MI 3.1.4-3.1.5 Quiz Review

In DNA microarray protocol, hybridization refers to

• converting mRNA from tissue samples to DNA.

• crossing healthy DNA with cancer DNA.

• upregulating genes in a healthy cell.

• combining cDNA from tissue samples with DNA on a microchip.

In DNA microarray protocol, what occurs after reverse transcription of the mRNA that is expressed?

• The cDNA that is produced is fluorescently tagged.

• The proteins that are translated are hybridized to the genes on the wells of the microarray chip.

• The mRNA is hybridized to the DNA on the wells of the microarray chip.

• The gene that produced the mRNA are turned off.

Each spot on a microarray card corresponds to DNA for one of the five genes of interest. Lanes 1–4 are controls. Controls help you interpret the colors you see in the results for each gene.

• All columns will be yellow.

• All columns will be black.

• Column 1 will be black, column 2 will be green, column 3 will be red, and column 4 will be yellow.

• Column 1 will be yellow, column 2 will be red, column 3 will be green, and column 4 will be black.

Which genes would be of interest to scientist to study further concerning gene expression in cancerous cells?

• Gene 4 only: because it is up-regulated

• Genes 2, 4 and 6: because expression is different than in healthy cells

• Gene 6 only: because it is turned on when it should be off

• Genes 1 and 5: because these are expressed

Up-regulated genes produce

• more mRNA.

• less mRNA.

• less cDNA

• more cancer.

The Human carcinoembryonic antigen (CEACAM6) gene

• codes for a protein that is involved with cell cycle checkpoints and is thought to be the “Guardian of the Genome”.

• codes for a protein that assists breathing and is not involved in the regulation of the cell cycle.

• codes for a protein that is involved with cell cycle regulation and is thought to be a proto-oncogene. When over-expressed, it becomes an oncogene, because it leads to unregulated cell division and inhibits cellular death.

• codes for a protein that catalyzes reactions involved in drug metabolism and is induced by some polycyclic aromatic hydrocarbons (PAHs), some of which are found in cigarette smoke.

Which of the following gene(s) would NOT be of interest to scientists who are studying the differences between healthy cells and cancerous cells, based on the microarray results shown here?

• Gene 3

• Gene 22

• Gene 9

• Gene 20

The figure shown here are the DNA microarray results for the four patients with lung cancer in activity 3.1.4.

What is the most logical reason for the difference in gene expression in gene 5 for patient 3 compared to the other patients?

• Gene 5 is more expressed in smokers, and patient 3 is a non-smoker so he showed less expression compared to the other patients.

• Gene 5 is a tumor suppressor, so it was working normally in patient 3 because he had a different type of lung cancer.

• Patient 3 is a non-smoker, so the gene was not affected by chemical in cigarette smoke.

• Gene 5 is an oncogene so it was expressed higher than normal which is what caused patient 3's type of cancer.

The figure shown here are the DNA microarray results for the four patients with lung cancer in activity 3.1.4.

The SRY gene (gene 4 in the lab) would most likely be expressed in

• the cells from non-cancerous lungs

• the cells from cancerous lungs

• the cells from both non-cancerous and cancerous lungs

• the cells from neither non-cancerous and cancerous lungs

The figure shown here are the DNA microarray results for the four patients with lung cancer in activity 3.1.4.

Which of the following genes would generally be expressed in a cancerous cell or tissue sample? *may be more than one answer

• Gene 1

• Gene 2

• Gene 3

• Gene 4

• Gene 5