Chromosomes Carry information for inherited traits, but can become damaged and changed
A sudden change of the genotype is called a mutation
Mutations can occur in every single body cell, and usually doesn’t have consequences
When mutation affects a sex cell, it might have consequences
Offspring of a mutated sex cell will have the mutation in every body cell, which might lead to a handicap
When the mutation is shown in the phenotype someone is called a mutant
An example of a mutant is an albino, whose skin pigment genes don’t count anymore.
Mutations occur in 3 ways: naturally, by exposure to radiation or by exposure to chemicals like tobacco smoke and asbestos. Chemicals or radiation which help mutations occur are called mutagenic factors
In 1945, atom bombs were dropped on Japan, nowadays this radiation still makes more mutants than in other countries
The reproductive organs should not be exposed to x-rays, sex cells can become mutated this way
Due to mutation, the rate of cell division can be accelerated
Too many cells in one place is called a tumour
Tumour develops slowly: benign tumour, they don’t disturb any other tissue
Tumour develops fast: malignant tumour (cancer), invades and destroys nearby tissues. When these cells come into the bloodstream they spread, which may result in death
When cancer tumours spread, treatment gets very complicated
Being in the sunlight for too long, which is ultraviolet radiation, may cause skin cancer
Chemicals increase the risk of lung cancer


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