Find the general solution of the differential equation that describes the harmonic motion of a 4-pound weight auached to a spring. where the spring constant is 1.5 pounds per foot and the damping force constant is 0.5.
Chapter 6 Overview of Protein - Body is made up of thousands of proteins - Contains nitrogen, carbon, hydrogen, and oxygen - General functions • Regulates and maintains body functions • Provides essential form of nitrogen (in the form of amino acids) Proteins - In the developed world: • Diet is typically rich in protein - In the developing world: • Protein is a deﬁciency is an issue • Important to focus on protein in diet planning - Aside from water, protein makes up the major part of the lean body tissue - About 17% of body weight Protein Structure - Amino acids are the building blocks of proteins - Amino acids contain nitrogen bonded to carbon • makes them unique from carbohydrates and fats Amino Acids - The proteins in our bodies are made up of 20 different amino acids • 9 are essentials • Some are limiting • 11 are nonessential • New category • Conditionally or acquired indispensable • Infants or disease states Amino Acid Structure - Central carbon - Acid group - Amino group - Side group - Hydrogen - Side group for each different amino acid is different • This gives each amino acid its own characteristics Peptide Bond - Amino acids are connected together by a peptide bond - 2 amino acids-dipeptide, 3 amino acids - tripeptide, etc. - Many amino acids-polypeptide - Some proteins contain multiple polypeptide chains Protein Structure - The sequence of amino acids is called the protein primary structure - Primary structure leads to the protein higher order structure - The higher order structure causes the protein to get into a speciﬁc shape (native conformation) This shape is necessary for the protein to work properly - Disruption of Normal Structure - Denaturation • Heat • Strong acids • Bases • Heavy metals - Protein unfolds - Can’t work properly Protein Primary Structure - The protein’s primary structure is determined by the genes (DNA). DNA is kept in the cell’s nucleus - The information of the protein’s primary structure gets transcribed into messenger RNA (mRNA) - mRNA leaves the nucleus and goes to the ribosome (rough ER) where the protein gets translated (made) Protein Synthesis - DNA contains coded instructions - Copies of codes • transferred to the cytoplasm (via mRNA) - Amino acids added one at a time • With aid of transfer RNA (tRNA) - Requires energy Central Dogma of Biology DNA <> RNA > Protein How to Change Protein Structure - Genetic alterations - Can change the protein’s primary structure - Sometimes this is no big deal - Sometimes it is • It can lead to genetic diseases Sickle Cell Anemia - A single base substitution • causes one amino acid to be changed in the polypeptide of the hemoglobin protein - Alters the higher order structure of the protein - The protein doesn't work as efﬁciently - Hemoglobin binds oxygen in red blood cells - With sickle cell anemia, RBC become sickle shapes instead of biconcave Digestion of Proteins - Pre-digestion—cooking • heat denatures proteins, softens food - Digestion begins in stomach 1. Acid (HCL) denatures proteins 2. Pepsin (enzyme) breaks peptide bonds of proteins resulting in protein fragments - Pepsin released by cells in stomach & activates by the acidic environment - What controls pepsin/stomach acid - gastrin: hormone - released in response to think about food, chewing, and digesting food - In the stomach is partially digested protein and other nutrients—chyme - gluten:protein (wheat), makes dough elasticity Movement to SI - Release of CCK (hormone)—chyme stimulates - CCK causes pancreas to release proteolytic enzymes (tripsin,chymotrypsin) - pepsin inactivates (elevated PH) - several peptidases (2-3 amino acid in length) & free amino acids absorbed by active transport - any intracellular peptides digested by enzymes within cells Amino Acid Absorption - Taken up by capillaries & taken to the liver via the portal vein - liver - amino acids used as building blocks to make liver proteins - broken down for energy - released into blood - converted to nonessential amino acids, glucose/fat Gluten Sensitivity: Celiac Disease - incomplete gluten breakdown in SI leaving small peptides & amino acids - Celiac disease, inﬂammatory response to small peptides & amino acids - Autoimmune response, genetic predisposition - Prevalence in US is 1 in 133 - In people with related symptoms: 1 in 56 Infant Digestion of Proteins - Up to 4-5 months of age - GI tract is somewhat permeable to small proteins (whole proteins can be absorbed) - If breasted, this allows antibodies to be passed from mother to baby - Recommendation: - waiting until infant is 6-12 mo. old before introducing allergy foods