Aids

Hepatitis

Viral pneumonia

Viral meningitis

Polio

Spongiform encephalopathies:

• Chronic wasting disease

• Creutzfeldt-Jakob disease (CJD)

— Amino acid chain

Table 11.1 Bacteria, viruses, and prions. The structure and replication of these pathogens are described.

Mode of reproduction or duplication

Mode of reproduction or duplication

1. Bacterium starts with one copy of circular DNA chromosome in nuclear region.

2. The circular chromosome is copied and each copy is attached to the plasma membrane.

3. Continued growth separates the two chromosomes. The plasma membrane grows inward in the middle and a new cell wall is constructed.

4. Daughter cells separate. Chromosomes return to nucleoid region.

1. Viral membrane fuses with host cell, the capsid is removed, and the genome enters.

Misfolded prion

2. The genome is copied and used to synthesize many copies of double stranded DNA.

3. The DNA is transcribed and translated by the host cell. More viral proteins and copies of the viral genome are produced.

4. Once assembled, new viruses leave the host cell and infect other cells.

Misfolded prion

2. The genome is copied and used to synthesize many copies of double stranded DNA.

3. The DNA is transcribed and translated by the host cell. More viral proteins and copies of the viral genome are produced.

1. A misfolded prion protein searches for a normal one and refolds it into the mutant form.

2. The number of misfolded prions is now doubled. Each refolds a normal prion protein into the mutant form.

3. The number of misfolded prions continues to double, eventually causing host cell to burst and spread infection to other cells.

Media Activity 11.1A Structure and Reproduction of Infectious Agents

0 0

Post a comment