Cell Cycle and Tumor Biology Quiz

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Questions and Answers

What is the key difference between a benign and a malignant tumor?

A malignant tumor spreads by invasion and metastasis, while a benign tumor only grows locally. (correct)

A benign tumor spreads by invasion and metastasis, while a malignant tumor only grows locally.

Malignant tumors are always more painful than benign tumors.

Benign tumors are always smaller than malignant tumors.

In the context of tumor development, what is the key difference between linear and parallel tumor development?

Linear development involves multiple groups arising simultaneously and parallel development involves a single dominant clone.

Linear development involves a single dominant clone while parallel development involves multiple groups arising simultaneously. (correct)

Linear development involves one dominant clone while parallel development involves multiple groups arising simultaneously.

Linear development involves multiple groups arising simultaneously while parallel development involves one dominant clone.

Which of the following is NOT a characteristic of clonal selection?

One change from identical cells becomes a tumor.

The existing cell population is overtaken by one cell with a specific trait. (correct)

One cell with a feature gets selected and copied over and over.

Doesn't affect the existing cell population.

What is the key difference between clonal dominance and clonal selection?

Clonal dominance involves one cell taking over the existing cell population, while clonal selection involves one change becoming a tumor. (C) Signup and view all the answers

Which step of tumor invasion is described by altering mitotic rate vs. apoptosis?

Cellular multiplication (A) Signup and view all the answers

During which phase of the cell cycle does the cell prepare for DNA replication?

G1 (C) Signup and view all the answers

What is the primary function of the G1/S checkpoint?

To check for and repair any DNA damage incurred during G1 (D) Signup and view all the answers

Which of the following occurs during the S phase of the cell cycle?

Duplication of chromosomes (B) Signup and view all the answers

What is the main function of the G2/M checkpoint?

To ensure that DNA replication has been completed (A) Signup and view all the answers

What is the role of the protein Rb in the G1/S checkpoint?

It binds to and inhibits transcription factors, preventing DNA synthesis (A) Signup and view all the answers

Which phase of the cell cycle is characterized by the division of the cytoplasm?

Cytokinesis (B) Signup and view all the answers

What is the primary role of the Spindle Assembly Checkpoint?

Verifying that all chromosomes are correctly attached to the mitotic spindle (B) Signup and view all the answers

Which of the following best describes the state of a cell in G0?

Metabolically inactive but not dead (B) Signup and view all the answers

What is the role of cyclin in the cell cycle?

Cyclin is a protein that binds to CDK and regulates its activity. (D) Signup and view all the answers

How does the phosphorylation of CDK relate to the cell cycle?

Phosphorylation activates CDK, allowing it to bind to cyclin and initiate the cell cycle. (A) Signup and view all the answers

Which of these is NOT a mechanism used to prevent the cell cycle?

Activation of the active site of CDK. (A) Signup and view all the answers

What is the role of Rb in the cell cycle?

Rb is a negative regulator that prevents cell cycle progression by inhibiting CDK. (D) Signup and view all the answers

Which of the following statements about checkpoint inhibitors is TRUE?

Checkpoint inhibitors work by inhibiting CDK activity, preventing the cell cycle from progressing. (B) Signup and view all the answers

What is the main difference between MCyclin and SCyclin?

MCyclin is involved in mitosis while SCyclin is involved in the synthesis phase. (E) Signup and view all the answers

How does Doxorubicin prevent the cell cycle?

Doxorubicin is a CDK inhibitor, blocking the activity of CDK and halting the cell cycle. (D) Signup and view all the answers

What is the connection between cell cycle regulation and cancer development?

Mutations in cell cycle regulatory genes can lead to uncontrolled cell proliferation, a hallmark of cancer. (B) Signup and view all the answers

Which of the following is NOT a characteristic of a teratogen?

Causes chromosome breaks and rearrangements (D) Signup and view all the answers

What is a point mutation, and what impact can it have?

A change in a single nucleotide that can have no effect, a positive effect, or a negative effect on the protein. (A) Signup and view all the answers

Which of the following statements is TRUE regarding carcinogens and mutagens?

All carcinogens are mutagens. (A) Signup and view all the answers

Which of the following is NOT an example of a mutagen?

Normal cellular processes. (A) Signup and view all the answers

Which of the following statements about the role of epigenetics in mutations is TRUE?

Epigenetics can influence both the development and passing on of mutations. (B) Signup and view all the answers

What type of polyp has a high likelihood of becoming cancerous?

Villous adenoma (B), Dysplastic polyps (C) Signup and view all the answers

Which of the following steps is NOT part of the Three-step Theory of Invasion?

Release of lytic enzymes (D) Signup and view all the answers

Which stage of cancer involves spread to distant sites?

Stage 4 (D) Signup and view all the answers

What is the primary function of Invadopodia during cancer invasion?

Degrading the extracellular matrix (C) Signup and view all the answers

What is the significance of the TNM system in cancer staging?

To provide a standardized method for describing the extent of cancer (B) Signup and view all the answers

Which of the following cellular changes is directly associated with increased cancer cell motility?

Decreased cell-to-cell adhesion (A) Signup and view all the answers

What is the primary difference between benign and malignant tumors?

Benign tumors do not spread to other tissues, while malignant tumors can (D) Signup and view all the answers

Which of the following is NOT a factor that can contribute to cancer cell invasion?

Increased cell size (C) Signup and view all the answers

What is the meaning of M-0 in the TNM system?

No evidence of metastasis (D) Signup and view all the answers

In the TNM system, what does a T-3 tumor indicate?

Tumor size greater than 5 cm, with potential invasion into surrounding tissues (A) Signup and view all the answers

Which of the following accurately describes the role of tumor suppressor genes in the regulation of the cell cycle?

Tumor suppressor genes inhibit cell cycle progression by promoting apoptosis. (D) Signup and view all the answers

What is the primary function of p53 in relation to DNA damage?

Activating DNA repair mechanisms and inducing apoptosis if repair fails. (A) Signup and view all the answers

Which of the following statements correctly describes the relationship between proto-oncogenes and oncogenes?

Proto-oncogenes are inactive forms of oncogenes that can become activated by mutations. (C) Signup and view all the answers

Why are germline mutations generally associated with a higher risk of developing cancer than somatic mutations?

Germline mutations are present in all cells of the body, while somatic mutations are confined to specific tissues or organs. (A) Signup and view all the answers

Which of the following situations can lead to an accumulation of damaged cells, potentially increasing the risk of cancer development?

Inactivation of tumor suppressor genes, allowing uncontrolled cell growth and division. (C) Signup and view all the answers

What is the primary mechanism by which increased mutation rates contribute to cancer development?

All of the above. (D) Signup and view all the answers

What is the main difference between a germline mutation and a somatic mutation?

Germline mutations are inherited from parents, while somatic mutations occur during an individual's lifetime. (C) Signup and view all the answers

How does p53 contribute to the regulation of the cell cycle?

p53 inhibits cyclin production, preventing cell cycle progression. (D) Signup and view all the answers

Study Notes

Cancer Biology

Cancer is a genetic disease, caused by uncontrolled cell division in a part of the body.
Cancer cells tend to cause death and deterioration.
They are invasive, metastasize, and can terminate a malignant tumor.
Changes in DNA sequence of key genes (cancer genes) cause abnormal behavior of cancer cells.
Biopsy is the only way to confirm uncontrolled cell division.
KI 67 is a marker of cell division.

Hallmarks of Cancer

Self-sufficiency in growth signals
Insensitivity to antigrowth signals
Evading apoptosis
Limitless replicative potential
Sustained angiogenesis (formation of new blood vessels)
Tissue invasion and metastasis

Cancer Cells

Cancer cells arise from single cells.
Their genomes are altered.
They lose contact inhibition.
They are usually clonal in origin (replicated clones).

Normal vs. Cancer Cells

Normal cells exhibit contact inhibition, while cancer cells do not.
Normal cells have large cytoplasm, single nucleus, and fine chromatin.
Cancerous cells have multiple nuclei, coarse chromatin, and small cytoplasm.

Tumour Cell Biological Markers

Substances produced by cancer cells or found on plasma cell membranes, in blood, CSF, or urine.
These include hormones, enzymes, genes, antigens and antibodies.

Neoplasia

Any abnormal new growth of cells.
Increased number of cells in one area describes hyperplasia.
Increased size of cells describes hypertrophy.
Disordered proliferation of cells, and changed cell form is called dysplastic.

In Situ Cancer

Cancer-looking cells are present in the original site, but no spread to nearby tissue.
These cells may become cancerous and spread into nearby tissue eventually.

Benign Tumors

Benign tumor cells grow locally and cannot spread by invasion or metastasis.

Malignant Tumors

Cancer cells invade surrounding tissues.
They enter blood vessels and become metastasized.
Primary tumor development is linear, arising from a single dominant clone.
Parallel tumor development occurs with multiple groups of cancer cells that arise simultaneously.

Clonal Selection

A change from identical cells can become a tumor.
One cell, with a characteristic, is selected and copied many times, replacing the original population.
When a cell trait is replicated enough, it can become the dominant cell/trait.

Invasion

Tumour invasion involves steps including cellular multiplication.
Altered mitotic rate, lytic enzymes release, and decreased cell-cell adhesion increase mobility in tumour cells.
Intravasation and extravasation processes allow entry and exit from blood vessels.

Benign Colonic Neoplasms

Tubular adenomas and villous adenomas are precancerous polyps.
About 15-25% of villous adenomas and 10% of tubular adenomas become cancerous.
Hyperplastic polyps are located in the colon rectum and sigmoid colon.
Dysplastic polyps display abnormal cell characteristics.

Essential TNM

A registry tool to reduce errors in cancer staging.
Metastasis is checked for using M status (M0 or M1) and determined
Tumor size (T status) is checked
Lymph node involvement is checked (N status)

Oncogenes, Protooncogenes, Tumor Suppressor Genes

Mutations in oncogenes increase the frequency of cancer.
Protooncogenes can become oncogenes.
Tumor suppressor genes usually suppress tumors.

p53

Master regulator of cell cycle.
Regulates DNA replication and repair.

Germline and Somatic Mutations

Germline mutations can be inherited from parents.
Somatic mutations are present in all body cells, except reproductive cells.

DNA Damage Repair Mechanisms

Base excision repair, mismatch repair, and nucleotide excision repair.

Chromosomal Mutations

Rearrangements include inversions and translocations; deletions, insertions, and duplications and substitutions; aneuploidy; and polyploidy.

Aneuploidy

Irregular number of chromosomes.

Mutagens, Carcinogens, Clastogens, Teratogens

Mutagens cause mutations.
Carcinogens cause cancer.
Clastogens produce chromosome breaks.
Teratogens cause congenital malformations.

Cell Cycle

A series of events that occur in a cell as it grows and divides.

Checkpoints

Control points in the cell cycle to ensure DNA replication and cell division proceed accurately.

Cyclins and CDKs

Cyclins are proteins that regulate CDKs (cyclin-dependent kinases) which are involved in regulating the cell cycle.
Phosphorylation activates proteins, thus enabling cell cycle progression.

Apoptosis

Regulated cell death (and sometimes an unregulated process), with mechanisms that destroy cells.

Intrinsick and Extrinsic Pathways to Apoptosis

Intrinsic - signals that trigger programmed cell death from inside the cell.
Extrinsic - signals outside of the cell trigger programmed cell death.

Cancer Cells and Membrane Flipping

Tumor Cells are often associated with membrane flipping.

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Description

Test your knowledge on the cell cycle phases, tumor development, and critical checkpoints. This quiz explores concepts such as clonal selection, tumor characteristics, and the roles of various proteins in cell regulation. Dive into the intricacies of malignant versus benign tumors and the mechanisms of cell division.