Which of the following statements is false?


a. Viruses may have circular DNA.
b. dsRNA is found in bacteria more often than in viruses.
c. Viral DNA may be linear.
d. Typically, viruses have DNA or RNA but not both.

Verified step by step guidance

1. Step 1: Understand the nature of viral genomes. Viruses can have DNA or RNA as their genetic material, and this can be either single-stranded or double-stranded. Additionally, viral DNA can be either circular or linear.
2. Step 2: Analyze statement (a): 'Viruses may have circular DNA.' This is true because some viruses, such as certain bacteriophages and animal viruses, have circular DNA genomes.
3. Step 3: Analyze statement (b): 'dsRNA is found in bacteria more often than in viruses.' This requires understanding that double-stranded RNA (dsRNA) genomes are characteristic of some viruses, but dsRNA is very rare in bacteria. Therefore, this statement is likely false.
4. Step 4: Analyze statement (c): 'Viral DNA may be linear.' This is true because many viruses, including some bacteriophages and animal viruses, have linear DNA genomes.
5. Step 5: Analyze statement (d): 'Typically, viruses have DNA or RNA but not both.' This is true; viruses generally contain either DNA or RNA as their genetic material, but not both simultaneously.

Key Concepts

Viral Genome Structure

Viruses can have genomes made of DNA or RNA, which may be single-stranded or double-stranded, and can be linear or circular. The structure varies widely among viruses, with some having circular DNA and others linear DNA or RNA genomes.

Double-Stranded RNA (dsRNA) in Viruses and Bacteria

Double-stranded RNA is a genetic material commonly found in certain viruses but is rare in bacteria. Most bacteria have double-stranded DNA genomes, making dsRNA more characteristic of viruses than bacterial cells.

Viral Genome Exclusivity

Typically, viruses contain either DNA or RNA as their genetic material, but not both simultaneously. This exclusivity is a key feature distinguishing viral genomes from cellular organisms, which have DNA genomes.