In Alzheimer disease the aggregation of this happens

Options

A. Phospholipids
B. Haemoglobin
C. Amyloid `beta`peptide
D. Nucleic acid.

Answer

### Step-by-Step Solution:

1. **Understanding Alzheimer’s Disease**: Alzheimer’s disease is a neurodegenerative disorder characterized by cognitive decline and memory loss. It is associated with specific pathological features in the brain.

2. **Identifying Aggregation**: The question asks about what aggregates in Alzheimer’s disease. Aggregation refers to the clumping together of proteins or peptides, which can lead to the formation of plaques.

3. **Analyzing the Options**:
- **Option A: Phospholipids** - These are components of cell membranes and are not primarily associated with Alzheimer’s disease.
- **Option B: Hemoglobin** - This protein is involved in oxygen transport in the blood and is not related to Alzheimer’s disease.
- **Option C: Amyloid beta-peptide** - This peptide is derived from the amyloid precursor protein (APP) and is known to aggregate and form amyloid plaques in the brains of Alzheimer’s patients.
- **Option D: Nucleic acid** - These are the molecules that make up DNA and RNA and are not involved in the aggregation seen in Alzheimer’s disease.

4. **Focusing on Amyloid Beta-Peptide**: Research has shown that amyloid beta-peptides, which are fragments of the amyloid precursor protein, are crucial in the development of Alzheimer’s disease. They aggregate to form plaques that disrupt cell function.

5. **Conclusion**: Based on the analysis, the correct answer to the question is **Option C: Amyloid beta-peptide**. This is the substance that aggregates in the brains of individuals with Alzheimer’s disease.