NTRI 2000, Chapter 6 week 1
NTRI 2000, Chapter 6 week 1 NTRI 2000-002
Popular in Nutrition and Health
verified elite notetaker
Popular in Nutrition and Food Sciences
This 3 page Class Notes was uploaded by Isabella Chappano on Wednesday March 23, 2016. The Class Notes belongs to NTRI 2000-002 at Auburn University taught by Michael Winand Greene in Fall 2015. Since its upload, it has received 41 views. For similar materials see Nutrition and Health in Nutrition and Food Sciences at Auburn University.
Reviews for NTRI 2000, Chapter 6 week 1
Report this Material
What is Karma?
Karma is the currency of StudySoup.
Date Created: 03/23/16
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