A disease is inherited in a family. Explain how genes are involved.
An inherited disease occurs when a faulty gene is passed from parents to offspring.
Key Concepts
| Term | Meaning |
|---|---|
| Gene | Unit of heredity carrying information |
| Mutation | Change in gene sequence |
| Inherited Disorder | Disease passed through genes |
Types of Inheritance
| Type | Pattern | Example Idea |
|---|---|---|
| Dominant | One faulty allele enough | Shows in every generation |
| Recessive | Two faulty alleles needed | May skip generations |
Stepwise Understanding
A gene gets mutated (faulty)
Parent carries this faulty gene
During reproduction, gene passes to child
If condition for expression is met (dominant or recessive)
Disease appears in offspring
Important Point
| Case | Outcome |
|---|---|
| One faulty gene (dominant) | Disease expressed |
| Two faulty genes (recessive) | Disease expressed |
| Carrier state | No disease but can pass gene |
Real Insight
Some people carry a disease gene without showing symptoms, but their children may still get affected if both parents pass that gene.
So inherited diseases are directly linked to genes being passed across generations.