Definitions Flashcards
What are gametes?
Gametes are haploid cells that are capable of fusion
Define fertilisation
Fertilisation is the union of two gametes to form a single cell called a zygote
What are alleles?
Alleles are different/alternative forms of the same gene
What is the locus of a gene?
The locus of a gene is its position on a chromosome
What is a dominant allele?
Dominant means the allele that prevents the recessive allele from being expressed
What is a recessive allele?
Recessive means the allele is prevented from being expressed by a dominant allele
Define genotype
Genotype means the genetic make up of an organism/ the genes that are presented
Define phenotype
Phenotype means the physical make-up or appearance of an organism
Define progeny
Progeny refers to offspring that are produced
What does homozygous mean?
Homozygous means that two alleles are identical
What does heterozygous mean?
Heterozygous means that the alleles are different
What is a Punnett square?
A Punnett square is a grid used to show the ratio of the genotypes of the progeny in a genetic cross
What is incomplete dominance?
(2)
Incomplete dominance means that neither allele is dominant or recessive with respect to the other
Both alleles are equally expressed in the heterozygous genotype to produce an intermediate phenotype
What is a pedigree?
A pedigree is a diagram showing the genetic history of a group of related individuals
What is the law of segregation/Mendel’s first law?
This states that inherited characteristics are controlled by pairs of alleles
These alleles segregate/separate from each other at gamete formation. with only one member of the pair being found in each gamete
Who is the ‘father of genetics’?
Gregor Mendel
What is a monohybrid cross?
A monohybrid cross involved the study of a single feature
What is a dihybrid cross?
A dihybrid cross involves the study of two characteristics
What is linkage?
Linkage means that genes are located on the same chromosome
What is the law of independent assortment?
2nd law: This states that when gametes are formed either of a pair of alleles is equally likely to combine with either of another pair of alleles
