2.11 Cloning

What does it mean to study gene expression?

To identify which genes are active (being transcribed into mRNA) in a cell or tissue

What is a nuclei acid probe?

A short, single-stranded synthetic nucleic acid that is complementary to an mRNA of interest.

What is DNA microarray (gene chip)?

A glass slide with thousands of tiny wells,each containing DNA from a different gene.

What does it mean if a spot on a microarray glows?

The gene in that spot is actively being transcribed in the sample cell.

How can DNA microarrays help in cancer research?

They can classify cancer types (like leukemia subtypes) based on which genes are active.

Key idea behind genetic potential in cells?

All body cells have a complete genome-even if they don’t express all their genes.

What is evidence that differentiated plant cells still have a full set of genes?

A plant can grow from a small cutting-one cell can regenerate into an entire adult plant.

What does this orchid cloning experiment prove?

Mature (differentiated) plant cells can reverse differentiation and become all the specialized cells of a new plant.

What is the method used to clone animals?

Nuclear transplantation.

What happens in nuclear transplantation?

The nucleus of an egg or zygote is replaced with the nucleus from an adult body cell.

What is reproductive cloning?

A cloning process that produces a new,genetically identical animal.

In reproductive cloning, who does the cloned animal genetically match?

The nucleus donor (NOT egg donor or the surrogate mother).

What is the goal of therapeutic cloning?

To create embryonic stem cells, not a whole organism.

How is therapeutic cloning different from reproductive cloning?

Therapeutic cloning creates stem cells;reproductive cloning creates a new grantsmanship.

What special abilities do embryonic stem cells have?

They can divided indefinitely and potentially become many types of specialized cells.

How do adult stem cells differ from embryonic stem cells?

Adult stem cells are more limited-they can make only a few related types of specialized cells

What recent discovery reduces ethical concerns?

Adult cells (like skin cells) can be reprogrammed to act like embryonic stem cells.

What is cancer at the genetic level?

A disease where cells escaped normal controls on growth and division due to changes in gene expression.

What is oncogene?

A cancer causing gene (tumor gene)

What is a proto-oncogene?

A normal gene that can turn into an oncogene if mutated

What do proto-oncogenes normally do?

They code for growth factors or cell-cycle proteins that regulate normal cell division.

What happens when proto-oncogenes normally do?

They code for growth factors or cell-cycle proteins that regulate normal cell division.

What happens when proto-oncogene products become overactive or abnormal?

They drive excessive cell division, leading to cancer.

What is a tumor-suppressor gene?

A gene that codes for a protein that inhibits cell division,helping prevent uncontrolled growth.

What happens when a tumor suppressor gene is mutated?

The protein becomes defective or absent,

-removing growth inhibition—> cells divide

-excessively—> tumor forms

Do cancers usually result from a single mutation?

No. They require multiple mutations (often 6+)

Are cancer-causing mutations usually in proto-oncogenes, tumor-suppressor genes,or both?

Both. Cancer typically involves mutations that activate oncogenes AND mutations that knock out tumor-suppressor genes.

Why does cancer take a long time to develop?

Because a malignant tumor forms only after a gradual accumulation of many mutations that activate oncogenes and disable tumor- suppressor genes.

Why can cancer run in families?

Because a person can inherit one of the necessary mutations, putting them one step closer to cancer development.

Which genes are commonly mutated in inherited breast cancer?

BRCA1 and BRCA2.

What causes most cancers: inherited mutations or environmental factors?

Environmental factors,especially carcinogens.

What is a carcinogen?

A substance or environmental factor that causes mutations leading to cancer.

How does plant fiber help prevent cancer?

Eating 20-30 g of plant fiber daily (like in 7 apples) may help prevent colon cancer by speeding up waste and reducing the colon lining’s exposure to carcinogens.

What is a dietary factor besides fiber, that can help prevent colon cancer?

Raring less animal fat.

What vitamins and compounds in fruits and vegetables are known to protect against various cancers?

Vitamins C and E and certain compounds related to Vitamin A.

What group of vegetables is thought to be especially rich in cancer-preventing substances?

Cabbage and its relatives, such as broccoli and cauliflower

What is the encouraging finding from nutrition research regarding cancer?

We can help reduce our risk of acquiring some of the most common forms of cancer by the food choices we make in our daily lives