ACT Preparation / Unit 22 ACT 2104 short lesson, about 20 seconds
DNA and Genes
Captions available
The idea
DNA is the hereditary material, organized into chromosomes in the nucleus. Genes are the units of inheritance carried on chromosomes, and alleles are different versions of a gene.
In practice
A gene for wing color in a beetle might have a black allele and a red allele.
Where people slip
Each individual carries two alleles for a gene, one from each parent.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
Builds on
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