MCAT Quiz 1 Final Questions
A nucleotide is composed of a nitrogenous base, a phosphate group, and a pentose sugar. a nitrogenous base and a phosphate group. a nitrogenous base and a pentose sugar. a nitrogenous base, a phosphate group, a pentose sugar, and an amino acid.
a nitrogenous base, a phosphate group, and a pentose sugar.
A double-stranded DNA molecule contains a total of 120 base pairs. This DNA molecule could be composed of 50 adenine, 70 guanine, 70 cytosine, and 50 thymine molecules. 40 adenine, 20 guanine, 20 cytosine, and 40 uracil molecules. 120 adenine and 120 guanine molecules. 30 adenine, 30 guanine, 30 cytosine, and 30 thymine molecules.
50 adenine, 70 guanine, 70 cytosine, and 50 thymine molecules.
Normal hemoglobin is a tetramer, consisting of two molecules of 𝛽-globin and two molecules of 𝛼-globin. In sickle-cell disease, because of a single amino acid change, the mutant hemoglobin tetramers associate with each other and assemble into large fibers. Based on this information alone, we can conclude that sickle-cell hemoglobin exhibits: Altered primary structure only Altered tertiary structure only Altered secondary and tertiary structures: the primary and quaternary structures may or mary not be altered Altered quaternary structure only Altered primary structure and altered quaternary structure: the secondary and tertiary structures may or may not be altered
Altered primary structure and altered quaternary structure: the secondary and tertiary structures may or may not be altered
Which of the following is a monomer used to build a biological polymer? Amino Acid Disaccharide Triglyceride DNA
Amino Acid
Which of the following is found in the RNA but not the DNA of a living cell? Thymine A double helix An additional hydroxyl group Hydrogen bonds
An additional hydroxyl group
Which of the following hydrocarbons has a double bond in its carbon skeleton? C3H8 C2H6 C2H4 C2H2
C2H4
Which two functional groups are always found in amino acids? Hydroxyl and carboxyl Carbonyl and Amino Ketone and Amino Carboxyl and amino
Carboxyl and amino
Which of the following best summarizes the relationship between dehydration reactions and hydrolysis? Dehydration reactions split water molecules and add hydroxyl groups to polymers and hydrolysis reactions remove hydroxyl groups from polymers Dehydration reactions assemble polymers and hydrolysis reactions break down polymers. Dehydration reactions create monomers, and hydrolysis reactions assemble polymers. Dehydration reactions breakdown polymers, and hydrolysis reactions create monomers.
Dehydration reactions assemble polymers and hydrolysis reactions break down polymers.
Metabolism of carbohydrates and fat spare protein tissue. All of the following are true of fats EXCEPT: Fats may be used in cell structure Fats may be used as hormones Fats are a more efficient from of energy storage than proteins Fats are a less effective form of energy storage than carbohydrates.
Fats are a less effective form of energy storage than carbohydrates.
One of the primary functions of RNA molecules is to Transmit genetic information to offspring Function in the synthesis of proteins Make a copy of itself, thus ensuring genetic continuity Act as a pattern or blueprint to from DNA
Function in the synthesis of proteins
What maintains the secondary structure of a protein? Peptide bonds between adjacent amino acids Hydrogen bonds between the amino group of one peptide bond and the carboxyl group of another peptide bond Disulfide bonds between the amino group of one peptide bond and the R group of another amino acid Hydrogen bonds between the carboxyl group of one peptide bond and the R group of another amino acid
Hydrogen bonds between the amino group of one peptide bond and the carboxyl group of another peptide bond
The most common catabolic reaction in the human body is: Dehydration Hydrolysis Condensation Elimination
Hydrolysis
Which of the following is always true concerning the base composition of DNA? In each single strand, the number of adenine residues equals the number of thymine bases In each single strand, the number of adenine residues equals the number of guanine bases. In a molecule of double stranded DNA, the ratio of adenine bases to thymine bases equals the ratio of cytosine to guanine bases. In a molecule of double stranded DNA, the number of adenine bases plus thymine bases equals the number of cytosine bases plus guanine bases.
In a molecule of double stranded DNA, the ratio of adenine bases to thymine bases equals the ratio of cytosine to guanine bases.
Which of the following statements about saturation is FALSE? It can describe the number of double or triple bond in a fatty acid tail It determine at least one of the properties of membrane More Saturated fatty acids make for a more fluid solution Fully saturated fatty acids have only single bonds.
More Saturated fatty acids make for a more fluid solution
The tertiary structure of a polypeptide is the: Linear sequence of amino acids in a polypeptide Localized region of a polypeptide chain that forms an alpha helix or beta pleated sheet Overall three-dimensional shape of a fully folded polypeptide Overall three-dimensional shape of a protein composed of more than one
Overall three-dimensional shape of a fully folded polypeptide polypeptide
Which bonds are created during the formation of the primary structure of a protein? Disulfide bonds Hydrogen bonds Peptide bonds Phosphodiester bonds
Peptide bonds
Which of the following large biological molecules will self-assemble into a bilayer when mixed with water? Steroids Triacylglycerols Cellulose Phospholipids
Phospholipids
A molecule of DNA contains all of the following EXCEPT: Deoxyribose sugars Polypeptide binds Phosphodiester bonds Nitrogenous bases
Polypeptide binds
The structural level of a protein least affected by a disruption in hydrogen bonding is the: Primary level Secondary level Tertiary Level Quaternary level
Primary level
Approximately 32 different monomeric carbohydrate subunits are found in various natural polysaccharides. Proteins are composed of 20 different amino acids. DNA and RNA are each synthesized from four nucleotides. Which class of biological polymer has the greatest functional variety? Polysaccharides Proteins DNA RNA
Proteins
Bonds formed between the side chains (R-groups) in a polypeptide are most important in stabilizing which of the following? Primary structure Secondary structure Tertiary structure Quaternary structure
Quaternary structure
Which of the following is a carbohydrate polymer that is stored in plants and digestible by animals? Starch Glycogen Cellulose Glucose
Starch
Polysaccharides, triacylglycerols, and proteins are similar in that they are: Synthesized from monomers by hydrolysis reactions Synthesized from monomers by dehydration reactions Synthesized through the formation of peptide bonds between monomers Broken down into their subunits by dehydration reactions
Synthesized from monomers by dehydration reactions
Proline is not technically an 𝛼-amino acid. Due to the ring structure of proline, it cannot conform to the geometry of the 𝛼-helix and creates a bend in the polypeptide chain. This phenomenon assists in the creation of what level of protein structure? Primary Secondary Tertiary Quaternary
Tertiary
Excessive amounts of nitrogen are found in the urine of an individual who has experienced a period of extended fasting. This is most likely due to: Glycogenolysis in the liver The breakdown of body proteins Lipolysis in adipose tissue A tumor on the posterior pituitary causing excessive ADH secretion
The breakdown of body proteins
A nutritional supplement developed for athletes is shown to contain only carbon, hydrogen, nitrogen, and oxygen. Based on these data you may safely conclude that: The food does not contain protein The food does not contain nucleic acids The food does not contain carbohydrates The food does not contain lipids.
The food does not contain nucleic acids
Which of the following statements accurately describes a similarity between the nucleotides of DNA and RNA? The nucleotides of DNA and RNA are connected through hydrogen bonds to a form the sugar-phosphate backbone The nucleotides of DNA and RNA contain a five-carbon sugar bonded to a phosphate group and a nitrogenous base The nucleotides of DNA and RNA contain the same nitrogenous bases The nucleotides of DNA and RNA contain the same five-carbon sugar
The nucleotides of DNA and RNA contain a five-carbon sugar bonded to a phosphate group and a nitrogenous base
A team of virologists has isolated a nucleic acid sample from a newly discovered virus. In order to classify the virus, they need to figure out whether the viral nucleic acid is RNA or DNA. Which of the following characteristics of the nucleic acid sample would best help classify the viral nucleic acid as DNA or RNA? The nucleotides of the virus contain phosphate group The nucleotides of the virus contain a five-carbon sugar The nucleotides of the virus contain covalent bonds The nucleotides of the virus contain uracil.
The nucleotides of the virus contain uracil.
Enzymes that break down DNA catalyze the hydrolysis of the covalent bonds that join nucleotides together. What would happen to DNA molecules treated with these enzymes? The two strands of the double helix would separate The phosphodiester linkages of the polynucleotide backbone would be broken. The pyrimidines would be separated from the deoxyribose sugars All bases would be separated form the deoxyribose
The phosphodiester linkages of the polynucleotide backbone would be broken.
Which of these statements concerning peptide bonds is FALSE? Their formation involves a reaction between an amino group and a carboxyl group. They are the primary bonds that hold amino acids together. They have a partial double bond character. Their formation involves hydration reactions.
Their formation involves hydration reactions.
Which of the following statements concerning unsaturated fats is true? They are more common in animals than in plants They have double bonds in their fatty acid chains They generally solidify at room temperature They contain more hydrogen than saturated fats having the same number of carbon atoms.
They have double bonds in their fatty acid chains
Cowpox is classified as a DNA virus because its genome, or genetic material, consists of double-stranded DNA. Which of the following claims is best supported by this information? Cowpox contains a five-carbon sugar called ribose in its nucleic acid structure. Cowpox has a single-stranded nucleic acid structure. Uracil nucleotides are not found in the cowpox genome. Thymine nucleotides are not found in the cowpox genome.
Uracil nucleotides are not found in the cowpox genome.
Like cellulose, chitin is a polysaccharide that cannot be digested by animals.. Chitin differs from cellulose by possessing an acetyl-amino group at the second carbon. What molecules is a reactant in the breaking of the 𝛽-1, 4-glycoside linkages of cellulose and chitin? Water Oxygen 𝛼-1, 4-glucosidase 𝛽-1, 4-glucosidase
Water
B1 Lactase is an enzyme composed of a single polypeptide that hydrolyzes the disaccharide lactose to produce monosaccharides. The optimal pH for lactase activity is 6. Transfer of lactase to pH 5 results in a substantial decrease in enzyme activity, likely due to the disruption of the secondary and tertiary structures of the enzyme. the secondary, tertiary, and quaternary structures of the enzyme. only the primary structure of the enzyme. the primary and secondary structures of the enzyme.
only the primary structure of the enzyme.
