Genetic Inheritance (OCR GCSE Biology A, Combined (Gateway Science Suite)): Flashcards
📚Flashcards
Practise the cards
14 cards from this deck
ShowHide
Practise the cards
14 cards from this deck
Gamete
Gamete
Reproductive cell with half chromosomes (23 in humans), haploid
Chromosome
Chromosome
DNA coiled around histones in nucleus, thread-like structure
Gene
Gene
DNA segment with instructions for building a specific protein
Allele
Allele
Different versions or forms of a gene
Dominant allele
Dominant allele
Allele expressed in phenotype even if only one copy present
Recessive allele
Recessive allele
Allele only expressed if two copies are present
Homozygous
Homozygous
Both alleles for a gene are the same (AA or aa)
Heterozygous
Heterozygous
Two alleles for a gene are different (Aa)
Genotype
Genotype
Genetic makeup in terms of alleles (e.g., AA, Aa, aa)
Phenotype
Phenotype
Observable physical or physiological traits of an organism
Number of alleles humans have for each gene
Number of alleles humans have for each gene
Two (one inherited from each parent)
Punnett square
Punnett square
Grid to determine probability of offspring inheriting alleles
Allele notation in Punnett squares
Allele notation in Punnett squares
Dominant = uppercase (A), recessive = lowercase (a)
% offspring showing dominant trait from Bb x Bb cross
% offspring showing dominant trait from Bb x Bb cross
75% (25% BB + 50% Bb show dominant trait)