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Name:_________________Period_____
Biology I: Chapter 14 Guided Reading
Chapter 12.4
When cells make mistakes by inserting an incorrect base or skipping a base, the mistakes that form are
called __________________.

Two types of gene mutations:
1. _______________________________
2. _______________________________
What is the difference between the two types of mutations?
Many, if not most, mutations are ________________, meaning that they have little or no effect on the
expression of genes or the function of the __________________ they code.
Mutations are the source of ______________ __________________ in a species.
The condition where an organism has extra sets of chromosomes is called ________________.
Chapter 14.1
Biologists can view a picture of chromosomes called a ________________, which shows chromosomes
arranged in a specific way.
How many chromosomes do humans have? How many pairs? ___________________
Two of the chromosomes are called ______ ______________ because they determine an individual’s
________. The remaining pairs of chromosomes are called ________________.

Females have _____ X chromosome(s) and _____ Y chromosomes.

Males have _____ X chromosomes and _______ Y chromosome.
Using the Punnett Square on the next page, show the offspring produced of a cross between a male and
female using sex chromosomes.
A __________ Chart shows the relationships within a family and how traits are passed from generation
to generation.
What type of counselor analyzes pedigree charts to infer the genotypes of family member?
Show what each symbol stands for in a pedigree chart:
Symbol
Meaning
Circle
Male
Vertical Line
Horizontal Line
Person expresses the trait
Unshaded square and circle
Draw a pedigree chart below for a family in which:

A man has unattached earlobes (the trait of interest) and a woman with attached
earlobes have three children: one boy, one girl, and then another boy.

The two boys have attached earlobes and the daughter has unattached earlobes.
Human blood comes in a variety of ______________ determined blood groups.
What can a transfusion of bad blood do to a patient?
What are the two best known blood groups?
1. ___________________
2. ___________________
Complete the following table:
Phenotype
(Blood Type)
A
B
AB
O
Genotype
Blood Groups
Antigen on Red
Blood Cell
Safe Transfusions
TO
Safe Transfusions
FROM
Many human genes have become known through the study of genetic disorders. One of the first genetic
disorders to be understood this way was __________________________.
What do people with the disease lack? How are they able to live with the disease?
Name two other autosomal disorders in humans and what the major symptoms include.
______________ are protective proteins in the blood that identify invaders and attack them. The name
of the protein identifies what it will attack.
Antigens are _____________ ___________________ that identify self from non self.
____________ __________________ is the common genetic disease that is caused by a recessive allele
on Chromosome 7.
How many bases are deleted in the middle sequence of a protein in patients with CF?
____________
People with this disease are unable to __________ chloride ions which causes
_______________________.
Chapter 14.2
A human ___________ cell contains more than _________________ base pairs of DNA. Only _______
percent of the DNA in your chromosomes functions as genes.
Name the two chromosomes that are the smallest autosomes and how mnay base pairs are in each:
1. ________; ____________ base pairs
2. ________; ____________ base pairs
Name the New York Yankee baseball player who
suffered from amyotrophic lateral sclerosis (ALS). What
does this disease cause?
Genes located on sex chromosomes are said to be _______-____________ genes. There have been over
_________ sex-linked genetic disorders mapped on the X chromosome.


What chromosome contains the gene for colored vision? _________
What is the disorder called where there is an inability to distinguish certain
colors?
________________. The most common form of this disorder is
_______-___________ _____________________.
Males/Females are more likely to have colorblindness. (Circle One)
Why is there such a large gender difference in the disorder discussed above?
Your book discusses two more disorders related to sex-linked traits. Give the two diseases and describe
each in 1 to 2 sentences.
1. ____________________________
2. ____________________________
If one X chromosome is enough for cells in males, how does the cell “adjust to the extra X chromosome
in female cells?
If a cat’s fur has three colors- white with orange and black spots- you can be almost certain that its
______________.
The most common error that occurs when homologous chromosomes fail to separate is called
___________________. If this happens, ______________ numbers of chromosomes may find their way
into _____________ and a disorder may result.
Name the most common disorder that is associated with nondisjunction. What’s the word used to
describe the “three bodies” that are present in chromosome 21?
Disorders that happen among sex-chromosomes can also occur. In females nondisjunction can lead to
_____________________________. A female with this disorder usually inherits only _______ X
chromosome. These women are ____________ which means that they are unable to
_________________. Their sex organs will not develop during puberty.
In males, nondisjunction causes _______________________ syndrome. The extra X chromosome
usually prevents these individuals from reproducing. Individuals can be genotype XXXY or ___________.
Which chromosome contains the sex determination in humans? ________
Does the Mother or Father determine the sex of their child? _______________