Noadswood Science, 2012

To understand how some diseases can be inherited

Wednesday, April 19, 2023

Huntington’s disease is an inherited disorder that affects the nervous system – symptoms do not usually present themselves before ~40 years old

It is caused by a dominant allele – this means it can be passed on by just one parent if they have the disorder: -

Cystic fibrosis is an inherited disorder that affects the cell membranes, causing the production of thick and sticky mucus

It is caused by a recessive allele meaning that it must be inherited from both parents

Cystic fibrosis – two parent carriers (25% chance of child being normal; 50% chance of child being a carrier and 25% chance of the child having cystic fibrosis)

Cystic fibrosis – one parent carrier (50% chance child will be normal and 50% chance the child will be a carrier)

The amino acid valine is inserted instead of glutamic acid, which is shown by the bottom strand of DNA

The protein synthesised is altered and no longer functions normally resulting in sickle-shaped red blood cells (sickle cell anaemia)

The amino acid valine is inserted instead of glutamic acid, which is shown by the bottom strand of DNA

The protein synthesised is altered and no longer functions normally resulting in sickle-shaped red blood cells (sickle cell anaemia)

Polydactyly is caused by a dominant allele and causes extra fingers or toes

The disorder is caused by a dominant allele (D) and so can be inherited by one parent…