more study questions Flashcards
when maternal and paternal chromosomes pair and physically exchange DNA segments
recombination
alleles of different genes are distributed independently of one another; maternal and paternal chromosomes line up next to each other along the midline of the cell and segregate into newly forming cells ;
pairs can line up in different ways
independent assortment
an allele that affects phenotype only if the organism has two copies of that allele; hidden by normal or dominate allele
recessive allele
two different alleles (Aa)
- phenotype is normal
- individual is a carrier
heterozygote
two identical alleles
homozygote
an individual will carry the recessive allele for CF, but will not have the disease because the alleles effect is masked by the dominate alleles
heterozygous carrier
an individual who is heterozygous for a particular gene of interest and therefore can pass on the recessive allele without showing any of its effects
carrier
a diagram to determine the probabilities of offspring having particular genotypes
based on genotypes of the parents
; matches up all possible gametes
punnett square
sex hormones are produced by ________
gonads
what are gonads
ovaries in females, testes in males
androgens
testosterone:males , estrogen: females
humans have 23 pairs of chromosomes
22 pairs are _______ and 1 pair are ________
autosomes and sex chromosomes
paired chromosomes present in both males and females; all chromosomes except the X and Y chromosomes
autosomes
paired chromosomes that differ between males and females, XX in females, XY in male
sex chromosomes
in the absence of a y chromosome, a fetus will develop into a
female (XX) (males are XY)
