Genes and Inheritance Flashcards
What is DNA?
DNA (deoxyribose nucleic acid) molecules are large and complex. They carry the genetic code that determines the characteristics of a living thing.
What is a gene?
A gene is a short section of DNA. Each gene codes for a specific protein by specifying the order in which amino acids must be joined together.
What is a chromosome?
The cell’s nucleus contains chromosomes made from long DNA molecules.
What is an allele?
An allele is one form of the same gene. For example: the gene for eye colour has an allele for blue eye colour and an allele for brown eye colour.
What is a dominant allele?
the characteristic controlled by a dominant allele develops if the allele is present on one or both chromosomes in a pair.
What is a recessive allele?
the characteristic controlled by a recessive allele develops only if the allele is present on both chromosomes in a pair.
What is a genotype.
The alleles in the organism are the genotype.
What is the phenotype?
The phenotype is what the organism will look like.
What causes cystic fibrosis?
Cystic fibrosis is an example of a inherited recessive genetic disorder.
What does cystic fibrosis do?
People with CF produce abnormally thick and sticky mucus in their lungs and airways. As a result, they are more likely to get respiratory infections.
What do you have to have to be able to get cystic fibrosis?
To inherit cystic fibrosis, you have to have at least 2 fault alleles.
What causes sickle cell disease?
Sickle cell disease is a recessive condition so the sufferer has two copies of a faulty gene.
What are the problems faced with sickle cell disease?
The red blood cells of sufferers are misshapen and can stick together which can block blood vessels. Sickle cell disease sufferers can become very tired and quickly get out of breath. If the sickle cells block a blood vessel, this can be fatal.
What is pedigree analysis?
Doctors can use a pedigree analysis chart to show genetic disorders are inherited in a family. They can use this to work out the probability (chance) that someone in a family will inherit a condition.
