OCR General Certificate of Secondary Education (GCSE) Biology Practice Exam

What condition can result from a lack of transmitter chemicals?

1. Euphoria

2. Parkinson's disease

3. Anxiety disorders

4. Insomnia

The correct answer is: Parkinson's disease

A lack of transmitter chemicals, particularly in the neurotransmitter dopamine, is closely associated with Parkinson's disease. This neurodegenerative condition is characterized by the degeneration of dopamine-producing neurons, which leads to symptoms such as tremors, stiffness, and difficulty with movement. Dopamine is crucial for coordinating smooth and controlled muscle movements. In contrast, while euphoria, anxiety disorders, and insomnia may also be related to neurotransmitter imbalances, they are not specifically linked to a deficiency in the same way that Parkinson's disease is. For instance, anxiety disorders can be associated with imbalances in serotonin or norepinephrine, while insomnia can be influenced by various neurotransmitters including those that regulate sleep-wake cycles. Therefore, the direct connection between a lack of transmitter chemicals and Parkinson's disease distinguishes it as the correct answer.