Genetic Disorders 0.0 / 5 ? BiologyDNA and inheritanceIGCSEAQA Created by: Nicole DCreated on: 07-12-13 19:44 Genetic Disorders 22 Questions 1 of 23 What are mutations? Changes in the base sequences of our genes 2 of 23 What are genetic disorders? Diseases that can be inherited 3 of 23 What is the result of polydactyly? Having extra fingers and toes 4 of 23 It is caused by a __________ allele Dominant 5 of 23 How many parents need to have the disorder for it to be passed on? One 6 of 23 What is cystic fibrosis? A disorder of the cell membranes 7 of 23 What is a sufferer of cystic fibrosis unable to do? Transport certain substances from one side to another 8 of 23 Mucus secretions become very___(1)___ and ____(2)____ (1) thick ; (2) sticky 9 of 23 What happens to the organs of a cystic fibrosis sufferer? They become clogged up which stop them working properly 10 of 23 Where are symptoms particularly evident? In lungs, pancreas and reproductive system 11 of 23 Caused by a ___________ allele Recessive 12 of 23 How can parents who do not suffer cystic fibrosis give birth to a child who does suffer? If both parents are heterozygous because this means that they are carriers but not a sufferer 13 of 23 Sickle-cell anaemia is caused by a __________ allele Recessive 14 of 23 How does Sickle-cell anaemia affect someone? Affects red blood cells so they are less able to carry oxygen 15 of 23 Possible symptoms of Sickle-cell anaemia? Breathlessness, lethargy, joint pain and tissue death 16 of 23 Common in ___________ zones Malarial 17 of 23 What is an advantage of being a carrier of sickle-cell anaemia? Makes you more likely to survive in high malaria prevalence areas 18 of 23 If someone has Down's Syndrome they have an extra ____________ Chromosome 19 of 23 Another name for this is ___________ Trisomy 20 of 23 Therefore how many chromosomes does the sufferer have in total? 47 21 of 23 Within the 23 pairs of chromosomes, at which pair is the extra chromosome? The 21st pair 22 of 23 How does the inheritance of Down's Syndrome differ from other genetic disorders? (1) not just the inheritance of one allele so can't call it hetero- or homo- zygous ; (2) parents aren't necessarily carriers 23 of 23
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