Inheritance (B4) Flashcards
Nucleus stores DNA as what chromosomes?
linear chromosomes
describe the chromosome structure
long thread like structure wrapped around proteins
what is a gene?
short section of a chromosome which carries genetic information to code for a protein. Genes determine characteristics.
how are dominant and recessive alleles portrayed in letters?
-dominant alleles are capital
-recessive alleles are lower case
genotype definition
genetic code in its cells. Alleles which control a characteristic.
how can genotypes be written?
there are two alleles for each gene, one from each parent. This means a genotype can be written as two letters, each letter representing one allele of a gene.
Phenotypes definition
the visible characteristics of an organism. Genes (genotypes) determine our phenotypes, although it can also be influenced by the surroundings.
what is a homozygous genotype?
2 alleles of the same gene present
what is a heterozygous genotype?
2 different alleles of that gene present.
How do dominant and recessive alleles determine the phenotype?
-one dominant allele will always be expressed
-2 recessive alleles are needed to determine the phenotype
what is a mating between two individuals called?
a cross
what is a monohybrid cross?
study of the inheritance of one characteristic- the impact of a single gene
describe the tongue rolling gene?
caused by dominant allele (T). Non-tongue rolling is caused by recessive gene.
describe polydactyly gene?
caused by dominant allele (D) (extra fingers/ toes)
Describe cystic fibrosis gene? and what is cystic fibrosis?
caused by recessive allele (f). The condition affects chloride ion transport across membranes, resulting in thick, sticky mucus.
