KEY. BI 212 Summer Exam I. July 27 th 2015

Transcription

1 KEY BI 212 Summer 2015 Exam I July 27 th 2015 On your scantron, please fill in: 1. Your name (First and Last) 2. Exam I 3. Date 4. Lab section: MW at 1 section 010; MW at 4 section 011; TR at 1 section 012

2 (50 questions, 2 pts each. Total 100 points.) Choose the one alternative that best completes the statement, answers the question, or matches the term/phrase/image. Make sure to fill in the corresponding choice on your scantron sheet. 1. Which phrase describes an ionic bond? A. two atoms sharing electrons equally B. two atoms sharing electrons unequally C. two opposite charged atoms attracted D. two atoms with partial charges attracted E. two atoms with moving electrons attracted 2. Why does oxygen have higher electronegativity than hydrogen? A. Because oxygen has more electrons B. Because oxygen is more prevalent C. Because oxygen makes more bonds D. Because oxygen has more protons E. Because oxygen has more neutrons 3. Which molecules are isomers? A. same atoms, different neutrons B. same protons, different neutrons C. same protons, different electrons D. same bonds, different atoms E. same atoms, different shape 4. Why might a polar covalent bond occur? A. one atom has taken an electron from another B. one atom has more attraction for electrons than another C. one atom has donated an electron to another D. two atoms have partial positive and negative charges E. two atoms have equal attraction for electrons 5. Which is TRUE about biological molecules? A. Proteins are built from amino acids B. Fatty acids are built from lipids C. Nucleic acids are built from amino acids D. Carbohydrates are built from nucleotides E. Lipids are built from nucleotides 6. Assuming they all have the same number of carbon atoms, which of the following has the most C-H bonds? A. an unsaturated fat B. a trans fat C. a polysaccharide D. a saturated fat E. a phospholipid

3 7. Which functional group is found in fats? A. phosphate B. methyl C. amino D. sulfhydryl E. none of these 8. Animals store glucose in the form of what molecule? A. amylose B. glycogen C. glycerol D. guanine E. cellulose 9. In the formation of a macromolecule, what type of bond would join two amino acid subunits? A. ionic bond B. phosphodiester bond C. hydrogen bond D. peptide bond E. disulfide bond 10. In the formation of a macromolecule, what type of reaction would join two subunits together? A. hydrophobic reaction B. hydrolysis reaction C. dehydration reaction D. denaturation reaction E. hydrophilic reaction 11. The globular shape of a protein is defined by what level of structure? A. primary structure B. secondary structure C. tertiary structure D. quaternary structure E. polypeptide structure 12. What happens during a hydrolysis reaction? A. protein coils into its secondary structure B. the bond between two subunits of a macromolecule is broken C. saturated fats become unsaturated D. a bond is formed between two subunits of a macromolecule E. water breaks ionic bonds 13. What type of macromolecule carries out catalysis in biological systems? A. proteins called enzymes B. carbohydrates called starches C. lipids called steroids D. nucleic acids called DNA E. carbohydrates called sugars

4 14. In nucleic acids, which two are the purine nitrogenous bases? A. uracil and thymine B. cytosine and guanine C. thymine and cytosine D. adenine and guanine E. guanine and thymine 15. Which is a difference between prokaryotic and eukaryotic cells? A. eukaryotes lack a nucleus B. eukaryotes lack a cell wall C. prokaryotes lack ribosomes D. eukaryotes lack a cell membrane E. prokaryotes lack mitochondria 16. Microtubules and microfilaments function to: A. make proteins and regulate their transport B. store and express genetic information C. capture and transform energy D. digest food particles or old cell parts E. provide motility and orchestrate cell division 17. The term "nuclear envelope" is more correct than the term "nuclear membrane" because A. the enclosure has pores which membranes do not B. the enclosure is made up of two membranes C. the chemical composition is inconsistent with cellular membranes D. the only real membrane in the cell is the plasma membrane E. None of the above. The two terms are perfect synonyms. 18. Which of the following is true about proteins synthesized by the rough ER? A. they are used for internal storage B. they are used to build more membranes in the cell C. they are used to digest food in lysosomes D. they are for internal regulation E. they are exported from the cell 19. Plants differ from animals in that plants have which of the following? A. an endoplasmic reticulum B. a central vacuole C. Golgi complexes D. vesicles E. organelles 20. In bacteria, some of the functions of eukaryotic cells are performed by which part? A. the plasma membrane B. lysosomes C. mitochondria D. nucleoli E. vesicles

5 21. What is the term for clusters of rrna where ribosomes are assembled? A. nuclei B. cisternae C. nucleoli D. Golgi apparatus E. centrioles 22. The smooth ER is especially abundant in cells that synthesize extensive amounts of A. toxins B. proteins C. enzymes D. lipids E. nucleic acids 23. In a tissue that needs to withstand high tension, which junctions would be used? A. tight junctions B. plasmodesmata C. desmosomes D. gap junctions E. chiasmata 24. Where are ribosomes found? A. only in the nucleus B. in the cytoplasm C. attached to the smooth endoplasmic reticulum D. only in eukaryotic cells E. in the cytoplasm and attached to the smooth e.r. 25. Which of the following involves the Golgi apparatus? A. transporting proteins that are to be released from the cell B. packaging proteins into vesicles C. altering or modifying proteins D. producing lysosomes E. all of the above 26.To cross the cell membrane, water must do which of the following? A. squeeze between phospholipid molecules B. pass through aquaporins C. be transported at the expense of ATP D. be moved by a cotransport system E. move through plasmodesmata 27. Which statement applies to integral transmembrane proteins? A. They are usually fixed in position B. They are always abundant C. They are often not fixed in position D. They are not abundant E. They are never degraded

6 28. Equilibrium is reached in an aqueous solution when what happens? A. random motion stops B. water molecules and dissolved molecules are moving at the same rate C. the dissolved molecules or ions are equally distributed throughout the solution D. molecular motion stops E. there are the same number of water molecules as dissolved molecules 29. A contractile vacuole is an organelle that pumps excess water out of many freshwater protozoan cells. A freshwater protozoan was placed in solution A and observed to pump contractile vacuoles 11 times per minute. The same protozoan was then placed in solution B and observed to pump contractile vacuoles 4 times per minute. Based on this information, which of the following statements is correct? A. Solution A is more hypotonic than solution B. B. Solutions A and B are both isotonic to the cell. C. Solution B is more hypotonic than solution A. D. Solutions A and B are the same concentration. E. More than one answer is true. 30. In cotransport processes, sugars can be brought into the cell against their concentrations gradients for what reason? A. there is an ATP-powered pump that pumps the sugars in B. sugars follow H+ ions traveling down their own concentration gradient C. the sugars are moved in by facilitated diffusion D. special channels are used that do not require energy E. sugars enters the cell by all of the processes listed above 31. Hydrophobic interiors of membrane bilayers: A. primarily contain fatty acids B. primarily contain glycerol C. primarily contain choline D. primarily contain phosphate E. primarily contain protein 32. Increasing the number of hydrogen atoms in the fatty acid chains of phospholipids would: A. decrease saturation B. allow tighter packing of phospholipids C. increase membrane fluidity D. decrease membrane permeability E. make the membrane more hydrophilic 33. The cell must input energy to carry out: A. facilitated diffusion B. osmosis C. simple diffusion D. cotransport E. all transport across membranes

7 34. How does water cross cell membranes? A. by active transport B. by simple diffusion C. via facilitated diffusion D. via plasmodesmata E. by evaporation 35.The fluid mosaic model of membrane structure suggests membrane proteins are mostly A. made of carbohydrates B. free to move within the bilayer C. outside the cell D. hydrophilic E. tethered to the cytoskeleton 36. Plasma membranes are freely permeable to all of the following, except: A. carbon dioxide B. steroids C. salt D. cholesterol E. oxygen 37. What molecule groups are parts of a phospholipid? A. fatty acids and proteins B. glycerol and fatty acids C. starches and phosphates D. proteins, glycerol and phosphates E. choline and cellulose 38. In which situation might a cell benefit by high phospholipid saturation? A. low temperatures B. in wet conditions C. when increased fluidity is desired D. high temperatures E. when increased permeability is desired 39. The energy required to destabilize existing chemical bonds is called ( ) energy. A. potential B. destabilization C. kinetic D. free E. activation 40. In an endergonic reaction, which is true? A. the reactants contain less free energy than the products B. the reactants contain more free energy than the products C. no activation energy is required D. catalysis cannot occur E. substrates outnumber enzymes

8 41. Why do large changes in the temperature or ph of a system alter enzyme activity? A. they change the three-dimensional shape of the enzyme B. they disrupt hydrogen and ionic bonds in the enzyme C. they disrupt hydrophobic/van der Waals interactions in the enzyme D. they change what substrates the enzyme can act upon E. more than one answer is correct 42. Why do cells hydrolyze ATP? A. To release energy used to power other reactions B. ATP is unstable and heats up the cell C. The cellular supply of ATP must be used up before the cell can make more D. Hydrolyzing ATP is the driving force for making inorganic phosphates E. The phosphates are removed to make water molecules 43. The laws of thermodynamics state that: A. Energy is used up in chemical reactions B. Energy can only be created during exergonic reactions C. Energy only becomes disorganized by endergonic reactions D. Energy progressively becomes more organized by chemical reactions E. Energy transfers are not completely efficient 44. Which describes ATP: A. phosphates are bonded to the base B. contains two phosphates C. contains two sugars D. contains the base adrenaline E. contains ribose sugar 45. Which type of enzyme inhibition blocks the allosteric site? A. non-competitive B. active C. passive D. competitive E. pharmaceutical 46. Consider the hypothetical biochemical pathway H I J K L to make compound L which the cell needs for growth. Which step should be inhibited if there is an excess of compound L? A. H I B. I J C. I H D. J K E. K L

9 For questions 47-49, refer to the graph below: C. A. D. B. 47. Which letter represents a graph region that would be altered by an enzyme? C 48. Which letter shows net change in free energy? D 49. Is this reaction: A. Exergonic B. Endergonic 50. Catabolism is to anabolism as ( ) is to ( ). A. exergonic; spontaneous B. exergonic; endergonic C. free energy; entropy D. work; energy E. glycolysis; fermentation