Mastering Biology Chapter 12: Mitosis

What is IGF-II?

A chemical that stimulates growth in pancreatic tumors.

If a eukaryotic cell is in the G1 phase of the cell cycle, which statement about the cell's chromosomes must be correct?

Each chromosome is made of a complex of DNA and associated proteins.

What must happen before a cell can begin mitosis?

The chromosomes must be duplicated.

Nucleoli are present during _____.

interphase

In the treated sample histogram, which phase of the cell cycle has the greatest number of cells?

the G1 phase

The centrosomes move away from each other and the nuclear envelope breaks up during which phase of mitosis?

Prophase

The success of cell therapy to treat cancer relies on which of the following?

T-cells

The chromosomes arrive at the poles and nuclear envelopes form during which phase of mitosis?

Telophase

_____ is a carcinogen that promotes colon cancer.

fat

Chromosomes become visible during _____.

prophase

Cytokinesis often, but not always, accompanies _____.

telophase

Which of the following is true?

Using more than one immunotherapy drug typically increases survival length.

Which of the following is a large reason behind the increase in breast cancer in developing countries?

Women are living longer.

You are a breast cancer survivor and advocate in the U.S. Why do you promote self breast exams to women under 50 rather than annual mammograms?

Women under 50 tend to have denser breast tissue which often make mammograms inconclusive.

- Drag the pink labels onto the pink targets to identify the two main phases of the cell cycle. - Then drag the blue labels onto the blue targets to identify the key stages that occur during those phases.

a. G1 phase b. S phase c. Interphase d. G2 phase e. Mitotic (M) phase f. Mitosis g. Cytokinesis

Spindle fibers attach to kinetochores during _____.

prometaphase

DNA replication produces two identical DNA molecules, called ___________, which separate during mitosis.

sister chromatid(s)

During _____ both the contents of the nucleus and the cytoplasm are divided.

the mitotic phase

What seems to be the main purpose of the article?

to summarize the data demonstrating the carcinogenic effects of UV radiation from indoor tanning

During _____ the cell grows and replicates both its organelles and its chromosomes.

interphase

Which of the following will have authorization to decide if and when CAR can be used?

Food and Drug Administration

You are the CEO of pharmaceutical company Merck. Your company has a new cancer drug it wishes to introduce to the market. Who do you need approval from?

Food and Drug Administration

After chromosomes condense, the _____________ is the region where the identical DNA molecules are most tightly attached to each other.

centromere(s)

The __________ are the organizing centers for microtubules involved in separating chromosomes during mitosis.

centrosome(s)

Your cousin has been added to a clinical trial for CAR. Which of the following will be a precursor to prepare him for this treatment?

chemotherapy

During interphase, most of the nucleus is filled with a complex of DNA and protein in a dispersed form called ___________.

chromatin

Cytochalasin B is a chemical that disrupts microfilament formation. How would this interfere with cell division?

cleavage

Your aunt is prescribed the new immunotherapy drugs for her cancer. Which of the following side effects is she most likely to experience?

colitis

At the end of the mitotic (M) phase, the cytoplasm divides in a process called _________________.

cytokinesis

In most eukaryotes, division of the nucleus is followed by ___________, when the rest of the cell divides.

cytokinesis

During telophase, the nonkinetochore microtubules __________.

disassemble

Immunotherapy works by blocking actions of which of the following?

proteins

Identify which phase of the cell cycle is represented by each region. The regions represent the same cell cycle phases in both histograms.

region A: G1 region B: S region C: G2

Which region shows the population of cells with the highest amount of DNA per cell?

region C

During prophase a homologous pair of chromosomes consists of _____.

two chromosomes and four chromatids

A woman in Uganda is diagnosed with breast cancer. If any treatment is done, what is it most likely to be?

Only a mastectomy.

Can you match these prefixes, suffixes, and word roots with their definitions?

- cell: -cyte (or cyto-) - between: inter- - many: multi- - end: telo- - segment, body section: -mere - moving: kin- (or kinet-) - thread: mito- - before: pro- - one: uni- - two: bi-

You are an oncologist specializing in colon cancer. A patient presents to you with disease that has spread to his bones and liver and there is no treatment available. What stage cancer is this?

4

Assign a numerical score for each category. Then add up the total score. (The highest possible score is 6; the lowest is 0.) In what range does this source fall?

5 to 6

On a scale of 0 to 6, where 6 is the most trustworthy, how would you rate this site? (Note that all responses will be marked as "correct" at this point.)

5-6 (very trustworthy)

A human bone marrow cell, in prophase of mitosis, contains 46 chromosomes. How many chromatids does it contain?

92

Which of the following patients is currently most likely to benefit from immunotherapy?

A 46 year old woman with advanced melanoma.

Your uncle has prostate cancer. Which of the following indicates improvement in his condition?

A decreasing PSA.

According to this research, a pancreatic cancer patient with which of the following would likely fair the best?

A patient with a large number of cheater cells.

In the control sample histogram, does the population of cells in the S phase show a distinct peak? Why or why not?

No; the DNA content per cell changes as the S phase progresses, so the cells in S phase have a range of fluorescence levels.

If this research holds true, which of the following would happen in treatment?

Non-producing cells would cause the destruction of a tumor.

In all cells, separation of replicated chromosomes is a prerequisite for cell division. However, the mechanism of chromosome separation in bacteria is distinct from that in eukaryotes in several ways. Sort the following statements into the appropriate bin.

- Bacteria only: Chromosome separation begins at the origin of replication on DNA. - Eukaryotes only: Before separation, duplicated chromosomes condense; Nuclear envelope fragments, permitting chromosome separation; Two copies of the duplicated chromosome are attached at their centromeres before separating. - Both bacteria and eukaryotes: Replicated chromosomes separate by attaching to some other structural feature of the cell; Chromosomes replicate before cell division.

Mitosis unfolds through a sequence of stages marked by specific events in the cell. The structural changes in the cell are brought about by a series of tightly coordinated underlying mechanisms. Sort each process into the appropriate bin to indicate the stage of mitosis in which it occurs. If a process occurs in more than one stage, sort it to the stage when it first occurs.

- Prophase: Cohesins join sister chromatids of duplicated chromosome; Tubulins assemble into spindle microtubules. - Prometaphase: Microtubules Attach to kinetochores. - Metaphase: Kinetochores are motionless in relation to poles of cell. - Anaphase: Cohesins break down; Kinetochores move toward poles of cell. - Telophase: Spindle microtubules disassemble.

Cytokinesis in animal cells is accomplished by constriction of the cell along the plane of cell division (formation of a cleavage furrow). In plant cells, which have cell walls, a completely different mechanism of cytokinesis has evolved. Which of the following statements are true of cytokinesis in plant cells? Select the two that apply.

- Vesicles from the Golgi apparatus move along microtubules, coalesce at the plane of cell division, and form a cell plate. - The cell plate consists of the plasma membrane and cell wall that will eventually separate the two daughter cells.

Can you match these prefixes, suffixes, and word roots with their definitions?

- without, lack of, not: a- (or an-) - to produce: -gen- - chromosomes: ploid - self: auto- - body: -some (or soma-) - small: micro- - single: haplo- - color: chrom- - same: homo- (or homeo-) - both, double: diplo-

Drag the terms on the left to the appropriate blanks on the right to complete the sentences.

1. A benign tumor is a lump of abnormal cells that, although growing out of control, remains at its original site. 2. A malignant tumor is an abnormally growing mass of cells that is actively spreading through the body. 3. Metastasis is the spread of cancer cells from their site of origin to other sites in the body. 4. An individual with a malignant tumor is said to have cancer. 5. The most common type of cancer is a carcinoma; this type always originates in tissues that line organs.

Plant and animal cells also require cytoskeletal proteins for cytokinesis, although the roles these proteins play differ among bacteria, plants, and animals. For each space in the table, drag the appropriate label to indicate if the statement is true or false for each group of organisms. 1. Cells divide by constriction of a ring of protein. 2. The presence of a cell wall prevents the cell from dividing by constriction. 3. Tubulin or tubulin-like molecules function in binary fission (in bacteria) or cytokinesis (in animals and plants).

1. Bacteria: true Animals: true Plants: false 2. Bacteria: false Animals: false Plants: true 3. Bacteria: true Animals: false Plants: true

Drag the labels onto the diagram to identify the stages of the cell cycle.

1. Most of a cell's life is spent in interphase, when growth occurs. Cells that are about to divide replicate their DNA. 2. In prophase, microtubules form the mitotic spindle, and the nuclear envelope breaks up. 3. In anaphase, sister chromatids separate and become full-fledged chromosomes that move to opposite poles. 4. In telophase, chromosomes become less condensed and new nuclear envelopes form. In cytokinesis the cytoplasm divides.

Consider an animal cell in which motor proteins in the kinetochores normally pull the chromosomes along the kinetochore microtubules during mitosis. Suppose, however, that during metaphase, this cell was treated with an inhibitor that blocks the function of the motor proteins in the kinetochore, but allows the kinetochore to remain attached to the spindle. The inhibitor has no effect on any other mitotic process, including the function of the nonkinetochore microtubules. Consider three questions concerning the animal cell that has been treated with the inhibitor. Drag the terms to answer the questions. Terms may be used once, more than once, or not at all. 1. Will this cell elongate during mitosis? 2. Will the sister chromatids separate from each other? 3. Will the chromosomes move to the poles of the cell?

1. Yes 2. Yes 3. No

Which of the following is found in binary fission but not in mitosis?

Duplicated chromosomes attach to the plasma membrane.

Which statement provides the best description of the interphase portion of the cell cycle?

During interphase, a cell is metabolically active.

Which of these phases encompasses all of the stages of mitosis but no other events?

E

The sister chromatids separate and begin moving toward opposite poles of the cell during which phase of mitosis?

Anaphase

Cell A has half as much DNA as cells B, C, and D in a mitotically active tissue. Cell A is most likely in

G1

Cells will usually divide if they receive the proper signal at a checkpoint in which phase of the cell cycle?

G1

Is the DNA condensed in all or part of this phase?

G1: No S: No G2: No Beginning of M (Prophase -> early anaphase): Yes End of M (late anaphase -> telophase): Yes

Are sister chromatids present in all or part of this phase?

G1: No S: Yes G2: Yes Beginning of M (Prophase -> early anaphase): Yes End of M (late anaphase -> telophase): No

Does the cell contain twice as much DNA in this phase as it did in the G1 phase?

G1: No S: Yes G2: Yes Beginning of M (Prophase -> early anaphase): Yes End of M (late anaphase -> telophase): Yes

Which of the following correctly matches a phase of the cell cycle with its description?

G1: follows cell division

The chromosomes line up in the center of the cell during which phase of mitosis?

Metaphase

You are an oncologist doing research that confirmed what was known about producer/cheater relationships in pancreatic tumors. What did you find out?

Producers get nothing from cheaters.

What is the affiliation of the writer?

The author is a medical doctor who serves leadership roles for cancer research and prevention organizations.

Which mechanism is the best explanation for how the stem cell-derived inhibitor might arrest the cancer cell cycle at the G1 stage?

The inhibitor might block the activity of a cyclin or signaling molecule of the G1 checkpoint.

You are an oncologist. A patient presents with advanced prostate cancer and you follow standard protocol. What do you do?

The patient is treated with chemical castration.

What do you find in the References list at the bottom of the page?

The references are all from primary sources.

What does the difference in distribution tell you about the cells in the treated sample?

The treated cancer cells are arrested at the G1 phase.

Which statement best describes the difference(s) in the distribution of cells in the treated sample compared to the control sample?

The treated cells are mostly in the G1 phase (region A), but in the control sample, there are peaks of cells in both G1 and G2 (region C).

What treatment is being compared to the control in the experiment?

The treated glioblastoma cells were cultured in the presence of an inhibitor from umbilical cord stem cells, but the control cells were cultured without the inhibitor.

If CAR is approved, which of the following will be true?

The treatment will be tailor-made for each patient.

Prior to this new technique, how were mice given cancerous tumors?

The tumors were implanted under the skin.

Which axis indirectly shows the relative amount of DNA per cell? By what relationship?

The x-axis; the DNA was stained, so there is a positive correlation between fluorescence and DNA content.

Which of the following is true of kinetochores?

They are sites at which microtubules attach to chromosomes.

Which of the following is true regarding prostate cancer cells?

They can activate and inactivate certain genes.

What is true of all cancers?

They have escaped normal cell cycle controls.

Why is it difficult to observe individual chromosomes with a light microscope during interphase?

They have uncoiled to form long, thin strands.

Which of the following is a hallmark of cancer cells?

They multiply quickly.

Why do some species employ both mitosis and meiosis, whereas other species use only mitosis?

They need both if they are producing animal gametes.

Which of the following is true of benign tumors, but not malignant tumors?

They remain confined to their original site

Which of the following is true?

Worldwide, breast cancer is the most common cancer in women, and the largest cancer killer of women.

Is the information provided by these sites consistent with what you found on the Skin Cancer Foundation web site?

Yes, other sites corroborate the information on the Skin Cancer Foundation site.

You are an endocrinologist studying new treatments for prostate cancer. You have a patient with an unusually large level of dihydrotestosterone. Which of the following is true?

Your patient's cancer has become resistant to the standard treatment.

- Drag the pink labels onto the pink targets to identify key events in mitosis. - Then drag the blue labels onto the blue targets to identify the stages of mitosis.

a. Mitotic spindle forming b. Sister chromatids centered c. Chromosomes separating d. Nuclear envelopes forming e. Interphase f. Prophase g. Metaphase h. Anaphase i. Telophase and cytokinesis

The cell cycle represents the coordinated sequence of events in the life of a cell from its formation to its division into two daughter cells. Most of the key events of the cell cycle are restricted to a specific time within the cycle. In this exercise, you will identify when various events occur during the cell cycle. Recall that interphase consists of the G1, S, and G2 subphases, and that the M phase consists of mitosis and cytokinesis. Drag each label to the appropriate target.

a. Non-dividing cells exit cell cycle b. At this point, cell commits to go through the cycle. c. DNA replicates. d. Centrosome replicates. e. Mitotic spindle begins to form. f. Cell divides, forming two daughter cells.

Which of these is NOT a carcinogen?

all of the above are carcinogens

Centromeres divide and sister chromatids become full-fledged chromosomes during _____.

anaphase

In dividing cells, most of the cell's growth occurs during ____________.

interphase

During mitosis, microtubules attach to chromosomes at the ___________.

kinetochore(s)

In some organisms, such as certain fungi and algae, cells undergo the cell cycle repeatedly without subsequently undergoing cytokinesis. What would result from this?

large cells containing many nuclei

During prophase, the microtubules of the mitotic spindle __________.

lengthen

During anaphase, the nonkinetochore microtubules ________ and move past each other, and the kinetochore microtubules ________.

lengthen; shorten

A patient with which of the following would be most likely to be successfully treated with CAR-T cell therapy?

leukemia

The ___________ is a cell structure consisting of microtubules, which forms during early mitosis and plays a role in cell division.

mitotic spindle(s)