UNE medical biochemistry Unit 1 Exam Questions with Correct Answers || ALREADY GRADED A+|| Updated Version

atom - ANSWER The basic unit of matter. electron - ANSWER A negatively charged particle with only 1/1840th the mass of a proton. element - ANSWER A pure substance that consists entirely of one type of atom. isotopes - ANSWER Atoms of the same element that differ in the number of neutrons. compound - ANSWER Substance formed by the chemical combination of two or more elements in definite proportions. ions - ANSWER Positively and negatively charged atoms. molecule - ANSWER The smallest unit of most compounds. hydrogen bond - ANSWER The attraction between a hydrogen atom with a partial positive charge and another atom with a partial negative charge. cohesion - ANSWER An attraction between molecules of the same substance. adhesion - ANSWER An attraction between molecules of different substances. solution - ANSWER Type of mixture in which all the components are evenly distributed. monomer - ANSWER Smaller units of macromolecules used to build other, larger molecules. polymer - ANSWER Large units of macromolecules created by monomers. carbohydrates - ANSWER Compounds made up of carbon, hydrogen, and oxygen atoms usually in a 1:2:1 ratio. lipids - ANSWER Made mostly from carbon and hydrogen atoms and are not generally soluble in water. nucleic acids - ANSWER Macromolecules containing hydrogen, oxygen, nitrogen, carbon and phosphorus. proteins - ANSWER Macromolecules that contain nitrogen as wells as carbon, hydrogen, and oxygen. reactant - ANSWER Elements or compounds that enter into a chemical reaction. product - ANSWER Elements or compounds produced by a chemical reaction. activation energy - ANSWER The energy needed to get a reaction started. lipid - ANSWER Macromolecule made mainly from carbon and hydrogen atoms; includes fats, oils, and waxes which store energy and make up cell membranes enzyme - ANSWER A type of protein that speeds up a chemical reaction in a living thing without being permanently changed or destroyed. protein - ANSWER Macromolecule that contains carbon, hydrogen, oxygen, and nitrogen, is made of one or more chains of amino acids, a principal component of all cells, and needed by the body for growth and repair. atoms - ANSWER The smallest units of an element that maintain the properties of that element. element - ANSWER a pure substance that cannot be broken down into simpler substances by chemical or physical means. compound - ANSWER A substance made up of two or more different elements joined by chemical bonds. catalyst - ANSWER A substance that speeds up the rate of a chemical reaction without itself undergoing a permanent chemical change. carbohydrate - ANSWER A macromolecule that can be broken down to release energy, contains carbon, hydrogen, and oxygen in a 1:2:1 ratio, and serves as a major source of energy for living organisms (sugars, starches, and cellulose). nucleic acid - ANSWER A macromolecule containing hydrogen, oxygen, nitrogen, carbon, and phosphorus, present in living cells, stores and transmits genetic information, made of nucleotides (DNA, RNA). covalent bond - ANSWER A chemical bond formed when two atoms share electrons. ionic bond - ANSWER A chemical bond formed when one or more electrons are transferred from one atom to another to form a positive ion, and the other atom gains an electron to form a negative ion. hydrogen bond - ANSWER A chemical bond in which two or more polar molecules are attracted to each other because of the uneven distribution of electrons. monomer - ANSWER A repeating structure unit within a polymer that can join with others of the same kind. polymer - ANSWER A large molecule made of many monomers linked together by covalent bonds. active site - ANSWER A region on an enzyme that binds to a protein or other substrate during a reaction. metabolism - ANSWER All of the chemical reactions that occur within an organism. denature - ANSWER To change the shape of a protein (such as an enzyme) that can be caused by changes in temperature or pH (among other things). adhesion - ANSWER An attraction between different substances. cohesion - ANSWER The force that holds molecules of a single substance together. polarity - ANSWER Molecules having uneven distribution of charges, such as the hydrogen end of a water molecule being positive and the oxygen end negative. amino acid - ANSWER Compounds that contains at least one amino group, one carboxyl group, and a side group, and are the monomers of proteins. monosaccharide - ANSWER A single (simple) sugar molecule such as glucose or fructose, the simplest type of sugar. polysaccharide - ANSWER Carbohydrates that are made up of more than two monosaccharides reactants - ANSWER Molecules that go into a chemical reaction. substrate - ANSWER The reactant that enters the active site, on which an enzyme works. products - ANSWER The substances that are created by a chemical reaction. peptide bond - ANSWER A type of covalent bond between amino acids that link together to form a peptide chain (proteins). high heat capacity - ANSWER the ability to absorb and release large amounts of heat before changing temperature (water does this) solute - ANSWER A substance that is dissolved in a solution. polar solvent - ANSWER Any liquid such as water that can easily dissolve polar solutes. solvent - ANSWER In a solution, the substance in which the solute dissolves. ice floats - ANSWER Extra hydrogen bonds cause frozen water molecules to move farther apart than in a liquid state, causing ice to float. homeostasis - ANSWER The process by which organisms maintain a relatively stable internal environment. In the case of a deficiency in phenylalanine hydroxylase which of the following amino acids will become essential? - ANSWER Tyrosine - ANSWER A deficiency in cystathionine β-synthase (transsulfuration pathway) can decrease synthesis of which of the following amino acids? - ANSWER cysteine Which of the following cofactors or vitamins is required for the conversion of homocysteine to cysteine? - ANSWER Pyridoxal Phosphate (B6) A 2-year-old boy is recently diagnosed with red-green color blindness which is an X-linked recessive disorder. Which of the following represents the correct genotypes of this individual's parents with respect to red-green color blindness? (X - wild type; X' recessive allele; R wild type autosomal allele; r recessive autosomal allele and Y chromosome) - ANSWER Mom X'X and Dad XY You are counseling a family with regards to Maple syrup urine disease (MSUD). The couple you are speaking with lets you know that they know their individual genotypes. The female is Rr while the male is RR. What is the likelihood that their child will be a carrier for MSUD? - ANSWER 50% Which of the following best describes the process during protein translation when the amino acid attached to the tRNA in the P site is transferred to the tRNA in the A site? - ANSWER peptidyl transferase reaction Which of the following is needed to facilitate protein targeting to its appropriate sub-cellular location? - ANSWER peptide signal sequence Which of the following genetic elements is within the transcribed region of a gene? - ANSWER Translational start site If a DNA coding strand sequence reads 5' ATG GGT GGT ATT 3' the corresponding transcribed mRNA will read: - ANSWER 5' AUG GGU GGU AUU 3' During protein translation, (after the initiation complex is formed), the addition of each amino acid to the growing polypeptide chain involves aminoacyl-tRNAs binding to which site on the ribosome? - ANSWER A- site When the Jak-STAT signaling cascade is activated which of the following occurs? - ANSWER phosphorylated-STAT translocates to the nucleus Monocytes are unique cells that secrete the cytokine, interleukin-1. Once released, this cytokine will bind a receptor on the outside of the monocyte and regulate its response. In this situation, Interleukin-1 is best described as which of the following? - ANSWER an autocrine signal Cortisol binds an intracellular receptor that translocates to the nucleus and directly regulates transcription. It does this by binding which of the following regions on DNA? - ANSWER GRE (glucocorticoid response element) When insulin binds its receptor, which of the following proteins will become activated? - ANSWER Protein kinase B hosphatidylinositol 3-Kinase (PI-3Kinase) can phosphorylate PI4,5 bis phosphate in the cell membrane to generate PI-3,4,5-tris phosphate. This compound, PI-3,4,5-tris phosphate can serve as a docking location for proteins with which of the following? - ANSWER Pleckstrin homology domains Allopurinol is an inhibitor of xanthine oxidase. Addition of this compound will result in a decrease in which of the following compounds? - ANSWER uric acid Which of the following enzymes or polymerases is responsible for the addition of the RNA primer to initiate DNA replication? - ANSWER DNA polymerase alpha The ribonucleotide reductase is regulated at both an activity site and a substrate specificity site. Which of the following compounds must always be bound to the activity site for the enzyme to be active? - ANSWER ATP