chapter 14 study review Flashcards
what chromosomes are found in each human egg cell?
sex chromosomes?
what is the probability that an offspring will be male?
50%
what percentage of human sperm cells carry an X chromosomes?
50%
how many chromosomes are in a normal human karyotype?
46-23 pairs
where are sex-linked genes found?
on the sex chromosomes, x or y; mostly x
why is colorblindness more common in males than in females?
because the gene for colorblindness is on the x chromosome, which males have 1 of and females have 2
what sex chromosomes do males have?
XY
what forms a Barr body?
in females, when the genes in one of the X chromosomes randomly switch
what do you know about a cat if it has spots of more than one color?
that it is female?
what ABO blood type genotypes result in the same phenotypes?
?
in a pedigree, what do you know about an individual that is dominant?
their symbol will be shaded
in a pedigree, what do you know about an individual that has a recessive trait?
their symbol will not be shaded
what do the different symbols in a pedigree represent?
a circle is female and a square is male
what human condition from our textbook does not appear in humans until late in a person’s life?
huntington’s disease
what is sickle cell disease caused by?
a defective allele
in cystic fibrosis, a change in a single gene causes the proteins CFTR to do what?
fold improperly
why are people that are heterozygous for sickle cell disease generally healthy?
they usually have some normal hemoglobin in their red blood cells
what is the failure of chromosomes to separate during meiosis called?
nondisjunction
according to info in our book, what has no baby ever been born without?
?
what sex chromosomes are necessary in order to be female?
XX
what can be used to cut DNA so it can be studied?
restriction enzymes
what field was formed because of the overlap of biology and information sciences?
bioinformatics
about how much of our DNA has the instructions for building proteins?
2%
why is it helpful to sequence many human genomes instead of just one?
so scientists can find how the human genome varies
what is the human genome project?
a research effort to sequence all of our DNA and locate within it all of the functionally important sequences, such as genes
what is true of more than 40% of the proteins coded for in the human genome?
they’re similar to proteins found in other organisms
what prevents insurance companies from discriminating against people based information derived from genetic tests?
discrimination based on genetic information is against the law
what chromosomes determine sex in humans?
the x and y
how is the probability of having an offspring of a particular sex related to the sex of previous offspring?
?
what tool can be used to determine if an individual has inherited the normal number of chromosomes?
a karyotype
from which parent does a boy who is colorblind inherit this trait?
his father
which blood alleles are codominant?
AB
if there are 3 different alleles for blood type and two are codominant, how many different blood types are possible?
4
what diagram can follow the inheritance of a single trait through generations in a family?
pedigree
in which disorder does a female inherit only one X chromosome?
turner’s syndrome
in which disorder does a male inherit an extra X chromosome?
klinefelter’s syndrome
what is the study of whole genomes known as?
genomics
if a man who is not colorblind and a woman who is a carrier have a son, what is the probability that he will be colorblind?
25%
why is a person who has Klinefelter’s syndrome a male?
because males with Klinefelter’s are born with an extra X chromosome (XXY)
if you were looking at a diagram of meiosis, how could you tell if nondisjunction had occurred?
?
