Term
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Definition
| They are constructed from the atoms of C, H, and O. They are polyhydroxyl aldehydes or ketones, or substances that produce these compounds when hydrolyzed. |
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Term
| Describe classes of carbohydrates: |
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Definition
| Two major classes: simple and complex. |
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Term
| What are the major simple carbohydrates? |
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Definition
| Monosaccharides and disaccharides |
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Term
| What are the major complex carbohydrates? |
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Definition
| oliogsaccharides (3-10 saccharide units) and polysaccharides (10 or more saccharide units) |
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Term
| What are the three types of polysaccharides? |
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Definition
| Starch - the most common digestible in plants. Glycogen - major form of stored carb in animal tissue. Cellulose - major component of cell walls in plants. |
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Term
| What are the two most important dietary carbohydrates nutritionally? |
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Definition
| polysaccharides and disaccharides because monosaccharides are not naturally present in diet in significant quantities. |
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Term
| What hormones affect carbohydrate metabolism? |
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Definition
| insulin, glucagon, epinephrine and corticosteroid hormones. |
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Term
| Outline Digestion of Polysaccharides: |
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Definition
Salivary alpha-amylase - Mouth
Pancreatic alpha-amylase - small intestine.
resistant starches are insoluble in water and are non-digestible |
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Term
| Outline digestion of dissacharides: |
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Definition
| Active in microvilli of enterocytes of upper small intestine. No digestion in mouth or stomach |
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Term
| What is a key enzyme in digestion of disaccharides? |
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Definition
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Term
| What carbon bonds are digested by isomaltase? |
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Definition
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Term
| What is the process by which glucose enters the mucosal cells? |
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Definition
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Term
| What hormonal changes occur in response to a rise in blood glucose concentration? |
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Definition
| increased insulin and decreased glucagon |
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Term
| What is the pathway by which glucose is released from glycogen? |
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Definition
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Term
| Which tissues release glucose to the blood between meals? |
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Definition
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Term
| Glycogenesis is a process involving: |
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Definition
| reactions that convert glucose to glycogen. |
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Term
| Where does the Kreb Cycle pathway occur? |
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Definition
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Term
| Describe means of absorption of glucose and galactose into cell and blood: |
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Definition
Into cell: active transport - SGLT1 (Na/K-ATPase symport system)
Into Blood: diffusion, GLUT2 |
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Term
| Describe absorption of fructose into cells and blood: |
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Definition
into cell: facilitated transport - GLUT5.
Into blood: GLUT2.
Absorption is limited in 60% of adults. |
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Term
| What are GLUT transporters? |
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Definition
| Glucose transporters that are: integral proteins, each have specific binding sites, undergoes conformational change upon binding the molecule, can reverse change when unbound. |
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Term
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Definition
GLUT1: basic supply of glucose to cells
GLUT2: low infinity transporter; glucose from enterocyte to blood
GLUT3: high-affinity for brain and other glucose dependent tissues
GLUT4: insulin sensitive, in muscle and adipose tissues
GLUT 5: fructose |
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Term
| What are the roles of insulin in cellular glucose absorption? |
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Definition
1. binds to membrane receptor.
2. Stimulates GLUT4 to move membrane
Overall maintains blood glucose levels |
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Term
| What organelle is missing from erythrocytes, requiring them to use glycolysis as the sole provider of ATP? |
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Definition
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Term
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Definition
| Conversion of glucose to glycogen |
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Term
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Definition
| Breakdown of glycogen to glucose. phosphorolysis process, regulation of phosphorylase (covalent regulation - glucagon, epinephrine and allosteric regulation- AMP) |
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Term
| Basic function of glycolysis? |
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Definition
| Degradation of glucose to pyruvate. |
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Term
| How many ATPs are formed by complete glucose oxidation? |
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Definition
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Term
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Definition
| the storage form of glucose synthesized in human liver and muscles. |
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Term
| What does the glycemic index indicate? |
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Definition
| Increase in blood glucose during a 2-hour period after consumption of a certain amount of carbs compared with equal carbs from a reference food. |
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Term
| What is the glycemic load? |
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Definition
| the glycemic index times gram of carb in 1 serving of food. |
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Term
| What is chemiosmotic theory? |
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Definition
| The theory that ATP synthesis within the mitochondria occurs by way of proton gradient which forms when electrons are passed through their inner membranes. When protons pass the inner membrane in the opposite direction, energy is released and used to make ATP. (page 95) |
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Term
| Define anapleurotic reaction: |
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Definition
| Occurs when bypassing the pyruvate kinase step in the TCA cycle. Oxaloacetate can be made from pyruvate by the addition of CO2 in the mitochondrial matrix. The reaction is catalyzed by pyruvate carboxylase. The pyruvate carboxylase reaction consumes an ATP bond and CO2. |
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Term
| What is substrate level phosphorylation ? |
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Definition
| Substrate level phosphorylation is the production of ATP from ADP by direct transfer of a high energy phosphate group from an intermediate (phosphoenolpyruvate and 1,3 diphosphoglycerate) metabolic compound in an exergonic catabolic pathway. |
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Term
| What is oxidative phosphorylation? |
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Definition
| The high energy output of the TCA cycle is attributed to mitochondrial electron transport with oxidative phosphorylation being the source of ATP production. |
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Term
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Definition
| The circulatory transport of muscle derived lactate to the liver and the return of glucose to the muscle. |
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Term
| How do fructose and galactose enter the glycolytic pathway? |
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Definition
Dietary fructose can be converted to either F 6-P or F 1-P.
Dietary galactose is phosphorylated and isomerized to Glu- 1-P. (page 83) |
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Term
| Describe ATP structure and formation: |
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Definition
ATP is a nucleotide with ribose sugar and three phosphate groups. The two end phosphate groups are connected by high-energy bonds.
95% of ATP is formed in the mitochondrial matrix by: 1. glycolysis. 2. Conversion of pyruvate to acetyl-CoA. 3. Krebs Cycle. 4. Oxidative phosphorylation. |
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Term
| What are the mechanisms of metabolism regulation? |
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Definition
| 1. Negative or positive modulation of allosteric enzymes. 2. hormonal activation by covalent modification/induction. 3. directional shifts in reactions. 4. translocation of enzymes within cells |
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Term
| What does allosteric mean? |
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Definition
| involving a change in shape and activity of an enzyme that results from molecular binding with a regulatory substance at a site other than the enzymatically active one. |
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Term
| Name allosteric modulators: |
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Definition
| AMP, ADP and ATP. The ratio of ADP to ATP is an important regulatory system in energy metabolism. Also, AMP accumulation can signify excessive breakdown and depletion of ATP. AMP and ADP as modulators always oppose ATP. |
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Term
| What hormones are important for regulation of glycogenolysis? |
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Definition
| Glucagon and epinephrine. Both stimulate glycogenolysis and are directed at the initial reaction with glycogen phosphorylase. Both function through cAMP. |
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Term
| What hormones strongly influence covalent regulation in glycogenolysis? |
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Definition
| Glucagon (liver and adipose) and Epinephrine (liver and muscle. They stimulate phosphorylase b kinase promoting formation of phosphorylase a kinase. |
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Term
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Definition
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Term
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Definition
| Production of glucose from non carb intermediates. |
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Term
| Role of hexose monophosphate shunt? |
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Definition
| production of 5-carbon monosaccharides and NADPH |
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Term
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Definition
| Oxidation of pyruvate and acetyl-CoA. |
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Term
| What hormones function antagonistically to insulin in regulating the balance of free glucose and glycogen? |
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Definition
| Epinepherine and glucagon |
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