ACS Biochemistry 2023 Exam Questions With Correct Answers

ACS Biochemistry 2023 Exam Questions With Correct Answers Nucleotide - ANSWERS monomer of nucleic acids made up of a 5-carbon sugar, a phosphate group, and a nitrogenous base nitrogenous base - ANSWERS adenine, guanine (2 hydrogen's) purines thymine, cytosine, uracil (3 Hydrogen's) pyrimidines Polymerase Chain Reaction Steps - ANSWERS 1. *Denaturation* of the *DNA sample* into *TWO STRANDS* 95c 2. *Anneal primers* to each Strand 50-60c 3. Copy each strand by a *heat-stable DNA POLYMERASE* 72c 4. *repeat cycle* DNA ligase - ANSWERS A linking enzyme essential for DNA replication; catalyzes the covalent bonding of the 3' end of a new DNA fragment to the 5' end of a growing chain. Telomerase - ANSWERS An enzyme that catalyzes the lengthening of telomeres in eukaryotic germ cells. Central Dogma - ANSWERS DNA -> RNA -> Protein RNA directionality - ANSWERS 5' to 3' DNA directionality - ANSWERS one end has an exposed hydroxl group on the 3' carbon of deoxiribose and the other end has an exposed phosphate group on a 5' carbon hydrogen bonding - ANSWERS the intermolecular force in which a hydrogen atom that is bonded to a highly electronegative atom is attracted to an unshared pair of electrons of an electronegative atom in a nearby molecule bonded to N, O or F Bronsted acid - ANSWERS donates a proton Lewis acid - ANSWERS electron pair acceptor dissociation constant - ANSWERS an equilibrium constant between a ligand and a protein, such as a receptor or an enzyme Kw equation - ANSWERS Kw=[H+][OH-] pH equation - ANSWERS pH = -log[H+] pKa equation - ANSWERS pKa = -logKa Henderson-Hasselbalch equation - ANSWERS pH = pKa + log [A-]/[HA] Buffer - ANSWERS compound that prevents sharp, sudden changes in pH amino acids - ANSWERS a simple organic compound containing both a carboxyl (—COOH) and an amino (—NH2) group. that are chiral expect glycine How to determine the charge of amino acids at different pH's? - ANSWERS The isoelctric point of an amino acid is: - ANSWERS The pH at which there is no net electrical charge on the amino acid Cation - ANSWERS A positively charged ion Anion - ANSWERS A negatively charged ion Using a positively charge column the _______ charged ions will elude first? - ANSWERS elude negatively charged molecules first Using a negatively charge column the _______ charged ions will elude first? - ANSWERS elude positively charged molecules first primary protein structure - ANSWERS sequence of amino acids help together by peptide bonds secondary protein structure - ANSWERS occurs when the sequence of amino acids are linked by hydrogen bonds -parallel bonding (tilled h-bonding) is more stable than anti parallel (straight h-bonding) tertiary protein structure - ANSWERS occurs when certain attractions are present between alpha helices and pleated sheets and created structure by the hydrophobic effect fiberous proteins - ANSWERS extended and strand-like insoluble in water, used for structure. The peptide chains are bound together by strong intermolecular hydrogen bonds in fibrous proteins The peptide chains are bound together by strong intermolecular hydrogen bonds in fibrous proteins globular proteins - ANSWERS these are compact, generally rounded, and soluble in water. The hydrophillic end is on the outside and the hydrophobic end is on the inside making them water soluble. held together by weak hydrpgen bonding quaternary protein structure - ANSWERS protein consisting of more than one amino acid chain and has several sub units and example of this is hemoglobin Michaelis-Menten equation - ANSWERS V=Vmax[S]/Km+[S] Lineweaver-Burk equation - ANSWERS 1/v = (Km/Vmax)(1/[S]) + 1/Vmax competitive inhibition - ANSWERS inhibitor binds to active site. ES or EI only cannot be at both sights at once no ESI Vmax unchanged Km increased noncompetitive inhibitor - ANSWERS Inhibitor that binds to a part of the enzyme other than the active site EI or ESI Vmax is decreased Km is raised or lowered uncompetitive inhibition - ANSWERS the inhibitor binds only to the enzyme-substrate complex ONLY ESI Vmax is decreased km is decreased Oxidation - ANSWERS loss of electrons reduction - ANSWERS gain of electrons reducing sugar - ANSWERS -any monosaccharide w/ a hemiacetal ring (since they can be oxidized, they are considered reducing agents) Cofactors - ANSWERS nonprotein enzyme helpers beta bonds - ANSWERS found in lactose and dietary fiber; not easily broken down by intestinal enzymes BETA= Queen B= Love On Top = BETA POINTING UP alpha bonds - ANSWERS Chemical bonds linking monosaccharides, which can be broken by human intestinal enzymes, releasing the individual monosaccharides. Starch, maltose, and sucrose contain alpha bonds. How to tell if it is in D or L form? - ANSWERS if the chrial carbon furthest from the carboxyl group has it OH group on the right = D (l is more naturally occuring) If the OH is on the left side = L form Glycolysis (10 steps) - ANSWERS 1. Glucose is phosphorylated to become glucose-6-phosphate. 2. Glucose-6-phosphate is reformed into fructose-6-phosphate 3. Fructose-6-phosphate is phosphorylated to become fructose-1,6-biphosphate 4. fructose-1,6-biphosphate interconverts between glyceraldehyde-3-phosphate and dihydroxyacetone phosphate 5. interconvert 6. glyceraldehyde-3-phosphate is oxidized (forms NADH) and becomes 1,3-biphosphoglycerate 7. 1,3-biphosphoglycerate loses a P (makes ATP) and becomes 3-phosphoglycerate 8. 3-phosphoglycerate moves p to 2 carbon, becomes 2-phosphoglycerate 9. 2-phosphoglycerate forms phosphoenolpyruvate 10. phosphoenolpyruvate loses P (forms ATP) and forms pyruvate product of glycolysis - ANSWERS 2 pyruvate and 2 ATP What regulates glycolysis? - ANSWERS Kinases What is the rate determining step in glycolysis? - ANSWERS Step 3, the phosphorylation of fructose 6-phosphate.