Chromosome number across generations
Chromosome number across generations
A chromosome is a DNA molecule carrying many genes. In human body cells, 46 chromosomes are arranged as 23 pairs. Homologous chromosomes are matching chromosomes with the same genes at the same loci, although they may carry different alleles.
Step-by-step lessons on Edexcel A A Level Biology Gametes, fertilisation and meiosis. Each one builds up to exam-style questions. Build a strong foundation in cell biology and biochemistry early on, since later topics on genetics, ecology and physiology all draw on these core concepts.