Scientists have discovered how to put together a bacteriophage with the protein coat of phage T2 and the DNA of phage lambda. If this composite phage were allowed to infect a bacterium, the phages produced in the host cell would have _________. (Explain your answer.)
a. The protein of T2 and the DNA of lambda
b. The protein of lambda and the DNA of T2
c. The protein and DNA of T2
d. The protein and DNA of lambda

Verified step by step guidance

1. Step 1: Understand the structure of a bacteriophage. A bacteriophage is composed of two main components: a protein coat (capsid) and genetic material (DNA or RNA). The protein coat determines the physical structure and the ability to attach to host cells, while the genetic material carries the instructions for replication.
2. Step 2: Analyze the composite phage described in the problem. The composite phage has the protein coat of phage T2 and the DNA of phage lambda. This means the protein coat will dictate which bacterium the phage can infect, while the DNA will determine the genetic instructions for replication inside the host cell.
3. Step 3: Consider the infection process. When the composite phage infects a bacterium, the protein coat of T2 will facilitate attachment and injection of the genetic material into the host cell. However, the DNA of lambda will be the genetic material that is injected and used for replication.
4. Step 4: Predict the outcome of replication. Inside the host cell, the DNA of lambda will direct the synthesis of new phages. The genetic instructions from lambda DNA will specify the production of lambda proteins and lambda DNA, not T2 proteins or DNA.
5. Step 5: Conclude the answer. The phages produced in the host cell will have the protein and DNA of lambda because the genetic material (lambda DNA) determines the characteristics of the progeny phages.

Key Concepts

Bacteriophage Structure

Bacteriophages, or phages, are viruses that specifically infect bacteria. They consist of a protein coat, known as a capsid, which encases their genetic material, either DNA or RNA. In this scenario, the phage T2's protein coat is combined with the DNA from phage lambda, which is crucial for understanding how the resulting phages will express their characteristics.

Genetic Material and Protein Expression

The genetic material of a virus dictates the proteins that will be produced during infection. When a phage infects a bacterium, it injects its DNA, which hijacks the host's cellular machinery to produce new phage particles. Therefore, the DNA of the composite phage will determine the genetic instructions for the proteins synthesized in the host cell.

Phage Assembly and Characteristics

During the assembly of new phages within an infected bacterium, the proteins and DNA combine to form complete viral particles. In this case, since the protein coat is derived from T2 and the DNA from lambda, the resulting phages will exhibit the protein characteristics of T2 while carrying the genetic information of lambda. This distinction is essential for predicting the properties of the newly formed phages.