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37 Cards in this Set
- Front
- Back
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In pedigree analysis, what symbol represents a male? |
Square |
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In pedigree analysis, what symbol represents a female? |
Circle |
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In pedigree analysis, what symbol represents an individual of unspecified sex? |
Diamond |
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What is the name an symbol given for nonidentical twins? |
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What is the symbol given for identical twins? |
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What is the symbol for an infected individual? |
A blacked out square/circle/diamond |
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What is the symbol for heterozygotes for autosomal recessive? |
Half blacked out square/circle/diamond |
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What is the symbol for the carrier of a sex linked recessive? |
Circle with a black dot in the center |
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What is the symbol for a deceased individual? |
Square/circle/diamond with a diagonal line running through it |
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What is meant by autosomal? |
Genes for trait not carried on the sex chromosome |
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What is meant by sex-linkage? |
Genes for trait carried on the sex chromosome |
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What is the mode of inheritance of Huntington's disease? |
Autosomal dominant |
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What are the symptoms of Huntington's disease? |
Involentary muscle movements, progressive neural deterioration leading to dementia, premature death |
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What is the gene for Huntington's? |
HD |
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What is the DNA sequence composed of? |
10- 35 CAG repeats |
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What causes the disease? |
A mutation whereby 36 or more CAG repeats are present and a mutant huntingtin protein is produced |
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What does the mutant huntingtin protein do? |
Causes decay of neurons |
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What is the mode of inheritance of cystic fibrosis? |
Autosomal recessive |
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What are the symptoms of cystic fibrosis? |
Persistant cough, recurring chest and lung infections, blocked pancreatic ducts, poor growth and weight gain, infertility, high salt concentration in sweat |
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What protein functions as chlorine channel in epithelial membranes? |
Cystic fibrosis transmembrane conductance regulator (CFTR) |
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What is the most common mutation in CFTR? |
Deletion of phenylalanine at position 508 |
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What is the effect of the mutation? |
Disrupts protein folding so it cannot take its place in the cell membrane. It is degraded in the cell. |
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What is the mode of inheritance of sickle cell anaemia? |
Autosomal recessive |
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What mutation causes the symptoms of sickle cell anaemia? |
A substitution of one amino acid in haemoglobin |
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What is the effect of sickle cell anaemia? |
When O2 content of an individual is low, the sickle cell Hb molecules aggregate into long rods that deform the red blood cell into a sickle shape. Sickle cells can clump and clog small blood vessels. |
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What happens if only one sickle cell allele is present? |
Some symptoms are present. At the organismal level therefore, the normal allele is incompletely dominant |
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What is meant by hemizygous? |
Only one copy of genes present. For example, males are hemizygous for genes on the x chromosome |
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Where are x linked recessive alleles expressed? |
All males with allele, females with homozygous recessive |
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Give an example of an x linked recessive disease |
Duchenne muscular dystrophy |
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What are the symptoms of DMD? |
Increasing muscle weakness and wasting, loss of motor skills and eventual paralysis, respiratory and heart failure, may be some cognitive dysfunction, life expectancy around 25 years |
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What is the role of the dystrophin gene? |
Produces dystrophin, a protein that connects the cytoskeleton of the muscle fibre to the surrounding extracellular matrix |
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Give two examples of x linked dominant disorders |
x-linked hypophosphatemia Rett syndrome |
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What happens if the mother is heterozygous for an x linked dominant disease? |
50% chance of offspring being infected whether male or female |
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What happens if the father is heterozygous for an x linked dominant disease? |
All daughters are infected, no sons are infected as they get their x from the mother and the y from the father |
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Why is Y linked dominance rare? |
There aren't many genes on the Y chromosome |
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Give one example of a Y linked dominant disorder |
Swyer syndrome |
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Where do mitochondria come from? |
Mother |
