gene mutations and chromosome aberrations Flashcards
What causes gene mutations?
Gene mutations occur during DNA replication when a base pair is added, left out, or doubled up, changing the sequence of bases in DNA
What are some examples of gene mutations?
Examples include haemophilia, colour-blindness, sickle cell anaemia, and albinism.
What are sex-linked gene mutations?
Sex-linked gene mutations, such as haemophilia and colour blindness, are located on the X-chromosome and are more common in males.
What causes sickle cell anaemia?
Sickle cell anaemia is caused by a gene mutation that produces a faulty haemoglobin molecule, causing red blood cells to become sickle-shaped. This leads to anaemia and blocks blood flow, damaging organs like the brain and kidneys.
What is albinism and what causes it?
Albinism is a rare genetic disorder caused by a recessive gene mutation that prevents the development of the pigment melanin, affecting skin, hair, and eye color. Individuals with albinism may have light-sensitive eyes and pale skin but are otherwise normal.
What are chromosome aberrations?
Chromosome aberrations occur when chromosomes don’t separate properly during Anaphase I of meiosis, resulting in a gamete with an abnormal number of chromosomes.
What is an example of a chromosome aberration?
Down syndrome is caused by a chromosome aberration where there is a non-disjunction of chromosome pair 21, resulting in a gamete with an extra or missing chromosome 21.
How does Down syndrome occur?
Down syndrome occurs when a gamete with an abnormal number of chromosome 21 fuses with a normal gamete, leading to a zygote with three (or only one) chromosome 21s.
