Name: ______

What do Normal and Sickled Cells Look Like

Objectives:

  1. Learn that there are two different conditions to this disease
  2. Solve genetic problems involving sickle cell anemia

Procedure:

Part A: Comparison of Sickle-Cell Trait with Sickle-Cell Anemia

  1. Examine table 1. Note that not all people that possess the sickle-cell gene have sickle-cell anemia. There are two different sickle-cell conditions that are determined by the genes that are received from the parents. Sickle-cell trait is less of a problem than sickle-cell anemia.

Table 1. Gene Combinations

Gene Combination / Blood Cell Shape / Name of disease
RR / All round / Normal
RR’ / Half Round
Half sickled / Sickle-cell trait
R’R’ / All Sickled / Sickle-cell anemia
  1. Examine Figure 1. These drawing represent blood samples from three different people. Count the number of normal and sickled cells in all three samples. Record your answers in Table 2.

Figure 1: Blood Samples

Table 2. Number of Normal and Sickled Cells Seen

Blood Sample / Number of normal cells / Number of sickled cell
A
B
C
  1. Examine your data and Table 1. Determine the blood condition for each of the samples and write the correct condition on the first line below the picture: normal, sickle-cell trait, sickle cell anemia.
  2. Examine your data and table 1. Determine the correct gene combination that produced each sample and write them on the second line below the picture: RR, RR’ or R’R’

Part B Genetics Problems

Construct and use a Punnett square for each of the following problems.

  1. Two parents have the following genes for blood cell shape. RR’ and RR. What kind of blood might their children have:

Number of children

Have Normal blood ______

Have sickle-cell trait______

Have sickle-cell anemia______

  1. Two parents have the following genes for blood cell shape: RR’ and RR’. What kind of blood might their children have?

Number of children

Have Normal blood ______

Have sickle-cell trait______

Have sickle-cell anemia______

  1. Two parents have the following genes for blood cell shape: RR’ and R’R’. What kind of blood might their children have?

Number of children

Have Normal blood ______

Have sickle-cell trait______

Have sickle-cell anemia______

Questions

  1. Describe the shape of normal blood cells
  1. Describe the shape of sickled cells
  1. Explain how the number of normal and sickled red blood cells differ in a person with sickle-cell trait and sickle cell anemia.
  1. What type of cell probably contains more hemoglobin? (Normal or sickled)
  1. The less hemoglobin a person has, the more difficult it is for the cells of the body to get enough oxygen. With too little oxygen, a person will tire easily and cannot do a lot of exercising. Would a person with sickle-cell trait be able to do more or less exercising than a person with sickle-cell anemia?

Explain why

  1. Which condition is more of a problem for a person, sickle-cell trait or sickle-cell anemia

Explain why

A scientist gathered the following information while studying people with sickle cell anemia. Number of children born in the United States with sickle cell-anemia:

To white parents – less than 1/100,000 births

To African-American parents – about 200/100,000 births

  1. Which racial group seems to suffer most from this genetic disorder?
  1. Why do we call sickle cell-anemia a genetic disorder?
  1. How does this disorder serve as an example of lack of dominance?