Download Human Heridity

Human Heridity
How many chromosomes do humans have?
total = ____
from mom= ___
from dad= ___
So how do scientists organize a person’s chromosomes in order to study then and figure out what
information is on them?
They use a _______________, a picture of the chromosomes grouped as _____________
*Bigger chromosomes carry more genetic information, they have smaller #’s
* ________________________ = ________________
*The first 22 pairs =called _______________
*The very last chromosomes (23rd) are the _________________ (X’s and Y’s)
*All human _____ cells carry an ___ chromosome
*________ cells carry either an _______________
*Human females are _____, males are _____
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To study human inheritance, biologists use _____________________ to show
relationships within a family.
*Males =
*Females =
*___________________________
*___________________________
*Can determine the _________________ of family members.
*Not all human traits can be followed through a pedigree because many human traits are
_________________ (skin tone, hair & eye color) and the environment can also affect
some traits.
Blood Typing
*The genes controlling blood type were among the first human genes ever identified.
*Red blood cells can carry 2 antigens, A & B
*Antigens are molecules that the immune system can recognize.
*A person with B antigen has B blood
*A person with A antigen has A blood
*A person with both antigens has AB blood
*A person with neither antigens has O blood
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*Red blood cells can also have an Rh antigen.
-People with the Rh antigen are Rh positive
-People without it are Rh negative
Type
Genotype
Antigens
Donate
to
Donate
from
Human Genetic Disorders
Genetic Recessive
-a person must inherit an allele for the disorder from ____________
-PKU- phenylketonuria- causes people to be unable to use the amino acid,
phenylalanine
-Tay-Sachs Disease- causes large deposits of fat to build up in the tissue and nerve
cells of the brain.
-Cystic Fibrosis- causes large amounts of mucous to build up and clog the organs
(lungs, pancreas, etc)
Genetic Recessive
-a person must inherit an allele from ________ of their parents
-Huntington’s Disease- causes degeneration of brain cells
-Sickle Cell Anemia-causes the shape of the red blood cells to change from circles
to sickle (half-moon) shaped and they get caught in veins and arteries.
-Polydactyly-when a person has extra fingers and/or toes. The severity of the
disease is different in each case
Human Chromosomes
*Genes on the X and Y chromosome are said to be _______________
*Males have only 1 X chromosome, so any X-linked alleles are expressed in males even if
they are recessive
-color-blindness and hemophilia
*Sometimes chromosomes don’t get separated during meiosis and
___________________________ occurs.
-If nondisjunction does occur, abnormal numbers of chromosomes may find their way
into the gametes and a disorder of chromosome number may occur.
-Down syndrome occurs when there are 3 copies of chromosome 21
-Turner’s syndrome (1 X chromosome) and Klinefelter’s syndrome (XXY)
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