Post on 29-Jan-2016
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 sequence of amino acids
Aminoacid 1
Aminoacid 2
Aminoacid 3
Aminoacid 4
Peptidebond
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:
Glu
Val
. . . .
. . . .
HbA:
HbS:
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 phenotypeAs sickle cell carrierSs 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!
AA Asssor
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