Biotechnology

Concept: Viruses consist of genetic material enclosed within a protein coat called the capsid. The capsid protects the viral genome and aids in infection.
Step 1: Understanding capsid structure.
The capsid is made up of repeating protein subunits.
Step 2: Identifying the structural unit.
These subunits are called capsomeres, which assemble to form the complete capsid.
Step 3: Function of capsomeres.

• Provide structural stability
• Protect viral nucleic acid
• Determine shape of the virus

Step 4: Eliminating other options.

• Glycoproteins: Found in viral envelopes
• Nucleoproteins: Associated with nucleic acids
• Lipoproteins: Present in envelopes, not capsid

Step 5: Conclusion.
Thus, capsomeres are the main structural protein units forming the viral capsid.

Concept: Glycolysis is the first stage of cellular respiration, occurring in the cytoplasm, where one molecule of glucose is broken down into two molecules of pyruvate.
Step 1: ATP investment phase.
During the initial steps of glycolysis, 2 ATP molecules are consumed.
Step 2: ATP generation phase.
In later steps, 4 ATP molecules are produced through substrate-level phosphorylation.
Step 3: Net ATP calculation.

Step 4: Additional products.

• 2 NADH molecules
• 2 pyruvate molecules

Step 5: Conclusion.
Thus, the net gain of ATP from glycolysis of one glucose molecule is 2 ATP.

Concept: Viruses are classified in different ways based on their properties. The Baltimore Classification is a widely accepted system based on molecular biology.
Step 1: Basis of classification.
The Baltimore system classifies viruses according to:

• Type of nucleic acid (DNA or RNA)
• Single-stranded or double-stranded nature
• Method of replication and mRNA synthesis

Step 2: Groups in the system.
There are seven groups (I to VII), including:

• dsDNA viruses
• ssDNA viruses
• dsRNA viruses
• ssRNA (+/-) viruses
• Retroviruses

Step 3: Significance.
This classification helps in understanding viral replication mechanisms and guides antiviral strategies.
Step 4: Eliminating other options.

• Shape and size: Used in morphological classification
• Host type: Used in ecological classification

Step 5: Conclusion.
Thus, the Baltimore Classification is based on genetic material and replication strategy.