BCHM 307 - Exam 1 ~Purdue 2023 with 100% correct questions and answers

In humans how much of the genome encodes for proteins? 1.5% Of lipids, carbohydrates, nucleotides, and amino acids - which is never found in a polymerized form? Lipids - they aggregate What is a polysaccharide's major function? Energy storage What is the buffer system that is in the blood stream? Carbonic acid as a reactant and bicarbonate and H ions as the products Metabolic acidosis often causes increased respiratory rates. What portion of the bloodstream buffer is lost through increased respiration? CO2 Photosynthetic organisms use energy from the sun to reduce CO2 to carbohydrates True The biological classification system categorizes organisms into what domains? Bacteria, Archaea and Eukarya In an aqueous solution, if the [OH-] is 3.0x10^-5 M. What is the [H+]? 3.3x10^-10 *The lower the pKa the lower the pH. Thus, the lower the pKa the stronger the acid True What is the conjugate acid of H2PO4-? H3PO4 What elements are found in simple carbohydrates? Carbon, Hydrogen, and Oxygen A spontaneous process has a delta G that is... Negative What is the most oxidized version of carbon? CO2 What are some differences between prokaryotes and eukaryotes Eukaryotes contain a nucleus, organelles, are larger and form multicellular organisms An A-T base pair contains______ H bonds, an C-G base pair contains _______ H bonds. 2 3 What term describes the process of converting the information found in DNA into the sequence of a protein? Expression The replication of DNA is made possible by the presence of complementary strands in the double helix of DNA True A genomic library contains all of an organisms DNA True What is the hydrophobic effect the exclusion of nonpolar substances from an aqueous solution What are some effects of the hydrophobic effect? -the lipid membrane of cells and organelles -protein folding that places hydrophobic amino acids in the interior -the separation of salad dressing -oil sheens seen on the ocean following an oil spill What does it mean when a molecule is amphiphilic? a molecule that has both a polar and a non polar region What are micelles? globules of up to several thousand amphiphilic molecules arranged with the hydrophilic groups on the surface and the hydrophobic groups buried in the center in aqueous solutions Fatty acid anions most commonly assemble into micelles in aqueous solution True Chargaff's Rule A+G=C+T A base found exclusively in DNA is thymine, while uracil is found only in RNA True The purines found in nucleic acids are ? adenine and guanine The pyrimidines found in nucleic acids are? thymine and cytosine what type of bond is made between nucleotides? phosphodiester physical properties of water that result from hydrogen binding: high boiling point relative to molecular weight a solid state that is less dense than the liquid state high surface tension ability to solubilize polar molecules The strongest noncovalent interactions are ionic interactions True When a non-polar substance is added to water, how do the molecules of water behave? The regular hydrogen bond pattern is disrupted resulting in a decrease of entropy Which of the following functional groups has two hydrogen bond donors and one hydrogen bond acceptor? Amine If a phosphate buffer (pK=6.82) was formulated such that its pH was 7.3, it would be best suited to buffer against _____. If instead, it was formulated such that its pH was 6.3, it would be best suited to buffer against _____. acid; base The 5' end of a polynucleotide contains _____, while the 3' end contains ________. a phosphate group; a hydroxyl group Bacteria and archaea typically have fewer than ________ genes while plants and animals typically have greater than ___________ genes. 5,000; 10,000 In DNA, the ribose derivative lacks an __________ on carbon __________. alcohol; 2 Which of the following amino acids has a thiol group in its side chain? (Look up structures if you need to!) Cys Which of the following amino acids is generally absent from an α-helix? Pro - it loops back on itself At physiological pH, all amino acids have at least ___ charged groups. 2 Disulfide bonds form between two residues of which amino acid? Cys The amino acid _____ is commonly phosphorylated. Ser The formation of a dipeptide from two amino acids requires ___. A loss of water - it is a condensation reaction When a cell moves along a surface, actin _____ occurs at the leading edge while _____ occurs at the trailing edge polymerization; depolymerization A plot of the binding of oxygen to myoglobin as a function of pO2 gives a _____ shape; a similar plot for hemoglobin gives a _____ shape. hyperbolic; sigmoidal Proteins such as hemoglobin are known as _____ proteins since binding of a molecule to one site alter binding to other sites. Allosteric During the formation of microfilaments, which of the following occurs? ATP hydrolysis is catalyzed by F-actin The central ion of the heme group of hemoglobin is _____. Fe2+ Which of the following details the nucleotide-binding site when tubulin dimers assemble into microtubules? the α site is bound to GTP; the β site is bound to GDP The individual hemoglobin subunits and myoglobin share similar _____ structure but have rather different _____ structure. secondary and tertiary; primary