INHERITANCE – FULL DETAILED EXPLANATION
1. What exactly is inheritance?
Inheritance is the biological process where information stored in genes is passed from parents to their children.It explains why you look like your family, why you may have your father’s eyes or your mother’s smile.
2. Where is this information stored?
All inherited information is stored in DNA.
DNA → Genes → Chromosomes
DNA is a long molecule shaped like a twisted ladder.
DNA is divided into genes (small sections that control traits).
Genes are packed into chromosomes.
Humans have 46 chromosomes (23 pairs).
23 come from your mother (egg)
23 come from your father (sperm)
This is why you are a unique mix of both.
3. How do genes control traits?
Each gene has two versions called alleles:
One allele from mother
One allele from father
Your traits depend on which allele combination you get.
4. Dominant and Recessive Alleles
Dominant Allele
Shows its effect even if you have only one copy.
Example: Brown eyes (B)
Recessive Allele
Shows effect only when both copies are recessive.
Example: Blue eyes (b)
Example:
BB → Brown eyes
Bb → Brown eyes
bb → Blue eyes
So a child can have brown eyes even if only one parent has brown eyes.
5. Why do traits skip generations?
Because recessive alleles can hide.
Example:
Parents both have brown eyes (Bb)
Child gets bb → blue eyesThe recessive trait reappears after one generation.
6. Types of traits you inherit
Physical traits
Eye colour
Hair colour
Height
Dimples
Skin colour
Blood group
Physiological traits
Metabolism rate
Hormone levels
Ability to taste certain chemicals (TT vs tt)
Behavioral/psychological tendencies
Intelligence potential
Learning abilityThese are influenced by genes but also shaped by environment.
Genetic disorders
Thalassemia
Haemophilia
Color blindness
Cystic fibrosisThese follow clear inheritance patterns.
7. Why is inheritance important in biology?
1. Explains characteristics
Why siblings resemble each other but are not identical.
2. Helps predict traits
Doctors can predict whether a child may inherit:
Genetic diseases
Blood group
Traits like colour blindness
3. Useful in selective breeding
Used in farming:
Cows that give more milk
Plants that resist diseases
4. Helps understand evolution
Traits that increase survival get passed on, shaping future generations.
8. Famous scientist of inheritance — Mendel
Gregor Mendel studied peas and discovered:
Dominant and recessive traits
How traits separate and recombine
How combinations create variation
His work is the foundation of genetics.