Bio 1500 Exam 3 UPDATED ACTUAL
Exam Questions and CORRECT Answers
Overview: The Key Roles of Cell Divisions
1. What is the cell cycle? - CORRECT ANSWER - the life of a cell from its formation to
its own division
2. What are three important functions of cell division? - CORRECT ANSWER - (a)
Reproduction
(b) Growth and
development
(c) Tissue renewal
Concept 9.1: Most cell division results in genetically identical daughter cells
3. Cellular Organization of the Genetic Material
a. What is a genome? - CORRECT ANSWER - All the DNA in a cell constitutes the cell's
genome
b. How does a prokaryotic genome differ from a eukaryotic genome? - CORRECT
ANSWER - A genome can consist of a single DNA molecule (common in prokaryotic
cells) or a number of DNA molecules (common in eukaryotic cells)
c. Before cell division, what must occur to the cellular genome? - CORRECT ANSWER -
Before the cell can divide to form genetically identical daughter cells, all of this DNA must be
copied, or replicated, and then the two copies must be separated so that each daughter cell ends
up with a complete genome.
,d. What is the shape of a eukaryotic chromosome? - CORRECT ANSWER - Each
eukaryotic chromosome consists of one very long, linear DNA molecule associated with many
proteins
e. What is chromatin? - CORRECT ANSWER - Together, the entire complex of DNA and
proteins that is the building material of chromosomes
f. What is the difference between a somatic cell and a gamete? - CORRECT ANSWER -
Somatic cells (nonreproductive cells) have two sets of chromosomes
Gametes (reproductive cells: sperm and eggs) have one set of chromosomes
g. How many chromosomes are found in the genome of a human somatic cell? - CORRECT
ANSWER - 46 chromosomes
h. How many chromosomes are found in a human gamete? - CORRECT ANSWER - 23
chromosomes
4. Distribution of Chromosomes During Eukaryotic Cell Division
a. How does the appearance of chromosomes differ during different stages of the cell cycle? -
CORRECT ANSWER - When a cell is not dividing, and even as it replicates its DNA in
preparation for cell division, each chromosome is in the form of a long, thin chromatin fiber.
After DNA replication, however, the chromosomes condense as a part of cell divi- sion: Each
chromatin fiber becomes densely coiled and folded, making the chromosomes much shorter and
so thick that we can see them with a light microscope.
b. Why is it important that chromosomes replicate prior to cell division? - CORRECT
ANSWER - so that an entire copy of the DNA that is in each sister chromatid is transferred
to the daughter cells.
c. When a chromosome duplicates prior to cell division, it consists of 2 attached sister
chromatids (see figure 9.4).
,i. How are the sister chromatids attached to each other? - CORRECT ANSWER - attached
by the centromere
ii. What is the centromere? What is its function? - CORRECT ANSWER - a region of the
chromosomal DNA where the chromatid is attached most closely to its sister chromatid.
iii. Once sister chromatids separate, what are they called? - CORRECT ANSWER -
individual chromosomes
d. In eukaryotic division, two processes must occur, mitosis and cytokinesis. What occurs in each
process? - CORRECT ANSWER - Mitosis, the division of the genetic material in the
nucleus, is usually followed immediately by cytokinesis, the division of the cytoplasm.
e. Why is mitotic cell division necessary in a multicellular eukaryotic organism? Which type of
cell is produced by mitotic cell division? - CORRECT ANSWER - From a fertilized egg,
mitosis and cytoki- nesis produced the 200 trillion somatic cells that now make up your body,
and the same processes continue to generate new cells to replace dead and damaged ones.
f. Which cellular process results in the production of gametes? - CORRECT ANSWER -
meiosis
g. Gametes have half the number of chromosomes (haploid) of a somatic cell (diploid). Why is
this important? - CORRECT ANSWER - to allow fertilization to fuse two gametes
together (sperm and egg) to create 46 chromosomes again
Concept 9.2: The mitotic phase alternates with interphase in the cell cycle
5. Phases of the Cell Cycle. The cell cycle is divided into three main phases, interphase, mitosis,
and cytokinesis.
, a. The majority of the cell cycle is spent in Interphase. Interphase can be subdivided into 3
subphases. What happens in each of these subphases:
i. G1 - CORRECT ANSWER - growth
ii. S - CORRECT ANSWER - continues to grow as it copies its chromosomes
iii. G2 - CORRECT ANSWER - grows more as it completes preparations for cell division
b. At the end of S phase, how many chromosomes will be present in the nucleus of a human
somatic cell? - CORRECT ANSWER - 92(?)
c. At the end of S phase, how many chromatids will be present in the nucleus of a human somatic
cell? - CORRECT ANSWER - 92(?)
6. The Mitotic Spindle: A Closer Look
a. Which type of protein fiber comprises the mitotic spindle? - CORRECT ANSWER -
fibers made of microtubules and associated proteins.
b. What is a centrosome? - CORRECT ANSWER - a subcellular region containing
material that functions throughout the cell cycle to organize the cell's microtubules.
c. What is the function of centrioles? - CORRECT ANSWER - A pair of centrioles is
located at the center of the centrosome, but they are not essential for cell division: If the
centrioles are destroyed with a laser microbeam, a spindle nevertheless forms during mitosis.
d. What is the function of the mitotic spindles? - CORRECT ANSWER - The spindle is
necessary to equally divide the chromosomes in a parental cell into two daughter cells during
both types of nuclear division: mitosis and meiosis
Exam Questions and CORRECT Answers
Overview: The Key Roles of Cell Divisions
1. What is the cell cycle? - CORRECT ANSWER - the life of a cell from its formation to
its own division
2. What are three important functions of cell division? - CORRECT ANSWER - (a)
Reproduction
(b) Growth and
development
(c) Tissue renewal
Concept 9.1: Most cell division results in genetically identical daughter cells
3. Cellular Organization of the Genetic Material
a. What is a genome? - CORRECT ANSWER - All the DNA in a cell constitutes the cell's
genome
b. How does a prokaryotic genome differ from a eukaryotic genome? - CORRECT
ANSWER - A genome can consist of a single DNA molecule (common in prokaryotic
cells) or a number of DNA molecules (common in eukaryotic cells)
c. Before cell division, what must occur to the cellular genome? - CORRECT ANSWER -
Before the cell can divide to form genetically identical daughter cells, all of this DNA must be
copied, or replicated, and then the two copies must be separated so that each daughter cell ends
up with a complete genome.
,d. What is the shape of a eukaryotic chromosome? - CORRECT ANSWER - Each
eukaryotic chromosome consists of one very long, linear DNA molecule associated with many
proteins
e. What is chromatin? - CORRECT ANSWER - Together, the entire complex of DNA and
proteins that is the building material of chromosomes
f. What is the difference between a somatic cell and a gamete? - CORRECT ANSWER -
Somatic cells (nonreproductive cells) have two sets of chromosomes
Gametes (reproductive cells: sperm and eggs) have one set of chromosomes
g. How many chromosomes are found in the genome of a human somatic cell? - CORRECT
ANSWER - 46 chromosomes
h. How many chromosomes are found in a human gamete? - CORRECT ANSWER - 23
chromosomes
4. Distribution of Chromosomes During Eukaryotic Cell Division
a. How does the appearance of chromosomes differ during different stages of the cell cycle? -
CORRECT ANSWER - When a cell is not dividing, and even as it replicates its DNA in
preparation for cell division, each chromosome is in the form of a long, thin chromatin fiber.
After DNA replication, however, the chromosomes condense as a part of cell divi- sion: Each
chromatin fiber becomes densely coiled and folded, making the chromosomes much shorter and
so thick that we can see them with a light microscope.
b. Why is it important that chromosomes replicate prior to cell division? - CORRECT
ANSWER - so that an entire copy of the DNA that is in each sister chromatid is transferred
to the daughter cells.
c. When a chromosome duplicates prior to cell division, it consists of 2 attached sister
chromatids (see figure 9.4).
,i. How are the sister chromatids attached to each other? - CORRECT ANSWER - attached
by the centromere
ii. What is the centromere? What is its function? - CORRECT ANSWER - a region of the
chromosomal DNA where the chromatid is attached most closely to its sister chromatid.
iii. Once sister chromatids separate, what are they called? - CORRECT ANSWER -
individual chromosomes
d. In eukaryotic division, two processes must occur, mitosis and cytokinesis. What occurs in each
process? - CORRECT ANSWER - Mitosis, the division of the genetic material in the
nucleus, is usually followed immediately by cytokinesis, the division of the cytoplasm.
e. Why is mitotic cell division necessary in a multicellular eukaryotic organism? Which type of
cell is produced by mitotic cell division? - CORRECT ANSWER - From a fertilized egg,
mitosis and cytoki- nesis produced the 200 trillion somatic cells that now make up your body,
and the same processes continue to generate new cells to replace dead and damaged ones.
f. Which cellular process results in the production of gametes? - CORRECT ANSWER -
meiosis
g. Gametes have half the number of chromosomes (haploid) of a somatic cell (diploid). Why is
this important? - CORRECT ANSWER - to allow fertilization to fuse two gametes
together (sperm and egg) to create 46 chromosomes again
Concept 9.2: The mitotic phase alternates with interphase in the cell cycle
5. Phases of the Cell Cycle. The cell cycle is divided into three main phases, interphase, mitosis,
and cytokinesis.
, a. The majority of the cell cycle is spent in Interphase. Interphase can be subdivided into 3
subphases. What happens in each of these subphases:
i. G1 - CORRECT ANSWER - growth
ii. S - CORRECT ANSWER - continues to grow as it copies its chromosomes
iii. G2 - CORRECT ANSWER - grows more as it completes preparations for cell division
b. At the end of S phase, how many chromosomes will be present in the nucleus of a human
somatic cell? - CORRECT ANSWER - 92(?)
c. At the end of S phase, how many chromatids will be present in the nucleus of a human somatic
cell? - CORRECT ANSWER - 92(?)
6. The Mitotic Spindle: A Closer Look
a. Which type of protein fiber comprises the mitotic spindle? - CORRECT ANSWER -
fibers made of microtubules and associated proteins.
b. What is a centrosome? - CORRECT ANSWER - a subcellular region containing
material that functions throughout the cell cycle to organize the cell's microtubules.
c. What is the function of centrioles? - CORRECT ANSWER - A pair of centrioles is
located at the center of the centrosome, but they are not essential for cell division: If the
centrioles are destroyed with a laser microbeam, a spindle nevertheless forms during mitosis.
d. What is the function of the mitotic spindles? - CORRECT ANSWER - The spindle is
necessary to equally divide the chromosomes in a parental cell into two daughter cells during
both types of nuclear division: mitosis and meiosis
