MCDB 1A UCSB Midterm 1 Exam Questions
with Correct Answers 2026
Condensation reaction - CORRECT ANSWER -(also called dehydration) results in the covalent
bonds between between monomers. A molecule of water is released when each covalent bond
is formed. Polymers form only if water molecules are removed and energy is added to the
system.
Hydrolysis - CORRECT ANSWER -results in the breakdown of polymers into their component
monomers. Water reacts with the covalent bonds that link the polymer together. For each
covalent bond that is broken, a water molecule splits into two ions (H+ and OH-), which each
become part of one of the products. Releases energy.
Nucleic acids - CORRECT ANSWER -polymers specialized for the storage, transmission, and use
of genetic information. Two types- DNA and RNA. grow in the 3'-5' direction
DNA - CORRECT ANSWER -macromolecule that encodes hereditary information and passes it
from one generation to another. The information encoded is used to specify the amino acid
sequences of proteins and control the expression synthesis of other RNAs. Pentose sugar is
deoxyribose. Carries genetic information in its sequence of base pairs rather than its three-
dimensional structure. Double stranded helix, right-handed helix, antiparallel, and has major
and minor grooves in which the outer edges of the nitrogenous bases are exposed.
RNA - CORRECT ANSWER -single stranded.
Nucleotide - CORRECT ANSWER -consists of a nitrogen containing base, a pentose sugar, and
one to three phosphate groups.
Phosphodiester linkage - CORRECT ANSWER -bond between two nucleotides. Occurs between
the phosphate group and the 3'-carbon on the last sugar
,DNA replication - CORRECT ANSWER -exact reproduction of DNA. Done by polymerization using
an existing strand as a base-pairing template. Depends on base pairings of nucleic acids.
Involves entire DNA molecule.
Transcription - CORRECT ANSWER -Copies DNA into RNA. Depends on base pairings of nucleic
acids. Consists of initiation, elongation, and termination
Translation - CORRECT ANSWER -Uses the nucleotide sequence in the RNA to specify a
sequence of amino acids in a polypeptide chain.
Gene expression - CORRECT ANSWER -overall process of transcription and translation.
Genome - CORRECT ANSWER -complete set of DNA in a living organism
Genes - CORRECT ANSWER -The sequences of DNA that are transcribed into RNA
Frederick Griffith - CORRECT ANSWER -demonstrated that some substance in cells can cause
heritable changes in other cells. Dead pneumonia cells continued to cause heritable change in
other cells.
Oswald Avery - CORRECT ANSWER -Identified the substance causing bacterial transformation.
We now know that the gene for the enzyme that catalyzes the synthesis of polysaccharide
capsule, which makes the bacterial colony look "smooth," was transferred into the R cells during
transformation.
Hershey and Chase - CORRECT ANSWER -discovered that DNA, not protein, enters bacterial cells
and directs the assembly of new viruses.
, Chargraffs rule - CORRECT ANSWER -In any DNA sample, the amount of adenine equals the
amount of thymine, and the amount of guanine equals the amount of cytosine. As a result, the
total abundance of purines (A+G) equals the total abundance of pyramidines (T+C)
Watson and Crick - CORRECT ANSWER -proposed that the two strands in dna are antiparallel
Polynucleotide - CORRECT ANSWER -phosphate group at 5' end and OH- group at 3' end. 5' end
is paired with the 3'end of another nucleotide
Semiconservative DNA replication - CORRECT ANSWER -each parent strand serves as a template
for a new strand, and the two new DNA molecules have one old and one new strand. 2 steps-
the double-helix is unwound to separate the two template strands and make them available for
new base pairing. As new nucleotides form complementary base pairs with the template DNA,
they are covalently linked together by phosphodiester bonds, forming a polymer whose base
sequence is complementary to the bases in the template strand.
DNA primer - CORRECT ANSWER -a short single strand of RNA. it is complementary to the DNA
template and is synthesized one nucleotide at a time by an enzyme called primase.
DNA polymerase - CORRECT ANSWER -catalyzes the addition of nucleotides to the 3' end of
each strand.
DNA helicase - CORRECT ANSWER -uses energy from ATP hydrolysis to unwind and separate the
strands, and single-stranded binding proteins bind to the unwound strands to keep them from
reassociating into a double helix.
Leading Strand - CORRECT ANSWER -newly replicating strand. Oriented so that it can grow
continuously at its 3' end as the replication fork opens up.
with Correct Answers 2026
Condensation reaction - CORRECT ANSWER -(also called dehydration) results in the covalent
bonds between between monomers. A molecule of water is released when each covalent bond
is formed. Polymers form only if water molecules are removed and energy is added to the
system.
Hydrolysis - CORRECT ANSWER -results in the breakdown of polymers into their component
monomers. Water reacts with the covalent bonds that link the polymer together. For each
covalent bond that is broken, a water molecule splits into two ions (H+ and OH-), which each
become part of one of the products. Releases energy.
Nucleic acids - CORRECT ANSWER -polymers specialized for the storage, transmission, and use
of genetic information. Two types- DNA and RNA. grow in the 3'-5' direction
DNA - CORRECT ANSWER -macromolecule that encodes hereditary information and passes it
from one generation to another. The information encoded is used to specify the amino acid
sequences of proteins and control the expression synthesis of other RNAs. Pentose sugar is
deoxyribose. Carries genetic information in its sequence of base pairs rather than its three-
dimensional structure. Double stranded helix, right-handed helix, antiparallel, and has major
and minor grooves in which the outer edges of the nitrogenous bases are exposed.
RNA - CORRECT ANSWER -single stranded.
Nucleotide - CORRECT ANSWER -consists of a nitrogen containing base, a pentose sugar, and
one to three phosphate groups.
Phosphodiester linkage - CORRECT ANSWER -bond between two nucleotides. Occurs between
the phosphate group and the 3'-carbon on the last sugar
,DNA replication - CORRECT ANSWER -exact reproduction of DNA. Done by polymerization using
an existing strand as a base-pairing template. Depends on base pairings of nucleic acids.
Involves entire DNA molecule.
Transcription - CORRECT ANSWER -Copies DNA into RNA. Depends on base pairings of nucleic
acids. Consists of initiation, elongation, and termination
Translation - CORRECT ANSWER -Uses the nucleotide sequence in the RNA to specify a
sequence of amino acids in a polypeptide chain.
Gene expression - CORRECT ANSWER -overall process of transcription and translation.
Genome - CORRECT ANSWER -complete set of DNA in a living organism
Genes - CORRECT ANSWER -The sequences of DNA that are transcribed into RNA
Frederick Griffith - CORRECT ANSWER -demonstrated that some substance in cells can cause
heritable changes in other cells. Dead pneumonia cells continued to cause heritable change in
other cells.
Oswald Avery - CORRECT ANSWER -Identified the substance causing bacterial transformation.
We now know that the gene for the enzyme that catalyzes the synthesis of polysaccharide
capsule, which makes the bacterial colony look "smooth," was transferred into the R cells during
transformation.
Hershey and Chase - CORRECT ANSWER -discovered that DNA, not protein, enters bacterial cells
and directs the assembly of new viruses.
, Chargraffs rule - CORRECT ANSWER -In any DNA sample, the amount of adenine equals the
amount of thymine, and the amount of guanine equals the amount of cytosine. As a result, the
total abundance of purines (A+G) equals the total abundance of pyramidines (T+C)
Watson and Crick - CORRECT ANSWER -proposed that the two strands in dna are antiparallel
Polynucleotide - CORRECT ANSWER -phosphate group at 5' end and OH- group at 3' end. 5' end
is paired with the 3'end of another nucleotide
Semiconservative DNA replication - CORRECT ANSWER -each parent strand serves as a template
for a new strand, and the two new DNA molecules have one old and one new strand. 2 steps-
the double-helix is unwound to separate the two template strands and make them available for
new base pairing. As new nucleotides form complementary base pairs with the template DNA,
they are covalently linked together by phosphodiester bonds, forming a polymer whose base
sequence is complementary to the bases in the template strand.
DNA primer - CORRECT ANSWER -a short single strand of RNA. it is complementary to the DNA
template and is synthesized one nucleotide at a time by an enzyme called primase.
DNA polymerase - CORRECT ANSWER -catalyzes the addition of nucleotides to the 3' end of
each strand.
DNA helicase - CORRECT ANSWER -uses energy from ATP hydrolysis to unwind and separate the
strands, and single-stranded binding proteins bind to the unwound strands to keep them from
reassociating into a double helix.
Leading Strand - CORRECT ANSWER -newly replicating strand. Oriented so that it can grow
continuously at its 3' end as the replication fork opens up.
