Activity 3.2.2: The Genetic Code
Introduction
In the previous activity, you learned how DNA encodes the instructions for creating proteins. You also learned about the basics of the process of protein synthesis. In this activity you will apply your knowledge of transcription and translation to decode a secret message as well as investigate the effect that various mutations have on protein production. You will then look specifically at the genetic mutation that causes sickle cell disease.
Equipment
Computer
Laboratory journal
DNA sequence
Activity 3.2.2: mRNA
Activity 3.2.2: tRNA
Activity 3.2.2: Codon – Amino Acid Dictionary
Scissors
Tape
Procedure
Part I: Transcribing and Translating the Genetic Code
1. Work through the Transcribe and
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You will analyze the first seven amino acids for normal versus sickle cell hemoglobin gene in order to determine what type of mutation is responsible for causing sickle cell disease. (Note that the gene coding for hemoglobin is 146 amino acids. In this activity you will only work with a small portion of this gene.) You will use a codon chart to determine the amino acids that correspond to the mRNA sequence. Codon charts are often
believed that genetically aberrant hemoglobin evolved as a protection against malaria."(2) It has also been said that, "People with a single copy of a particular genetic mutation [sickle cell trait] have a survival advantage. One copy of the mutation confers a benefit." (3) Its quite interesting to find that original purpose of this gene was
Sickle Cell Disease is an autosomal recessive genetic disease that occurs due to a mutation in the β-globin gene of hemoglobin. Autosomal meaning that it is not linked to a sex chromosome, so either parent can pass on the gene to their child. This mutation is a result of a single substitution of amino acids, Glutamic for Valine at position 6 of a β globin chain. The presence of this mutation causes
Sickle cell crisis is an acute form of sickle cell disease where pain and sickling are extensive (Byar, 2013). SCD is a genetic disease that predominantly affects black people of African decent (Gersten, 2016). Abnormal hemoglobin chains are the main issue with SCD (Byar, 2013). Normal hemoglobin chains are comprised of 99% hemoglobin A (HbA) however, in SCD an abnormal form of the gene, hemoglobin S (HbS) is present in approximately 40% of total hemoglobin (Byar, 2013). In order for a person to be born with SCD, both parents must carry the abnormal gene, HbS (Byar, 2013). HbS is extremely sensitive to the changes in oxygen amount of the RBC and when exposed to decreased oxygen the HbS cause the RBC to distort and become sickle-shaped,
This mutation paper is to give information on the Sickle Cell disease. This is a negative disease to have because the Sickle Cell Disease decreases the health of the person that has the disease and limits what they can and cannot do. Sickle Cell Disease is a red blood cell disease that causes ab normal hemoglobin to from in the veins. Hemoglobin is the protein that carries oxygen throughout the body to help with the respiratory system. The cause of the genetic mutation is inheritance or getting the disease from the parents the disease is found on chromosome 13 while the hemoglobin is still in beta phase on gene HB A. The disease typically shows symptoms within the first 5 to 6 months of birth and being diagnosed with Sickle Cell Disease. The symptoms include painful swelling on the hands and feet, and Jaundice, which causes a white color to form under the eyes, and turns the skin color yellow.
Sickle cell anemia (SCA) is an autosomal recessive genetic disorder. This missense mutation is characterized by mutant beta globin subunits that tend to stick together (Cummings, 2014). As a result, abnormally shaped red blood cells are produced by this disorder. The erythrocytes are sickle or crescent shaped. Sickling occurs under hypoxic conditions, in which there is insufficient supply of oxygen delivered throughout the body (Sun & Xia, 2013). In order to inherit this monogenic disease, one copy of the sickle globin gene from each parent must be passed on to the offspring (Ashley-Koch,
Sickle-Cell Anemia is an inherited, chronic blood disease in which the body produces abnormally shaped red blood cells. When the blood cells become crescent/sickle shaped, they are unable to deliver adequate amounts of oxygen to other cells. Also, these unusual “sickle” cells block blood pathways to the limbs and organs, limiting the amount of blood flowing throughout the body. It causes pain, organ damage, and anemia (low blood count). Unfortunately, however, when sufferers are born with this disease, they live life knowing it is incurable.
The effects of the sickle cell mutation can be traced back to DNA in which the mutated gene is replicated and transcribed to mRNA. This mRNA is then used to synthesize polypeptides in the ribosomes where it translates the mutant genetic code (GUG) which codes for valine. Instead of the genetic code for glutamic acid (GAG) which is the amino acid found in the normal haemoglobin. This causes the haemoglobin to be clumped up together in the red blood cells and depriving them if oxygen causing a sickle shaped cell instead of the normal round, biconcave
Sickle beta thalassemia is an inherited condition that affects hemoglobin, the protein in red blood cells that carries oxygen to different parts of the body. It is a type of sickle cell disease. Affected people have a different change (mutation) in each copy of their HBB gene: one that causes red blood cells to form a "sickle" or crescent shape and a second that is associated with beta thalassemia, a blood disorder that reduces the production of hemoglobin. Depending on the beta thalassemia mutation, people may have no normal hemoglobin (called sickle beta zero thalassemia) or a reduced amount of normal hemoglobin (called sickle beta plus thalassemia). The presence of sickle-shaped red blood cells, which often breakdown prematurely and can
Sickle cell disease, SCD, is an inherited autosomal recessive genetic disorder that affects 1 in 500 Americans of West African descent with one in 12 African Americans and one in 100 Hispanics being carriers (“Learning.” 2014). SCD is prevalent in individuals with origins in equatorial countries, such as central Africa, Near East, Mediterranean area, and in parts of India (McCance, 2010). Sickle cell anemia, sickle cell-thalassemia, and sickle cell-Hb C are all forms of sickle cell disease with sickle cell anemia being the most severe. Within the general population there is a 0.7% chance of two African American parents having a child with sickle cell anemia, a 1 in 800 birth risk for sickle cell-Hb C, and 1 in 1700 birth risk for sickle- cell thalassemia (2010). The incidence of sickle cell trait carriers can range from 7% to 13% in blacks and up to 45% in people from Eastern Africa. In comparison to the other forms of SCD, sickle cell anemia is present in a homozygous form. Individuals are considered to be sickle cell trait carriers when they inherit Hb S from one parent and normal hemoglobin from the other parent, these individuals rarely present with any clinical manifestations (2010).
Sickle cell anemia is the most famous, prevalent, and the subject of this paper. This blood disease is a genetically inherited blood illness in which the construction of unusually shaped red bloods cells occurs. This happens when a victim of this vicious disease receives two mutant copies of the hemoglobin gene from the individual’s parents. Hemoglobin A, A2, and F are the normal forms of hemoglobin in individuals without sickle cell disease or trait. The difference between the normal forms of hemoglobin is the nucleotides that decide which protein is made and how it’s folded. A-type is made up of two alpha chains and two beta chains. A2 is made up of two alpha and delta chains. F is made up of two alpha and gamma chains. Normally, the first six weeks after a child’s birth hemoglobin F is the main source of oxygen transport. After those initial six weeks, A-type hemoglobin takes control of the vascular
A point mutation distinguishes the sickle-cell hemoglobin from the normal adult hemoglobin; in Hb S a valine is substituted in place
Sickle cell anemia is caused by a defect in the gene that controls the production of normal hemoglobin, which is an iron-containing protein in red blood cells that transports oxygen from the lungs to body tissues. The defective gene results in the production of abnormal hemoglobin known as hemoglobin S. If you have the disorder, you inherited one gene for hemoglobin S from each of your parents. The gene is recessive, so if you received a copy of the gene from just one parent, you are a carrier of the sickle cell gene.
Sickle cell disease, also known as SCD, is a hereditary blood disorder that takes place due to mutation in the hemoglobin gene that is found in red blood cells. While it is said to have originated in Africa and is mostly predominant in African Americans, sickle cell disease is now common among different ethnic groups all over the world. Sickle cell anemia (HbSS) infects “an estimated 70,000 to 100,000 Americans”(Housman) and accounts for approximately 70% of anemia in the United States. Hemoglobin functions as an oxygen carrying protein as it carries oxygen from the lungs through the arteries and to the rest of the body. In sickle cell disease,
Sickle Cell Anemia is a genetic disease that causes some red blood cells to take the form of a sickle this form is more easily destroyed which can lead to anemia. The disease is caused by defective hemoglobin. There are different types of hemoglobin, but Hemoglobin A is the primary hemoglobin affected by sickle cell. Hemoglobin A is made up of 2 alpha globin chains and 2 beta globin chains. The beta globin chain becomes misshapen due to a mutation. The mutation in the beta globin chain occurs when the sixth amino acid is valine instead of glutamic acid. Valine is Hydrophobic which has different properties than glutamic acid which is Hydrophilic. When the cell is deoxygenated it combinates with other cells that have the mutation
People who have sickle cell anemia inherit two abnormal hemoglobin genes one from each parent . In all forms of SCD, at least one of the two abnormal genes may causes hemoglobin S.