Question

Identify the correct statements among the following: A. Probes are generally ss RNA or ss DNA
B. Probes are complementary to desired DNA
C. The efficiency of uptaking DNA fragments by bacteria decreases when they are treated with Ca\(^{2+}\) ions
D. Cloning vectors should have low molecular weight

• A. A, B, C only
• B. A, B, D only
• C. A, C, D only
• D. B, C, D only

Hint:

Understanding the properties of cloning vectors and the role of probes in molecular biology is essential for effective genetic engineering practices.

Answer 1

The Correct Option is B

Let's evaluate each statement: - A) Probes are generally ss RNA or ss DNA: This is true. Probes are short, single-stranded nucleic acid sequences (either RNA or DNA) used to detect the presence of complementary sequences in a sample by hybridization. - B) Probes are complementary to desired DNA: This is true. Probes are designed to be complementary to the specific sequence of the target DNA, allowing them to bind (hybridize) to it. - C) The efficiency of uptaking DNA fragments by bacteria decreases when they are treated with Ca\(^{2+}\) ions: This is false. The treatment of bacteria with Ca\(^{2+}\) ions actually increases the efficiency of DNA uptake. This process is called transformation and is commonly used in genetic engineering to introduce plasmids into bacterial cells. - D) Cloning vectors should have low molecular weight: This is true. While cloning vectors do not necessarily need to be of very low molecular weight, they should be sufficiently small to facilitate easy manipulation and insertion of foreign DNA. This helps ensure efficient transformation and replication within the host. Thus, the correct statements are A, B, and D only.