Cell & Molecular Biology Exam 1
Questions with Accurate Answers
Base pair - ANSWERSTwo complementary nucleotides in an RNA and a DNA molecule
that are held together by hydrogen bonds.
Cell cycle - ANSWERSThe orderly sequence of events by which a cell duplicates its
contents and divides into two.
Centromere - ANSWERSSpecialized DNA sequence that allows duplicated
chromosomes to be separated during M phase; can be seen as the constricted region of
a mitotic chromosome.
Chromatin - ANSWERSComplex of DNA and proteins that makes up the chromosomes
in a eukaryotic cell.
Chromatin-remodeling complex - ANSWERSEnzyme that uses the energy of ATP
hydrolysis to alter the arrangement of nucleosomes in eukaryotic chromosomes,
changing the accessibility of the underlying DNA to other proteins, including those
involved in transcription.
Chromosome - ANSWERSLong, threadlike structure composed of DNA and proteins
that carries the genetic information of an organism; becomes visible as a distinct entity
when a plant or animal cell prepares to divide.
Complementary - ANSWERSDescribes two molecular surfaces that fit together closely
and form noncovalent bonds with each other.
Deoxyribonucleic acid (DNA) - ANSWERSDouble-stranded polynucleotide formed from
two separate chains of covalently linked deoxyribonucleotide units. It serves as the cell's
store of genetic information that is transmitted from generation to generation.
Double helix - ANSWERSThe typical structure of a DNA molecule in which the two
complementary polynucleotide strands are wound around each other with base-pairing
between the strands.
Euchromatin - ANSWERSOne of the two main states in which chromatin exists within
an interphase cell. Prevalent in gene-rich area, its less compacted structure allows
access for proteins involved in transcription.
, Gene - ANSWERSUnit of heredity containing the instructions that dictate the
characteristics or phenotype of an organism; in molecular terms, a segment of DNA that
directs the production of a protein or functional RNA molecule.
Gene expression - ANSWERSThe process by which a gene makes a product that is
useful to the cell or organism by directing the synthesis of a protein or an RNA
molecules with a characteristic activity.
Genetic code - ANSWERSSet of rules by which the information contained in the
nucleotide sequence of a gene and its corresponding RNA molecule is translated into
the amino acid sequence in a protein.
Genome - ANSWERSThe total genetic information carried by all the chromosomes of a
cell or organism.
Heterochromatin - ANSWERSHighly condensed region of an interphase chromosome;
generally gene-poor and transcriptionally inactive.
Histone - ANSWERSOne of a group of abundant highly conserved proteins around
which DNA wraps to form nucleosomes, structures that represent the most fundamental
level of chromatin packing.
Karyotype - ANSWERSAn ordered display of the full set of chromosomes of a cell
arranged with respect to size, shape, and number.
Nucleolus - ANSWERSLarge structure within the nucleus where ribosomal RNA is
transcribed and ribosomal subunits are assembled.
Replication origin - ANSWERSNucleotide sequence at which DNA replication is
initiated.
Telomere gene - ANSWERSRepetitive nucleotide sequence that caps the ends of linear
chromosomes. Counteracts the tendency of the chromosome otherwise to shorten with
each round of replication.
Cancer - ANSWERSDisease caused by abnormal and uncontrolled cell proliferation,
followed by invasion and colonization of body sites normally reserved for other cells.
DNA ligase - ANSWERSEnzyme that reseals nicks that arise in the backbone of a DNA
molecule; in the laboratory, can be used to join together two DNA fragments.
Polymerase - ANSWERSGeneral term for an enzyme that catalyzes addition of subunits
to a nucleic acid polymer.
DNA repair - ANSWERSCollective term for the enzymatic processes that correct
deleterious changes affecting the continuity or sequence of a DNA molecule.
Questions with Accurate Answers
Base pair - ANSWERSTwo complementary nucleotides in an RNA and a DNA molecule
that are held together by hydrogen bonds.
Cell cycle - ANSWERSThe orderly sequence of events by which a cell duplicates its
contents and divides into two.
Centromere - ANSWERSSpecialized DNA sequence that allows duplicated
chromosomes to be separated during M phase; can be seen as the constricted region of
a mitotic chromosome.
Chromatin - ANSWERSComplex of DNA and proteins that makes up the chromosomes
in a eukaryotic cell.
Chromatin-remodeling complex - ANSWERSEnzyme that uses the energy of ATP
hydrolysis to alter the arrangement of nucleosomes in eukaryotic chromosomes,
changing the accessibility of the underlying DNA to other proteins, including those
involved in transcription.
Chromosome - ANSWERSLong, threadlike structure composed of DNA and proteins
that carries the genetic information of an organism; becomes visible as a distinct entity
when a plant or animal cell prepares to divide.
Complementary - ANSWERSDescribes two molecular surfaces that fit together closely
and form noncovalent bonds with each other.
Deoxyribonucleic acid (DNA) - ANSWERSDouble-stranded polynucleotide formed from
two separate chains of covalently linked deoxyribonucleotide units. It serves as the cell's
store of genetic information that is transmitted from generation to generation.
Double helix - ANSWERSThe typical structure of a DNA molecule in which the two
complementary polynucleotide strands are wound around each other with base-pairing
between the strands.
Euchromatin - ANSWERSOne of the two main states in which chromatin exists within
an interphase cell. Prevalent in gene-rich area, its less compacted structure allows
access for proteins involved in transcription.
, Gene - ANSWERSUnit of heredity containing the instructions that dictate the
characteristics or phenotype of an organism; in molecular terms, a segment of DNA that
directs the production of a protein or functional RNA molecule.
Gene expression - ANSWERSThe process by which a gene makes a product that is
useful to the cell or organism by directing the synthesis of a protein or an RNA
molecules with a characteristic activity.
Genetic code - ANSWERSSet of rules by which the information contained in the
nucleotide sequence of a gene and its corresponding RNA molecule is translated into
the amino acid sequence in a protein.
Genome - ANSWERSThe total genetic information carried by all the chromosomes of a
cell or organism.
Heterochromatin - ANSWERSHighly condensed region of an interphase chromosome;
generally gene-poor and transcriptionally inactive.
Histone - ANSWERSOne of a group of abundant highly conserved proteins around
which DNA wraps to form nucleosomes, structures that represent the most fundamental
level of chromatin packing.
Karyotype - ANSWERSAn ordered display of the full set of chromosomes of a cell
arranged with respect to size, shape, and number.
Nucleolus - ANSWERSLarge structure within the nucleus where ribosomal RNA is
transcribed and ribosomal subunits are assembled.
Replication origin - ANSWERSNucleotide sequence at which DNA replication is
initiated.
Telomere gene - ANSWERSRepetitive nucleotide sequence that caps the ends of linear
chromosomes. Counteracts the tendency of the chromosome otherwise to shorten with
each round of replication.
Cancer - ANSWERSDisease caused by abnormal and uncontrolled cell proliferation,
followed by invasion and colonization of body sites normally reserved for other cells.
DNA ligase - ANSWERSEnzyme that reseals nicks that arise in the backbone of a DNA
molecule; in the laboratory, can be used to join together two DNA fragments.
Polymerase - ANSWERSGeneral term for an enzyme that catalyzes addition of subunits
to a nucleic acid polymer.
DNA repair - ANSWERSCollective term for the enzymatic processes that correct
deleterious changes affecting the continuity or sequence of a DNA molecule.
