Objective 14 Quiz

Last updated over 4 years ago

4 questions

Sickle-cell anemia is a disease caused by the smallest of genetic changes. Here, the alteration of a single nucleotide in the gene for the beta chain of the hemoglobin protein (the oxygen-carrying protein that makes blood red) is all it takes to turn a normal hemoglobin gene into a sickle-cell hemoglobin gene. This may only be a single nucleotide change, but the results are devastating. Beta hemoglobin (beta globin) is a single chain of 147 amino acids. 

Figure 1. Below are the DNA strands and amino acid sequences for both the wild-type (normal) and mutated (sickle cell) hemoglobin gene. 

Prove this claim: "A change in a single nucleotide in the hemoglobin gene sequence causes a different amino acid to be added to the protein chain." Use SPECIFIC evidence from figure 1 and supporting background knowledge from class to make your case.

Figure 2. Below is an image of the normal hemoglobin protein (left) and the sickled (mutated) hemoglobin protein (right).

Does a change in the order of amino acids in the hemoglobin protein affect the shape of the hemoglobin protein? Answer by first stating your claim. Then provide evidence (from both figures 1 and 2) with a supporting explanation (think back to Wednesday's video notes).

Hemoglobin proteins, when functioning properly, serve a purpose in red blood cells. They binds to oxygen, allowing red blood cells to carry out their function of delivering oxygen from the lungs and heart, to the body cells to use in making energy. 

 Figure 3. Hemoglobin binding to oxygen in normal red blood cells 

A change in the shape of the hemoglobin protein also results in a change in the shape of the red blood cell as shown below. 

Figure 4. Normal Red Blood Cell shape vs. Sickled Red Blood Cell Shape 

*Note: Normal red blood cells have the normal hemoglobin protein while sickled red blood cells have the mutated hemoglobin protein 

Figure 5. Normal Red Blood Cell function vs. Sickled (mutated) Red Blood cell function 

Prove this claim: "The shape of a red blood cell, affects its ability to carry oxygen and move through blood vessels easily" Use evidence from figures 3, 4 and 5 to support your answer.

Figure 6: Sickle Cell Disease Symptoms: 

A person with sickle cell disease may experience any of the following symptoms: 

Anemia. Anemia means lack of blood. Because sickled cells are short-lived or destroyed, there are less red blood cells available in the body. This results in anemia. Severe anemia can make you feel dizzy, short of breath, and tired.
Pain crisis, or sickle crisis. This occurs when the flow of blood is blocked to an area because the sickled cells have become stuck in the blood vessel. The pain can occur anywhere, but most often occurs in the chest, arms, and legs. Infants and young children may have painful swelling of the fingers and toes. Interruption in blood flow may also cause tissue death.
Acute chest syndrome. This occurs when sickling occurs in the chest. This can be life-threatening. It often occurs suddenly, when the body is under stress from infection, fever, or dehydration. The sickled cells stick together and block the flow of oxygen in the tiny vessels in the lungs. It resembles pneumonia and can include fever, pain, and a violent cough.
Splenic sequestration (pooling). The spleen is in the upper left abdomen, it is responsible for filtering blood. Crises are a result of sickle cells pooling in the spleen. This can cause a sudden drop in hemoglobin and can be life-threatening if not treated promptly. The spleen can also become enlarged and painful from the increase in blood volume. After repeated episodes,  the spleen becomes scarred, and permanently damaged. Most children, by age 8, do not have a working spleen either from surgical removal, or from repeated episodes of splenic sequestration. The risk of infection is a major concern of children without a working spleen. Infection is the major cause of death in children younger than age 5 in this population.
Stroke. This is another sudden and severe complication of people with sickle cell disease. The misshapen cells can block the major blood vessels that supply the brain with oxygen. Any interruption in the flow of blood and oxygen to the brain can result in severe brain damage. If you have one stroke from sickle cell anemia, you are more likely to have a second and third stroke.
Jaundice, or yellowing of the skin, eyes, and mouth. Jaundice is a common sign and symptom of sickle disease. Sickle cells do not live as long as normal red blood cells and, therefore, they are dying faster than the liver can filter them out. Bilirubin (which causes the yellow color) from these broken down cells builds up in the system causing jaundice.

Support the following claim: "A person with a single nucleotide mutation in their hemoglobin gene, will feel very different on a day to day basis, from a person without this mutation" Include evidence from figure 6 but also be sure to tie it back to the initial gene sequence in figure 1.

You have finished the quiz! Please either read the article linked here about how sickle cell disease affects NFL athletes https://www.espn.com/blog/atlanta-falcons/post/_/id/22859/tevin-coleman-with-sickle-cell-trait-unsure-about-playing-in-denver OR the video about life with sickle cell disease https://youtu.be/2CsgXHdWqVs. After reading/ watching, type in the chat "I watched the video/read the article (whichever you did write) and I learned that______________". That is your exit ticket!! After you type that- you may leave! Another quiz down! Have a wonderful 3 day weekend---> No homework :) 