Chapter 6: Cancer

What is a tumor?

A tumor is formed by unregulated cell division.

What are the characteristics of a benign tumor?

Benign tumors stay in one place, do not invade surrounding tissues, and do not prevent surrounding tissues and organs from functioning.

What are the characteristics of a malignant tumor?

Malignant tumors are invasive, spread to surrounding tissues, and can start new cancers.

What is metastasis?

Metastasis is the movement of cancer cells from their original location through the blood or lymphatic system to start new cancers, making them the most dangerous tumors.

How do cancer cells primarily differ from normal, healthy cells in terms of their life cycle?

Cancer cells typically lose the ability to undergo apoptosis, which is programmed cell death.

What are some controllable risk factors for cancer?

Controllable cancer risk factors include limiting UV light exposure, not smoking, eating a healthy diet, exercising, maintaining a healthy weight, and minimizing alcohol consumption.

How does diet specifically affect cancer risk?

A high-fat, low-fiber diet increases cancer risk.

What is the relationship between melanin and skin cancer risk?

The higher the level of the pigment melanin, the lower the risk of developing skin cancer.

Why is skin cancer the most common type of cancer?

Skin cancer is the most common because skin is constantly replenished, and cells that divide rapidly undergo more mutations.

Why are colon cells particularly susceptible to cancer?

The colon is susceptible to cancer because its cells are replaced frequently by the process of mitosis.

What is the basic structure of a chromosome?

Chromosomes are composed of DNA wrapped around proteins.

What is the primary function of a chromosome?

Chromosomes carry genes.

What are sister chromatids?

Sister chromatids are exact, genetically identical copies of one chromosome that are attached to each other.

How many chromosomes do human cells typically have?

Human cells have 46 chromosomes.

Describe the template model of DNA replication.

During DNA replication, one strand of the double-stranded DNA molecule is used as a template for the synthesis of a new, complementary daughter strand of DNA.

What is the role of DNA polymerase?

The enzyme DNA polymerase facilitates pairing nucleotides by tying them together on the forming daughter strand during DNA replication.

What is the function of the MLH1 gene?

The MLH1 gene codes for proteins that fix mismatched base pairs in newly replicated DNA.

What happens during the interphase of the cell cycle?

Interphase consists of two gap phases (G1 and G2) where the cell grows and prepares for division, and the S phase where DNA replicates.

When does DNA replication occur during the cell cycle?

DNA replication occurs during the S (synthesis) phase of interphase, which takes place between G1 and G2.

What is mitosis?

Mitosis is a type of cell division where one parent cell divides to form two daughter cells that are exact genetic copies of the parent cell.

What happens during prophase of mitosis?

During prophase, the replicated chromosomes condense.

What happens during metaphase of mitosis?

At metaphase, replicated chromosomes composed of two sister chromatids align across the middle, or equator, of the cell.

What happens during anaphase of mitosis?

At anaphase, sister chromatids separate from each other and align at opposite poles of the cells.

What happens during telophase of mitosis?

At telophase, separate nuclear envelopes re-form around the linear chromosomes present at both poles of the cell.

What is cytokinesis?

Cytokinesis is the division of the cytoplasm into two portions, one for each daughter cell.

How does cytokinesis differ between plant and animal cells?

In animal cells, a band of filaments pinches one cell into two, whereas in plant cells, a new cell wall is constructed in the middle of the subdivided cell.

What are tumor suppressors?

Tumor suppressors are normal genes that encode proteins to stop cell division if conditions are unfavorable and can repair damage to the DNA.

How do mutations to cell cycle regulating genes lead to cancer?

When genes that control the cell cycle, like p53, undergo mutations, the cell can override controls meant to stop division, allowing it to divide uncontrollably.

What is a biopsy?

A biopsy is the process of removing and analyzing a lump to determine whether it is cancerous.

How does chemotherapy treat cancer?

Chemotherapy uses chemicals that target and destroy rapidly dividing cells.

How does radiation therapy treat cancer?

Radiation therapy kills cells and damages tumors by exposing them to high-energy particles.

How does immunotherapy treat cancer?

Immunotherapy targets cancer-specific markers located in cell membranes.

What is sexual reproduction?

Sexual reproduction involves two parents producing offspring that have a unique combination of genes.

What does the root word "cyto-" mean?

The root word "cyto-" relates to cells.

What does the root word "-kinesis" mean?

The root word "-kinesis" means motion.

What does the root word "mal-" mean?

The root word "mal-" means bad or evil.

What does the root word "meta-" mean?

The root word "meta-" means change or between.

What does the root word "mito-" mean?

The root word "mito-" means a thread.

What does the root word "telo-" mean?

The root word "telo-" means end or completion.