Powell: BIOL 261 - Exam II Test
Questions With 100% Correct Answers
2025-2026 Updated.
gene - Answer contains the codes for mRNA to make a protein; located in chromosomes or
in plasmids -
genetic code - Answer the correspondence between nucleic acid sequence and amino acid
sequence of proteins -
genetic element - Answer a structure that carries genetic information, such as a
chromosome, a plasmid, or a virus genome -
genome - Answer the complete instructions for making an organism, consisting of all the
genetic material in that organism's chromosomes -
nucleotide - Answer a monomer of a nucleic acid containing a nitrogenous base, one or
more molecules of phosphate, and a sugar -
nucleoside - Answer nitrogenous base + sugar; lacking a phosphate -
codon - Answer a sequence of three bases in mRNA that encodes an amino acid -
codon bias - Answer the nonrandom usage of multiple codons encoding the same amino
acid; the relative proportions of different codons encoding the same amino acid vary in different
organisms -
adenine
guanine
cytosine
thymine - Answer nitrogenous bases of DNA -
adenine
guanine
cytosine
uracil - Answer nitrogenous bases of RNA -
,adenine
guanine - Answer purine bases -
cytosine
thymine
uracil - Answer pyrimidine bases -
A-T
C-G - Answer complementary base pairs of DNA -
two - Answer how many hydrogen bonds do adenine and thymine have? -
three - Answer how many hydrogen bonds do cytosine and guanine have? -
cytosine and guanine because they have three hydrogen bonds, rather than two. - Answer
which of the complementary base pairs are stronger? -
hydrogen bonds - Answer bonds that hold together nitrogenous bases -
covalent bonds - Answer bonds that hold alternating phosphates and the pentose sugar of
the DNA backbone -
phosphodiester bond - Answer a type of covalent bond that links nucleotides together in a
polynucleotide; the linkage between the 3' carbon atom of one sugar molecule and the 5'
carbon atom of the other -
antiparallel - Answer in reference to double-stranded DNA, the two strands run in opposite
directions; one runs 5' to 3' and the complementary strand runs 3' to 5'. -
1 kilobase pair (kbp) - Answer 1,000 base pairs -
1 megabase pair (mbp) - Answer 1,000,000 base pairs -
4.64 mbp - Answer size of E. coli -
topoisomerases - Answer enzymes that inserts and removes supercoils of DNA -
, positive supercoiling - Answer right-handed coiling of DNA; clockwise -
archaea because it helps prevent DNA melting at high temperatures. - Answer in what
domain would you find positive supercoiling? -
negative supercoiling - Answer left-handed coiling of DNA; counterclockwise -
negative supercoiling - Answer what type of supercoiling is found in most cells? -
the central dogma of molecular biology explains the flow of genetic information in cells from
DNA to mRNA to a protein. - Answer what is the central dogma of molecular biology? -
gene expression - Answer conversion of the information encoded in a gene first into
messenger RNA and then to a protein -
messenger RNA - Answer type of RNA molecule that contains the genetic information to
encode one or more polypeptides -
ribosomal RNA - Answer type of RNA that combines with proteins to form ribosomes -
ribosomal RNA associates with a set of proteins to form ribosomes. these complex structures,
which physically move along an mRNA molecule, catalyze the assembly of amino acids into
protein chains. they also bind tRNAs and various accessory molecules necessary for protein
synthesis - Answer what functional roles does rRNA play in protein synthesis? -
once the completed polypeptide chain is released from the ribosome, the ribosomal subunits
dissociate and the 30S and 50S subunits are then free to form new initiate complexes and
repeat the process. - Answer what happens once the completed polypeptide chain is
released from the ribosome? -
transfer RNA - Answer type of RNA molecule that transfers amino acids to ribosomes during
protein synthesis -
origin of replication - Answer site where DNA replication begins -
replication - Answer DNA is copied and duplicated by DNA polymerase -
Questions With 100% Correct Answers
2025-2026 Updated.
gene - Answer contains the codes for mRNA to make a protein; located in chromosomes or
in plasmids -
genetic code - Answer the correspondence between nucleic acid sequence and amino acid
sequence of proteins -
genetic element - Answer a structure that carries genetic information, such as a
chromosome, a plasmid, or a virus genome -
genome - Answer the complete instructions for making an organism, consisting of all the
genetic material in that organism's chromosomes -
nucleotide - Answer a monomer of a nucleic acid containing a nitrogenous base, one or
more molecules of phosphate, and a sugar -
nucleoside - Answer nitrogenous base + sugar; lacking a phosphate -
codon - Answer a sequence of three bases in mRNA that encodes an amino acid -
codon bias - Answer the nonrandom usage of multiple codons encoding the same amino
acid; the relative proportions of different codons encoding the same amino acid vary in different
organisms -
adenine
guanine
cytosine
thymine - Answer nitrogenous bases of DNA -
adenine
guanine
cytosine
uracil - Answer nitrogenous bases of RNA -
,adenine
guanine - Answer purine bases -
cytosine
thymine
uracil - Answer pyrimidine bases -
A-T
C-G - Answer complementary base pairs of DNA -
two - Answer how many hydrogen bonds do adenine and thymine have? -
three - Answer how many hydrogen bonds do cytosine and guanine have? -
cytosine and guanine because they have three hydrogen bonds, rather than two. - Answer
which of the complementary base pairs are stronger? -
hydrogen bonds - Answer bonds that hold together nitrogenous bases -
covalent bonds - Answer bonds that hold alternating phosphates and the pentose sugar of
the DNA backbone -
phosphodiester bond - Answer a type of covalent bond that links nucleotides together in a
polynucleotide; the linkage between the 3' carbon atom of one sugar molecule and the 5'
carbon atom of the other -
antiparallel - Answer in reference to double-stranded DNA, the two strands run in opposite
directions; one runs 5' to 3' and the complementary strand runs 3' to 5'. -
1 kilobase pair (kbp) - Answer 1,000 base pairs -
1 megabase pair (mbp) - Answer 1,000,000 base pairs -
4.64 mbp - Answer size of E. coli -
topoisomerases - Answer enzymes that inserts and removes supercoils of DNA -
, positive supercoiling - Answer right-handed coiling of DNA; clockwise -
archaea because it helps prevent DNA melting at high temperatures. - Answer in what
domain would you find positive supercoiling? -
negative supercoiling - Answer left-handed coiling of DNA; counterclockwise -
negative supercoiling - Answer what type of supercoiling is found in most cells? -
the central dogma of molecular biology explains the flow of genetic information in cells from
DNA to mRNA to a protein. - Answer what is the central dogma of molecular biology? -
gene expression - Answer conversion of the information encoded in a gene first into
messenger RNA and then to a protein -
messenger RNA - Answer type of RNA molecule that contains the genetic information to
encode one or more polypeptides -
ribosomal RNA - Answer type of RNA that combines with proteins to form ribosomes -
ribosomal RNA associates with a set of proteins to form ribosomes. these complex structures,
which physically move along an mRNA molecule, catalyze the assembly of amino acids into
protein chains. they also bind tRNAs and various accessory molecules necessary for protein
synthesis - Answer what functional roles does rRNA play in protein synthesis? -
once the completed polypeptide chain is released from the ribosome, the ribosomal subunits
dissociate and the 30S and 50S subunits are then free to form new initiate complexes and
repeat the process. - Answer what happens once the completed polypeptide chain is
released from the ribosome? -
transfer RNA - Answer type of RNA molecule that transfers amino acids to ribosomes during
protein synthesis -
origin of replication - Answer site where DNA replication begins -
replication - Answer DNA is copied and duplicated by DNA polymerase -
