BS 161 MSU EXAMINATION SOLUTIONS
GUIDE 2026 FULL ANSWERS GRADED A+
⫸ Most of the cells in the human body, with the exception of the
gametes, contain _______ chromosomes?. Answer: 46
⫸ homologous chromosomes. Answer: Pairs of chromosomes,
matching in size and appearance, that carry the same set of genes; one
of each pair was received from the mother, the other from the father.
⫸ sex chromosome. Answer: Any of the chromosomes associated
with sex.
⫸ haploid. Answer: Describes a cell with one complete set of
chromosomes.
⫸ diploid. Answer: Describes a cell with two complete sets of
chromosomes.
⫸ sister chromatids. Answer: The two copies of a chromosome
produced by DNA replication.
⫸ centromere. Answer: A constriction that physically holds sister
chromatids together; the site of the attachment of the spindle fibers
that move the chromosome in cell division.
,⫸ Which DNA sequences are more alike: a pair of sister chromatids
or a pair of homologous chromosomes?. Answer: Sister chromatids
are the result of DNA replication during S phase, and so they have
identical DNA sequences (with the exception of a few changes due to
rare mutations). The two homologous chromosomes are inherited
from two different parents. The DNA sequences of these
chromosomes are therefore similar, but not identical.
⫸ prophase. Answer: The stage of mitosis characterized by the
appearance of visible chromosomes.
⫸ mitotic spindle. Answer: A structure in the cytosol made up
predominantly of microtubules that pull the chromosomes into
separate daughter cells.
⫸ centrosome. Answer: A compact structure that is the microtubule
organizing center for animal cells.
⫸ prometaphase. Answer: The stage of mitosis in which the nuclear
envelope breaks down and the microtubules of the mitotic spindle
attach to chromosomes.
⫸ kinetochore. Answer: The protein complexes on a chromatid
where spindle fibers attach.
⫸ metaphase. Answer: The stage of mitosis in which the
chromosomes are aligned in the middle of the dividing cell.
,⫸ anaphase. Answer: The stage of mitosis in which the sister
chromatids separate.
⫸ telophase. Answer: The stage of mitosis in which the nuclei of the
daughter cells are formed and the chromosomes uncoil to their
original state.
⫸ contractile ring. Answer: In animal cells, a ring of actin filaments
that forms at the equator of the cell perpendicular to the axis of what
was the spindle at the beginning of cytokinesis.
⫸ phragmoplast. Answer: In dividing plant cells, a structure formed
by overlapping microtubules that guide vesicles containing cell wall
components to the middle of the cell.
⫸ What would be the consequence if a cell underwent mitosis but
not cytokinesis?. Answer: A cell that undergoes mitosis but not
cytokinesis will become a single cell with two nuclei (and therefore
with twice the normal amount of DNA); this type of cell is called a
multinucleate cell.
⫸ cyclin. Answer: A regulatory protein whose levels rise and fall
with each round of the cell cycle.
, ⫸ cyclin-dependent kinase (CDK). Answer: A kinase that is always
present within the cell but active only when bound to the appropriate
cyclin.
⫸ checkpoint. Answer: One of multiple regulatory mechanism that
coordinate the temporal sequence of events in the cell cycle.
⫸ p53. Answer: When DNA is damaged by radiation, a specific
protein kinase is activated that phosphorylates a protein called p53.
Phosphorylated p53 binds to DNA, where it turns on the expression of
several genes.
⫸ oncogene. Answer: A cancer-causing gene.
⫸ proto-oncogene. Answer: The normal cellular gene counterpart to
an oncogene, which is similar to a viral oncogene but can cause
cancer only when mutated.
⫸ tumor suppressors. Answer: A family of genes that encode
proteins whose normal activities inhibit cell division.
⫸ benign. Answer: is relatively slow growing and does not invade
the surrounding tissue
⫸ malignant. Answer: it grows rapidly and invades surrounding
tissues
GUIDE 2026 FULL ANSWERS GRADED A+
⫸ Most of the cells in the human body, with the exception of the
gametes, contain _______ chromosomes?. Answer: 46
⫸ homologous chromosomes. Answer: Pairs of chromosomes,
matching in size and appearance, that carry the same set of genes; one
of each pair was received from the mother, the other from the father.
⫸ sex chromosome. Answer: Any of the chromosomes associated
with sex.
⫸ haploid. Answer: Describes a cell with one complete set of
chromosomes.
⫸ diploid. Answer: Describes a cell with two complete sets of
chromosomes.
⫸ sister chromatids. Answer: The two copies of a chromosome
produced by DNA replication.
⫸ centromere. Answer: A constriction that physically holds sister
chromatids together; the site of the attachment of the spindle fibers
that move the chromosome in cell division.
,⫸ Which DNA sequences are more alike: a pair of sister chromatids
or a pair of homologous chromosomes?. Answer: Sister chromatids
are the result of DNA replication during S phase, and so they have
identical DNA sequences (with the exception of a few changes due to
rare mutations). The two homologous chromosomes are inherited
from two different parents. The DNA sequences of these
chromosomes are therefore similar, but not identical.
⫸ prophase. Answer: The stage of mitosis characterized by the
appearance of visible chromosomes.
⫸ mitotic spindle. Answer: A structure in the cytosol made up
predominantly of microtubules that pull the chromosomes into
separate daughter cells.
⫸ centrosome. Answer: A compact structure that is the microtubule
organizing center for animal cells.
⫸ prometaphase. Answer: The stage of mitosis in which the nuclear
envelope breaks down and the microtubules of the mitotic spindle
attach to chromosomes.
⫸ kinetochore. Answer: The protein complexes on a chromatid
where spindle fibers attach.
⫸ metaphase. Answer: The stage of mitosis in which the
chromosomes are aligned in the middle of the dividing cell.
,⫸ anaphase. Answer: The stage of mitosis in which the sister
chromatids separate.
⫸ telophase. Answer: The stage of mitosis in which the nuclei of the
daughter cells are formed and the chromosomes uncoil to their
original state.
⫸ contractile ring. Answer: In animal cells, a ring of actin filaments
that forms at the equator of the cell perpendicular to the axis of what
was the spindle at the beginning of cytokinesis.
⫸ phragmoplast. Answer: In dividing plant cells, a structure formed
by overlapping microtubules that guide vesicles containing cell wall
components to the middle of the cell.
⫸ What would be the consequence if a cell underwent mitosis but
not cytokinesis?. Answer: A cell that undergoes mitosis but not
cytokinesis will become a single cell with two nuclei (and therefore
with twice the normal amount of DNA); this type of cell is called a
multinucleate cell.
⫸ cyclin. Answer: A regulatory protein whose levels rise and fall
with each round of the cell cycle.
, ⫸ cyclin-dependent kinase (CDK). Answer: A kinase that is always
present within the cell but active only when bound to the appropriate
cyclin.
⫸ checkpoint. Answer: One of multiple regulatory mechanism that
coordinate the temporal sequence of events in the cell cycle.
⫸ p53. Answer: When DNA is damaged by radiation, a specific
protein kinase is activated that phosphorylates a protein called p53.
Phosphorylated p53 binds to DNA, where it turns on the expression of
several genes.
⫸ oncogene. Answer: A cancer-causing gene.
⫸ proto-oncogene. Answer: The normal cellular gene counterpart to
an oncogene, which is similar to a viral oncogene but can cause
cancer only when mutated.
⫸ tumor suppressors. Answer: A family of genes that encode
proteins whose normal activities inhibit cell division.
⫸ benign. Answer: is relatively slow growing and does not invade
the surrounding tissue
⫸ malignant. Answer: it grows rapidly and invades surrounding
tissues
