Biology · GCSE · Reproduction & Genetics
The language of genetics
The language of geneticsFree6:19Heddy Score 3 of 7, below the standard
What you need to know
- A gene is a section of DNA on a chromosome that codes for a characteristic; humans have 23 pairs of chromosomes, one of each pair from each parent.
- An allele is a different version of a gene, and you inherit one allele of each gene from each parent.
- A dominant allele (capital letter) shows its effect even with one copy; a recessive allele (lower-case letter) only shows when there are two copies.
- Genotype is the pair of alleles, such as TT, Tt or tt; phenotype is the characteristic that results.
- Two parents who both carry a recessive allele can have a child who shows the recessive trait.
In this clip
Runs 6:19, from 1:26 to 7:45 of the full video.
Heddy ScoreSeven checks every clip must pass before students see it: trusted, on the map, accurate, focused, accessible, safe, and proven by students.3/7, Below the standard
See the seven stars
- Trusted source · passed. The creator's own upload, live and playable here.
- On the map · not judged yet. A teacher watched it: it mainly teaches this map topic.
- Spec-true · not judged yet. Accurate, and right for the current UK specification.
- Focused · passed. One idea, short enough to watch in one go.
- Accessible · passed. Good captions, clear sound and pictures.
- Safe for children · not judged yet. Right for 11 to 16 year olds, with no sales pitch.
- Proven · not judged yet. Earned from our students: they learn from it, find it helpful and watch it to the end.
Our students
Not enough students yet
Our own students' answers. These are what move ★7 Proven.On YouTube
How the Heddy Score works4.95M views · 48.9K likes · Amoeba Sisters 2.98M subscribers
As reported by YouTube on 2026-11-01. Not part of the Heddy Score.Why we picked it
A warm, step-by-step worked example (tasting PTC) that makes gene, allele, dominant, recessive, genotype and phenotype stick.
Amoeba Sisters on YouTubechecked 2026-10-22
Plays from youtube-nocookie.com. No YouTube cookies until you press play.