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68 Cards in this Set
- Front
- Back
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What is a D sugar? |
All sugars that terminate in the same configuration asD-glyceraldehyde |
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What is an epimer? |
Epimers are diastereomers that contain more than one chiral center but differ from each other in the absolute configuration at only one chiral center. (In this class, the term mostly refers to sugars.) |
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What sugar is an epimer of glucose at C4? What sugar is an epimer of glucose at C2? |
D-galactose at C4 D-mannose at C2 |
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What are the 3 important ketoses? |
1) dihydroxyacetone 2) D-ribulose 3) D-fructose |
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What is an anomer? |
An epimer (or pair of epimers) that differ only in the configura@on at the anomeric carbon atom |
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What is an anomeric carbon? |
A stereocenter in a carbohydrate. |
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What is mutarotation? |
The process of interconversion of the α- and β-anomers in solution |
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What makes up the disaccharide maltose? What glycosidic linkage does it have? |
made of an α-D glucose and a D-glucose. Has an α(1-->4) glycosidic bond |
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What makes up the disaccharide Lactose? What kind of glycosidic linkage does it have? |
β-D-galactose and D-glucose. Has a β(1-->4) glycosidic bond |
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What makes up the disaccharide sucrose? What kind of glycosidic linkage does it have? |
α-D-glucose and β-D-fructose. has an α(1-->2) glycosidic bond |
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What makes up the disaccharide cellobiose? What kind of glycosidic linkage does it have? |
β-D-glucose and D-glucose Has a β(1-->4) glycosidic bond |
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What is the structure of the polysaccharide Starch? What kind of glycosidic linkages does it have? |
Made of amylose and amylopecti consisting of α-D-glucose residues. Linked by α(1-->4) glycosidic bonds linearly; amylopectin branches are linked to the main chain by α(1-->6)glycosidic bonds. |
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What is the structure of the polysaccharide Cellulose? What kind of glycosidic linkages does it have? |
Linear polysaccharide made of β-D-glucoses. Linked by β(1-->4) glycosidic bonds |
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What is the structure of the polysaccharide Glycogen? What is it similar to? What kind of glycosidic linkages does it have? |
A branched chain polymer of α-D-glucoseresidues linked by α(1-->4) glycosidic bonds. Similar to amylopectin, branches are connected to the main chain with α(1->6) glycosidic bonds. Branching is more dense than amylopectin. |
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What are the products of hydrolysis triacylglycerols? |
1 glycerol molecule 3 fatty acid chains |
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What kind of bond links fatty acids? |
ester linkages |
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What is the effect of fatty acid chain length on the melting point of the fat/triacylglycerol? |
The longer the chain, the more hydrophobic interactions, meaning a higher melting point. |
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What is the chain length of oleic acid? How many double bonds does it have? |
18-carbon chain 1 double bond |
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What is the chain length of stearic acid? How many double bonds does it have? |
18-carbon chain 0 double bonds |
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What is the chain length of palmitic acid? How many double bonds does it have? |
16-carbon chain 0 double bonds |
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What are the constituents that make up a glycerophospholipid? |
Glycerophospholipids consist of 2 fatty acids, a glycerol, a phosphate and an alcohol |
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Where do you find the phosphodiester bond in glycerophospholipids (except for phosphatidic acid, which has a phosphoester linkage) |
Between the phosphate group and the head group alcohol. (called diester because of the oxygen linkages on either side of the phosphate) |
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True or false: normal amino acids have the alpha-L configuration. |
TRUE |
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Is an amino acid going to be protonated or deprotonated if the pH is ABOVE the PI of the compound? What if the pH is below the PI of the compound? What if the pH is equal to the PI? (*Note: PI=isoelectric point) |
-It will be protonated at pH above the PI -It will be deprotonated at pH below the pI -When pH=PI, the compound will be a zwitterion and will have a net zero charge. The Carboxyl group will be deprotonated (COO-) and the amino group will be protonated (NH3+) |
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What is a zwitterion? |
A neutral compound containing both positive and negatively charged groups in equal number. Amino acids are zwitterions at the isoelectric point, but not necessarily at physiological pH. |
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What is Edman degradation? What is it used for? |
A method of determining the amino acid sequence of a protein by chewing off the amino acid found at the N-terminal, one-at-a-time. |
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What links amino acids together in proteins? |
Peptide bonds |
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What is the effect that resonance has on the peptide bond in proteins? |
Since the peptide bond has partial double bond character, thereis no free rotation about the peptide bond. |
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What is the shape/geometry of the peptide bond? What are the bond angles about the N atom? Is the peptide bond cis or trans? Does it possess a dipole? |
Planar shape Bond angle=120 degrees It's trans It DOES possess a dipole |
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What stabilizes alpha helices and beta sheets? |
H-bonds (point along the axis in alpha helices) |
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Do alpha helices found in protein have a dipole? Are they right or left-handed? |
TRUE; they're right-handed |
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What's the difference between parallel and antiparallel beta sheets in proteins? |
Anti-parallel: the polarity ( N-->C) of adjacentstrands is opposite. Parallel – the polarity (N-->C ) of adjacentstrands is the same. |
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What are the 5 common structural motifs found in the tertiary structure of proteins? |
1) Beta turns/bends 2) Beta-alpha-Beta motif 3) anti-parallel alpha helix bundles 4) Beta barrels |
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What are the 5 factors which stabilize the 3-dimensional structure of proteins? |
1) H-bonds 2) Van der Waals interactions 3) ionic interactions (charge-charge or salt bridges) 4) hydrophobic effect 5) disulfide bonds |
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What amino acid can form disulfide bonds? |
cysteine |
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How many subunits does hemoglobin have? How many subunits does myoglobin have? Thus, how many molecules of O2 or CO2 can each molecule of hemoglobin/myoglobin bind? |
hemoglobin=4 subunits (2 alpha, 2 beta) (it's a tetramer) myoglobin=1 subunit (a monomer) Therefore, hemoglobin can carry 4 molecules (O2 or CO2) whereas myogblobin can only carry 1. |
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What is the structure of a heme group (found in hemoglobin and myoglobin. |
A heterocyclic porphyrin ring structure with an Fe2+ at its center |
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What does the binding curve of oxygen for hemoglobin look like on a graph? What about myoglobin? What is the significance of these shapes? |
-Hemoglobin: sigmoidal -Myoglobin: hyperbola -The sigmoidal shape of the hemoglobin binding curve reflects the fact that it performs cooperative binding (R state has high affinity for oxygen). |
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What is the effect of increasing CO2 concentration in the blood on the fractional saturation/binding curve of hemoglobin by O2? |
Increasing [CO2] leads to an increase in [H+]; as the environment gets more acidic, hemoglobin will release O2 and bind CO2. Think of this on a bulk scale, not on an individual scale. Increasing CO2 pushes the curve down. |
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What is the effect of increasing [2,3-bisphosphoglycerate] concentration in the blood on the fractional saturation/binding curve of hemoglobin by O2?Why is 2,3-BPG produced? |
2,3-BPG binds to deoxyhemoglobin and stabilizes it, leasing to the release of O2 (so O2 bound goes down and it more likely to be released by hemoglobin). Bulk scale, not individual scale. 2,3-BPG is produced in response to low oxygen conditions such as high altitude as a means of wringing hemoglobin dry of oxygen so that oxygen can get to oxygen-deprived tissue. Increasing 2,3-BPG pushes the curve down. |
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What is the effect of increasing pH on the fractional saturation/binding curve of hemoglobin by O2? |
Decreasing [H+] (increasing pH) causes HHb (hemoglobin with a proton attached) to bind more O2. Increasing pH pushes the curve up and vice versa. |
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Some enzymes act via Transition State Stabilization. What does this mean? |
They lower the activation energy and stabilize the normally unstable transition state intermediate, increasing the probability that the reaction will be pushed to completion/to the products' side. |
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What coenzyme is derived from the vitamin Riboflavin and what type of reaction is the coenzyme involved in? |
FAD. Involved in redox rxns |
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What coenzymes are derived from the vitamin Niacin B3 (nicotinamide) and what type of reaction are these coenzymes involved in? |
NAD+ and NADP+ involved in Redox reactions |
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What coenzyme is derived from the vitamin Pantothenic acid and what type of reactions it this coenzyme involved in? |
Coenzyme A Fatty acid metabolism. |
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What is meant by the term "Vmax" in reference to enzyme-catalyzed reactions? |
Vmax= the maximum velocity of a reaction when all the enzymes are saturated with substrate. |
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What is meant by the term "Km" in reference to enzyme-catalyzed reactions? What is the relationship between Km and Vmax? |
Km=The Michaelis constant, which is the substrate concentration producing half the maximum velocity. -Occurs at 1/2 Vmax |
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What are the 3 products of hydrolysis of DNA/RNA? |
1) Phosphate 2) base (A, G, T, C) 3) pentose sugar |
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What's the difference between a nucleoside and a nucleotide? |
-Nucleoside: Just the base + pentose sugar -Nucleotide: The base + pentose sugar + ONE phosphate |
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What are Chargaff's rules concerning DNA? |
1) The amount of G is equal to C, 2) the amount of A is equal to T 3) Therefore, amount of total purines=amount of total pyrimidines |
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What are the 4 aspects of Watson and Crick's structural rules of B-DNA? |
1) Right-handed double helix 2) plectonemically coiled 3) anti-parallel strands 4) A pairs with T and C pairs with G |
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What are RNA stem-loops and why do they form? |
They occur when the single strand of RNA folds up on itself and base pairs with itself to form a loop/hairpin to stabilize it. |
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What is a phosphoryl transfer reaction? |
It's when the phosphate group from one compound is cleaved off and the resulting energy is used to phosphorylate another compound. Happens a ton in metabolism. |
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What is a kinase/what does it do? |
An enzyme that phosphorylates something. |
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What is the overall purpose of glycolysis? |
Breaking down glucose to produce energy/energy-yielding products (pyruvate)
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What are the 3 irreversible reactions in glycolysis (and what 3 enzymes catalyze them)? You need to know this because the fact that these 3 irreversible reactions exist in glycolysis imply the existence of gluconeogenesis (otherwise, the pathway could just reverse itself to make glucose). |
1) Glucose to Glucose-6-Phosphate -catalyzed by hexokinase 2) Fructose-6-phosphate to Fructose-1,6-bisphosphate. -catalyzed by phosphofructokinase-1 3) Phosphoenolpyruvate to pyruvate -catalyzed by pyruvate kinase |
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What are the 2 products of the pentose-phosphate pathway? What are they used for? |
1) Produces NADPH -used in lipid biosynthesis 2) Produces ribose-5-phosphate -used in DNA biosynthesis |
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What does fat (TAGs) get broken down into during lipolysis? What enzyme does this? |
Breaks down into 1 glycerol and 3 fatty acids -performed by lipoprotein lipase |
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What is the fuel for beta oxidation? What are the 2 important products of beta oxidation? |
Fuel=fatty acyl CoA -important products: NADH, FADH2 |
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What is the overall purpose of the Citric Acid Cycle? |
To produce the following from the oxidation of acetyl Coa to 2CO2: 1 FADH2 3 NADH 1 GTP -Intermediates are important for biosynthesis |
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Which complex of the Electron Transport Chain uses NADH? Which complex used FADH2? |
Complex I uses NADH Complex II uses FADH2 |
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What's the distinguishing protein in complex I? What does it/complex I do? |
A flavoprotein (with a flavin mononucleotide (FMN) group).It's what passes the electron from NADH to Coenzyme Q. |
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What are the pertinent proteins that CoQ interacts with(/transfers electrons to) in complex 3? |
Either to: 1) an Fe-S protein --> cytochrome C 2) Cytochrome B |
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What is the half reaction for the oxidation of FADH2? |
FADH2 --> FAD + 2H+ + 2e- |
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What is the half reaction for the reduction of NAD+? |
NAD + 2H+ + 2e- ---> NADH |
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What is the half reaction for the reduction of molecular oxygen by the electron transport chain? |
1/2O2 + 2H+ + 2e- ---> H20 |
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What does the Chemiosmotic hypothesis say? |
Electron transport is coupled to the generation of a proton gradient across the inner mitochondrial membrane which drives the synthesis of ATP from ADP + Pi |
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What's the distinguishing protein(s) in complex II? What do they do? |
The FAD-linked dehydrogenases. They accept/transfer electrons from FADH2 to coenzyme Q. |
