Mistakes In Meiosis Flashcards
A gamete may end up with one extra chromosome or one missing chromosome. If this faulty gamete fuses with a normal gamete, the resulting zygote will have a missing or an extra chromosome, this kind of mistake is called…
Non-disjunction
One kind of non-disjunction involves…
Chromosome 21
Chromosome 21 is a very small chromosome. If a gamete with an extra chromosome 21 fuses with a normal gamete; the resting individual will have…
3 chromosome 21s
And their chromosome number will be 47 instead of 46
A person with 3 chromosome 21s has…
Down’s syndrome
Down’s syndrome children account for one in every…
800-1000 births
The risk of having a child with Down’s syndrome increases with the…
Age of the mother, although they may be born to mothers of any age
Characteristics of people with Down’s syndrome are…
Flatter head Smaller ears Protruding tongue Shorter than average Hands have a single fold across the palm May have heart defects Degree of learning difficulty
Children with Down’s syndrome usually have a very…
Happy disposition and are very affectionate
Some adults are able to enter…
Employment and lead independent lives, although others will need lifelong care
Average life expectancy:
60
