lecture 2/1/16 Flashcards
which of the following most influences the development of a female fetus?
- BC
the precedence of any two X chromosomes
the presence of a y chromosome
if a man has an x- linked recessive disease, can his sons inherit that disease from him?
-no, all his sons inherit their x chromosomes maternally
why do some people have unusual chromosome combinations, such as XYY and XXX
-errors occurred in chromosomes segregation during meiosis in their fathers or mothers
which of the following inheritance patterns includes an environment contribution
-multifactorial
how is co-dominant inheritance different from incomplete dominant inheritance?
- in codomincance two alleles are expressed equally; in incomplete dominance neither the dominant or recessive phenotypes seen in heterozygotes
what determines biological sex?
Sex hormones produced by gonads
sex hormones are produced by what
gonads
in a fetus, sex hormones shape development of ______________
sexual anatomy
humans have _____pairs of chromosomes
23
out of 23 chromosomes 22 pairs are ______
autosomes
in the absence of a Y chromosome, a fetus will
develop into a female
females are
XX
males are
XY
sons inherit Y chromosome from the _____
father
sons inherit X chromosome from the _____
mother
SRY gene on ______chromosome signals testes to develop
Y
testes produce ____
testosterone
if the sperm has an x chromosome, an embryo will usually develop __________
female sexual organs
ovaries produce
estrogen
a phenotype that is determined by allele on an X chromosome
x linked trait
normal copy on one X chromosome masks the recessive disease allele on the other x chromosome
recessive x linked trait
a male has a single x chromosome so he will show the effect of any recessive allele located on his
x chromosomes
a family tree where you can track the traits; a visual representation of the occurrence of phenotypes across generations
a pedigree
very small and few genes; study ancestry and identify paternity
y chromosome
