Inheritance
- Chromosomes, genes and proteins
- Chromosomes
- made of DNA
- contain genes
- Gene and allele
- gene: DNA coding for protein
- allele: alternative form
- Inheritance of sex
- XX female, XY male
- sperm decides sex
- 1 : 1 ratio
- Bases decide amino acids Supplement
- amino acid sequence
- gives protein shape
- Making a protein Supplement
- gene stays in nucleus
- mRNA copy to cytoplasm
- ribosome assembles amino acids
- Gene expression Supplement
- same genes in body cells
- only some expressed
- Haploid and diploid Supplement
- haploid: one set
- diploid: two sets
- human: 23 pairs
- Chromosomes
- Mitosis and meiosisSupplement
- Mitosis Supplement
- identical cells
- chromosomes copied first
- number maintained
- Roles of mitosis Supplement
- growth
- repair
- replacement
- asexual reproduction
- Stem cells Supplement
- unspecialised
- divide by mitosis
- daughters specialise
- Meiosis Supplement
- makes gametes
- reduction division
- diploid to haploid
- genetically different
- Mitosis Supplement
- Monohybrid inheritance
- Key terms
- Genotype
- Phenotype
- Homozygous
- Heterozygous
- Dominant and recessive
- Dominant: expressed if present
- Recessive: needs no dominant
- Pure-breeding
- Identical homozygous parents
- Heterozygous: not pure-breeding
- Genetic diagrams
- Punnett squares
- 3 : 1 ratio
- 1 : 1 ratio
- Pedigree diagrams
- Squares male, circles female
- Unaffected parents, affected child: recessive
- Test cross Supplement
- Unknown × homozygous recessive
- All dominant: homozygous
- Some recessive: heterozygous
- Codominance Supplement
- Both alleles expressed
- ABO: IA, IB, Io
- Sex linkage Supplement
- Gene on X chromosome
- Colour blindness
- More common in males
- Key terms