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Name __________________________________________ Date _______________ Period ________
KARYOTYPES
Go to this web site http://learn.genetics.utah.edu/units/disorders/karyotype/
Vocab Review
A karyotype is an organized profile of a person's ________________.
Chromosome - One of the threadlike "packages" of genes and other DNA in
the nucleus of a cell. Different kinds of organisms have different numbers of
chromosomes. Humans have ___ pairs of chromosomes, ___ in all.
Autosome - Any chromosome other than the ______ chromosomes
(_________). How many pairs of autosomes do humans have? _______
How is a karyotype arranged?
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How do scientists read chromosomes?
Three things that scientists use to identify chromosomes are ___________,
banding ____________, and _______________ position. Three words that
describe centromere position are ______________________ (in the middle),
________________________ (at the end), or _______________________
(somewhere in between).
Try it yourself
Can you click and drag the chromosomes to make a karyotype? When you
finish, have your teacher initial here _____.
Using Karyotypes to Predict Genetic Disorders Babies can end up with an
altered number of chromosomes if something goes wrong during meiosis. Play
the video clip for meiosis and determine the number of chromosomes in each
gamete ________. Gametes are combined during fertilization. Play the video
clip and give the name for combined sperm and egg ____________.
Too many or too few chromosomes
Sometimes chromosomes are incorrectly distributed into the egg or sperm
cells during meiosis. This can result in an abnormal number of chromosomes.
If a sperm with an extra chromosome fertilizes an egg with a normal
chromosome number, the resulting zygote will have 3 copies of one
chromosome. This is called _________. If a sperm that is missing a
chromosome fertilizes an egg, then the resulting zygote will have only one
copy of that chromosome. This is called __________.
Missing pieces of chromosomes
Cris du chat syndrome is caused by a _______________ on chromosome___.
The chromosomal deletion that causes Williams Syndrome is so small that it
cannot be seen in a __________________. However, the deletion can be
observed using a special technique called fluorescent in situ hybridization, or
__________. This technique allows DNA sequences to be labeled so they
show up under _____ light. Two types of chromosomal deletions are called
_______________ and _________________ deletions.
Mixed-up pieces
A _________________is a chromosome rearrangement in which part of a
chromosome breaks off and then reattaches to a different chromosome. There
are two different types of translocations that can occur:
______________________ (switching of pieces between nonhomologous
chromosomes) and ________________________ (joining of the long arms of
two chromosomes and loss of the short arms.
QUIZ yourself After playing all the clips and answering all the above
questions, take the quiz and write your answers here:
______________________________ ______________________________
______________________________ ______________________________
______________________________ ______________________________
______________________________ ______________________________
Bonus: Draw a chromosome and
label the p and q arms correctly in
the box to the right.