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54 Cards in this Set
- Front
- Back
What are enantiomers?
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-2 biomolecules containing 1 or more chiral centers which are nonsuperimposable mirror images of each other
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What is definition of conformation?
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-the spatial arrangement of substituent groups that are free to assume different positions in space WITHOUT BREAKING BONDS
-elcipse -staggered -boat -chair |
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How do you spot oxidation?
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-molecule gains an O
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How do you spot reduction?
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-molecule gains H
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What does it mean if G is +'ve?
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-not spontaneous, needs input of free energy to proceed; endergonic
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What does it mean if G is -'ve?
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-spontaneous, releases free energy which can be used to do work; exergonic
-continues until equilibrium is reached |
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What does it mean if H is -'ve?
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-exothermic; heat is released
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What does it mean if H is +'ve?
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-endothermic, heat is absorbed
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What does it mean if S is -'ve?
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-less random, more structured
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What does it mean if S is +'ve?
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-more random, less structured
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What are enzymes?
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-biological catalyests which allow chemical reactions to proceed quickly and efficiently
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How is information transfered living organisms?
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DNA->transcription->RNA->translation->
PROTEIN->function **the 3-D shapes of proteins are unique and important. if the shape changes, due to mutations, the function changes** |
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What are some characteristics of water?
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-has high heat of vaporization
-has high heat capacity -solvent for polar and ionic biomolecules -contributes to structure and function of biomolecules -medium for biochemical processes and reactions -Hydrogen bonding gives water its unusual properties |
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What is electronegativity?
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-the ability of an atom to attract electrons to its nucleus
**the greater the difference in electronegativity between 2 atoms, the greater the polarity of the bond** |
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What 2 behaviors of water affect the behavior of biological molecules?
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1)Polarity: it's cohesive and it likes other polar molecules too
2)Tendency to dissociate into OH and H |
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How many H-bonds can a single water molecule form?
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-4
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What is hydration/solvation?
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-the insulation of charged particles by water
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What does amphipathic mean?
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-molecules with a polar group (hydrophilic) and a nonpolar region (hydrophobic)
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Consider bilayers and micelles. Which allows water to have more entropy?
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-micelles allow water to have more entropy
**just in case, micelles are those globular amphipathic balls** |
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What are the 4 major types of noncovalent interactions that influence the structure and function of biomolecules?
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1)Ionic Interactions: attract and repel
2)Hydrogen Bonds: H bonds 3)Van der Waals forces: a)Dipole-Dipole b)Dipole-Induced Dipole c)Transient dipole-transient dipole 4)Hydrophobic interactions: nonpolar molecules create a 'water shell'. Increase in entropy of surrounding water |
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How do you calculate pH? or p anything for the matter.
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pH = -log[H]
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Why is it important to maintain constant pH in living organisms? 2 reasons
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1) Maintain catalytic activity of enzymes
2) Maintain homeostasis intracellularly and extracellularly |
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What does it mean if K is a large number?
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-means that the molecule is more likely to ionize
**therefore, if K is large, acid is strong** |
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What does it mean if pKa is a large number?
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-means that the acid strength is decreasing
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Whats the difference between Monoprotic, Diprotic and Triprotic acids?
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-Monoprotic acids lose 1 H
-Diprotic acids lose 2 H -Triprotic acds lose 3 H **Monoprotic is weak, triprotic is strong** |
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When is a weak acid best able to resist change in pH?
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-when pH=pK
-when [HA]=[A] |
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What are the 3 main types of carbohydrates?
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1)Monosaccharides- single sugar
2)Oligosaccharides- 2 to 20 sugars 3)Polysaccarides- more than 20 sugars |
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What are the 5 main functions of carbohydrates?
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1) Primary source of energy metabolism
2) Storage form of energy 3) Biosynthesis 4) Structural components 5) Informational roles |
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What is an epimer?
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-2 monoscaccharides which differ only in the configuration about a SINGLE chiral center
-that chiral center is now called an epimeric carbon |
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What is a hemiacetal?
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-a chiral carbon with an -OH and a -OR
**Acetals have 2 -OR's** |
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What is alpha bonding?
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-occurs when monosaccharides form a ring
-OH group is trans to the CHHOH on the 6 carbon (across the O) **Remember: When 2 rings join, the bond type of the leftmost ring takes priority and that bond is used in the final name!** |
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What is Beta bonding?
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-occurs when monosaccharides form a ring
-OH group is cis to the CHHOH on the 6 carbon (across the O) **Remember: When 2 rings join, the bond type of the leftmost ring takes priority and that bond is used in the final name!** |
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What are reducing sugars?
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-sugars which contain a potentially reactive aldehyde group that can be oxidized (ie: has a free OH at the anomeric carbon)
-reducing sugars are the rightmost group of sugar when drawn properly (ie: from left to right) |
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What's the difference between linear and branched polysaccharide chains?
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-linear chains are in a straight, single line
-branched chains branch off from main chains **sugars are removed from the non-reducing end** |
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What's the difference between amylose and amylopectin in terms of linkage?
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-amylose is a linear polysaccharide, composed of 10->1000 D-flucose residues. Bonds are alpha(C1->C4)
-amylopectin is a branched polysaccaride composed of 300->6000 sugars or more. Bonds are alpha(C1->C4) on linear sugars but are alpha(C1->C6) on branching sugars. |
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What is glycogen?
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-it's like amylopectin but with way more branches (I'm talking about a branch every 8-10 glucoses!!!)
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What is cellulose?
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-linear polysaccharides
-differs from the rest because it has Beta(C1->C4) bonding |
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What are the 7 amino acids that belong to the 'nonpolar, aliphatic R groups'?
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-glysine
-alanine -proline -valine -leucine -isoleucine -methionine |
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What are the 3 amino acids that belong to the 'aromatic R groups'?
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-phenylalanine
-tyrosine -tryptophan |
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What are the 5 amino acids that belong to the 'polar, uncharged R groups'?
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-serine
-threonine -cysteine -asparagine -glutamine |
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What are the 3 amino acids that belong to the 'positively charged R groups'?
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-lysine
-arginine -histidine |
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What are the 2 amino acids that belong to the 'negatively charged R groups'?
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-aspartate
-glutamate |
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What's so special about tyrosine. serine and thereonine?
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-there OH group can be phosphorylated
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Are amino acids S or R configured?
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-they are 'S' configured
-remember: CORN [1]CO=COO [2]R=R group [3]N=NH3 |
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What so special Proline, Glycine and Cysteine?
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-Proline has a rigid backbone
-Glycine has a flexible backbone -Cysteine can form S-S (disulphide bonds) |
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What are zwitterions?
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-result of amino acid being dissolved in water
-a dipolar ion, with spatially separated positive and negative charges -can act as an acid or a base |
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What is pI?
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-it is the isoelectric point
-the point at which the net electric charge is zero **so if pH is less then pI, amino acid is more acidic therefor have a relatively larger postive charge. if pH is greater than pI, amino acid is more basic therefor having a relatively larger negative charge** |
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How does an amino acid titration curve work... or any titration curve for the matter?
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-farthest right is where it is most acidic.
-as the titration plateaus (ie hits a pK value), the original amino acid becomes more basic (ie: loses an H) when more base is added **so... curve rises, plateaus, turns more basic, rises, plateaus, turns more basic, etc.** |
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How do amino acids form peptide bonds?
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-amino acids join head to tail by dehydration. OH of carboxylic head makes off with H of tail.
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What is the 'direction' of amino acids?
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N---> Residues---> C
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What is residue?
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-each amino acid in the chain is referred to as residue
-proteins are about 60-800 residues long -average weight is 110 Daltons |
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What are some characteristics to peptide bonds?
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*Consists of O=C-N-H
-O and H are trans 99% of the time -rigid and planar -has partial double bonds (ie:O or N can be double bonded to C at any time) *N-C[alpha] bonds are called phi *C-C[alpha] bonds are called psi -phi and psi bonds are free to rotate |
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For amino acids, what is the alpha carbon?
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-the central, chiral carbon is referred to as the alpha carbon
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How do you calculate G?
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G = G + RT(lnKeq)
G = H - TS |