Chapter 16 Mastering Biology

An understanding of gene regulation mechanism has led to several interesting and important applications. For example, the loss of gene regulation can result in ?, or out of control cell growth.

Cancer.

Operons are a standard method for gene regulation in?

Prokaryotes but not eukaryotes.

A normal gene that, if mutated, can lead to cancer is called a(n) ?

Proto-oncogene.

Eukaryotes have more complex modes of control, including the packing of chromosomes, ? (which can produce several mRNAs from a single gene), and the control of translation.

RNA splicing.

For many years, it was believed that heavy consumption of what increased a person's chance of getting colon cancer?

Red meat.

? can produce new live individuals, while ? can produce potentially therapeutic stem cells.

Reproductive cloning. Therapeutic cloning.

You are an epidemiologist studying the effects of years of vigorous exercise on health. You ask participants to recall how much they have exercised per week every week for the last three years. What type of study are you conducting?

Retrospective.

In prokaryotic cells, related genes may be organized into ?, which can be turned on and off as a single unit.

Operons.

Your body is composed of a dazzling array of different cell types. Each cell type develops its own unique properties. How does this happen?

All cells (with very few exceptions) contain the same set of genes, but the process of gene expression determines which genes are active in each cell.

What kind of individual is most likely to get cancer?

An obese male who eats a lot fo fruits and vegetables.

Within an operon, repressors ?

Block gene transcription to RNA by attaching to the operator.

You are an oncologist and agree with the 1997 findings published by the World Cancer Research Fund and the American Institute for Cancer Research. What do you believe?

Eating judicious amounts of fruits and vegetables will decrease a person's risk of developing cancer.

? is the carcinogen that promotes colon cancer.

Fat.

All organisms must regulate ? by turning genes on and off in different cells at different times.

Gene expression.

A(n) ? is a protein that promotes cell division. In excess, such a protein may lead to cancer.

Growth factor.

The lac operon controls expression of three genes that produce lactose-digesting enzymes. What role does lactose play in regulating the lac operon?

It binds to and disables the repressor protein.

What would appear to be the most beneficial in preventing cancer?

Not smoking.

A gene that causes a cell to become cancerous is called a(n) ?

Oncogene.

What are some carcinogens?

Testosterone, fat, cigarette smoke, and UV light.

To begin the process of gene transcription, RNA polymerase attaches to?

The promoter associated with the target gene.

A(n) ? is a gene that encodes proteins that inhibit cell division. Such proteins normally help prevent cells from becoming cancerous.

Tumor-supressor gene.