Transcript Amino acids
Unit 3: Seminar Sickle Cell Anemia Types of Biomolecules Figure 2-17 Molecular Biology of the Cell (© Garland Science 2008) Amino Acids Amino acids are the basic subunits of proteins. Each amino acid contains the following parts: Amino Acids 20 different types of amino acids typically use in proteins The “R” group is what makes each unique Polypeptides Multiple amino acids are joined together through peptide bonds to form polypeptides. Protein Structure The function of a protein is related to its structure. There are 4 levels of protein structure: Protein Structure The function of a protein is related to its structure. There are 4 levels of protein structure: Primary Secondary Tertiary Quaternary Primary Protein Structure Primary structure = the linear Amino acid 1 sequence of amino acids Peptide bond Amino acid 2 Amino acid 3 Amino acid 4 Secondary Protein Structure Secondary structure = folding of polypeptides into alpha-helices or beta-sheets Tertiary Structure Tertiary structure = 3-dimensional folded “globular” structure Quaternary Structure Quaternary structure = combination of multiple folded polypeptides Sickle Cell Anemia: Molecular Basis A single nucleotide polymorphism in the gene for the beta- subunit of hemoglobin Results in a single amino acid change: Sickle Cell Anemia: Molecular Basis A single nucleotide polymorphism in the gene for the beta- subunit of hemoglobin Results in a single amino acid change: HbA: Gl u .... HbS: Val .... Sickle Cell Anemia: Molecular Basis Normal hemoglobin = the major protein which fills red blood cells Sickle Cell Anemia: Molecular Basis Normal hemoglobin = the major protein which fills red blood cells Carries oxygen from the lungs to body tissues Carries carbon dioxide away from body tissues to the lungs Sickle Cell Anemia: Molecular Basis Normal hemoglobin = the major protein which fills red blood cells Carries oxygen from the lungs to body tissues Carries carbon dioxide away from body tissues to the lungs Oxygenated: Deoxygenated: Normal hemoglobin floats free in the RBC. Sickle Cell Anemia: Molecular Basis Normal hemoglobin = the major protein which fills red blood cells Carries oxygen from the lungs to body tissues Carries carbon dioxide away from body tissues to the lungs Oxygenated: Deoxygenated: Normal hemoglobin floats free in the RBC. HbS sticks together when it becomes deoxygenated, forming long, rigid strands. Normal vs. Sickle Cell Sickle Cell Disease Sickle Cell Disease Consequences: Anemia (low hemoglobin) due to removal of abnormal RBCs Fatigue Shortness of breath Enlarged spleen Vaso-occlusion (blockage of blood vessels) Pain Necrosis Stroke Renal failure Sickle Cell Gene Distribution Why is the sickle cell gene (HbS) so prevalent in certain areas of the world? Sickle Cell Genetics Each person has two copies of the gene for beta- hemoglobin A = “normal” dominant form S = sickle cell, recessive form AA normal phenotype As sickle cell carrier Ss sickle cell disease Sickle Cell and Malaria Sickle cell has higher prevalence in regions where malaria is endemic. HbS and the “Heterozygote Advantage” Sickle cell actually has a protective effect against malaria! ss AA or As Sickle Cell Anemia: Treatment Prevention of sickle cell crisis episodes Management of symptoms Bone marrow transplant Unit 4 Discussion topic: Antibiotics Lab Project #2: Continue data collection Test #1: 30 multiple choice questions on units 1-4