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NUTRITION 445 - Exam 1 Study Guide. What are the functional categories of proteins? Catalysts (change the rate of reactions occurring in the body) Messengers o E.g. hormones Structural Elements o Contractile proteins o Fibrous proteins Buffers F$13.99
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NUTRITION 445 - Exam 1 Study Guide. What are the functional categories of proteins? Catalysts (change the rate of reactions occurring in the body) Messengers o E.g. hormones Structural Elements o Contractile proteins o Fibrous proteins Buffers F
NUTRITION 445 - Exam 1 Study Guide.
What are the functional categories of proteins? Catalysts (change the rate of reactions occurring in the body) Messengers o E.g. hormones Structural Elements o Contractile proteins o Fibrous proteins Buffers Fluid Balancers Immunoprotecto...
nutrition 445 exam 1 study guide what are the functional categories of proteins catalysts change the rate of reactions occurring in the body messengers o eg hormones structural elements
Nutrition 445
Exam 1 Study Guide
What are the functional categories of proteins?
Catalysts (change the rate of reactions occurring in the body)
Messengers oE.g. hormones Structural Elements oContractile proteins oFibrous proteins Buffers Fluid Balancers Immunoprotectors Transporters Acute Phase responders What are the types of cellular proteins and what do they do?
Receptors: protein that are specific that sit on outside of cell and allow for cell signaling. o3 types:
those that bind the ligand stimulus & convert it into an internal signal that alters behavior of affected cell
E.g. Cyclic AMP
those that function as ion channels
those that internalize their stimulus intact Transport proteins: allow for movement of tuff in an out of cell; highly regulated. May also function a carriers or pump or they may provide protein line passage (pores) Structural proteins: responsible for scaffolding and infrastructure Catalytic proteins (enzymes): speed up reactions but are not part of the product. Most enzymes are
found intracellularly and work intracellularly except digestive enzymes. How do we regulate the function of enzymes? Name the three regulation mechanisms and describe, in detail, how they work. Covalent regulation: by removal or addition of phosphate group (reversible)
Allosteric regulation: modulators bind to an allosteric site to inhibit or activate the specific enzyme
Induction: creates changes in concentration of certain inductible enzymes by increasing enzyme synthesis oUsually occurs by action of certain hormones and is exerted thru changes in the expression of genes encoding enzymes Dietary changes can elicit the induction of enzymes necessary to cope with nutrient
load
oThis regulatory mechanism is relatively slow compared to the first two. What is the difference between inducible and constitutive enzymes? Inductible enzyme are synthesized at variable rates dictated by cellular circumstances
Consititutive enzymes are synthesized at a relatively constant rate uninfluenced by external stimuli Describe enzyme kinetics and any relevant terms.
oKm is the equilibrium konstant aka Michaelis constant. It tells us how enzymes react in the living cell and represents the concentration of substrate that is found in a rxn at half of Vmax
oKm=Vmax
2This study source was downloaded by 100000846041611 from CourseHero.com on 02-13-2023 01:39:19 GMT -06:00
https://www.coursehero.com/file/64097247/Nutr-445-Study-Guide-Exam-1docx/STUDY GUIDE o↑ Km means the enzyme has a low affinity for its substrate and takes more substrate to react with the active site of the enzyme. oE.g. glucokinase (liver) has a high Km meaning it has a low affinity for glucose. If it has a high affinity (low Km) too much glucose would be removed from the blood during periods
of fasting
o
What are the 6 enzyme categories and what are their main functions?
Oxidoreductases: rxn’s in which one compound is oxidized another is reduced. oSpecific examples: dehydrogenases, reductases, oxidases, peroxidases, hydroxylases, oxygenases oEx: enzymes found in ETC Transferases: functional group is transferred from one substrate to another oSpecific example: transketolase, transalsolase, transmethylase, transaminase
Hydrolases: catalyze cleavage of bonds between a C and another atom by adding an H2O
oSpecicifically: esterases, amidases, peptidasesphosphatases, glycosidases oEx: digestive enzymes Lyases: catalyze cleavage of C-C,C-S and some C-N bonds without hydrolysis or redox oDecarboxylases,alsolases,synthetases, cleavage hydratases, dehydratases Isomerases: catalyze the interconversion of optical or geometric isomers Ligases: catalyze the formation of bonds between C & O,S,N o*REQUIRES ENERGY PROVIDED BY ATP* How are the inherent kinetic characteristics of an enzyme related to regulation of a metabolic pathway/ process?
the enzymes that are going to be the most highly regulated are the ones that catalyze commited/irrevesible steps of the metabolic pathways which have the large negative delta G's, are exergonic and are unidirectional
What are the criteria for enzymes to have diagnostic capability?
Enzyme must have sufficiently high degree of organ or tissue specificity A steep concentration gradient of enzyme activity must exist between the interior and exterior of the cells under normal conditions. This makes small increases in serum activity detectible. The enzyme must function in the cytoplasmic compartment of the cell so that it leaks out whenever the plasma membrane suffers significant damage. The enzyme must be stable for a reasonable period of time in the vascular compartment
What is the difference between diffusion, facilitated diffusion (aka carrier-mediated), active transport, and
endocytosis?
Understand energy release and consumption in chemical reactions. (p21)
Simple combustion- energy liberated is in the form of heat & CO & H2O are by products
Cellular oxidation-energy released is in form of ATP (40%) and heat (59%) Know the common units of energy. Calorie =4.18J Kcal=4.18kJ 1kcal=1000cal Describe free energy and any relevant terms.
Free energy- the capacity of the system to do work This study source was downloaded by 100000846041611 from CourseHero.com on 02-13-2023 01:39:19 GMT -06:00
https://www.coursehero.com/file/64097247/Nutr-445-Study-Guide-Exam-1docx/
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