General Biology 2 — Third Quarter Examination (Second Semester)

Directions: Read the questions carefully. Choose the letter of the best answer. What is a plasmid?

• A protein molecule found in bacterial cells.

• A sequence of RNA found in the cytoplasm.

• A structure that forms part of the bacterial cell membrane.

• A circular piece of DNA that replicates independently of chromosomal DNA

Directions: Read the questions carefully. Choose the letter of the best answer. Why are plasmids important in genetic engineering?

• They provide a natural source of protein for genetic studies.

• They can carry genes of interest into host cells for expression.

• They are used as enzymes to cut DNA at specific sequences.

• They are responsible for the metabolic processes in bacterial cells.

Directions: Read the questions carefully. Choose the letter of the best answer. A scientist grows two bacterial cultures: one with a plasmid containing a gene for fluorescence and one without it. Under UV light, only one culture fluoresces. What conclusion can be drawn?

• Plasmids are always visible under UV light.

• Fluorescence is an inherent property of all bacterial cells.

• UV light causes plasmid DNA to degrade, producing fluorescence.

• The plasmid enables the bacteria to fluoresce by expressing the gene it carries.

Directions: Read the questions carefully. Choose the letter of the best answer. Which is a transgenic organism?

• A rat with rabbit hemoglobin genes.

• A human given corrected blood clotting genes.

• A fern grown in cell culture from a single fern root cell.

• A bacterium that has received genes via conjugation.

Directions: Read the questions carefully. Choose the letter of the best answer. Which is not an application of recombinant DNA technology in medicine?

• Blood clotting factor VIII

• Golden rice

• Growth Hormone

• Insulin

Directions: Read the questions carefully. Choose the letter of the best answer. What is a major advantage of transformation for bacteria?

• It allows bacteria to become immune to viral infections.

• It prevents the spread of plasmids among bacterial populations.

• It requires direct contact between bacterial cells, ensuring genetic diversity.

• It enables bacteria to acquire new genetic traits, such as antibiotic resistance.

Directions: Read the questions carefully. Choose the letter of the best answer. Which statement best describes bacterial conjugation?

• It requires a virus to mediate the exchange of genetic material.

• It is the uptake of free DNA from the environment by a bacterial cell.

• It involves the direct transfer of DNA between two bacteria through a pilus.

• It occurs when a bacteriophage carries DNA from one bacterium to another.

Directions: Read the questions carefully. Choose the letter of the best answer. Arrange the followings steps in making cloned genes in recombinant plasmids in chronological order. I. DNA ligase joins the two DNA molecules, form in a recombinant DNA plasmid. II. Under the right conditions, a bacterial cell takes up the recombinant plasmid. III. The sticky ends of the plasmid match up with the sticky ends of the human DNA fragment according to the base-pairing rules. IV. A restriction enzyme cuts the plasmid in only one place, but cuts the human DNA molecule at thousands of sites. One of those fragments carries the protein V gene. V. Cell division results in many identical copies of the bacterial cell, all carrying the protein V gene. When the genes are expressed, multiple copies of protein V are made.

• I, II, III, IV, V

• II, V, I, II, IV

• IV, III, I, II, V

• III, I, IV, II, V

Directions: Read the questions carefully. Choose the letter of the best answer. In bacterial transduction, DNA is transferred between bacteria by what mechanism?

• A sex pilus

• A bacteriophage (virus)

• Direct contact between bacterial cells

• Plasmid uptake from the environment

Directions: Read the questions carefully. Choose the letter of the best answer. Which of the following is true about plasmids in gene transfer?

• Plasmids are only found in eukaryotic cells.

• Plasmids are always transferred by transduction.

• Plasmids are always incorporated into the bacterial chromosome.

• Plasmids can replicate independently of the bacterial chromosome.