Cell & Molecular Biology Karp Chapters 1-4 Exam Questions With 100% Verified Solutions

Cell & Molecular Biology Karp Chapters 1-4 Exam Questions With 100% Verified Solutions A molecule that is capable of releasing or donating a hydroxyl ion is termed a _____________. - ANSWER- acid Ionic bonds: a)are attractions between fully charged anions. b) are of limited importance in living cells because of the prevalence of water. c) are always weak.. d) All of these statements are true. - ANSWER- All of these statements are true. Which of the following statements about hydrogen bonds is true? a)They can occur between most polar molecules. b) They are weak attractive interactions. c) They can be found between the two strands of a DNA molecule. d) All of these statements are correct - ANSWER- All of these statements are correct Which of the following is a NOT a property of water? a)It is an essential nutrient. b) It is a highly asymmetric molecule. c) It is composed of two polar covalent bonds. d) All three atoms in a water molecule can form hydrogen bonds. - ANSWER- It is an essential nutrient Observe the following reaction: HCǑ- + H+ ó H2CǑ Bicarbonate Hydrogen Carbonic ion ion acid The reaction shown above is carried out in the blood to maintain: a)low pH. b) normal pH. c) high pH. d) excess of H+ ions. - ANSWER- normal pH Name the properties of water that facilitate life: - ANSWER- 1. Cohesion/adhesion 2. ability to moderate temperature 3. expansion upon freezing 4. versatile solvent (polarity) Protein, Nucleic acid, Lipid or Carbohydrate: Chitin... Hemoglobin... RNA... Collagen... Glucose... Cholesterol... - ANSWER- Chitin... Carbohydrate Hemoglobin... Protein RNA... Nucleic acid Collagen... Protein Glucose...Carbohydrate Cholesterol... Lipid What are the levels of protein structure and what type of chemical bonds are involved in each? - ANSWER- Primary- peptide bonds Secondary - hydrogen bonds Tertiary- hydrogen bonds, ionic bonds, covalent bonds forming disulfide bridges Van der Waals Interactions and hydrophobic interactions Quaternary- hydrogen bonding, disulfide bridges and salt bridges In addition to functioning as stores of chemical energy, carbohydrates: a) are important in cellular metabolism. b) can serve as strong building materials for biological construction. c) can be highly water soluble. d) can have a large number of stereoisomers. - ANSWER- can serve as strong building materials for biological construction. Which of the following carbohydrates are NOT polysaccharides? a) glucose b) glycogen c) starch d) cellulose - ANSWER- glucose The two ends of a fatty acid molecule have different properties; the hydrocarbon chain is hydrophobic, whereas the carboxyl group is hydrophilic. Molecules having both properties are called: a) amphipathic b) saturated c) unsaturated d) polyunsaturated - ANSWER- amphipathic Some of the functions of proteins include: a) regulation. b) antibodies. c) growth factors. d) All of these. - ANSWER- All of these. Amino acids: a)can form peptide bonds. b) are composed of a central carbon surrounded by an amino group, a carboxyl group, a hydrogen atom and a variable side chain. c) can have side chains that are polar, nonpolar, or with unique properties. d) All of these statements are true. - ANSWER- All of these statements are true. Which of the following structures of proteins is composed of two or more polypeptide chains? a) Primary b) Secondary c) Tertiary d) Quaternary - ANSWER- Quaternary All of the following are parts of a nucleotide EXCEPT: a) a five-carbon sugar. b) a six-carbon sugar. c) a phosphate group. d) a nitrogenous base. - ANSWER- a six-carbon sugar. Which of the following is NOT found in DNA? a) adenine b) uracil c) cytosine d) thymine - ANSWER- uracil Compare the structures of starch and Cellulose. What keeps us from digesting cellulose? - ANSWER- In starch all the glucose repeat units are orientated in the same direction. In cellulose each successive glucose is rotated 180 degrees. Starch contains alpha linkage, cellulose has beta linkage. cellulose is stronger forming fibers and does not dissolve in water. We do not have enzymes to break down cellulose. Compare the covalent bonds found in saturated vs. unsaturated fatty acids. - ANSWER- saturated- single covalent bonds