BY5.4 - Inheritance Flashcards
Define homozygous
When both chromosomes in a pair have the same allele, they form a homologous pair
Define alleles
Different versions of the same gene
Define heterozygous
The alleles on the chromosomes of a homologous pair, are genetically different
What allele has to be present on only one chromosome for an individual to have the characteristic?
Dominant
How many alleles have to have a recessive allele in order for the characteristic to be expressed?
Both chromosomes in a homologous pair
Define genotype
The alleles possessed by an organism
Define phenotype
The physical characteristics of an organism
What controls the phenotype?
The genotype
What does dihybrid inheritance involve?
The inheritance of two genes that are not carried on the same chromosome
If the parental gametes were RRYY and rryy for a pea plant - what would the first generation offspring genotype be?
RrYy
Heterozygous
What chromosomes control gender?
X and Y sex chromosomes
What are the 5 types of DNA mutations that can occur?
- Addition
- Deletion
- Substitution
- Inversion
- Duplication
What happens when a ‘addition’ mutation of DNA occurs?
Nucleotides are inserted into a DNA sequence
What happens when a ‘deletion’ mutation of DNA occurs?
Nucleotides are removed from a DNA sequence
What happens when a ‘substitution’ mutation of DNA occurs?
A section of nucleotides is swapped for other nucleotides
