Understanding Cancer and Cell Growth Regulation

What is the primary cause of cancer according to the text?

• Lack of sleep

• Uncontrolled cell division

• Poor diet

• Excessive exercise

Answer explanation

The primary cause of cancer is uncontrolled cell division, which leads to the formation of tumors. Other factors like lack of sleep, poor diet, and excessive exercise do not directly cause cancer.

Tags

NGSS.HS-LS1-4

What role do cell cycle inhibitors play in cancer prevention?

• They prevent cells from dividing when conditions aren’t right

• They promote cell division

• They increase the speed of cell division

• They mutate genes

Answer explanation

Cell cycle inhibitors play a crucial role in cancer prevention by preventing cells from dividing when conditions aren’t right, thereby stopping the proliferation of potentially cancerous cells.

What is a characteristic of cancer cells in culture?

• They can multiply without growth factors

• They require growth factors to multiply

• They die quickly

• They stop dividing when crowded

Answer explanation

Cancer cells in culture are characterized by their ability to multiply without the need for growth factors, unlike normal cells that require these signals to divide. This independence is a hallmark of their uncontrolled growth.

Replicative immortality in cancer cells is the ability to (a)  

• The ability to grow slowly
• The ability to die quickly
• The ability to stop dividing
• The ability to divide indefinitely

Answer explanation

'Replicative immortality' refers to cancer cells' ability to divide indefinitely, allowing them to proliferate without the normal limits that apply to healthy cells. This characteristic is a key feature of cancer progression.

What enzyme do cancer cells express to maintain their chromosome ends?

• Amylase

• Protease

• Lipase

• Telomerase

Answer explanation

Cancer cells express telomerase, an enzyme that adds repetitive nucleotide sequences to the ends of chromosomes (telomeres), preventing their shortening during cell division. This allows cancer cells to replicate indefinitely.

Tags

NGSS.HS-LS3-2

What is metastasis in the context of cancer?

• The process of cells shrinking

• The process of cells stopping division

• The process of cells migrating to other parts of the body

• The process of cell death

Answer explanation

Metastasis refers to the process of cancer cells migrating from the original tumor to other parts of the body, forming new tumors. This is a key characteristic of cancer progression, distinguishing it from benign growths.

What are oncogenes?

• Genes that stop cell division

• Genes that repair DNA

• Normal genes that suppress tumors

• Overactive forms of genes that promote cancer

Answer explanation

Oncogenes are mutated or overactive forms of normal genes that promote cell growth and division, leading to cancer. They differ from tumor suppressor genes, which normally inhibit cell division.

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NGSS.HS-LS3-2

The role of tumor suppressor genes is to (a)  

• To enhance protein synthesis
• To increase mutation rates
• To block cell cycle progression
• To promote cell division

Answer explanation

Tumor suppressor genes play a crucial role in regulating the cell cycle by blocking cell cycle progression. This prevents uncontrolled cell division, which is essential for maintaining normal cellular function and preventing cancer.

Tags

NGSS.HS-LS1-4

What is the function of the p53 protein?

• To repair DNA damage

• To destroy healthy cells

• To produce growth factors

• To accelerate cell division

Answer explanation

The p53 protein plays a crucial role in maintaining genomic stability by repairing DNA damage. It acts as a tumor suppressor, preventing the proliferation of cells with damaged DNA, which is essential for cancer prevention.

Match the following statements with their outcomes.

• A mutation leads to fixing genetic errors

• It becomes a tumor suppressor

• A mutation leads to cancer development

• It repairs DNA

• A mutation leads to uncontrolled cell growth

• It stops cell division

• A mutation leads to inhibiting cancer growth

• It becomes an oncogene

Answer explanation

When a proto-oncogene mutates, it can become an oncogene, which promotes uncontrolled cell division and can lead to cancer. This is why the correct answer is that it becomes an oncogene.

Tags

NGSS.HS-LS1-4