Chapter 5 Lesson 2 Human Genetic Disorders

Ms. Schreurs

7th Grade Life Science

Cells and Heredity

My Planet Diary

Doggie Diagnosis

Page 140

How Are Genetic Disorders Inherited in Humans?

• ___________________= an abnormal condition that a person inherits through genes or chromosomes – Can be caused by:

1. ___________________________________

2. Changes in the overall structure or number of chromosomes

Cystic Fibrosis • Genetic disorder in which the body

produces abnormally thick mucus in the lungs and intestines – Makes it hard for the

person to breathe

– ________________ ________________

– 3 bases have been removed from a DNA molecule

http://www.cbsnews.com/video/watch/?id=4615368n

Sickel-Cell Disease • Causes sickle-shaped red blood cells

that cannot carry as much __________ and can clog vessels – Trait is codominant (S= sickle-cell trait, A=

normal) • Will produce both types

of cells (AS)

– Must have ______ sickle-cell alleles (SS) to have disease

Figure 1 on Page 141

Hemophilia • Genetic disorder in which a

person’s blood clots very ____________________ – Caused by a recessive allele

on the _____ chromosome

– Sex-linked disorder (occurs more frequently in males than in females)

Figure 2, Page 142 (Interactive Art)

Down Syndrome • Person’s cells have an extra copy of

______________________ – Occurs when chromosomes fail to separate

properly during ___________

– Have some degree of mental retardation, and heart defects are also common

Chapter 5 Lesson 2 Human Genetic Disorders

(Continued)

Ms. Schreurs

7th Grade Life Science

Cells and Heredity

How Are Genetic Disorders Traced, Diagnosed, and Treated?

#1- _________________

• = a chart or “family tree” that tracks which members of a family have a particular trait

• Can be an ordinary trait (eye color) or a __________________________

Apply it, page 143

#2- Karyotypes

• = ____________________________ ______________________________

• Determines if a person has the correct number of chromosomes in their cells

Is this a normal or abnormal karyotype?

#3- Genetic Counseling

• Genetic counselors help couples understand their chances of having a child with a particular ______________________ – Use karyotypes, pedigrees, and punnett squares

Dealing with Genetic Disorders • ____________________ help people

with symptoms of some disorders - Example: folic acid (a vitamin) for people with sickle-cell

• Education and job training programs help people with genetic disorders find work

Family Puzzles Cystic Fibrosis

Ian is Joshua and Bella’s son, they want to know the probability of their future children having cystic fibrosis

-Draw a pedigree representing this information -Fill in the family’s genotypes (Cystic fibrosis is

inherited through a recessive allele, the letter N will represent the dominant allele, n will represent the

recessive allele)

Colorblindness

Family Puzzles

Jack and Jill have a son Joe who is colorblind, and a daughter Jess who is not colorblind, neither Jack or Jill are colorblind.

Joe marries Miranda who is not colorblind. Joe and Miranda have two children a daughter Melissa and a son Morgan who are both

colorblind.

1. Draw a pedigree to show this family’s inheritance of colorblindness, use the key to fill in the pedigree

2.Fill in the Genotypes of all the family members on the pedigree

3. If Joe and Miranda have another child, what is the probably it will not be colorblind?

XCXC

XCY

XCXc

XcXc or XcY

Trisomy X

This occurs when a female is born with 3 X chromosomes, draw a complete Karyotype showing this chromosomal

disorder.

Triple X syndrome most often causes no unusual physical features or medical problems.

Triple X syndrome occurs in around 1 in 1,000 girls. On average, five to ten girls with triple X syndrome are

born in the United States each day