BIO 235 (Kovacs) Exam 1 Questions and
Answers 100% Correct
what are the phases G1, S, and G2 collectively called? interphase
during what phase in interphase does the cell grow in volume? G1
what is the name of the phase a cell is in when progression through the cell cycle is postponed or
when a cell decides to never divide again? (ex: nerve cells) G0
what are the cells called who decide to never divide again? terminally differentiated cells
or post-mitotic cells
during what phase in interphase are the chromosomes replicated? S
two copies of a replicated chromosome chromatids
two copies of a replicated chromosome joined at the centromere sister chromatids
during what phase in interphase does the cell accumulate the materials and molecular machinery
that are necessary for nuclear and cellular division? G2
what is the difference between a kinetochore and a centromere? kinetochore are the
proteins attached to the centromere and the centromere is the DNA that is hidden beneath the
kinetochore proteins
during what phase are the chromosomes relaxed and unable to be seen individually under a
microscope? interphase
,by the end of interphase, what has happened to the chromosomes? they have already
replicated, but the pairs of sister chromatids are not seen until prophase
what is the name of the point of origin of the mitotic spindle centrosome
what happens to the centrosome in interphase? it divides
what are the key events that happen in prophase? nuclear envelope begins to dissociate
into small vesicles, chromatids condense into more compact structures, centrosomes begin to
separate, and the mitotic spindle apparatus is formed
what is the mitotic spindle apparatus composed of? microtubules
what are the key events that happen in prometaphase? centrosomes move to opposite
ends of the cell (forming spindle poles), spindle fibers interact with the sister chromatids,
kinetochore microtubules grow from the two poles, and the two kinetochores on a pair of sister
chromatids are attached to microtubules from opposite poles
what are the key events that happen in metaphase? chromosomes (pairs of sister
chromatids) align themselves along the metaphase plate and each pair of chromatids is attached
to both poles by kinetochore microtubules
what are the key events that happen in anaphase? the connection holding the sister
chromatids together is broken, each chromatid (now an individual chromosome) is linked to only
one pole, kinetochore microtubules shorten, chromosomes move to opposite poles, polar
microtubules lengthen and move further away from each other
what are the key events that happen in telophase and cytokinesis? chromosomes reach
their respective poles and decondense, nuclear membrane reforms to form two separate nuclei
what forms during cytokinesis in animals? cleavage furrow
, what forms during cytokinesis in plants? cell plate
mitosis ensures what? a diploid mother cell generates two daughter cells that are diploid
and genetically identical to the mother cell
why is mitosis so important? it maintains the same genome in every somatic cell
throughout the entire lifespan of an organism
how does mitosis maintain the same genome in every somatic cell throughout the entire lifespan
of an organism by making exact copies of the DNA (sister chromatids) during S phase
and passing both full sets of chromosomes to the new cells
what does meiosis produce? four genetically different haploid cells
why is meiosis so important? it is a division that results in a combinatorial change of the
genetic information which leads to genetic diversity due to crossing over
are the products of meiosis haploid or diploid? haploid
do the products of meiosis contain one or two sets of chromosomes? one
how many chromosomes does a human gamete contain? 23
how many chromosomes does a human autosomal cell contain? 46
simplified steps of meiosis chromosomes duplicate once before meiosis I, nucleus divides
once in meiosis I (interkinesis), and the nucleus divides once again in meiosis II (cytokinesis)
Answers 100% Correct
what are the phases G1, S, and G2 collectively called? interphase
during what phase in interphase does the cell grow in volume? G1
what is the name of the phase a cell is in when progression through the cell cycle is postponed or
when a cell decides to never divide again? (ex: nerve cells) G0
what are the cells called who decide to never divide again? terminally differentiated cells
or post-mitotic cells
during what phase in interphase are the chromosomes replicated? S
two copies of a replicated chromosome chromatids
two copies of a replicated chromosome joined at the centromere sister chromatids
during what phase in interphase does the cell accumulate the materials and molecular machinery
that are necessary for nuclear and cellular division? G2
what is the difference between a kinetochore and a centromere? kinetochore are the
proteins attached to the centromere and the centromere is the DNA that is hidden beneath the
kinetochore proteins
during what phase are the chromosomes relaxed and unable to be seen individually under a
microscope? interphase
,by the end of interphase, what has happened to the chromosomes? they have already
replicated, but the pairs of sister chromatids are not seen until prophase
what is the name of the point of origin of the mitotic spindle centrosome
what happens to the centrosome in interphase? it divides
what are the key events that happen in prophase? nuclear envelope begins to dissociate
into small vesicles, chromatids condense into more compact structures, centrosomes begin to
separate, and the mitotic spindle apparatus is formed
what is the mitotic spindle apparatus composed of? microtubules
what are the key events that happen in prometaphase? centrosomes move to opposite
ends of the cell (forming spindle poles), spindle fibers interact with the sister chromatids,
kinetochore microtubules grow from the two poles, and the two kinetochores on a pair of sister
chromatids are attached to microtubules from opposite poles
what are the key events that happen in metaphase? chromosomes (pairs of sister
chromatids) align themselves along the metaphase plate and each pair of chromatids is attached
to both poles by kinetochore microtubules
what are the key events that happen in anaphase? the connection holding the sister
chromatids together is broken, each chromatid (now an individual chromosome) is linked to only
one pole, kinetochore microtubules shorten, chromosomes move to opposite poles, polar
microtubules lengthen and move further away from each other
what are the key events that happen in telophase and cytokinesis? chromosomes reach
their respective poles and decondense, nuclear membrane reforms to form two separate nuclei
what forms during cytokinesis in animals? cleavage furrow
, what forms during cytokinesis in plants? cell plate
mitosis ensures what? a diploid mother cell generates two daughter cells that are diploid
and genetically identical to the mother cell
why is mitosis so important? it maintains the same genome in every somatic cell
throughout the entire lifespan of an organism
how does mitosis maintain the same genome in every somatic cell throughout the entire lifespan
of an organism by making exact copies of the DNA (sister chromatids) during S phase
and passing both full sets of chromosomes to the new cells
what does meiosis produce? four genetically different haploid cells
why is meiosis so important? it is a division that results in a combinatorial change of the
genetic information which leads to genetic diversity due to crossing over
are the products of meiosis haploid or diploid? haploid
do the products of meiosis contain one or two sets of chromosomes? one
how many chromosomes does a human gamete contain? 23
how many chromosomes does a human autosomal cell contain? 46
simplified steps of meiosis chromosomes duplicate once before meiosis I, nucleus divides
once in meiosis I (interkinesis), and the nucleus divides once again in meiosis II (cytokinesis)
