BIO 1500 EXAM #3 QUESTIONS WITH
VERIFIED ANSWERS
13. Loss of Cell Cycle Control in Cancer Cells
a. What are some ways a cancer cell differs from a normal cell? - ANSWER-normal
cells divide only about 20 to 50 times before they stop dividing, age, and die, while
cancer cells divide nonstop. cancer cells evade the normal controls that trigger a cell
to undergo a type of programmed cell death called apoptosis when something is
wrong—for example, when an irreparable mistake has occurred during DNA
replication preceding mitosis.
They also do not exhibit anchorage dependence or density-dependent inhibition.
b. What is transformation? - ANSWER-Cells in culture that acquire the ability to
divide indefinitely are said to have undergone a process called transformation,
causing them to behave (in cell division, at least) like cancer cells.
c. What is the difference between a benign and a malignant tumor? - ANSWER-if the
cell evades destruction, it may proliferate and form a tumor, a mass of abnormal
cells within otherwise nor- mal tissue. The abnormal cells may remain at the original
site if they have too few genetic and cellular changes to survive at another site. In
that case, the tumor is called a benign tumor.
d. What occurs in metastasis? - ANSWER-Cancer cells may also secrete signaling
molecules that cause blood vessels to grow to- ward the tumor. A few tumor cells
may separate from the origi- nal tumor, enter blood vessels and lymph vessels, and
travel to other parts of the body. There, they may proliferate and form a new tumor.
This spread of cancer cells to locations distant from their original site is called
metastasis
e. What are two methods of treating cancerous cells? - ANSWER-A tumor that
appears to be localized may be treated with high-energy radiation, which damages
DNA in cancer cells much more than DNA in normal cells, apparently because the
majority of cancer cells have lost the ability to repair such damage. To treat known or
suspected metastatic tumors, che- motherapy is used, in which drugs that are toxic
to actively dividing cells are administered through the circulatory system.
Overview: Variations on a Theme
1. Genetics is the study of heredity and variation. Define these terms. - ANSWER-
Heredity is the transmission of traits from one generation to the next
Variation is demonstrated by the differences in appearance that offspring show from
parents and siblings
Concept 10.1: Offspring acquire genes from parents by inheriting chromosomes
9. Binary Fission in Bacteria: Prokaryotic cells divide by a different process called
binary fission.
,a. Binary fission is asexual reproduction. What does this mean? - ANSWER-The
term binary fission, mean- ing "division in half," refers to this process and to the
asexual reproduction of single-celled eukaryotes, such as the amoeba
b. Describe the structure of the bacterial chromosome. - ANSWER-consists of a
circular DNA molecule and associated proteins.
c. In the bacterium E. coli, cell division is initiated with DNA replication. What is an
origin of replication? - ANSWER-In E. coli, the process of cell division is initiated
when the DNA of the bacterial chromosome begins to replicate at a specific place on
the chromosome called the origin of replication, producing two origins.
d. After DNA replication what occurs in the remainder of binary fission? - ANSWER-
When replication is complete and the bacterium has reached about twice its initial
size, its plasma membrane pinches inward, dividing the parent E. coli cell into two
daughter cells
Concept 9.3: The eukaryotic cell cycle is regulated by a molecular control system
11. Frequency of cellular division varies among both plant and animal cells.
a. What is an example of a human cell that divides regularly? - ANSWER-human
skin cells
b. What is an example of a human cell that divides only when necessary (repair)? -
ANSWER-liver cells
c. What is an example of a human cell that never divides in a mature human? -
ANSWER-nerve cells and muscle cells
12. Checkpoints of the cell Cycle Control System
a. Why is cell cycle control important? - ANSWER-These signals report whether
crucial cellular processes that should have occurred by that point have in fact been
completed correctly and thus whether or not the cell cycle should proceed
b. What is a cell cycle checkpoint? - ANSWER-a control point where stop and go-
ahead signals can regulate the cycle.
c. Sometimes cells exit the cell cycle and enter G0. What are some reasons a cell
would exit the cell cycle? - ANSWER-cells fail to divide if an essential nutrient is
lacking in the culture medium.
And even if all other conditions are favorable, most types of mammalian cells divide
in culture only if the growth medium includes specific growth factors.
d. What is the function of growth factors in the regulation of the cell cycle? -
ANSWER-a growth factor is a protein released by certain cells that stimulates other
cells to divide. Different cell types respond specifically to different growth factors or
combinations of growth factors.
, e. There are some external physical factors that affect normal mammalian division.
Explain how the following impact cell division:
i. Density-dependent inhibition: - ANSWER-a phenomenon in which crowded cells
stop dividing.
cultured cells normally divide until they form a single layer of cells on the inner
surface of a culture flask, at which point the cells stop dividing. If some cells are
removed, those bordering the open space begin di- viding again and continue until
the vacancy is filled.
ii. Anchorage dependence: - ANSWER-To divide, they must be attached to a
substra- tum, such as the inside of a culture flask or the extracellular matrix of a
tissue.
2. Inheritance of Genes
a. Parents pass down physical characteristics called traits by passing genes to their
children. What is a gene? - ANSWER-Genes are the units of heredity and are made
up of segments of DNA
b. What type of information is provided by a gene? - ANSWER-The genetic program
is written in the language of DNA, the polymer of four different nucleotides
c. Gametes are the vehicles to transmit genes into the next generation. What is a
gamete? - ANSWER-reproductive cells (sperm and eggs)
d. Where is the majority of DNA located in a eukaryotic cell? In what form is DNA
found? - ANSWER-the DNA of a eukaryotic cell is packaged into chromosomes
within the nucleus.
e. How do gametes differ from somatic cells? Give an example of each. - ANSWER-
somatic cells have 46 chromosomes while gametes have 23
f. What is a gene locus? - ANSWER-A gene's specific location along the length of a
chromosome is called the gene's locus
3. Comparison of Asexual and Sexual reproduction
a. What occurs in asexual reproduction? Give an example of a prokaryote and a
eukaryote capable of asexual reproduction. - ANSWER-In asexual reproduction, a
single individual passes genes to its offspring without the fusion of gametes
single-celled eukaryotic organisms can reproduce asexually by mitotic cell division,
in which DNA is copied and allocated equally to two daughter cells.
Some multicellular organisms are also capable of reproducing asexually
b. Asexual reproduction results in the production of a clone. What is a clone? -
ANSWER-a group of genetically identical individuals
VERIFIED ANSWERS
13. Loss of Cell Cycle Control in Cancer Cells
a. What are some ways a cancer cell differs from a normal cell? - ANSWER-normal
cells divide only about 20 to 50 times before they stop dividing, age, and die, while
cancer cells divide nonstop. cancer cells evade the normal controls that trigger a cell
to undergo a type of programmed cell death called apoptosis when something is
wrong—for example, when an irreparable mistake has occurred during DNA
replication preceding mitosis.
They also do not exhibit anchorage dependence or density-dependent inhibition.
b. What is transformation? - ANSWER-Cells in culture that acquire the ability to
divide indefinitely are said to have undergone a process called transformation,
causing them to behave (in cell division, at least) like cancer cells.
c. What is the difference between a benign and a malignant tumor? - ANSWER-if the
cell evades destruction, it may proliferate and form a tumor, a mass of abnormal
cells within otherwise nor- mal tissue. The abnormal cells may remain at the original
site if they have too few genetic and cellular changes to survive at another site. In
that case, the tumor is called a benign tumor.
d. What occurs in metastasis? - ANSWER-Cancer cells may also secrete signaling
molecules that cause blood vessels to grow to- ward the tumor. A few tumor cells
may separate from the origi- nal tumor, enter blood vessels and lymph vessels, and
travel to other parts of the body. There, they may proliferate and form a new tumor.
This spread of cancer cells to locations distant from their original site is called
metastasis
e. What are two methods of treating cancerous cells? - ANSWER-A tumor that
appears to be localized may be treated with high-energy radiation, which damages
DNA in cancer cells much more than DNA in normal cells, apparently because the
majority of cancer cells have lost the ability to repair such damage. To treat known or
suspected metastatic tumors, che- motherapy is used, in which drugs that are toxic
to actively dividing cells are administered through the circulatory system.
Overview: Variations on a Theme
1. Genetics is the study of heredity and variation. Define these terms. - ANSWER-
Heredity is the transmission of traits from one generation to the next
Variation is demonstrated by the differences in appearance that offspring show from
parents and siblings
Concept 10.1: Offspring acquire genes from parents by inheriting chromosomes
9. Binary Fission in Bacteria: Prokaryotic cells divide by a different process called
binary fission.
,a. Binary fission is asexual reproduction. What does this mean? - ANSWER-The
term binary fission, mean- ing "division in half," refers to this process and to the
asexual reproduction of single-celled eukaryotes, such as the amoeba
b. Describe the structure of the bacterial chromosome. - ANSWER-consists of a
circular DNA molecule and associated proteins.
c. In the bacterium E. coli, cell division is initiated with DNA replication. What is an
origin of replication? - ANSWER-In E. coli, the process of cell division is initiated
when the DNA of the bacterial chromosome begins to replicate at a specific place on
the chromosome called the origin of replication, producing two origins.
d. After DNA replication what occurs in the remainder of binary fission? - ANSWER-
When replication is complete and the bacterium has reached about twice its initial
size, its plasma membrane pinches inward, dividing the parent E. coli cell into two
daughter cells
Concept 9.3: The eukaryotic cell cycle is regulated by a molecular control system
11. Frequency of cellular division varies among both plant and animal cells.
a. What is an example of a human cell that divides regularly? - ANSWER-human
skin cells
b. What is an example of a human cell that divides only when necessary (repair)? -
ANSWER-liver cells
c. What is an example of a human cell that never divides in a mature human? -
ANSWER-nerve cells and muscle cells
12. Checkpoints of the cell Cycle Control System
a. Why is cell cycle control important? - ANSWER-These signals report whether
crucial cellular processes that should have occurred by that point have in fact been
completed correctly and thus whether or not the cell cycle should proceed
b. What is a cell cycle checkpoint? - ANSWER-a control point where stop and go-
ahead signals can regulate the cycle.
c. Sometimes cells exit the cell cycle and enter G0. What are some reasons a cell
would exit the cell cycle? - ANSWER-cells fail to divide if an essential nutrient is
lacking in the culture medium.
And even if all other conditions are favorable, most types of mammalian cells divide
in culture only if the growth medium includes specific growth factors.
d. What is the function of growth factors in the regulation of the cell cycle? -
ANSWER-a growth factor is a protein released by certain cells that stimulates other
cells to divide. Different cell types respond specifically to different growth factors or
combinations of growth factors.
, e. There are some external physical factors that affect normal mammalian division.
Explain how the following impact cell division:
i. Density-dependent inhibition: - ANSWER-a phenomenon in which crowded cells
stop dividing.
cultured cells normally divide until they form a single layer of cells on the inner
surface of a culture flask, at which point the cells stop dividing. If some cells are
removed, those bordering the open space begin di- viding again and continue until
the vacancy is filled.
ii. Anchorage dependence: - ANSWER-To divide, they must be attached to a
substra- tum, such as the inside of a culture flask or the extracellular matrix of a
tissue.
2. Inheritance of Genes
a. Parents pass down physical characteristics called traits by passing genes to their
children. What is a gene? - ANSWER-Genes are the units of heredity and are made
up of segments of DNA
b. What type of information is provided by a gene? - ANSWER-The genetic program
is written in the language of DNA, the polymer of four different nucleotides
c. Gametes are the vehicles to transmit genes into the next generation. What is a
gamete? - ANSWER-reproductive cells (sperm and eggs)
d. Where is the majority of DNA located in a eukaryotic cell? In what form is DNA
found? - ANSWER-the DNA of a eukaryotic cell is packaged into chromosomes
within the nucleus.
e. How do gametes differ from somatic cells? Give an example of each. - ANSWER-
somatic cells have 46 chromosomes while gametes have 23
f. What is a gene locus? - ANSWER-A gene's specific location along the length of a
chromosome is called the gene's locus
3. Comparison of Asexual and Sexual reproduction
a. What occurs in asexual reproduction? Give an example of a prokaryote and a
eukaryote capable of asexual reproduction. - ANSWER-In asexual reproduction, a
single individual passes genes to its offspring without the fusion of gametes
single-celled eukaryotic organisms can reproduce asexually by mitotic cell division,
in which DNA is copied and allocated equally to two daughter cells.
Some multicellular organisms are also capable of reproducing asexually
b. Asexual reproduction results in the production of a clone. What is a clone? -
ANSWER-a group of genetically identical individuals
