Chapter 4 - Chromosomes and Heredity Flashcards
transmission of genetic characteristics from parent to offspring
heredity
chart of 46 chromosomes laid out in order by size
karyotype
two members of each pair of the 23 pairs are called
homologous chromosomes
22 pairs of the 23 pairs of chromosomes are called
autosomes
the 1 pair of the 23 pairs of chromosomes is called
sex chromosome ( x and y)
know what a karyotype looks like and what it is
describes any cells with 23 pairs of chromosomes
diploid
describes cells containing half as many chromosomes as somatic cells; that is, sperm and egg cells
haploid
sperm and egg cells are called
germ cells
this restores diploid number to fertilized egg and somatic cells arise from it
fertilization
the location of particular gene on a chromosome
locus
different forms of gene at same locus on two homologous chromosomes
alleles
- masks recessive allele
- often produces protein responsible for visible trait
- represented by a capital letter
dominant allele
- represented by lowercase letter
- often codes for nonfunctional variant of protein
- corresponding trait only seen when recessive allele present on both homologous chromosomes
recessive allele
alleles an individual possesses for a particular trait
genotype
two types of genotypes
homozygous and heterozygous
individuals - two identical alleles for the trait
homozygous
individuals - different alleles for that gene
heterozygous
an observable trait
phenotype
a diagram showing possible genotype and phenotype outcomes from parents of known genotype
punnet square
an allele is _______ if it shows in the phenotype of an individual
expressed
they perform genetic testing and advise couples on probability of transmitting genetic diseases
genetic counselors