Question | Answer |
How many chromosomes are there in a haploid human cell? | 23 chromosomes |
What is a karyotype? | The number and appearance of chromosomes in the nucleus of a eukaryotic cell |
How many chromosomes are there in a diploid human cell? | 23 pairs of chromosomes |
What are the female sex chromosomes? | XX |
What are the male sex chromosomes? | XY |
Each cell has two sets of information, where do these come from? | Mother and father |
What are genes? | They are coding for a specific characteristic |
Where are genes located? | They are found on locus' on each chromosome |
What are alleles? | Variations of a characteristic coded for on a gene |
What is it called when two genes carry identical alleles? | Homozygous |
What is it called when two genes carry different alleles? | Heterozygous |
What is a phenotype? | An expression of a characteristics determined by genetics and potentially the environment |
What is a genotype? | Genetic make-up represented as a letter |
What is Mendels first law? | The law of segregation |
What is Mendels second law? | The law of independent assortment |
What does the law of segregation state? | That two alleles separate during gamete formation (e.g. a Tt parent can produce both T gametes and t gametes) |
What is a monohybrid cross? | A cross involving one characteristic (two alleles) |
What does the law of independent assortment state? | Each pair of alleles segregate independently of other pairs of alleles, this is because of random assortment during meiosis |
What is dihybrid inheritance? | Inheritance of two separate characteristics, each controlled by a pair of genes, the genes for two different characteristics are found on separate chromosomes and so are inherited independently |
What is discontinuous variation? | Involves clear cut differences where there is no overlap, can be in one group or another and is controlled by one set of genes |
What is continuous variation? | Involves characteristics that do not fall into groups and are controlled by several genes (polygenic) |
What is co-dominance/incomplete dominance? | Where two genes or alleles are equally dominant and results in a new phenotype |
Define dominant? | A gene that 'over powers' a recessive gene and is therefore expressed in the phenotype |
Define recessive? | A gene that is 'over powered' by a dominant gene and is therefore not expressed |
What is a sex-linked disorder? | A disorder caused by a gene found on the X chromosome |