Intro to cell bio TEST 1
Write the complementary sequence for the following DNA sequence, in order from 3' to 5': 5′−CGATATTGAGCTAAGCTT−3′
3′− GCTATAACTCGATTCGAA −5′
A food company hydrogenated a barrel of vegetable oil. The treatment ...... (Choose all that apply) A- raised the melting point of the fat B- made the fat less fluid C- put more bends (kinks) in the fat tails D- made the fat less saturated E- lengthened the fat tails
A B
A function of cholesterol that does not harm health is its role _____. A- as a component of animal cell membranes B- in calcium and phosphate metabolism C- as the primary female sex hormone D- the most abundant male sex hormone E- All of cholesterol's effects cause the body harm.
A- as a component of animal cell membranes
The molecular formula for glucose is C6H12O6. What would be the molecular formula for a polymer made by linking ten glucose molecules together by dehydration reactions? A-C60H102O51 B-C6H12O6 C-C60H100O50 D-C60H120O60 E-C60H111O51
A-C60H102O51
Cells of which organisms lack cell walls? A-animals B-bacteria C-plants D-fungi
A-animals
Which functional group is commonly called an acid group and donates H ions to solutions at biolgical pH? A-carboxyl B-hydroxyl C-aldehyde D-amino
A-carboxyl
Which of the following polysaccharides composes the cell wall of fungi and the exoskeleton of insects? A-chitin B-starch C-peptidoglycan D-glycogen
A-chitin
Which of these does NOT contain a structural protein? A-ovalbumin B-tendons C-ligaments D-spider silk E-muscles
A-ovalbumin
Which of the following is a characteristic feature of a carrier protein in a plasma membrane? A- It is a peripheral membrane protein. B- It exhibits a specificity for a particular type of molecule. C- It has no hydrophobic regions. D- It requires the expenditure of cellular energy to function. E- It works against diffusion.
B- It exhibits a specificity for a particular type of molecule.
Which fact is most important in causing phospholipids to behave as they do in water? A- Phosphate groups can bind together. B- Water molecules make hydrogen bonds. C- Hydrocarbons attract one another. D- Nonpolar groups repel water. E- Hydrogen is more electronegative than oxygen.
B- Water molecules make hydrogen bonds.
Which of the following allows water to move much faster across cell membranes? A- the sodium-potassium pump B- aquaporins C- the hydrophobic interior of a cell membrane D- ATP E- peripheral proteins
B- aquaporins
Decreasing the saturation of the fatty acid chains on a particular type of phospholipid would result in the formation of ________ A- a bilayer with decreased permeability to CO2 B- more fluid bilayers C- glycerol D- cholesterol
B- more fluid bilayers
From its atomic number of 15, it is possible to predict that the phosphorus atom has _____. A-8 electrons in its outermost electron shell B-15 protons and 15 electrons C-15 neutrons and 15 protons D-30 neutrons E-5 neutrons, 5 protons, and 5 electrons
B-15 protons and 15 electrons
If a DNA double helix contains 28% T nucleotides, then what is the percentage of A nucleotides? A-44% B-28% C-22% D-56%
B-28%
Which part of an amino acid is always acidic? A-Side chain ("R group") B-Carboxyl functional group C-Amino functional group D-None of the above
B-Carboxyl functional group
Which of the following complex carbohydrates is listed with its correct function? A-Starch: primary energy-storage molecule in animals B-Cellulose: structural component of plant cell walls C-Chitin: constituent of bacterial cell walls D-Amylose: main component of plant starch
B-Cellulose: structural component of plant cell walls
Which linking verb phrase would best connect the hydrogen bonds term in the map to one of the other terms? A-Hydrogen bonds only form between atoms that are engaged in covalent bonds that are nonpolar. B-Hydrogen bonds only form between atoms that are engaged in covalent bonds that are polar. C-Hydrogen bonds only form between atoms that have high valence. SubmitMy AnswersGive Up
B-Hydrogen bonds only form between atoms that are engaged in covalent bonds that are polar.
Nonpolar amino acid residues are typically found in the interior of globular proteins like trypsin. Which chemical force is most directly responsible? A-Ionic bonding B-Hydrophobic interactions C-Covalent bonding D-Tertiary structure
B-Hydrophobic interactions
Which feature is shared by all monosaccharides? A-They are all pentoses. B-In their linear forms, they all contain a carbonyl and several hydroxyl functional groups. C-They all contain more than one sugar. D-In their linear forms, that all contain a carboxyl and severl hydroxyl functional groups.
B-In their linear forms, they all contain a carbonyl and several hydroxyl functional groups.
Many RNA molecules exhibit tertiary structure, whereas most DNA molecules do not. Which statement best explains why? A-RNA has secondary structure but DNA does not, so only RNA can have tertiary structure. B-RNA's secondary structure can leave bases free for interactions that produce tertiary structure; DNA's secondary structure generally does not. C-RNA contains uracil (U) while DNA contains thymine (T), so only RNA can have tertiary structure. D-RNA has an extra oxygen atom in its backbone, which makes RNA much less stable than DNA.
B-RNA's secondary structure can leave bases free for interactions that produce tertiary structure; DNA's secondary structure generally does not.
Which statement accurately summarizes a difference between ribonucleotides and deoxyribonucleotides? A-Ribonucleotides have a hydroxyl group bonded to their 3' carbon; deoxyribonucleotides have an H at the same location. B-Ribonucleotides have a hydroxyl group bonded to their 2' carbon; deoxyribonucleotides have an H at the same location. C-Ribonucleotides contain only purines; deoxyribonucleotides contain only pyrimidines. D-In ribonucleotides, the sugar is a pentose; deoxyribonucleotides have a hexose.
B-Ribonucleotides have a hydroxyl group bonded to their 2' carbon; deoxyribonucleotides have an H at the same location.
_________ describes the alpha-helices and beta-sheets that are formed by hydrogen bonding between backbone atoms located near each other in the polypeptide chain. A-Primary structure B-Secondary structure C-Tertiary structure D-Quaternary structure
B-Secondary structure
Which of the following is true of protein folding? A-Misfolded proteins can still function correctly. B-Some proteins can fold spontaneously. C-Once proteins fold, their structure doesn't change. D-Correct folding is aided by high temperatures.
B-Some proteins can fold spontaneously.
How would you expect the structure of ribozymes in organisms that grow in very hot environments, such as hot springs or deep-sea vents, to differ from those in organisms that grow in cooler environments? A-These ribozymes would have more hairpin secondary structures. B-The hairpins would have more G's and C's in the primary structure. C-The hairpins would have more A's and U's in the primary structure. D-These ribozymes would exhibit no tertiary structure.
B-The hairpins would have more G's and C's in the primary structure.
The partial negative charge at one end of a water molecule is attracted to the partial positive charge of another water molecule. What is this attraction called? A-a van der Waals interaction B-a hydrogen bond C-an ionic bond D-a hydrophilic bond E-a covalent bond
B-a hydrogen bond
A glycosidic linkage is analogous to which of the following in proteins? A-a disulfide bond B-a peptide bond C-an amino group D-a β-pleated sheet
B-a peptide bond
Which functional group typically acts as a base at biological pH? A-carboxyl B-amino C-aldehyde D-hydroxyl
B-amino
By convention, biologists write the sequence of amino acids in a polypeptide in which direction? A-carboxy- to amino-terminus B-amino- to carboxy-terminus C-charged residues to uncharged residues D-polar residues to nonpolar residues
B-amino- to carboxy-terminus
A simple sugar is composed of equal parts carbon and water, which gave rise to the general name of any sugar as a___________ A-polysaccharide B-carbohydrate C-disaccharide D-monosaccharide
B-carbohydrate
A DNA molecule consists of two nucleotide strands twisted into a A-triple helix. B-double helix. C-straight chain. D-folded chain.
B-double helix.
Which of the following classes of macromolecules always contains a carbohydrate portion? A-proteins B-nucleic acids C-lipids D-water
B-nucleic acids
Which of the following meals would have the highest amount of carbohydrates? A-steak and mushrooms B-spaghetti C-bacon and eggs D-chicken breast
B-spaghetti
What component of amino acid structure varies among different amino acids? A-the long carbon-hydrogen tails of the molecule B-the components of the R-group C-the presence of a central C atom D-the glycerol molecule that forms the backbone of the amino acid
B-the components of the R-group
The partial negative charge in a molecule of water occurs because _____. A-the oxygen atom forms hybrid orbitals that distribute electrons unequally around the oxygen nucleus B-the electrons shared between the oxygen and hydrogen atoms spend more time around the oxygen atom nucleus than around the hydrogen atom nucleus C-the oxygen atom has two pairs of electrons in its valence shell that are not neutralized by hydrogen atoms D-one of the hydrogen atoms donates an electron to the oxygen atom E-the oxygen atom donates an electron to each of the hydrogen atoms
B-the electrons shared between the oxygen and hydrogen atoms spend more time around the oxygen atom nucleus than around the hydrogen atom nucleus
What are the consequences? Check all that apply. A- α-1,4-glycosidic linkages are much more likely to form linear fibers and sheets. B- α-1,4-glycosidic linkages more resist to degradation. C- β-1,4-glycosidic linkages are much more likely to form linear fibers and sheets. D- β-1,4-glycosidic linkages more resist to degradation.
C D
Which of the following types of molecules would have the highest capacity to store chemical energy? A- a two-carbon molecule rich in C-O bonds, such as ethanol. B- a two-carbon molecule rich in C-H bonds, such as ethane. C- a six-carbon molecule rich in C-H bonds, such as a lipid. D- a six-carbon molecule righ in C-O bonds, such as a hexose.
C- a six-carbon molecule rich in C-H bonds, such as a lipid.
A 'mystery molecule' was isolated in a laboratory and investigators found that the molecule readily crossed artificial membranes. Which of the following molecules can be ruled out as the 'mystery molecule'? A- H2O B- O2 C- chloride ion D- CO2
C- chloride ion
In fat synthesis ______________ and fatty acids combine to make fats plus _____________. A- esters; phosphate B- esters; water C- glycerol; water D- glucose; phosphate E- phosphate; glycerol
C- glycerol; water
In fat synthesis,________and fatty acids combine to make fats plus________. A- phosphate; glycerol B- esters; phosphate C- glycerol; water D- glucose; phosphate E- esters; water
C- glycerol; water
If a strand of DNA has the nitrogen base sequence 5'-ATTTGC-3', what will be the sequence of the matching strand? A-3'-ATTTGC-5' B-3'-GCAAAT-5' C-3'-TAAACG-5' D-3'-TUUUCG-5' E-3'-UAAACG-5'
C-3'-TAAACG-5'
Which statement best explains the energy transformation that occurs when methane burns (CH4 + 2 O2 → CO2 + 2 H2O)? A-The absorption of heat results in an increase in potential energy from reactants to products. B-An increase in entropy from reactants to products is released as heat. C-A decrease in potential energy from reactants to products is released as heat. D-A decrease in entropy from reactants to products is released as heat.
C-A decrease in potential energy from reactants to products is released as heat.
Which of the following is not attached to the central carbon atom in an amino acid? A-An amino functional group B-A side chain ("R group") C-An oxygen D-A carboxyl functional group
C-An oxygen
Hereditary information is stored in A-RNA, ribonucleic acid. B-proteins C-DNA, dexoyribonucleic acid. D-proteins and DNA
C-DNA, dexoyribonucleic acid.
Where is the information that directs different polypeptides to fold into different shapes? A-In the medium that surrounds the molecule B-In the secondary structure C-In the primary structure D-In the tertiary structure
C-In the primary structure
Which molecule is not a carbohydrate? A-Glycogen B-Starch C-Lipid D-Cellulose
C-Lipid
Which monomers make up RNA? A-Amino acids B-Simple sugars C-Nucleotides D-Polymers
C-Nucleotides
Which polymers are composed of amino acids? A-Nucleic acids B-Monomers C-Proteins D-Carbohydrates
C-Proteins
__________ is achieved when a protein folds into a compact, three-dimensional shape stabilized by interactions between side-chain R groups of amino acids. A-Primary structure B-Secondary structure C-Tertiary structure D-Quaternary structure
C-Tertiary structure
In eukaryotic cells DNA has the appearance of a _____. A-single strand B-letter U C-double helix D-triple helix E-circle
C-double helix
The first law of thermodynamics states that _____. A-during reactions entropy tends to decrease B-reactions must be endothermic C-energy is neither created nor destroyed D-spontaneous reactions require an input of energy
C-energy is neither created nor destroyed
In a polypeptide, what bonds are responsible for the primary structure? A-disulfide bonds that form between cysteine residues B-hydrogen bonds that form between the core C=O and N-H groups on different residues. C-peptide bonds D-hydrogen bonds and other interactions between side chains
C-peptide bonds
The condensation reaction that forms nucleic acid polymers occurs between a _____ group on one nucleotide and a _____ group on a second nucleotide. A-carbon, carbon B-nitrogenous base, sugar C-phosphate, hydroxyl D-nitrogenous base, nitrogenous base
C-phosphate, hydroxyl
Which kinds of bonds are present in a single water molecule? A-hydrogen bonds B-ionic bonds C-polar covalent bonds D-nonpolar covalent bonds
C-polar covalent bonds
What type of energy is stored in the chemical bonds of a molecule? A-thermal energy B-equilibrium energy C-potential energy D-kinetic energy
C-potential energy
What is an active site? A-the site on an antibody where it binds to bacterial cells or viruses B-the place where a molecule or ion binds to a protein to induce a shape change C-the position in an enzyme where substrates bind D-the portion of a motor protein that is involved in moving cargo in a cell
C-the position in an enzyme where substrates bind
Which of the following statements best sums up the number of covalent bonds that can be formed by the four most common atoms in living things? A-N > O > C > H B-C > H > N > O C-C = H = N = O D-C > N > O > H
D-C > N > O > H
_____ is the most abundant organic compound on Earth. A-Glucose B-Lactose C-Starch D-Cellulose E-Glycogen
D-Cellulose
Which polysaccharide contains a modified monosaccharide? A-Glycogen B-Starch C-Cellulose D-Peptidoglycan
D-Peptidoglycan
__________ is the result of two or more protein subunits assembling to form a larger, biologically active protein complex. A-Primary structure B-Secondary structure C-Tertiary structure D-Quaternary structure
D-Quaternary structure
Proteins are polymers of _____. A-nucleotides B-CH2O units C-hydrocarbons D-glycerol E-amino acids
E-amino acids
The secondary structure of a protein results from _____. A-ionic bonds B-bonds between sulfur atoms C-hydrophobic interactions D-peptide bonds E-hydrogen bonds
E-hydrogen bonds
A polypeptide could best be described as a A-polymer containing 20 peptide bonds. B-polymer containing 20 amino acids molecules C-monomer of a protein polymer D-polymer containing 19 peptide bonds. E-polymer of amino acids.
E-polymer of amino acids.
Identify three possible components of a DNA nucleotide. A-deoxyribose, phosphate group, uracil B-cytidine, phosphate group, ribose C-cytosine, phosphate group, ribose D-guanine, phosphate group, ribose E-adenine, phosphate group, ribose F-deoxyribose, phosphate group, thymine
F-deoxyribose, phosphate group, thymine
Which bonds are created during the formation of the primary structure of a protein? 1-C. disulfide bonds 2-B. phosphodiester bonds 3-A, B, and C 4-D. peptide bonds 5-A. hydrogen bonds
4-D. peptide bonds
Nucleic acids are directional, meaning that there are two different ends. What functional groups define the two different ends. Check all that apply. A-a free phosphate group on the 5' carbon. B-a free hydroxyl group on the 3' carbon. C-a free phosphate group on the 3' carbon. D-a free hydroxyl group on the 5' carbon.
A B
Fats vary with respence to the _____________ (Choose all that apply) A- the number of double bonds in the tails for unsaturated fatty acids B- the presence or absence of double bonds in the tails C- length of the fatty acid tails (the number of C atoms in the tails) D- the number of phosphate molecules in the tails
A B C
What is the difference between linking glucose molecules with α-1,4-glycosidic linkages versus β-1,4-glycosidic linkages? Check all that apply. A-The linkages have different orientation of the glucose monomers. B-In α-1,4-glycosidic linkages the glucose monomers are linked in the same orientation. C-In α-1,4-glycosidic linkages every other glucose flipped in orientation. D-The linkages are located on opposite sides of the plane of the glucose rings. E-In β-1,4-glycosidic linkages every other glucose flipped in orientation. F-In β-1,4-glycosidic linkages the glucose monomers are linked in the same orientation.
A B D E
The presence of many C-C and C-H bonds causes fats to be .... (Choose all answers that apply) A- insoluble in water B- low in energy C- rich in energy
A C
A food company hydrogenated a barrel of fat. The treatment ... A- (a) made the fat less fluid. B- (b) made the fat less saturated. C- (c) lengthened the fat tails. D- (d) put more bends (kinks) in the fat tails. E- Both (a) and (d).
A- (a) made the fat less fluid.
Which statement most accurately describes how the structure of fats, steroids, and phospholipids compare? A- Fats and phospholipids contain glycerol whereas steroids do not. B- Steroids contain fatty acids whereas fats and phospholipids do not.
A- Fats and phospholipids contain glycerol whereas steroids do not.
Which statement most accurately describes how the structures of fats, steroids, and phospholipids compare? A- Fats and phospholipids contain glycerol whereas steroids do not. B- Steroids contain fatty acids whereas fats and phospholipids do not
A- Fats and phospholipids contain glycerol whereas steroids do not.
You have a planar bilayer with equal amounts of saturated and unsaturated phospholipids. After testing the permeability of this membrane to glucose, you increase the proportion of unsaturated phospholipids in the bilayer. What will happen to the membrane's permeability to glucose? A- Permeability to glucose will increase. B- Permeability to glucose will stay the same. C- Permeability to glucose will decrease. D- You cannot predict the outcome. You simply have to make the measurement.
A- Permeability to glucose will increase.
A "mystery molecule" was isolated in a laboratory and scientists found that the molecule readily crossed artificial membranes. Which of the following molecules can be ruled out as the "mystery molecule?" A- chloride ion B- CO2 C- O2 D- H2O
A- chloride ion
In the reaction that builds a fat, __________ groups react with ____________ groups. A- hydroxyl; carboxyl B- hydroxyl; phosphate C- phosphate; amino D- carboxyl; amino E- sulfhydryl, carboxyl
A- hydroxyl; carboxyl
In the reaction that builds a fat,________ groups react with ________ groups. A- hydroxyl; carboxyl B- phosphate; amino C- hydroxyl; phosphate D- carboxyl; amino E- sulfhydryl; carboxyl
A- hydroxyl; carboxyl
o find the best source of phospholipids, look at ... A- membranes. B- storage droplets. C- nasal mucus. D- cell walls. E- surfaces of leaves.
A- membranes.
It is difficult for molecules to pass through the phospholipid bilayer because ... A- polar molecules attract one another. B- hydrocarbons repel water. C- there is a water film between the monolayers. D- cholesterol holds phospholipids in place. E- proteins hold phospholipids in place.
A- polar molecules attract one another.
Ions diffuse across membranes through specific ion channels down _____. A- their electrochemical gradients B- the osmotic potential gradients C- their concentration gradients D- the electrical gradients E- their chemical gradients
A- their electrochemical gradients
QUANTITATIVE If nucleotides from the DNA of a human were quantified and 30 percent of them consisted of adenine, what percentage of guanine nucleotides would be present? A-20 percent B-30 percent C-40 percent D-70 percent
A-20 percent
How many different primary sequences can be generated by randomly assembling amino acids into peptides that are five residues long? A-20^5=3,200,000 B-20×5=100. C-20 D-The number is infinite.
A-20^5=3,200,000
Which of the following statements about the formation of polypeptides from amino acids is true? A-A bond forms between the carboxyl functional group of one amino acid and the amino functional group of the other amino acid. B-The reaction occurs through the addition of a water molecule to the amino acids. C-Polypeptides form by condensation or hydrolysis reactions. D-A bond can form between any carbon and nitrogen atom in the two amino acids being joined.
A-A bond forms between the carboxyl functional group of one amino acid and the amino functional group of the other amino acid.
Which complex carbohydrate contains only a-1,4-glycosidic linkages? A-Amylose B-Amylopectin C-Glycogen D-Cellulose
A-Amylose
Carbon is important to the structure of macromolecules because it has a valence of 4. What does this mean? A-Carbon can engage in four covalent bonds. B-Carbon has four electron shells. C-Carbon has four electrons. D-Carbon has four protons and four neutrons and thus an atomic mass of eight.
A-Carbon can engage in four covalent bonds.
Which of the following correctly describes all chemical equilibrium? A-Forward and reverse reactions continue with no net effect on the concentrations of the reactants and products. B-Reactions stop only when all reactants have been converted to products. C-There are equal concentrations of reactants and products, and the reactions have stopped. D-Concentrations of products are higher than the concentrations of the reactants. E-There are equal concentrations of products and reactants while forward and reverse reactions continue.
A-Forward and reverse reactions continue with no net effect on the concentrations of the reactants and products.
Nonpolar amino acid residues are typically found in the interior of globular proteins like trypsin. Which chemical force is most directly responsible? A-Hydrophobic interactions B-Covalent bonding C-Tertiary structure D-Ionic bonding
A-Hydrophobic interactions
Which statement best explains why a relatively small difference in the location of a carbonyl or hydroxyl group can lead to dramatic changes in the properties and function of a monosaccharide? A-It changes the shape of the monosaccharide. B-It changes the amount of energy stored in the monosaccharide. C-It changes the number of covalent bonds in the monosaccharide. D-It changes the chemical formula of the monosaccharide.
A-It changes the shape of the monosaccharide.
Which of the following statements about monosaccharide structure is true? A-Monosaccharides can be classified according to the spatial arrangement of their atoms. B-All monosaccharides contain carbon, hydrogen, oxygen, and nitrogen atoms. C-A six-carbon sugar is called a pentose. D-Aldoses and ketoses differ in the position of their hydroxyl groups.
A-Monosaccharides can be classified according to the spatial arrangement of their atoms.
Place molecular nitrogen (N2), calcium bromide (CaBr2), and sulfur dioxide (SO2) on the electron-sharing continuum from equal sharing of electrons to full transfer of electron. A-N2→SO2→CaBr2 B-SO2→CaBr2→N2 C-CaBr2→SO2→N2 D-N2→CaBr2→SO2
A-N2→SO2→CaBr2
Which statement best explains the physical basis for why oil (molecules containing only carbon and hydrogen) and water do not mix? A-Oils are nonpolar molecules that cannot interact with water molecules via hydrogen bonding. B-Oil molecules interact via hydrogen bonding more strongly with other oil molecules than with water molecules. C-Oils are negatively charged molecules that are repelled by the partial negative charges on water molecules. D-Oils are positively charged molecules that are repelled by the partial positive charges on water molecules.
A-Oils are nonpolar molecules that cannot interact with water molecules via hydrogen bonding.
Which statement best summarizes a key difference in the structure of polysaccharides that function in energy storage versus those used in structural support? A-Polysaccharides that function in energy storage are built from α glycosidic linkages, whereas polysaccharides used in structural support form straight chains that bond with adjacent chains. B-Polysaccharides that function in energy storage are built from β glycosidic linkages, whereas polysaccharides used in structural support form straight chains that bond with adjacent chains. C-Polysaccharides that function in energy storage form straight chains that bond with adjacent chains, whereas polysaccharides used in structural support are built from α glycosidic linkages. D-Polysaccharides that function in energy storage are built from α glycosidic linkages, whereas polysaccharides used in structural support form helical chains that are highly branched.
A-Polysaccharides that function in energy storage are built from α glycosidic linkages, whereas polysaccharides used in structural support form straight chains that bond with adjacent chains.
1. _______ is the sequence of amino acids in a protein. A-Primary structure B-Secondary structure C-Tertiary structure D-Quaternary structure
A-Primary structure
Which functional group is least polar? A-Sulfhydryl B-Amino C-Carboxyl. D-Hydroxyl
A-Sulfhydryl
How are the structures of RNA and DNA similar? A-Their sugar-phosphate backbones are formed by phosphodiester linkages. B-they both have the same tertiary structure. C-Adenine pairs with thymine in both D-they both contain the sugar ribose
A-Their sugar-phosphate backbones are formed by phosphodiester linkages
The hydrogen bonds among water molecules endow water with which property? A-Water has a high specific heat. B-Solid water (ice) is denser than liquid water. C-Water has low cohesion. D-Water is a good solvent for nonpolar molecules.
A-Water has a high specific heat.
The hydrogen bonds among water molecules endow water with which property? A-Water has a high specific heat. B-Water is a good solvent for nonpolar molecules. C-Solid water (ice) is denser than liquid water. D-Water has low cohesion.
A-Water has a high specific heat.
Glycogen is _____. A-a polysaccharide found in animals B-a source of saturated fat C-the form in which plants store sugars D-a transport protein that carries oxygen E-a polysaccharide found in plant cell walls
A-a polysaccharide found in animals
Elements found on the left side of the periodic table contain outer shells that are _____; these elements tend to form _____ in solution. A-almost empty; cations B-almost full; cations C-almost empty; anions D-almost full; anions
A-almost empty; cations
Which of teh following types of glycosidic bonds are more readily broken by hydrolysis? A-alpha linkages B-glucose linkages C-Hydrolysis will occur equally across all of these linkages. D-beta linkages
A-alpha linkages
A substance that gives up a proton during a chemical reaction, raising the hydrogen ion concentration of water, is most appropriately called _____. A-an acid B-a buffer C-a base D-an isotope
A-an acid
What two functional groups are present on every amino acid? A-an amino group and a carboxyl group B-an amino group and a hydroxyl group C-a carbonyl (C=O) group and a carboxyl group D-an N−H group and a carbonyl group
A-an amino group and a carboxyl group
Which of the following is a property of liquid water? Liquid water _____. A-has a heat of vaporization that is higher than that for most other substances B-is less dense than ice C-is nonpolar D-has a specific heat that is lower than that for most other substances
A-has a heat of vaporization that is higher than that for most other substances
Defensive proteins are manufactured by the _____ system. A-immune B-integumentary C-nervous D-cardiovascular E-digestive
A-immune
Which of the following is a characteristic of a polysaccharide? A-long chains composed of monosaccharides bonded together B-found only in plants C-only used to store energy D-the ring form of a disaccharide
A-long chains composed of monosaccharides bonded together
Organize the types of bonds according to the degree to which electrons are shared between two atoms. A-nonpolar covalent bonds > polar covalent bonds > ionic bonds B-polar covalent bonds > nonpolar covalent bonds > ionic bonds C-ionic bonds > polar covalent bonds > nonpolar covalent bonds
A-nonpolar covalent bonds > polar covalent bonds > ionic bonds
A covalent bond is likely to be polar when _____. A-one of the atoms sharing electrons is more electronegative than the other atom B-the two atoms sharing electrons are equally electronegative C-carbon is one of the two atoms sharing electrons D-one of the atoms has absorbed more energy than the other atom E-the two atoms sharing electrons are the same elements
A-one of the atoms sharing electrons is more electronegative than the other atom
A sugar that has the chemical formula C5H10O5 would be characterized as a(n) _____. A-pentose B-hexose C-triose D-oligosaccharide
A-pentose
A sugar that has the chemical formula C5H10O5 would be charaterized as a(n) A-pentose B-triose C-oligosaccharide D-hexose
A-pentose
What type of bond joins the monomers in a protein's primary structure? A-peptide B-hydrophobic C-ionic D-hydrogen E-S - S
A-peptide
Tertiary structure is NOT directly dependent on _____. A-peptide bonds B-ionic bonds C-bonds between sulfur atoms D-hydrogen bonds E-hydrophobic interactions
A-peptide bonds
Which of the following polysaccharides contains peptide bonds? A-peptidoglycan B-glycogen C-starch D-chitin
A-peptidoglycan
The condensdation reaction that forms nucleic acid polymers occurs between a _________ group on one nucleotide and a ________ group on a second nucleotide A-phosphate, hydroxyl B-nitrogenous base, sugar C-nitrogenous base, nitrogenous base D-carbon, carbon
A-phosphate, hydroxyl
In a single molecule of water, two hydrogen atoms are bonded to a single oxygen atom by _____. A-polar covalent bonds B-ionic bonds C-nonpolar covalent bonds D-van der Waals interactions E-hydrogen bonds
A-polar covalent bonds
A carbohydrate that yields many monosaccharides when hydrolyzed is a ____________ A-polysaccharide B-carbohydrate C-disaccharide D-monosaccharide
A-polysaccharide
Which of the following parts of an amino acid vary among different amino acids? A-the side chain, or R group B-the amino group C-the carboxyl group D-the hydrogen on the central carbon
A-the side chain, or R group
Which statement most accurately explains why cholesterol and phospholipids are amphipathic but fats are not? A- Cholesterol and phospholipids contain both hydrophilic and hydrophobic regions; fats are primarily hydrophilic B- Cholesterol and phospholipids contain both hydrophilic and hydrophobic regions; fats are primarily hydrophobic C- Cholesterol and phospholipids are primarily hydrophilic; fats are primarily hydrophobic D- Cholesterol and phospholipids are primarilhy hydrophobic; fats are primarily hydrophilic.
B- Cholesterol and phospholipids contain both hydrophilic and hydrophobic regions; fats are primarily hydrophobic
Which of the following is true of osmosis? A- Osmosis is an energy-demanding or "active" process. B- In osmosis, water moves across a membrane from areas of lower solute concentration to areas of higher solute concentration. C- Osmosis only takes place in red blood cells. D- In osmosis, solutes move across a membrane from areas of lower water concentration to areas of higher water concentration.
B- In osmosis, water moves across a membrane from areas of lower solute concentration to areas of higher solute concentration.
In an experiment involving planar bilayers, a solution of table salt (sodium and chloride ions in water) is added on the left side of the membrane while pure water is added on the right side. After 30 minutes the researchers test for the presence of ions on each side of the membrane. The right side tests negative for ions. What can you conclude? A- The left side would probably also test negative for ions. B- Ions cannot cross planar bilayers. C- The water somehow blocked the movement of ions across the membrane. D- The experiment failed.
B- Ions cannot cross planar bilayers.
Which lipid is most amphipathic? A- Cholesterol B- Phospholipid C- Wax D- Fat E- Triglyceride
B- Phospholipid
Which of these is NOT a lipid? A- steroids B- RNA C- phospholipid D- cholesterol E- wax
B- RNA
Select the statement that is incorrect. A-Complex sugars are carbohydrates. B-All carbohydrates have the general formula Cn(H2O)n. C-Simple sugars are carbohydrates. D-Simple sugars contain only carbon, oxygen, and hydrogen atoms.
B-All carbohydrates have the general formula Cn(H2O)n.
Your body contains tens of thousands of different proteins, each with a specific structure and function. The unique three-dimensional shape of each of these diverse proteins is based on several superimposed levels of structure. Which of the following statements is an accurate description of proteins? A-The 20 amino acids found in proteins differ in the composition of their R groups, which may be either polar or charged. B-The primary structure of a protein is the order of amino acids in a polypeptide, as coded for in the DNA of a gene. C-Secondary structures, which include the alpha helix or beta pleated sheet, are held together by interactions between R groups. D-Tertiary structure is the overall shape of a polypeptide, which may be stabilized by hydrophobic interactions, hydrogen bonds, ionic bonds, and peptide bonds. E-Quaternary structure is only found in proteins that have four identical polypeptide subunits.
B-The primary structure of a protein is the order of amino acids in a polypeptide, as coded for in the DNA of a gene.
The individual building blocks of DNA, which are made of a phosphate, sugar, and base are called A-genes. B-nucleotides. C-promoters. D-nucleosomes.
B-nucleotides.
Which of the following polysaccharides contains peptide bonds? A-chitin B-peptidoglycan C-glycogen D-starch
B-peptidoglycan
Which kinds of bonds are present in a single water molecule? A-nonpolar covalent bonds B-polar covalent bonds C-hydrogen bonds D-ionic bonds
B-polar covalent bonds
An RNA molecule that can catalyze chemical reactions is called a_____. A-stem-loop B-ribozyme C-protein D-Tetrahymena
B-ribozyme
How many electrons are involved in a single covalent bond? A-one B-two C-three D-four
B-two
The tertiary structure of a protein is the A-order in which amino acids are joined in a polypeptide chain. B-unique three-dimensional shape of the fully folded polypeptide. C-organization of a polypeptide chain into an alpha helix or beta pleated sheet. D-overall protein structure resulting from the aggregation of two or more polypeptide subunits. E-bonding together of several polypeptide chains by weak bonds.
B-unique three-dimensional shape of the fully folded polypeptide.
In a membrane, the________of the phospholipids in one monolayer face the________of the phospholipids in the other monolayer. A- (a) heads; heads B- (b) heads; tails C- (c) tails; tails D- Sometimes (a), sometimes (c). E- None of these; a membrane is a monolayer.
C- (c) tails; tails
Which statement most accurately explains why cholesterol and phospholipids are amphipathic but fats are not? A- Cholesterol and phospholipids are primarily hydrophilic; fats are primarily hydrophobic. B- Cholesterol and phospholipids contain both hydrophilic and hydrophobic regions; fats are primarily hydrophilic. C- Cholesterol and phospholipids contain both hydrophilic and hydrophobic regions; fats are primarily hydrophobic. D- Cholesterol and phospholipids are primarily hydrophobic; fats are primarily hydrophilic.
C- Cholesterol and phospholipids contain both hydrophilic and hydrophobic regions; fats are primarily hydrophobic.
You have just discovered an organism that lives in extremely cold environments. Which of the following would you predict to be true about the phospholipids in its membranes, compared to phospholipids in the membranes of organisms that live in warmer environments? A- The membrane phospholipids of cold-adapted organisms will have more saturated hydrocarbon tails. B- The membrane phospholipids of cold-adapted organisms will have longer hydrocarbon tails. C- The membrane phospholipids of cold-adapted organisms will have more unsaturated hydrocarbon tails.
C- The membrane phospholipids of cold-adapted organisms will have more unsaturated hydrocarbon tails.
Which feature is shared by all monosaccharides? A-They are all pentoses. B-In their linear forms, they all contain a carboxyl and several hydroxyl functional groups. C-In their linear forms, they all contain a carbonyl and several hydroxyl functional groups. D-They all contain more than one sugar.
C-In their linear forms, they all contain a carbonyl and several hydroxyl functional groups.
Which of the following correctly orders amino acids Asp, Tyr, and Val from most hydrophobic (on the left) to most hydrophilic (on the right)? A-Asp, Val, and Tyr B-Tyr, Val, and Asp C-Val, Tyr, and Asp D-Val, Asp, and Tyr
C-Val, Tyr, and Asp
Which class(es) of amino acids possess side chains that would be unable to form hydrogen bonds with water? A-amino acids with acidic side chains B-amino acids with polar side chains C-amino acids with nonpolar side chains D-amino acids with basic side chains
C-amino acids with nonpolar side chains
Which of the following types of amino acids would you predict to be present in the DNA binding sites of these proteins? A-acidic amino acids B-uncharged polar amino acids C-basic amino acids D-nonpolar amino acids
C-basic amino acids
Which of the following would you expect to have the most free energy per gram? The most free energy per gram would be found in a molecule with _____. A-hydrogen and oxygen atoms only B-carbon, hydrogen, and oxygen atoms only C-carbon and hydrogen atoms only D-a variety of atoms that are found in cells
C-carbon and hydrogen atoms only
Which of these is a polysaccharide? A-sucrose B-galactose C-cellulose D-lactose E-glucose
C-cellulose
Which of the following polysaccharides composes the cell wall of fungi? A-glycogen B-peptidoglycan C-chitin D-starch
C-chitin
Lactose, the sugar in milk, is a ___________, because it can be split into two monosaccharides. A-polysaccharide B-carbohydrate C-disaccharide D-monosaccharide
C-disaccharide
A strong acid like HCl _____. A-dissociates completely in aqueous solutions and is a strong buffer at low pH B-is a strong buffer at low pH C-dissociates completely in an aqueous solution D-increases the pH when added to an aqueous solution E-reacts with strong bases to create a buffered solution
C-dissociates completely in an aqueous solution
Which of the following is NOT a polymer? A-cellulose B-chitin C-glucose D-DNA E-starch
C-glucose
Water has a high specific heat because of the _____. A-ionic bonds formed between the hydrogen of one water molecule and the oxygen of another water molecule B-polar covalent bond formed between the oxygen and a hydrogen of a single water molecule C-hydrogen bond formed between the hydrogen of one water molecule and the oxygen of another water molecule D-covalent bond formed between the hydrogen of one water molecule and the oxygen of another water molecule
C-hydrogen bond formed between the hydrogen of one water molecule and the oxygen of another water molecule
Where is the information that directs different polypeptides to fold into different shapes? A-in the secondary structure B-in the medium that surrounds the molecule C-in the primary structure D-in the tertiary structure
C-in the primary structure
Which of these is a source of lactose? A-starch B-potatoes C-milk D-sugar beets E-sugar cane
C-milk
Bonds between two atoms that are equally electronegative are _____. A-van der Waals interactions B-ionic bonds C-nonpolar covalent bonds D-polar covalent bonds E-hydrogen bonds
C-nonpolar covalent bonds
Which of the following classes of macromolecules always contains a carbohydrate portion? A-proteins B-lipids C-nucleic acids D-water
C-nucleic acids
DNA is composed of building blocks called _____. A-nucleic acids B-Gs C-nucleotides D-adenines E-amino acids
C-nucleotides
Why is each element unique with respect to its chemical properties? Each element has a distinctive _____. A-atomic mass B-radioactive property C-number of protons D-number of neutrons E-number of electrons
C-number of protons
A covalent chemical bond is one in which _____. A-outer-shell electrons of one atom are transferred to fill the inner electron shell of another atom B-electrons from the same atom, but opposite spins, are paired C-outer-shell electrons of two atoms are shared so as to satisfactorily fill their respective orbitals D-electrons are removed from one atom and transferred to another atom so that the two atoms become oppositely charged E-protons and neutrons are shared by two atoms so as to satisfy the requirements of both atoms
C-outer-shell electrons of two atoms are shared so as to satisfactorily fill their respective orbitals
In a polypeptide, what bonds are responsible for the primary structure? A-disulfide bonds that form between cysteine residues B-hydrogen bonds that form between the core C=O and N−H groups on different residues C-peptide bonds D-hydrogen bonds and other interactions between side chains
C-peptide bonds
Each of the 20 different amino acids found in polypeptides exhibit different chemical and physical properties because of different A-carboxyl groups attached to an alpha carbon. B-alpha carbons. C-side chains (R groups). D-amino groups attached to an alpha carbon. Ebeta carbons
C-side chains (R groups).
An atom has four electrons in its valence shell. What types of covalent bonds is it capable of forming? A-single and double only B-double bonds only C-single, double, or triple D-single bonds only
C-single, double, or triple
Which of the following can vary among monosaccharides? A-the presence of hydroxyl groups B-the presence of a carbonyl group C-the number of carbon atoms D-the presence of sulfur groups
C-the number of carbon atoms
Which of the following chemical bonds have the lowest potential energy? A) C-H bonds B) C-C bonds C) All of these bonds have equivalent potential energy. D) C-O bonds
D) C-O bonds
Which of the following chemical bonds have the lowest potential energy? A-All of these bonds have equivalent potential energy B) C-H bonds C) C-C bonds D) C-O bonds
D) C-O bonds
Which statement is true of phospholipids? A- (a) Their synthesis uses fatty acids. B- (b) Some of their tails have double bonds. C- (c) They all ionize. D- All the above. E- Both (a) and (b).
D- All the above.
Which of the following is the best explanation for why cholesterol decreases the permeability of biological membranes? A- Because cholesterol is amphipathic, it forms tiny vesicles that trap solutes. B- Cholesterol has four rings in its structure that can sequester (trap) solutes. C- Cholesterol binds to the outside surface of a membrane, thus blocking the movement of solutes. D- Because cholesterol is amphipathic, it fits in between the phospholipids and blocks diffusion through the membrane.
D- Because cholesterol is amphipathic, it fits in between the phospholipids and blocks diffusion through the membrane.
The presence of many C-C and C-H bonds causes fats to be ... A- (a) rich in energy. B- (b) insoluble in water. C- (c) low in energy. D- Both (a) and (b). E- Both (b) and (c).
D- Both (a) and (b).
Triglycerides vary with respect to the number of ... A- (a) hydrocarbon tails. B- (b) C atoms in the tails. C- (c) double bonds in the tails. D- Both (b) and (c). E- All of the above.
D- Both (b) and (c).
Which of the following would likely move through the lipid bilayer of a plasma membrane most rapidly? A- starch B- glucose C- K+ D- CO2 E- an amino acid
D- CO2
What do phosphoglycerides and fats have in common? A- A role in membrane structure. B- A tendency to form bilayers. C- A strongly polar group. D- Ester linkages. E- Three fatty acid tails.
D- Ester linkages.
How do fats differ from proteins, nucleic acids and polysaccharides? A- Only fats are organic compounds. B- Only fats play a structural role in cells. C- Only fats are found in membranes. D- Only fats do not form from the polymerization of monomers.
D- Only fats do not form from the polymerization of monomers.
What do DNA, proteins, and fats have in common? A- They are polar. B- They contain nitrogen. C- They contain phosphorus. D- They contain carbonyl groups. E- They are polymers.
D- They contain carbonyl groups.
Celery stalks that are immersed in fresh water for several hours become stiff. Similar stalks left in a 0.15 M salt solution become limp. From this we can deduce that the fresh water_____. A- and the salt solution are both hypertonic to the cells of the celery stalks B- is hypertonic and the salt solution is hypotonic to the cells of the celery stalks C- is isotonic and the salt solution is hypertonic to the cells of the celery stalks D- is hypotonic and the salt solution is hypertonic to the cells of the celery stalks E- and the salt solution are both hypotonic to the cells of the celery stalks
D- is hypotonic and the salt solution is hypertonic to the cells of the celery stalks
Galactosemia is a potentially fatal disease that occurs in humans who lack the enzyme that converts galactose to glucose. To treat this disease, physicians exclude the monosaccharide galactose from the diet. Which of the following would you also predict to be excluded from the diet? A- mannose B- starch C- maltose D- lactose
D- lactose
Which of these is rich in unsaturated fats? A- lard B- beef fat C- a fat that is solid at room temperature D- olive oil E- butter
D- olive oil
Phospholipids are most important for ... A- stiffening cells. B- lubricating cells. C- storing energy. D- preventing leakage from cells. E- waterproofing cell walls.
D- preventing leakage from cells.
Where would you most likely find an integral membrane protein? A- floating freely in the cytoplasm B- on the outside surface of the cell membrane C- on the inside surface of the cell membrane D- spanning the cell membrane, with parts of the protein visible from both the inside and the outside of the cell
D- spanning the cell membrane, with parts of the protein visible from both the inside and the outside of the cell
The most unsaturated fats have .... A- the highest ratio of H to C B- the shortest hydrocarbon tails C- the longest hydrocarbon tails D- the most double bonds E- the fewest double bonds
D- the most double bonds
Lipids are insoluble in water because_____. A- The statement is not true. Lipids are soluble in water. B- they contain multiple hydroxyl groups C- they are very large with many carbon atoms D- they contain nonpolar C-C and C-H bonds
D- they contain nonpolar C-C and C-H bonds
A solution with a pH of 5 has how many more protons in it than a solution with a pH of 7? A-5 times B-10 times C-1000 times D-100 times
D-100 times
How many monosaccharides are found in a disaccharide? A-1 B-4 C-3 D-2
D-2
By convention, nucleotide sequences are always written from the ______ A-sugar end to the phosphate end B-amino terminus to the carboxyl terminus C-3' end to the 5' end D-5'end to the 3' end
D-5'end to the 3' end
If a DNA double helix is 100 nucleotide pairs long and contains 25 adenine bases, how many guanine bases does it contain? A-50 B-150 C-200 D-75 E-25
D-75
In terms of their structure and how they are functioning in your body right now, which statement best explains how carbohydrates compare to DNA, RNA, or proteins? A-Due to their regularity of structures, carbohydrates are able to provide the information required to copy themselves, like DNA and RNA. B-Due to their variety of structures, carbohydrates are more functionally complex than proteins. C-Due to the simplicity of their structures, carbohydrates perform fewer overall functions than DNA. D-Despite their variety of structures, carbohydrates are less functionally complex than proteins.
D-Despite their variety of structures, carbohydrates are less functionally complex than proteins.
Which statement most accurately describes the relative potential energies (P.E.) of the electrons in the following molecules: H2, O2, and H2O? A-Electrons in H2 and H2O have relatively high P.E; electrons in O2 have relatively low P.E. B-Electrons in H2 and O2 have relatively low P.E; electrons in H2O have relatively high P.E. C-The P.E. of electrons are equivalent in all three molecules. D-Electrons in H2 and O2 have relatively high P.E; electrons in H2O have relatively low P.E.
D-Electrons in H2 and O2 have relatively high P.E; electrons in H2O have relatively low P.E.
Both carbohydrates and fats are used as fuel in cells, but fats store twice as much energy per gram as carbohydrates. Which statement best explains why? A-Fats have more C-C and C-H bonds with low potential energy, and fewer C-O bonds with high potential energy. B-Fats have more C-O bonds with low potential energy, and fewer C-C and C-H bonds with high potential energy. C-Fats have more C-O bonds with high potential energy, and fewer C-C and C-H bonds with low potential energy. D-Fats have more C-C and C-H bonds with high potential energy, and fewer C-O bonds with low potential energy.
D-Fats have more C-C and C-H bonds with high potential energy, and fewer C-O bonds with low potential energy.
The R-group, or side chain, of the amino acid serine is -CH2-OH. The R-group, or side chain, of the amino acid leucine is -CH2-CH-(CH3)2. Where would you expect to find these amino acids in a globular protein in aqueous solution? A-Serine and leucine would both be in the interior of the globular protein. B-Serine would be in the interior, and leucine would be on the exterior of the globular protein. C-Serine and leucine would both be on the exterior of the globular protein. D-Leucine would be in the interior, and serine would be on the exterior of the globular protein.
D-Leucine would be in the interior, and serine would be on the exterior of the globular protein.
Which statement best explains the physical basis for why oil (molecules containing only carbon and hydrogen) and water do not mix? A-Oil molecules interact via hydrogen bonding more strongly with other oil molecules than with water molecules. B-Oils are negatively charged molecules that are repelled by the partial negative charges on water molecules. C-Oils are positively charged molecules that are repelled by the partial positive charges on water molecules. D-Oils are nonpolar molecules that cannot interact with water molecules via hydrogen bonding.
D-Oils are nonpolar molecules that cannot interact with water molecules via hydrogen bonding.
Carbon-12 is the most common isotope of carbon and has a mass number of 12. However, the average atomic mass of carbon found on a periodic table is slightly more than 12 daltons. Why? A-Some carbon atoms in nature have an extra proton. B-Some carbon atoms in nature have a different valence electron distribution. C-Some carbon atoms in nature have undergone radioactive decay. D-Some carbon atoms in nature have more neutrons. E-The atomic mass does not include the mass of electrons.
D-Some carbon atoms in nature have more neutrons.
Which of the following is true of protein folding? A-Correct folding is aided by high temperature B-Once protein fold, their structuree doesn't change C-Misfolded proteins can still function correctly. D-Some proteins can fold spontaneously
D-Some proteins can fold spontaneously
What could happen if a mutation in a gene caused a hydrophobic amino acid in a polypeptide to be replaced by a hydrophilic amino acid? A-The shape of the protein would not be affected if only one amino acid in the primary structure is changed. B-The hydrophilic amino acid could not form the proper peptide bond in its new location, so both the shape and function of the protein would be affected. C-There would be no effect as long as the protein had quaternary structure, because primary structure does not affect that level. D-The new amino acid would not form the same interactions with hydrophobic R groups, and the protein's shape would likely be affected.
D-The new amino acid would not form the same interactions with hydrophobic R groups, and the protein's shape would likely be affected.
If water were a linear (not bent) molecule, electrostatic interactions between water molecules would be much weaker. Why? A-The O-H bond would be less polar and less able to participate in hydrogen bonding. B-The partial positive charges on the hydrogen atoms would stick out less and be less able to participate in hydrogen bonding. C-Oxygen and hydrogen would not have partial charges in a linear water molecule. D-The partial negative charge on oxygen would stick out less and be less able to participate in hydrogen bonding.
D-The partial negative charge on oxygen would stick out less and be less able to participate in hydrogen bonding.
How could two four-sugar oligosaccharides be structurally different even if both consist of two glucose monomers and two galactose monomers? A-One oligosaccharide could contain aldoses while the other contains ketoses. B-Only the location and geometry of glycosidic linkages could vary. C-Only the sequence of monomers along the chain could vary. D-The sequence of monomers along the chain or the location and geometry of glycosidic linkages could vary (or both).
D-The sequence of monomers along the chain or the location and geometry of glycosidic linkages could vary (or both).
Which of the following structural features is common to cellulose, chitin, and peptidoglycan? A-They are all composed of glucose in either the α or β form. B-They all contain peptide bonds. C-They are all composed of highly branched fibers. D-They can all form bonds between polymer chains that create parallel strands.
D-They can all form bonds between polymer chains that create parallel strands.
Which one of the following is NOT a component of each monomer used to make proteins? A-an amino functional group, NH2 B-a side chain, R C-a carboxyl group, COOH D-a phosphorus atom, P
D-a phosphorus atom, P
What are the components of a nucleotide? A-a sugar, an amino acid and a nitrogenous base. B-a sugar, a sulfate group and a purine. C-a sugar, a sulfate group and a pyrimidine. D-a sugar, a phosphate group and a nitrogenous base.
D-a sugar, a phosphate group and a nitrogenous base.
Proteins help cells with which task(s)? A-transport B-signaling C-catalysis D-all of the above
D-all of the above
Which functional group contains nitrogen? A-carboxyl B-sulfhydryl C-hydroxyl D-amino
D-amino
A substance that gives up a proton during a chemical reaction, raising the hydrogen ion concentration of water, is most appropriately called _____. A-a buffer B-a base C-an isotope D-an acid
D-an acid
Lactose, a sugar in milk, is composed of one glucose molecule joined by a glycosidic linkage to one galactose molecule. How is lactose classified? A-as a hexose B-as a monosaccharide C-as a polysaccharide D-as a disaccharide E-as a pentose
D-as a disaccharide
The _______ of DNA strands pair in a consistent complementary fashion. A-ribose sugars B-sugars C-phosphate groups D-bases
D-bases
Which two types of atoms bond to form the ring structure of a monosaccharide? A-hydrogen and oxygen B-carbon and carbon C-hydrogen and carbon D-carbon and oxygen
D-carbon and oxygen
About twenty-five of the ninety-two natural elements are known to be essential to life. Which four of these twenty-five elements make up approximately 96 percent of living matter? A-carbon, sodium, hydrogen, nitrogen B-carbon, oxygen, nitrogen, calcium C-carbon, oxygen, phosphorus, hydrogen D-carbon, hydrogen, nitrogen, oxygen E-oxygen, hydrogen, calcium, nitrogen
D-carbon, hydrogen, nitrogen, oxygen
During protein synthesis, the peptide bond between amino acids is formed by the process of _____. A-hydrogen bonding B-ionic bonding C-hydrolysis D-condensation
D-condensation
The bond that joins two monosaccharides into a disaccharide is a(n) __________ A-van der Waals bond B-ionic bond C-hydrogen bond D-glycosidic bond
D-glycosidic bond
Humans can digest starch but not cellulose because _____. A-starch monomers are joined by covalent bonds and cellulose monomers are joined by ionic bonds B-the monomer of starch is glucose, while the monomer of cellulose is galactose C-humans have enzymes that can hydrolyze the β-glycosidic linkages of starch but not the α-glycosidic linkages of cellulose D-humans have enzymes that can hydrolyze the α-glycosidic linkages of starch but not the β-glycosidic linkages of cellulose E-the monomer of starch is fructose, while the monomer of cellulose is glucose
D-humans have enzymes that can hydrolyze the α-glycosidic linkages of starch but not the β-glycosidic linkages of cellulose
In a DNA double helix, what kind of chemical bonds form between the complementary nitrogenous bases? A-nitrogen bonds B-polar covalent bonds C-phosphodiester bonds D-hydrogen bonds
D-hydrogen bonds
The two strands of a DNA double helix are held together by _____ that form between pairs of nitrogenous bases. A-ionic bonds B-covalent bonds C-hydrophilic interactions D-hydrogen bonds E-S—S bonds
D-hydrogen bonds
Which of the following is not a characteristic of monosaccharides? A-all have carbon, hydrogen, and oxygen in a 1:2:1 ratio B-often exist as either a straight chain or a ring C-always contain a double bond between a carbon atom and an oxygen atom D-link together to form a long chain and act as enzymes
D-link together to form a long chain and act as enzymes
A ___________ cannot be hydrolyzed any further. A-polysaccharide B-carbohydrate C-disaccharide D-monosaccharide
D-monosaccharide
In a nucleic acid polymer, the bonds that help to hold regions of double-strandedness together occur between what parts of the nucleotide monomers? A-sugars and phosphates B-nitrogenous bases and phosphates C-sugars D-nitrogenous bases
D-nitrogenous bases
You disrupt all hydrogen bonds in a protein. What level of structure will be preserved? A-secondary structure B-quaternary structure C-tertiary structure D-primary structure
D-primary structure
The main reason that proteins outperform other macromolecules in terms of catalytic ability is because ____. A-proteins are soluble in water B-proteins are polymers C-peptide bonds are covalent D-proteins can contain a variety of R groups
D-proteins can contain a variety of R groups
The alpha helix and the beta pleated sheet are both common polypeptide forms found in which level of protein structure? A-tertiary B-quantenary C-primary D-secondary E-all of the above
D-secondary
What is the major structural difference between starch and glycogen? A-whether glucose is in the α or β form B-the type of glycosidic linkages in the molecule C-the types of monosaccharide subunits in the molecules D-the amount of branching that occurs in the molecule
D-the amount of branching that occurs in the molecule
The tertiary structure of a protein is the _____. A-overall protein structure resulting from the aggregation of two or more polypeptide subunits B-order in which amino acids are joined in a polypeptide chain C-organization of a polypeptide chain into an α-helix or β-pleated sheet D-unique three-dimensional shape of the fully folded polypeptide
D-unique three-dimensional shape of the fully folded polypeptide
Which of the following membrane activities requires energy from ATP? A- facilitated diffusion of chloride ions across the membrane through a chloride channel B- movement of carbon dioxide out of a paramecium C- movement of water into a cell D- movement of glucose molecules into a bacterial cell from a medium containing a higher concentration of glucose than inside the cell E- movement of Na+ ions from a lower concentration in a mammalian cell to a higher concentration in the extracellular fluid
E- movement of Na+ ions from a lower concentration in a mammalian cell to a higher concentration in the extracellular fluid
The most unsaturated fats have ... A- the longest hydrocarbon tails. B- the highest ratio of H to C. C- the shortest hydrocarbon tails. D- the fewest double bonds. E- the most double bonds.
E- the most double bonds.
Polymers that contain sugars ... A-(a) may store hereditary information. B-(b) may store energy. C-(c) may protect cells. D-Both (b) and (c). E-(a), (b), and (c).
E-(a), (b), and (c).
What is the difference between covalent bonds and ionic bonds? A-Covalent bonds involve the transfer of electrons between charged atoms; ionic bonds involve the sharing of electrons between atoms. B-Covalent bonds involve the sharing of pairs of electrons between atoms; ionic bonds involve the sharing of single electrons between atoms. C-Covalent bonds involve the sharing of electrons between atoms; ionic bonds involve the sharing of protons between charged atoms. D-Covalent bonds require carbon while ionic bonds do not. E-Covalent bonds involve the sharing of electrons between atoms; ionic bonds involve the electrical attraction between charged atoms.
E-Covalent bonds involve the sharing of electrons between atoms; ionic bonds involve the electrical attraction between charged atoms.
Nitrogen (N) is more electronegative than hydrogen (H). Which of the following is a correct statement about the atoms in ammonia (NH3)? A-Ammonia has an overall positive charge. B-Ammonia has an overall negative charge. C-There are covalent bonds between the hydrogen atoms and polar bonds between each hydrogen atom and the nitrogen atom. D-The nitrogen atom has a partial positive charge; each hydrogen atom has a partial negative charge. E-Each hydrogen atom has a partial positive charge; the nitrogen atom has a partial negative charge.
E-Each hydrogen atom has a partial positive charge; the nitrogen atom has a partial negative charge.
glucose + glucose —> _____ by _____. A-cellulose + water ... hydrolysis B-starch + water ... dehydration synthesis C-lactose + water ... hydrolysis D-sucrose + water ... dehydration synthesis E-maltose + water ... dehydration synthesis
E-maltose + water ... dehydration synthesis
A nucleotide is composed of a(n) _____. A-glycerol, a nitrogen-containing base, and a five-carbon sugar B-phosphate group, a nitrogen-containing base, and a hydrocarbon C-sulfhydryl group, a nitrogen-containing base, and a five-carbon sugar D-amino group, a nitrogen-containing base, and a five-carbon sugar E-phosphate group, a nitrogen-containing base, and a five-carbon sugar
E-phosphate group, a nitrogen-containing base, and a five-carbon sugar
Knowing the atomic mass of an element allows inferences about which of the following? A-the number of electrons in the element B-the number of protons plus electrons in the element C-the number of neutrons in the element D-the number of protons in the element E-the number of protons plus neutrons in the element
E-the number of protons plus neutrons in the element
True or false? Enzymes in the digestive tract catalyze hydrolysis reactions. True False
TRUE
True or false? Peptidoglycan is a polysaccharide found only in bacteria. True False
TRUE
