reactions.

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

Which of the following is true of an asymmetric carbon atom? -A carbon with hydrogens attached at two locations is usually asymmetric. -Molecules may have only one asymmetric carbon atom. -Only amino acids have asymmetric carbon atoms. -A carbon with hydrogens attached at three locations is usually asymmetric. -Asymmetric carbon atoms create stereoisomers.

-Asymmetric carbon atoms create stereoisomers

Why is a selectively permeable membrane so important to living things? -The membrane may absorb several times its weight in cholesterol. -Proteins will avoid a selectively permeable membrane. -It allows cells to attach to adjacent tissues. -It provides a good barrier between the inside and outside of the cell. -all of the above

-It provides a good barrier between the inside and outside of the cell.

Nucleic acids are assembled in the _____ direction. 2' to 3' 1' to 5' 5' to 1' 5' to 3' 4' to 5'

5' to 3'

Ribose has five carbon atoms, of which three are asymmetric. What is the maximum number of stereoisomers that may exist for ribose? 2 4 6 8 10

8

Which of the following molecules is involved with assisted assembly? -helper proteins -water molecules -tobacco mosaic viruses -molecular chaperones -none of the above

-molecular chaperones

Which of the following is a basic principle of macromolecular assembly? -Monomers activated by ATP are added to only one end of a polymer by condensation. -Addition of monomers to the polymer involves the addition of water molecules. -Monomers are added to both ends of a polymer simultaneously. -A monomer need not be activated before being added to the polymer.

-Monomers activated by ATP are added to only one end of a polymer by condensation.

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

-Proteins

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

-The synthesized enzyme was not folded correctly because molecular chaperones were not present.

You wish to obtain a purified sample of mitochondria from lysed cells. The best way to obtain this sample would be -chromatography. -centrifugation. -both centrifugation and polyacrylamide gel electrophoresis. -agarose gel electrophoresis. -polyacrylamide gel electrophoresis.

-centrifugation.

Gregor Mendel was most influential in which field of biology? -prokaryotic transformation -cytology -biochemistry -chromatography -genetics

-genetics

To which of the following do Mendel's observations relate? -thermodynamics -ideal gas laws -diffusion -gravity -heredity

-heredity

The scientific work that established DNA, rather than protein, as the molecule of heredity was performed prior to -Antonie van Leeuwenhoek's observation of internal cell structures. -the formation of the chromosome theory of heredity. -the elucidation of the double helix structure of DNA. -Mendel's work on heredity. -the description of the enzymatic steps of glycolysis.

-the elucidation of the double helix structure of DNA.

In a chemical reaction at equilibrium, the concentration of R (the reactant) is 3.0 mol/L and the concentration of P (the product) is 0.9 mol/L. At 25∘C, what would be the Keq ? 1.0 0.3 1.5 3.0 37.5

0.3

In a nucleotide, the nitrogenous base is attached to the sugar's _____ carbon and the phosphate group is attached to the sugar's _____ carbon. 2' ... 1' 1' ... 5' 1' ... 2' 2' ... 3' 1' ... 3'

1' ... 5'

Which of the following is not a basic need of the cell? molecular building blocks information 100% efficiency chemical catalysts energy

100% efficiency

In a reversible chemical reaction at equilibrium, the concentration of X (the reactant) is 0.75 mol/L, and the concentration of Y (the product) is 2.25 mol/L. At 25°C, what would be the Keq? 0.33 37.5 1.50 1.69 3.0

3.0

Which of the following is true of a nanometer? -A nanometer is one millionth of a meter. -A nanometer is about the size of a common bacterial cell. -The nanometer is the most common measurement used in measuring whole cells. -A nanometer is equivalent to 10 Angstroms (Å). -none of the above

A nanometer is equivalent to 10 Angstroms (Å).

Imagine this futuristic scenario: Life has been discovered on Mars and shown to contain a new type of macromolecule, named marsalive. You have been hired to study this new compound and want to determine whether marsalive is a structural or an informational macromolecule. A repetitive pattern consisting of one or two different monomers would suggest a structural macromolecule. A repetitive pattern consisting of several different monomers would suggest a structural macromolecule. A random pattern consisting of several different monomers would suggest an informational macromolecule. A random pattern consisting of several different monomers would suggest a structural macromolecule.

A random pattern consisting of several different monomers would suggest an informational macromolecule. A repetitive pattern consisting of one or two different monomers would suggest a structural macromolecule.

Which of the following statements is false concerning the value ΔH? In biology, ΔH is basically the same as ΔE. A reaction with a positive ΔH value is exothermic. ΔH is the change in heat content. ΔH is the change in enthalpy. ΔH=ΔE+Δ(PV)

A reaction with a positive ΔH value is exothermic.

Based on the principle of complementary base pairing, you would expect the percentage of __________ to be equal to the percentage of __________. A; C T; C T; G A; T

A; T

Which of the following statements is false? -All cells arise from preexisting cells. -Cells come in a wide variety of sizes and shapes. -The cell is the basic unit of structure for all organisms. -All organisms consist of one or more cells. -All cells have a membrane-bound nucleus.

All cells have a membrane-bound nucleus.

Which of the following is NOT a consequence of the polar nature of water? Water has a high heat of vaporization. Water has a high surface tension. Water has a high specific heat. All of the other answer choices are consequences of the polar nature of water.

All of the other answer choices are consequences of the polar nature of water.

Many cell biologists claim that monosaccharides are older (chronologically and evolutionarily) than nucleotides. Which of the following observations supports this hypothesis? Monosaccharides are metabolized by cells to make nucleotides (i.e., glucose is metabolized by the enzymes of glycolysis to make ATP). Nucleotides have more chemically complicated structures than monosaccharides . All nucleotides contain monosaccharides. All of the other answer choices support this hypothesis.

All of the other answer choices support this hypothesis.

Which of the following statements does NOT correctly validate the three strands that compose modern cell biology? -Cellular structure arises from the combined structures of the macromolecules that compose cells. -Cellular DNA contains information about the structure and function of cellular proteins. -Mutations in the cellular DNA can compromise cellular and macromolecular structure and function. -All of the other available answer choices validate the relationships between the three strands that compose modern cell biology.

All of the other available answer choices validate the relationships between the three strands that compose modern cell biology.

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

An oxygen

________ improved the original light microscope in the late 1600s, allowing the visualization of ________. -Theodor Schwann; the internal structures of cells, such as ribosomes, nuclei, and Golgi bodies -Rudolf Virchow; collagen and muscle cells -Robert Hooke; bacteria and viruses -Robert Brown; cell structures using fluorescent antibodies -Antonie van Leeuwenhoek; sperm cells, bacteria, algae, and other protists

Antonie van Leeuwenhoek; sperm cells, bacteria, algae, and other protists

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

Carboxyl functional group

Biochemical strand

Centrifugation/ultracentrifugation Chromatography/electrophoresis

Which of the following is an informational macromolecule? glycogen starch ATP polypeptide DNA

DNA

Suggest one advantage that electrophoresis has over chromatography. -Electrophoresis separates molecules based on charge differences, thereby making it possible to separate molecules that are similar in size, shape, and density. -Electrophoresis separates molecules based on differences in solubility, thereby making it possible to separate molecules that are similar in mass and size. -Electrophoresis separates molecules based on mass differences, thereby making it possible to separate molecules that are similar in molar mass. -Electrophoresis separates molecules based on differences in chemical properties, thereby making it possible to separate molecules that undergo similar chemical reactions.

Electrophoresis separates molecules based on charge differences, thereby making it possible to separate molecules that are similar in size, shape, and density.

Which of the following accurately describes the structure of fibrous proteins? Fibrous proteins have an extensive tertiary and quaternary structure that affects the strength and elasticity of each fiber. Fibrous proteins are composed of an equal mixture of α helices and β sheets with interconnecting looped segments. Fibrous proteins are usually composed of either α helices or β sheets throughout the molecule, giving them a highly ordered, repetitive structure. Fibrous proteins have a simple primary structure and very little secondary structure, resulting in long, thin fibers. Fibrous proteins usually contain a number of different domains with different structural motifs.

Fibrous proteins are usually composed of either α helices or β sheets throughout the molecule, giving them a highly ordered, repetitive structure.

Which of the following is an application of immunofluorescence microscopy? -Visualization of the surface structures of a specimen. -Construction of three-dimensional images of structures smaller than 10 nm. -Identifying which organelle or cellular compartment contains a particular protein. -Identification of specific components of the immune -system. -Visualization of the natural fluorescence of a specimen under UV light.

Identifying which organelle or cellular compartment contains a particular protein.

Genetic strand

Nucleic acid hybridization/DNA sequencing Sequencing of a genome/bioinformatics

What is true about a process that is spontaneous at all temperatures? One possibility is that ΔH will be positive and the TΔS term will be negative. One possibility is that ΔH will be positive and the TΔS term will be positive. The reaction is at equilibrium. One possibility is that ΔH will be negative and the TΔS term will be positive.

One possibility is that ΔH will be negative and the TΔS term will be positive.

__________ trap solar energy by pigment systems and convert __________ into more complex cellular materials via __________ chemistry. Chemotrophs; oxygen; oxidation Chemotrophs; carbon dioxide and water; hydrolysis Phototrophs; oxygen; isomerization Phototrophs; carbon dioxide and water; reduction

Phototrophs; carbon dioxide and water; reduction

Two proteins associated with a rare neurodegenerative disorder have been sequenced. Protein A contains many polar amino acids with small regions containing nonpolar, hydrophobic amino acids. Protein B is rich in nonpolar, hydrophobic amino acids with only two small regions containing polar amino acids. What might this suggest about the two proteins? The two proteins may have different secondary structures. Protein A is fibrous and Protein B is globular. Protein A and Protein B are complementary parts of a supramolecular structure. Protein A is most likely and enzyme and Protein B is most likely a storage protein. Protein A may be a cytoplasmic protein and Protein B may be a membrane associate protein.

Protein A may be a cytoplasmic protein and Protein B may be a membrane associate protein.

Which of the following is true of purines? Cytosine is a purine. Purines have a double-ringed structure. Both adenine and thymine are purines. Adenine's bonding to thymine is stronger than is guanine's to cytosine. Purines bind readily to deoxyribose but not to ribose.

Purines have a double-ringed structure.

Suggest one advantage that scanning electron microscopy has over transmission electron microscopy. -Scanning electron microscopy makes it possible to only visualize cells and tissues as if in two dimensions. -Scanning electron microscopy makes it possible to only visualize cells and tissues as if in three dimensions. -Scanning electron microscopy makes it possible to visualize subcellular structures and macromolecules as if in two dimensions. -Scanning electron microscopy makes it possible to visualize subcellular structures and macromolecules as if in three dimensions.

Scanning electron microscopy makes it possible to visualize subcellular structures and macromolecules as if in three dimensions.

Suggest one advantage that bioinformatics has over sequencing of a genome. -Sequencing of a genome simply provides a large amount of data about the DNA present on a chromome, whereas bioinformatics provides a large amount of data about the DNA present in the entire genome. -Sequencing of a genome uses computer analysis to aid in understanding and interpreting those data in terms of gene numbers and expression, whereas bioinformatics simply provides a large amount of data about the DNA present in the genome. -Sequencing of a genome simply provides a large amount of data about the DNA present in the genome, whereas bioinformatics uses computer analysis to aid in understanding and interpreting those data in terms of gene numbers and expression. -Sequencing of a genome simply provides a large amount of data about the DNA present in the genome, whereas bioinformatics techniques such as image and signal processing allow extraction of useful results from small amounts of raw data.

Sequencing of a genome simply provides a large amount of data about the DNA present in the genome, whereas bioinformatics uses computer analysis to aid in understanding and interpreting those data in terms of gene numbers and expression.

How does brightfield microscopy allow images to be visualized? -Specimens are illuminated with white light. -Electrons strike the specimen being examined. -Specimens are fixed and have bright fluorescent molecules attached to them. -Specimens are viewed under phased light to improve magnification. -Specimens are illuminated with blue light to visualize internal features of cells smaller than 100 nm.

Specimens are illuminated with white light.

Which of the following statements is the most accurate reflection of native protein tertiary structure? Protein tertiary structure is present only to allow for the formation of protein quaternary structure. Protein tertiary structure is present only to allow for the formation of multiple functional domains. The protein tertiary structure results from all amino acids in a protein adopting secondary structure. Tertiary structure is the overall three-dimensional shape of a protein. It is determined by hydrogen bonds, interactions between hydrophobic R groups, ionic bonds between R groups, van der Waals interactions, and disulfide bridges.

Tertiary structure is the overall three-dimensional shape of a protein. It is determined by hydrogen bonds, interactions between hydrophobic R groups, ionic bonds between R groups, van der Waals interactions, and disulfide bridges.

Cellulose, chitin, and the polysaccharide that makes up the cell walls of many bacteria are the structural polysaccharides, whereas starch and glycogen are the main storage polysaccharides. What must be true about these two classes of polysaccharides? The alpha-glycosidic bonds of storage polysaccharides are more stable than the beta-glycosidic bonds of structural polysaccharides. The alpha-glycosidic bonds of storage polysaccharides are less stable than the beta-glycosidic bonds of structural polysaccharides. The beta-glycosidic bonds of storage polysaccharides are more stable than the alpha-glycosidic bonds of structural polysaccharides. In addition, chemical stability correlates with permanence or nonreactivity. Which of the two types of polysaccharides would be expected to remain the same for longer? The beta-glycosidic bonds of storage polysaccharides are less stable than the alpha-glycosidic bonds of structural polysaccharides.

The alpha-glycosidic bonds of storage polysaccharides are less stable than the beta-glycosidic bonds of structural polysaccharides.

Given the chemical nature of glutamate and valine, can you suggest why substitution of valine for glutamate at position 6 of the β chain would be especially deleterious? The amino acid glutamate is hydrophobic and nonionic, whereas valine is hydrophilic and ionizes at cellular pH. The amino acid glutamate is hydrophobic and ionizes at cellular pH, whereas valine is hydrophilic and nonionic. The amino acid glutamate is hydrophilic and nonionic, whereas valine is hydrophobic and ionizes at cellular pH. The amino acid glutamate is hydrophilic and ionizes at cellular pH, whereas valine is hydrophobic and nonionic.

The amino acid glutamate is hydrophilic and ionizes at cellular pH, whereas valine is hydrophobic and nonionic.

Will the contribution of ΔS to the free energy change be positive or negative? The contribution of ΔS to the free energy change will be positive for protein folding. The contribution of ΔS to the free energy change will be negative for protein folding.

The contribution of ΔS to the free energy change will be positive for protein folding.

The fourth reaction of glycolysis is the aldol cleavage of fructose-1,6-bisphosphate (F-1,6-BP) to dihydroxyacetone phosphate (DHAP) and glyceraldehyde-3-phosphate (GAP): F-1,6-BP → DHAP + GAP What about this process suggests that the forward reaction can be expected to occur based on the second law of thermodynamics? The reaction is endergonic. The process is characterized by a negative ΔH. The process results in an increase in entropy. The process is at equilibrium.

The process results in an increase in entropy.

You are researching a cytoplasmic protein associated with a nerve disorder. The native form of the enzyme appears to be globular protein; however, when a sample of the purified protein is treated with a chemical that reduces disulfide bonds, the enzymatic activity decreases dramatically and multiple globular proteins can be detected in the sample. What does this tell you about the protein? The protein is most likely composed of \alpha helices that are held together by disulfide bonds. The protein is most likely composed of multiple polypeptide chains that are held together by disulfide bonds. The protein is most likely composed of \betha sheets that are held together by disulfide bonds. The primary and secondary structure of the protein depends on disulfide bonds. The primary structure of the protein contains multiple cysteine residues that are hydrolyzed by the chemical reductant.

The protein is most likely composed of multiple polypeptide chains that are held together by disulfide bonds.

In a chemical reaction, the standard free energy change (ΔG°') is calculated to be 3.67 cal/mol. What can be said of the chemical reaction? The reaction is at equilibrium under standard conditions. The reaction goes spontaneously to the right under standard conditions. Products predominate over reactants at equilibrium under standard conditions. There can be no reaction. The reaction is not spontaneous under standard conditions.

The reaction is not spontaneous under standard conditions.

You are investigating the structure of the seeds of a newly discovered tropical plant. There is storage material inside the seed. You treat the seed with peptidase (an enzyme that breaks peptide bonds), glycoside hydrolases (an enzyme that breaks β glycosidic bonds), and amylase (an enzyme that breaks α glycosidic bonds). Only the amylase appears to dissolve the storage material in the seed. What does this tell you about the identity of the storage material? The seed contains globular proteins to store carbon and energy. The seed contains starch to store carbon and energy. The seed contains cellulose to store carbon and energy. The seed contains lipids to store carbon and energy. The seed contains fibrous proteins to store carbon and energy.

The seed contains starch to store carbon and energy.

How can two polymers consisting of the same repeating subunit have such different properties? The two polymers have very different properties because they differ in structure as a result of different molecular mass. Low molecular mass of cellulose gives it a rigid, fibrous structure not seen in starch, which has high molecular mass. The two polymers have very different properties because they differ in structure as a result of different molecular mass. High molecular mass of cellulose gives it a rigid, fibrous structure not seen in starch, which has low molecular mass. The two polymers have very different properties because they differ in structure as a result of differing 1→4 linkages between glucose monomers. The β(1→4) linkage of cellulose gives it a rigid, fibrous structure not seen in starch, which has an α(1→4) linkage between glucose monomers. The two polymers have very different properties because they differ in structure as a result of differing 1→4 linkages between glucose monomers. The α(1→4) linkage of cellulose gives it a rigid, fibrous structure not seen in starch, which has an β(1→4) linkage between fructose monomers.

The two polymers have very different properties because they differ in structure as a result of differing 1→4 linkages between glucose monomers. The β(1→4) linkage of cellulose gives it a rigid, fibrous structure not seen in starch, which has an α(1→4) linkage between glucose monomers.

Can you suggest an explanation for naturally curly hair? There is probably a genetic difference in the positioning of cysteine groups and hence in the formation of disulfide bonds. There are probably no disulfide bonds in α-keratin molecules. There is probably a genetic difference in the positioning of serine groups and hence in the formation of disulfide bonds. There are probably no disulfide bonds in β-keratin molecules.

There is probably a genetic difference in the positioning of cysteine groups and hence in the formation of disulfide bonds.

Which of the following statements are false concerning phototrophs? They capture light energy. They store energy as glucose. They provide energy for chemotrophs. They can be bacteria. They are not autotrophs.

They are not autotrophs.

Which is true of heterotrophs? They can obtain energy by consuming phototrophs. They store energy in the form of heat. They can function as autotrophs in an emergency. They capture light energy. They cannot be unicellular.

They can obtain energy by consuming phototrophs.

Suggest one advantage that ultracentrifugation has over centrifugation. -Ultracentrifugation is capable of much higher speeds and hence much greater centrifugal force than conventional centrifugation. -Ultracentrifugation allows to separate biomolecules based on their size, shape, and/or density, whereas separation in a conventional centrifugation is based on molecular mass only. -Ultracentrifugation allows to separate biomolecules with different physical properties, whereas conventional centrifugation precipitates all the biomolecules. -Ultracentrifugation allows to separate mixtures containing charged molecules, whereas conventional centrifugation separates neutral biomolecules only.

Ultracentrifugation is capable of much higher speeds and hence much greater centrifugal force than conventional centrifugation.

Which of the following statements about the polymerization of macromolecules is false? -The polymer chain usually has two different ends. -A monomer is usually activated by the coupling of the monomer to a carrier. -Macromolecules are synthesized by the stepwise addition of monomers. -Water is added to join the monomers of the -macromolecules. -Often the energy needed for polymerization is supplied by ATP.

Water is added to join the monomers of the macromolecules.

Why do ionic substances such as NaCl dissolve so readily in water? -NaCl is a very dry powder, and the water is able to soak into the salt. -The sodium ions repel the negative end of the water molecule. -Water molecules form spheres of hydration around the sodium and chloride ions. -The charged ends of the water molecules are able to surround the oppositely charged salt ion. -Water molecules form spheres of hydration around the sodium and chloride ions. Also the charged ends of the water molecules are able to surround the oppositely charged salt ion.

Water molecules form spheres of hydration around the sodium and chloride ions. Also the charged ends of the water molecules are able to surround the oppositely charged salt ion.

Is it possible that two proteins could differ at several points in their amino acid sequence and still be very similar in structure and function? Yes, if the substitutions are always of like-for-like amino acids in terms of elemental composition. No, the substitutions always essentialy change chemical properties of proteins. No, the substitutions always essentialy change elemental composition of proteins. Yes, if the substitutions are always of like-for-like amino acids in terms of chemical properties.

Yes, if the substitutions are always of like-for-like amino acids in terms of chemical properties.

A discrete, locally folded unit of protein tertiary structure usually having a specific function best describes __________. quaternary structure a complex a motif a domain

a domain

The components of a nucleotide are a carboxyl group, an amine group, and a variable R group. a three-carbon alcohol with a hydroxyl group on each carbon and three fatty acids. a six-carbon sugar, an ester linkage, and a four-ringed hydrocarbon. a five-carbon sugar, a phosphate group, and a nitrogen-containing aromatic base. two six-carbon sugars attached with an α(1→4) glycosidic bond.

a five-carbon sugar, a phosphate group, and a nitrogen-containing aromatic base.

Which of these is exhibiting kinetic energy? the high-energy phosphate bonds of a molecule of ATP an archer with a flexed bow a rock on a mountain ledge a person sitting on a couch while watching TV a space station orbiting Earth

a space station orbiting Earth

Which of the following is a phototroph? a mushroom soil bacterium an earthworm a person a tree

a tree

Which of the following is closest to a micrometer in size? -the width of a strand of DNA -the length of a plant cell -the length of a chicken egg -a typical prokaryotic cell -the size of a ribosome

a typical prokaryotic cell

Energy is important to life forms because all life forms require a continuous supply of energy. energy is required to do work. all life forms require a continuous supply of energy, energy is required to do work, and energy is required to make specific alterations in the cell. energy is required to make specific alterations in the cell. all life forms require a continuous supply of energy and energy is required to do work.

all life forms require a continuous supply of energy, energy is required to do work, and energy is required to make specific alterations in the cell.

From the equation ΔG = ΔH − TΔS, it can be concluded that __________. increasing the change in entropy of a system will increase the probability of spontaneous change the capacity of a system to perform useful work is related to the total free energy of the system increasing the temperature of a system will increase the probability of spontaneous change all of the other answer choices are true

all of the other answer choices are true

Which of the following functional groups and compounds is polar, contains one or more electronegative atoms in a bond, and can reversibly ionize within the physiological pH range? carbonyl/ketone hydrocarbon amine alcohol (--OH)

amine

Which of the following is not an activated monomer? aminoacyl tRNA glucose-6-phosphate amino acid adenosine triphosphate uracil triphosphate

amino acid

Proteins are polymers of _____. amino acids hydrocarbons glycerol CH2O units nucleotides

amino acids

Which of the following has the greatest number of glycosidic bonds? triacylglycerol DNA glucose amylose vitamin A

amylose

Bioenergetics can be simply defined as the application of biological principles to physics. applied thermodynamics. the units in which energy is expressed. a subdivision of biology. holding constant the variables in the universe.

applied thermodynamics.

Cells maintain themselves in a steady state, with most of their reactions __________. Cells accomplish this by __________. having products and reactants that are the same; violating the second law of thermodynamics having K′eq near 1; doing no useful work far from thermodynamic equilibrium; having a continuous input of matter and energy from their surroundings relying on an increase in entropy to create a negative ΔG; maintaining a constant temperature

ar from thermodynamic equilibrium; having a continuous input of matter and energy from their surroundings

Cell biology emerged from which of the following fields of biology? -biochemistry -cytology and biochemistry -cytology -genetics -biochemistry, cytology, and genetics

biochemistry, cytology, and genetics

Fireflies have the ability to convert the energy in ATP to light. Which of the following types of work is performed by the firefly? heat concentration electrical mechanical bioluminescent

bioluminescent

Which type of microscopy enhances and amplifies slight changes in the phase of transmitted light? -digital video microscopy -both differential interference contrast microscopy and phase-contrast microscopy -fluorescence microscopy -differential interference contrast microscopy -phase-contrast microscopy

both differential interference contrast microscopy and phase-contrast microscopy

Early microscopes did not allow clear visualization of cells because they were limited by -resolution. -number of kernels. -refraction. -magnification. -both magnification and resolution.

both magnification and resolution.

Cellulose belongs to which of the following groups of macromolecules? proteins nucleic acids carbohydrates lipids none of these

carbohydrates

What atom forms the backbone of almost all biological molecules? sulfur phosphorus carbon hydrogen nitrogen

carbon

In your body, what process converts the chemical energy found in glucose into the chemical energy found in ATP? cellular respiration digestion potentiation anabolism redox

cellular respiration

Which of the following is a structural polysaccharide? cellulose starch glycogen fructose All of the above are structural polysaccharides.

cellulose

Which one of the following biological polymers is mismatched with its monomer? -protein - amino acid -DNA - nucleotide -cellulose - amino acid -chitin - monosaccharide -enzyme - amino acid

cellulose - amino acid

Nerve impulses travel along neurons by the opening of channels that allow sodium ions to flow inward, followed by an outward flow of potassium ions. In order to ensure that the impulse may be produced at any time, sodium is actively transported out of the cell and potassium is transported into the cell by the sodium/potassium pump. Which of the following types of work is performed by the sodium/potassium pump? synthetic electrical concentration mechanical bioluminescent

concentration

Which of the following types of light microscopy improves the resolution of thick specimens by illuminating one plane of the specimen at a time? -phase-contrast microscopy -confocal microscopy -brightfield microscopy -fluorescence microscopy -differential interference contrast microscopy

confocal microscopy

Robert Hooke coined the term cell when studying thin slices of cork. These ________ were the first cells observed because ________. -dead animal cells; they were immobile and did not need to be fixed before viewing -compartments; they were actually the result of multiple cells that had merged and died to form large compartments that were easy to view -"little rooms"; they were 100 nm in diameter, much larger than most plant cells -immune cells; they produce antibodies that embed in the cell membrane to make it visible -dead plant cells; the thick cells walls did not require high resolution or magnification to view

dead plant cells; the thick cells walls did not require high resolution or magnification to view

Bioluminescence can be driven by chemical oxidation. ATP. either ATP or chemical oxidation. mushrooms. green fluorescent protein.

either ATP or chemical oxidation.

Which type of microscopy has the greatest resolving power? -confocal scanning microscopy -digital video microscopy -electron microscopy -phase-contrast microscopy -fluorescence microscopy

electron microscopy

The tendency of an atom to pull electrons toward itself is referred to as its _____. covalency ionic potential polarity electronegativity tonicity

electronegativity

Which of the following biochemical techniques uses an electrical field to separate macromolecules based on their mobility through a semisolid gel? -mass spectrometry. -ultracentrifugation. -light microscopy. -electrophoresis. -chromatography.

electrophoresis.

"Conservation of energy" refers to the fact that _____. if you conserve energy you will not be as tired the entropy of the universe is always increasing energy cannot be created or destroyed but can be converted from one form to another no chemical reaction is 100 percent efficient the net amount of disorder is always increasing

energy cannot be created or destroyed but can be converted from one form to another

Energy-requiring reactions can occur in biological systems because they can be coupled with reactions that are unlikely. endergonic. not spontaneous. exergonic. spontaneous and endergonic.

exergonic.

Life is possible because living cells maintain themselves in a steady state, with most of their reactions far from thermodynamic equilibrium. conserving matter. conserving energy and matter. conserving energy. near thermodynamic equilibrium.

far from thermodynamic equilibrium.

Animals that regulate their body temperature independently of the environment are called poikilotherms. homeotherms. heterotherms. biotherms. abiotherms.

homeotherms

Which of the following is important in protein folding after the formation of a polypeptide? -hydrogen bonding, ionic bonding, van de Waals interactions, and hydrophobic interactions. -ionic bonding -hydrophobic interactions -hydrogen bonding -van der Waals interactions

hydrogen bonding, ionic bonding, van de Waals interactions, and hydrophobic interactions.

The secondary structure of a protein results from _____. peptide bonds bonds between sulfur atoms hydrogen bonds hydrophobic interactions ionic bonds

hydrogen bonds

The two strands of DNA are held together by ________; thus ________. covalent bonds; double-stranded DNA is very stable at a range of temperatures hydrogen bonds; double-stranded DNA separates into two separate strands at high temperatures antiparallel bonds; double-stranded DNA is amphipathic ionic bonds; double-stranded DNA separates into two separate strands in water hydrophobic interactions; double-stranded DNA separates into two separate strands when dissolved in a hydrocarbon (hydrophobic) solvent

hydrogen bonds; double-stranded DNA separates into two separate strands at high temperatures

Which of the following contributes to the stability of the DNA double helix? hydrophobic interactions between aromatic bases at the center of the double helix hydrogen bonding between the phosphate and sugar groups in the backbone of the double helix hydrophobic interactions between aromatic bases at the center of the double helix and ionic bonds between the negatively charged phosphate groups and the positively charged pyrimidine bases ionic bonds between the negatively charged phosphate groups and the positively charged pyrimidine bases. covalent bonding between complementary purine and pyrimidine bases.

hydrophobic interactions between aromatic bases at the center of the double helix

What are the three general types of amino acids? α helices, β sheets, and looped segments covalent, noncovalent, and van der Waals forces positive, negative, and noncharged hydrophobic, polar (noncharged), polar (charged) acidic, basic, and neutral

hydrophobic, polar (noncharged), polar (charged)

Which of the following is an endothermic process? neutralization reactions of the addition of strong acid directly to a strong base adding a strong acid directly to water combustion reactions oxidation of metals ice melting

ice melting

RNA and DNA differ in that RNA contains ribose and DNA contains deoxyribose. in that RNA contains nucleosides and DNA contains nucleotides. in that RNA contains uracil and DNA contains thymine. in that RNA contains ribose and uracil, and DNA contains deoxyribose and thymine. All of these are correct.

in that RNA contains ribose and uracil, and DNA contains deoxyribose and thymine.

Self-assembly of some structures may depend on -the size of the monomers. -the presence of lipids in the cytosol. -information supplied by preexisting structures. -the time associated with forming noncovalent interactions. -all of the above.

information supplied by preexisting structures.

Phosphatidyl ethanolamine is a major class of membrane phospholipid. Therefore, it is __________. -very soluble in water -made up of a polar head and two nonpolar tails -made up of a nonpolar head and two polar tails -completely hydrophobic

made up of a polar head and two nonpolar tails

DNA is composed of building blocks called _____. nucleic acids Gs nucleotides adenines amino acids

nucleic acids

Consider the following three types of macromolecules: proteins, nucleic acids, and polysaccharides. Which of the following answer choices ranks these macromolecules in order of increasing variability of function for a cell (smallest number of functions to largest number of functions)? -nucleic acids, proteins, polysaccharides -nucleic acids, polysaccharides, proteins -proteins, polysaccharides, nucleic acids -polysaccharides, proteins, nucleic acids

nucleic acids, polysaccharides, proteins

Which monomers make up RNA? Amino acids Simple sugars Nucleotides Polymers

nucleotides

Which of the following pairs correctly matches the monomer with its polymer? amino acids; polysaccharides nucleotides; nucleic acids peptides; proteins terpenes; nucleic acids glucose; proteins

nucleotides; nucleic acids

Which organelle stores most of the DNA in plant and animal cells? -nucleus -mitochondrion -Golgi complex -chloroplast -lysosome

nucleus

Imagine this futuristic scenario: Life has been discovered on Mars and shown to contain a new type of macromolecule, named marsalive. You have been hired to study this new compound and want to determine whether marsalive is a structural or an informational macromolecule. What features would you look for? the physical properties of monomers the frequency of occurrence of the most stable form number of different kinds of monomers the energy of bonding between monomers the elemental composition of monomers the arrangement of monomers

number of different kinds of monomers the arrangement of monomers

Oxidation involves the removal of oxygen atoms from a molecule. occurs when oxygen atoms are added to a molecule and energy released. is rare in biological reactions. occurs when an atom accepts electrons. is endothermic.

occurs when oxygen atoms are added to a molecule and energy released.

What type of bond joins the monomers in a protein's primary structure? hydrogen S - S ionic hydrophobic peptide

peptide

Tertiary structure is NOT directly dependent on _____. hydrophobic interactions ionic bonds peptide bonds bonds between sulfur atoms hydrogen bonds

peptide bonds

Part A Part complete Which of the following is smallest? -ribosome -virus -mitochondrion -prokaryote -protein

protein

When ΔG′=0 in a chemical reaction, under standard conditions, the reaction is spontaneous to the left. reactants and products are at equilibrium; no work can be done; no energy required. reactants and products are at equilibrium. work can be done; energy is required. no work can be done; no energy is required.

reactants and products are at equilibrium; no work can be done; no energy required.

When the ΔG°' of a chemical reaction is positive (K'eq < 1.0) under standard conditions, the reaction is spontaneous to the right. reactants and products are at equilibrium. the reaction is exothermic. work can be done under these conditions. reactants predominate over products.

reactants predominate over products.

Choose amino acids that would be much less likely than valine to cause impairment of hemoglobin function if substituted for the glutamate at position 6 of the β chain. tyrosine, cysteine, aspartate, isoleucine threonine, tyrosine, cysteine, isoleucine serine, threonine, tyrosine, isoleucine serine, threonine, tyrosine, cysteine, aspartate

serine, threonine, tyrosine, cysteine, aspartate

Cholesterol is a ________, which ________. steroid; is a component of eukaryotic membranes and is the basis for many animal and plant hormones steroid; is the basis for many animal and plant hormones fatty acid; functions in energy storage steroid; is a component of eukaryotic membranes terpene; is the basis for many animal and plant vitamins

steroid; is a component of eukaryotic membranes and is the basis for many animal and plant hormones

A general trend in the structure of many biomolecules is that the order and bonding of monomers form the basis for the secondary and tertiary structure of the polymer. that four different monomers form the basis for the functional and structural properties of each polymer. that they are all soluble in water independent of the size of the polymer. that each class of biomolecule forms one type of secondary structure independent of the order of the monomers in the polymer. that each class of biomolecule can form either fibrous or globular conformations depending on the chemical conditions inside the cell.

that the order and bonding of monomers form the basis for the secondary and tertiary structure of the polymer.

The ΔG for the oxidation of glucose to carbon dioxide and water is −686 kcal/mol. The ΔG for the synthesis of glucose from carbon dioxide and water is +686 kcal/mol. This is proof of __________. the first law of thermodynamics the irreversibility of chemical reactions the fact that the biosphere is a closed system the second law of thermodynamics

the first law of thermodynamics

"The total amount of mass-energy in the universe is constant," is a statement of the second law of thermodynamics. thermodynamic spontaneity. entropy. enthalpy. the first law of thermodynamics.

the first law of thermodynamics.

In a DNA double helix an adenine of one strand always pairs with a(n) _____ of the complementary strand, and a guanine of one strand always pairs with a(n) _____ of the complementary strand. guanine ... adenine thymine ... cytosine cytosine ... thymine cytosine ... uracil uracil ... cytosine

thymine ... cytosine

In a DNA double helix an adenine of one strand always pairs with a(n) _____ of the complementary strand, and a guanine of one strand always pairs with a(n) _____ of the complementary strand. uracil ... cytosine thymine ... cytosine cytosine ... uracil guanine ... adenine cytosine ... thymine

thymine ... cytosine

The function of triglycerides is to store energy. to form semipermeable membranes. to transport substances in and out of cells. store information. to form semipermeable membranes and to transport substances in and out of cells.

to store energy.

Which of the following is found exclusively in RNA? thymine uracil cytosine adenine guanine

uracil