Reproduction & Inheritance

Asexual Reproduction

• Involves 1 parent

• Offspring is genetically identical to the parent

• E.g. strawberries

Sexual Reproduction

• Involves 2 parents → male & female

• Offspring is genetically different to parents

• E.g. humans

Gamete

Sex cell

Genetics

The study of inherited characteristics

Inherited Characteristics

• Traits that are passed from a parent to their children

• Controlled by genes

• E.g. eye colour

Acquired Characteristics

• Traits that are not passed from a parent to their children, but are learned

• Not controlled by genes

• E.g. ability to play piano

Chromosomes

• Tiny thread-like structures found in the nucleus that are composed of DNA & protein

• all cells have 46 (23 pairs)

• exception: gamete - 23 chromosomes

DNA

• Deoxyribonucleic acid

• Found in chromosomes

• Carries instructions for development, functioning, growth and reproduction of an organism

Nucleotide

• Basic unit of DNA

• Made of a phosphate-sugar backbone attached to a base

DNA Structure → 4 types of bases

• Adenine

• Thymine

• Guanine

• Cytosine

Shape of DNA

Double Helix

Gene

A section of DNA that contains specific instructions for making a certain protein

Dominant Genes

• Genes that are always shown e.g. brown hair

• Always in capital letters

Recessive Gene

• Genes that are only shown if dominant genes aren’t there

• Always in lowercase letters

Genotype

Our genetic make-up e.g. BB

Phenotype

Our physical appearance e.g. brown hair