Mistakes In Replication Flashcards
When would a mutation be present in every cell
If a mutation occurs in the DNA of an ovary/testis cell that is dividing to form an egg/sperm meaning the mutation would be present in every cell produced from the fertilised egg
Describe the mutation that results in sickle cell anaemia
-substitution mutation in the gene that codes for one of the polypeptide chains in haemoglobin
-A replaces T at one position meaning mRNA produced contains a non-polar amino acid rather than the polar one it is supposed to contain
-causes haemoglobin to be less soluble and when oxygen levels are low these molecules form long fibres that stick together inside the RBC resulting in half moon shaped cells
Result of the mutation that causes sickle cell anaemia
-RBCs carry and deliver less oxygen and can also block blood vessels
Mutation that causes cystic fibrosis
-CF gene is a section of DNA on chromosome 7 coding for CFTR protein
-many dif mutations have been identified as giving rise to CF
What is locus
Where on a chromosome a specific gene is
What are homologous chromosomes
The chromosomes in each pair
What are alleles
Different versions of the same gene
What is genotype
The specific combination of alleles a person possesses
What is phenotype
Expressed characteristic caused by the interaction between an individual’s genes and the environment
What is homozygous
When a person possesses two identical copies of the allele
What is heterozygous
When a person possesses two different alleles of a gene
What is a dominant allele
An allele that will be expressed even if only one copy is present
What is a recessive allele
An allele that will only be expressed if both alleles are recessive
What is a carrier
Someone who has the allele for a genetic disorder but does not themself have the genetic disorder
