biology unit 2 exam guide pt 2
What are somatic cells?
(nonreproductive cells) have two sets of chromosomes (2n)
Homework questions: proto-oncogenes-
- code for proteins the promote the cell cycle - prevent apoptosis, or death - essentially accelerate the cell cycle
Homework questions: Cancerous cell:
-Abnoral cells undergo division -can result from mutations due to enviornmental assults -undergoes angiogenesis or metastasis -contains abnormal number of nuclei -grow in layers without restraint -lacks differentiation
Homework questions: Typical cell:
-Checkpoints occur at various points in cell cycle -Enters cell cycle approximately -Apoptosis occurs when cells become worn out or mutated -Produces other differentiated cells -Attaches to sub substrate and respond to inhibitory signals
Homework questions: tumor suppressort genes-
-promote apoptosis, or cell death -code for proteins that inhibit the cell cycle -essentially slow the cell cycle
Cancer cells are rogue clones. Describe three mutations that allow these cells to escape the normal restrictions placed on cell division:
1. DNA. mutates and enough mutations can bypass the checkpoints and failsafes causing the cell to divide recklessly 2. The cell's interphase period is much shorter, thus it grows and spreads at a faster rate 3. When a cancer cell duplicates, it passes on its defected genes, leading to more cancer cells
What are the three phases of interphase?
1. G1 2. S 3. G2
What are some ways in which you can play an active roles in cancer prevention?
1. Get regular cancer screening tests 2. Get to and stay at a healthy weight 3. Exercise regularly 4. Eat a healthy diet 5. Avoid smoking 6. Limit alcohol
What is the role of BRCA1 and other genes in this class?
1. Helps determine how fast cells should divide 2. Stops cell from dividing if they are damaged (fixes/repairs) 3. Slows down the cycle
What are genetic changes that also contribute to cancer development?
1. absence of telomere shortening 2. chromosomal rearrangement
What are the characteristics of cancer cells? (5)
1. cancer cells lack differentiation 2. cancer cells have abnormal nuclei 3. cancer cells do not undergo apoptosis 4. cancer cells form tumors 5. cancer cells undergo metastasis and promote angiogenesis
Multicellular Eukaryotes depend on cell division for what?
1. development from a fertilized egg 2. growth 3. repair
Eukaryotic cell division consists of what two things?
1. mitosis 2. cytokinesis
What are the types of treatment for cancer?
1. surgery 2. chemotherapy 3. radiation 4. immunotherapy
Interphase takes up what percent of the cell cycle?
90 percent
Some individuals have a reoccurrence of their cancer and the same treatment is no longer successful. Explain why that is the case.
A tumor is a dynamic, interconnected ecosystem in which cancer cells communicate with each another and healthy cells. They can induce normal cells and interfere with immune system to suppress its function in identifying cancer cells; *cancer cells are masters at adaptation, adjusting their cellular and molecular characteristics to survive under stress. When receiving treatment they can change their gene expression to protect themselves*
Which of the following would be most likely to cause a cell to become cancerous? -Inactivation of a proto-oncogene and inactivation of a tumor suppressor gene. -Inactivation of a proto-oncogene and activation of a tumor suppressor gene. -Activation of a proto-oncogene and inactivation of a tumor suppressor gene. -Activation of a proto-oncogene and activation of a tumor suppressor gene.
Activation of a proto-oncogene and inactivation of a tumor suppressor gene.
What is the specific role of BRCA1 in the cell?
Check for mutations in the DNA of a cell
What needs to be done to prepare for cell division?
DNA is replicated and the chromosomes condense
What is chromatin?
DNA molecules that are tightly coiled around proteins call histones
Interphase: 2. S phase
DNA replication; "synthesis"
How would you explain to someone why two individuals with the same type of cancer might not have the same success with the same type of treatment?
Each individual has different cancer cells with different gene expressions and genetic mutations. That is why one form of treatment may be successful for one person but not the other
Why is early detection so important?
Early detection is important in order to stop it from spreading throughout the body; you can also treat it with surgery and avoid radiation or chemotherapy
Chemotherapy and radiation exclusively target cancer cells and do not damage normal cells. State true or false.
False
In order to be successful, chemotherapy drugs have to stop cell division. The most likely method for this would be to:
Interfere with the function of the spindle fibers so the chromosomes can't separate
Why doesn't a cancerous cell die off after just one rogue division?
It cannot die off because cancer cells do not respond to the signals to initiate apoptosis meaning they continue to divide
What is a Benign tumor?
It is a tumor that is usually contained within a capsule and therefore cannot invade adjacent tissues (not cancerous)
Sometimes cancer treatments are ineffective. Why is it so difficult to cure cancer?
It is difficult to cure cancer because of cancer cell heterogeneity meaning any one targeted treatment is highly unlikely to eliminate all cancer cells by itself
How do mutations relate to cancer?
It takes several mutations to form cancer; it disrupts the cell cycles pathway and results to uncontrollable cells which lead to cancer
How are mutations linked to cancer?
Mutations in genes can cause cancer by accelerating cell division rates or inhibiting normal controls on the system, such as cell cycle arrest or programmed cell death
A second class of genes associated with cancer are the photo-oncogenes. These genes normally function similarly to the gas pedal in a car. If only a single photo-oncogene is mutated, a cell can start to lose control of cell division. Why would this be the case?
Proto-oncogenes promotes the cell cycle (default is off=only turned on for special reasons); sometimes they get a mutation and become an oncogene which is considered bad because it accelerates the cell cycle and default is switched to on
What is the first line of treatment for most solid tumors? -Radiation -Surgery -Chemotherapy -Immunotherapy
Surgery
If a cell obtains a mutation that inactivates BRCA1, what will this do to cell division?
The cell would divide without being checked which leads to cells that don't know their specific function; increases susceptibility to cancer because there is not checkpoint/regulation in place within the cycle
What is a Malignant tumor?
These are tumors that are inverse and may spread throughout the body; cells in these tumors may travel through the blood or lymph to start new tumors elsewhere within the body (metastasis)
What is clonal heterogeneity, and how does it affect treatment of cancer?
Tumors can have multiple population of slightly different cancerous cells. Tumors can then have sub-clones when different genetic mutations can accumulate. It makes treatment difficult because it can have some affect on some sub-clones but not all of them
genetic changes that also contribute to cancer development: 2. Chromosomal rearrangements-
When the chromosomes of cancer cells become unstable, portions of the DNA double helix may be lost, duplicated, or scrambled. For example, the portion of a chromosomes may break off and reattach to another chromosome; these events, called *translocations* may lead to cancer, especially if they disrupt genes that regulate the cell cycle
What is a duplicated chromosome?
a chromosome that has two sister chromatids (joined copies of the original chromosome), attached along their lengths by cohesions
The term oncogene refers to.....
a gene that can cause cancer
Which of these is a behavior that could help prevent cancer? -maintaining a healthy weight -eating more dark green, leafy vegetables, carrots, and various fruits -not smoking -avoid salt cured and processed foods -all of these are correct
all of these are correct
As additional mutations occur, the tumor cells release a growth factor, which causes neighboring blood vessels to branch into the cancerous tissue. What is this process called? -metastasis -angiogenesis -carcinogenesis -parthenogenesis
angiogensis
To what class of genes does BRCA1 belong?
belongs to a class of genes called tumor suppressor genes
characteristics of cancer cells: 3. cancer cells do not undergo apoptosis
cancer cells do not respond to the signals to initiate apoptosis meaning they continue to divide
What is metastasis?
cancer cells leaving a tumor and invading other parts of the body; cancer cells are motile-able to travel through the blood or lymphatic vessels to other parts of the body where they start distant tumors
characteristics of cancer cells: 4. cancer cells form tumors
cancer cells lose all restraints; they pile on top of one another and grow in multiple layers forming tumors
characteristics of cancer cells: 1. cancer cells lack differentiation
cancer cells lose their specialization and do not contribute to the functioning of a body part; a cancer cell looks distinctly abnormal and they enter the cell cycle repeatedly
Telomerase is an enzyme that can rebuild telomeres. Which of the following statements is accurate about the activity of the telomerase enzyme in cancer cells? -cancer cells show decreased telomerase activity and the telomeres are shortened -cancer cells show increased telomerase activity and the telomeres are not shortened. -cancer cells show decreased telomerase activity and the telomeres are not shortened -cancer cells show increased telomerase activity and the telomeres are shortened
cancer cells show increased telomerase activity and the telomeres are not shortened.
Interphase: 1. G1 phase
cell grows and organelles replicate; "first gap"
What occurs in interphase?
cell growth and copying of chromosomes in preparation for cell division
How might a cell use a combination of photo-oncogenes and tumor suppressor genes to regulate cell division? Under what circumstances might a cell need to divide faster?
cells do a really goof job to regulate the two; for example when you have a wound, it is encouraged to have more cell division to fix it (proto-oncogene)
Homework questions: Another common option is _______________, which consists of highly potent chemicals that lead to the death of cancer cells by damaging their genetic material or interfering with DNA synthesis.
chemotherapy
Homework questions: Some forms of ______________, such as vinblastine, are derived from plant extracts.
chemotherapy
Suppose a patient has a late-stage form of cancer that has metastasized. If only one cancer treatment could be used, the treatment that might have a chance at helping this person would be:
chemotherapy
Why does chemotherapy affect healthy cells? How does this lead to side effects?
chemotherapy targets the body as a whole if you have cancer in various parts of your body. This leads to side effects because chemo is unable to detect which cells are cancerous or healthy so it targets all cells that divide frequently (hair, skin, blood, stomach)
What do chromosomes contain?
chromatin (DNA and protein)
DNA molecules in a cell are packaged into
chromosomes
Every eukaryotic species has a characteristic number of what?
chromosomes in each cell nucleus
What are tumor suppressor genes?
code for proteins that inhibit the cell cycle and promote apoptosis (brake pedal-slow down- cell cycle and stops cell from dividing inappropriately)
Immunotherapy includes all of the following except.... a. boosting the killing power of the immune system b. making cancer cells more recognizable to the immune system c. enhancing the body's ability to repair and replace normal cells d. destroying blood vessels that serve tumors e. all of these are part of immunotherapy
destroying blood vessels that serve tumors
What is the genome of an organism?
entire genetic material of that organism; all the DNA in a cell constitutes
Which of the following is not a feature of cancer cells? -exhibiting contact inhibition -having enlarged nuclei -stimulating the formation of new blood vessels -being capable of traveling through blood and lymph
exhibiting contact inhibition
T or F: The sister chromatids are attached by the centromere.
false; the centromere is the site of where they are connected but it does not keep the sister chromatids together; the kinetochore is responsible for holding them together
What is angiogenesis?
growth factor which causes neighboring blood vessels to branch in the cancerous tissue and they are able to invade underlying tissues; the formation of new blood vessels; additional nutrients and oxygen reach tumor allowing it to grow larger
Homework questions: Another cancer treatment option is _________________, which prevents cancer cell growth by inhibiting the chemical signals needed for cell division.
hormone therapy
The cell cycle consists of what two stages?
interphase and mitotic phase
types of treatment for cancer: immunotherapy-
involves using the patient's own immune system cells to target cancerous cells for destruction. These treatments involve identifying distinct differences between cancer cells and normal cells of the body
types of treatment for cancer: surgery-
is often the first line of treatment; when cancer is detected at an early stage, surgery may be sufficient to cure the patient by removing all cancerous cells
What factor differentiates a malignant tumor from a benign tumor? -it causes death -it grows at a faster rate -it invades and metastasizes -it shows more enlarged nuclei
it invades and metastasizes
What is the centromere?
it is the narrow "waist" of the duplicated chromosome, where the two chromatids are most closely attached
Suppose that a cell has a mutation in one of its BRCA1 genes that inactivates the gene. What will this do to the rate at which the cell divides?
it will have no effect on the rate at which the cell divides
Which type of tumor is actually considered to be cancerous? Why?
malignant tumor; it metastasizes and promotes angiogenesis while benign tumors do not
How are gametes produced?
meiosis
Why are gametes produced in meiosis genetically different?
meiosis yields non-identical daughter cells that have half as many chromosomes as the parent cell
Cancer cells can travel through the blood or lymphatic vessels and form tumors at distant locations. What is this process called? -metastasis -malignancy -angiogenesis -apoptosis
metastasis
What happens in the mitotic (M) phase?
mitosis and cytokinesis
Cancer cells are different from other cells in that they have lost their contact inhibition. "Contact inhibition" means.....
most cells stop dividing when they bump up against other cells
A / an ______________ is an alteration or change in an organism's DNA.
mutation
What are proto-oncogenes?
normal version of oncogenes; they code for proteins that promote the cell cycle and inhibit apoptosis (gas pedal-acceleration- on cell cycle)
characteristics of cancer cells: 5. cancer cells undergo metastasis and promote angiogenesis
promotes both in malignant tumors
What are the two types of genes that are often linked to the development of cancer when a mutation arises in them?
proto-oncogenes; tumor suppressor genes
Homework questions: Another treatment, ____________________, uses high-energy beams that are directed at the _____________ to damage the cells' DNA and induce _____________
radiation therapy; tumor; apoptosis
What are Gametes?
reproductive cells (sperm and egg); have half as many chromosomes as somatic cells (n)
List some ways in which we can detect cancer:
screenings, mammograms, PAPS, prostate exams, colonoscopy
Cancer cells are able to retain their immortality due, in part, to......
the ability to lengthen the telomeres on their chromosomes.
Cell division is an integral part of.....
the cell cycle
Which of the following statements is not true? -cancer is always a genetic disease -cancer is caused by a lack of regulation in the cell cycle -the development of cancer requires a single mutation -it often takes several years for cancer to develop
the development of cancer requires a single mutation
What is cancer?
the disease caused by an uncontrolled division of abnormal cells in a part of the body
What is cytokinesis?
the division of the cytoplasm
What is mitosis?
the division of the genetic material in the nucleus
types of treatment for cancer: chemotherapy-
the goal is to kill cancer cells that have spread throughout the body; like radiation, chemo drugs lead to the death of cells by damaging their DNA or interfering with DNA synthesis
types of treatment for cancer: radiation-
the goal is to kill cancer cells within a specific tumor by directing high-energy beams at the tumor. DNA is damaged to the point that replication can no longer occur, and the cancer cells undergo apoptosis
What is the cell cycle?
the life of a cell form formation to its own division
characteristics of cancer cells: 2. cancer cells have abnormal nuclei
the nuclei of cancer cells are enlarged and may contain abnormal number of chromosomes; chromosomes are abnormal and gene amplification is seen much more
Cancer spreads through the process of metastasis, which means......
the shedding of cells from a malignant tumor and transport of those cells to different parts of the body.
Cancer represents an inability of the body to control....
the speed at which cells divide
genetic changes that also contribute to cancer development: 1. Absence of telomere shortening-
the telomeres at the end of chromosomes play an important role in regulating cell division. Just as the caps at the end protect them from unraveling, telomeres promote chromosomal stability; cells have an enzyme called telomerase that can rebuild telomeres; these codes for telomerase is turned on in cancerous cells; if this happens, telomeres do not shorten and cells can divide over and over again.
Why are tumor suppressors called its name?
they are called tumor suppressor genes because tumors may occur when mutations cause genes to become nonfunctional
Why are chemotherapy drugs generally successful against cancer cells?
they can attack every cell in the body but only cells that divide most frequently are susceptible
What are some protective behaviors you can do to lower your risk of developing cancer?
to lower the risk of developing certain cancers, people are advised to avoid smoking, sunbathing, and excessive alcohol consumption
Homework questions: One option for cancer treatment is removal of the __________, especially if detected at an early stage
tumor
What are some protective diet choices you can make to lower your risk of developing cancer?
weight loss can reduce cancer risks 1. Increase your consumption of foods that are rich in vitamins A and C 2. Avoid salt-cured or pickled foods because they can increase risk of stomach and esophageal cancers 3. Include in the diet vegetables from the cabbage family (cabbage, broccoli, Brussels sprouts,cauliflower); eating veggies reduces risk of gastrula intestinal and respiratory tract cancers
