Abnormal Meiosis (Chromosome Mutation) (Grade 12 NSC Matric Life Sciences): Flashcards
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Non-disjunction
Non-disjunction
Chromosomes fail to separate properly during meiosis
Anaphase I non-disjunction - structures affected
Anaphase I non-disjunction - structures affected
Homologous chromosomes
Anaphase II non-disjunction - structures affected
Anaphase II non-disjunction - structures affected
Sister chromatids
Result of non-disjunction
Result of non-disjunction
Gametes with extra or missing chromosomes
Normal human gamete chromosome number
Normal human gamete chromosome number
23
Cause of Down Syndrome
Cause of Down Syndrome
Non-disjunction of chromosome 21
Trisomy 21 meaning
Trisomy 21 meaning
Three copies of chromosome 21
Chromosome count in Down Syndrome
Chromosome count in Down Syndrome
47 (instead of normal 46)
Amniocentesis
Amniocentesis
Procedure detecting chromosomal abnormalities in pregnancy
Main risk factor for non-disjunction
Main risk factor for non-disjunction
Increasing parental age (especially maternal)