HUN 3224 Test 2 Study Guide General information: 1. Know the general structure of an amino acid a. 2. know the groups of amino acids and know which amino acids belong in each a. Aliphatic – Glycine, Alanine, Valine, Leucine, Isoleucine b. (OH) group – Serine, Threonine c. Sulfur – Methionine, Cysteine d. Carboxyl/Amide – Aspartic Acid, Glutamic Acid, Asparagine, Glutamine e. Basic Group – Arginine, Lysine, Histidine f. Aromatic Rings – Phenylalanine, Tyrosine, Tryptophan g. Imino Acid - Proline 3. know the functions we discussed in class and some examples of those functions a. Energy – determined by energy needs of cell i. Gluconeogenesis ii. Fatty Acid Synthesis b. Buffers – can accept H+ c. Synthesis of Neurotransmitters i. Tyrosine – dopamine, norepinephrine, epinephrine ii. Glutamate – gamma-amino butyric acid iii. Tryptophan – serotonin d. Protein Formation 4. Know the essential and non-essential amino acids and conditionally essential and why they are designated as such a. Non-essential Amino Acids – Body can make b. Essential Amino Acids – Body cannot make, and must ingest i. His, Leu, Lys, Lle, Phe, Val, Met, Trp, Thr c. Conditionally Essential – made from essential amino acids i. Cys, TyrIntro to Proteins: 1. Understand and be able to describe the structure of proteins, primary, secondary, tertiary and quaternary. Be able to give examples where relevant. a. Primary – Sequence of Amino Acids in a polypeptide chain b. Secondary – Folding of primary structure i. a-Helix – coiling to form cylindrical shape ii. b-sheets c. Tertiary – Overall Structure of polypeptide chain d. Quaternary – Involving two or more polypeptide chain (ex. Hemoglobin, Anitbodies) 2. Know the different functions of proteins in the body, be able to give examples a. Enzymes – catalyst b. Hormones – Chemical Messanger c. Structural Proteins: i. Contractile proteins – muscle (actin, myosin) ii. Fibrous proteins – collagen (cartilage, hair, bone) d. Cell Membrane Proteins i. Membrane channels/transporter (Glucose/Na+ transporter) ii. Receptors – (LDL, Insulin) Protein Digestion and Absorption: 1. Know the digestive secretions related to protein digestion ie: gastrin, HCL, pepsinogen, a. Gastrin – stimulated by thought of food – produces HCl b. HCl – produced by parietal cells. i. Denatures protein ii. Converts pepsinogen to pepsin c. Pepsinogen – secreted into lumen of stomach by gastric chief cells d. Pepsin – cleaves proteins at Leu and aromatic residues, (Met, dicarboxylic) 2. Describe the duodenal digestion of polypeptides, know enzymes, what stimulates them a. Chyme Enters duodenum b. Secretin secreted by intestinal mucosa i. Stimulates pancreatic acinar cells ii. Trypsinogen secretion c. CCK secreted by mucosa i. Stimulates pancreatic bicarbonate ii. Stimulates intestinal production of enterokianse d. Trypsin i. activates pancreatic endopeptidases 1. Trypsinogen → Trypsin 2. Protelastase → Elastase 3. Chymotrypsinogen → Chymotrypsin ii. Activates pancreatic exopeptidases 1. Procarboypeptidase A & B → Carboxypeptidase A & B e. Enzymes i. Trypsin – basic amino acids ii. Elastase – aliphatics iii. Chymotrypsin – aromatics iv. Carboxy A – Aromatic and Aliphatic v. Carboxy B – Basic f. Digestive Products: free amino acids, some di & tripeptides, and oligopeptides 3. Know the difference between endogenous and exogenous proteins a. Endogenous Proteins – Protein present within the human body for metabolism (formed in body) b. Exogenous Proteins – Proteins that come from outside the body (ingested via diet)4. Understand mechanisms by which amino acids are taken up at the brush border a. Absorption of endogenous and exogenous proteins occur i. Mostly sodium dependent transport, some sodium independent ii. Competition for transport: (fastest to slowest) 1. BCAA before small AA 2. Neutral before acidic/basic 3. Essential before non-essential 4. 2 dicarboxylic amino acids: Glu & Asp 5. Peptides are absorbed quicker than free AA Amino Acid Metabolism: 1. Know the four processes by which amino acids are degraded. Give the function and an example of each a. Decarboxylation – removal of carboxyl group b. Side Chain Cleavage – removal of R chain c. Deamination – removal of amino group (NH3) d. Transamination – movement of amino group (NH3) from one molecule to another i. Formation of non-essential amino acids 2. Know which amino acids are glucogenic, ketogenic and keto-glucogenic a. Glucongenic – converted to pyruvate and krebs intermediates i. Ala, Gly, Cys, Ser, Asp, Asn, Glu, Gln, Arg, Met, Val, His, Pro b. Ketogenic – converted to acetyl CoA and acetoacetone i. Lys, Leu c. Both Ketogenic and Glucogenic i. Phe, Ile, Thr, Trp, Tyr 3. Be able to explain what makes an amino acid gluco- or ketogenic, or both a. Glucongenic – Amino acids that can be converted to Glucose b. Ketogenic – Amino Acids that can be converted to keto bodies 4. Know the metabolism of branched chain amino acids as discussed in class a. See # 4 in Organ Specific AA Metabolism 5. Understand the glucose-alanine cycle a. Production of Glucose from Alanine (formed from muscle with production of lactate) in the liver b. Removes Nitrogen from muscle to liver (urea) c.Urea Cycle 1. Know the relationship between the Krebs and the urea cycle, be able to draw these pathways a. 2. Understand the regulation of CPS I, including N-AcetylGlutamate and glutamate a. CPS I (carbamoyl phosphate synthase I) – rate limiting enzyme, forms monomer (active) or dimer – makes Carbamoyl Phosphate i. Allosterically (non-active site) regulated by: N-AcetylGlutamate 1. Acetyl Coa + Glutamine → N-AcetylGlutamate 2. Splits dimers into monomers 3. Know the relationship between dietary protein and the urea cycle a. High Protein Diet = increase of Urea Cycle and production of Urea Cycle Enzymes Organ Specific AA Metabolism: 1. know the role of the liver in amino acid metabolism a. site of storage/metabolism of amino acids b. gluconeogenesis (glucose-alanine cycle) c. Urea Synthesis (excretion of nitrogen) 2. Understand the relationship between liver enzymes and liver functioning tests a. AST, ALT – indicators of liver fxn – increase in transamination/enzyme = liver malfuction b. Arginase – Urea Cycle c. Phenylalanine Hydroxylase –
View Full Document
Unlocking...