genetic inheritance 6.1.4

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isobelle

Cards (25)

characteristics are controlled by genes, located on chromosomes, which are found in the nucleus of a cell
chromosomes are made of dna
one gene encode for the production of one protein
genes can have different forms called alleles
some alleles are dominant - the characteristic they code for is always expressed
other alleles are recessive- they are only expressed if no dominant alleles are present
some characteristics are controlled by a single gene
dominant alleles are represented by capital letters
recessive alleles are represented by lowercase letters
you have two copies of each gene for one on each chromosome in a pair
a genotype is the combinations of alleles you have
a phenotype is the characteristics you have
homozygous is when an organism has two alleles for a particular gene that are the same, both copies of the gene are the same allele
homozygous recessive are two recessive alleles
homozygous dominant are two dominant alleles
heterozygous is when an organism has two alleles for a particular gene that are different
a carrier is when a person inherits one recessive allele but this characteristic is not expressed
carriers are heterozygous because it contains one recessive allele and one dominant allele
if there isnt a key provided for a punnet square, give a key for the letters you used
on the punnet square itself:
label the parents gametes
write the phenotype of the offspring as well as the genotype
write either a percentage, fraction or decimal to show the probability of inheriting each phenotype
the alleles A and B both code for different proteins found on the surface of red blood cells (called antigens)
the two forms of the sex chromosomes are XX and XY
the sex chromosomes determine the gender
XY is the male, XX is the female
for genetic tree diagrams:
find parents with the same phenotype who have offspring with two different phenotypes
these parents are heterozygous
whichever phenotype the parents have is caused by the dominant allele