MICROBIOLOGY 2420 - EXAM II A

MARK THE MOST CORRECT ANSWER

1. Organisms need energy for

1. synthesis of large molecules
2. reproduction
3. production of ADP
4. a and b
5. b and c

2. Which of the following would contain the greatest amount of entropy?

1. a rock
2. a typewriter
3. a bacterium
4. a virus
5. any of the above

3. Energy may not be created or destroyed but may be transformed is a statement of

1. the second law of thermodynamics
2. the first law of thermodynamics
3. the third law of thermodynamics
4. smith’s theorem
5. none of the above

4. Two or more atoms chemically combined define a (an)

1. molecule
2. ion
3. mixture
4. colloid
5. none of the above

5. Lipids are composed of

1. carbon, nitrogen and hydrogen
2. carbon, phosphorous and hydrogen
3. carbon, oxygen and nitrogen
4. carbon, phosphorous and nitrogen
5. none of the above

6. Starch, glycogen and cellulose are examples of

1. lipids
2. nucleic acids
3. carbohydrates
4. proteins
5. none of the above

7. The actual traits or characteristics which a cell exhibits are due directly to the

1. lipids
2. carbohydrates
3. nucleic acids
4. proteins
5. none of the above

8. The alpha carbon of an amino acid has attached (bonded) to it

1. an amino group
2. an acid (carboxyl) group
3. a hydrogen atom
4. an "R" group which can be any of a number of different chemical groups
5. all of the above

9. The reason for the great diversity of proteins is that

1. there are a great number of different kinds of peptide bonds
2. amino acids are all identical
3. there are approximately 21 different amino acids which can be put together in any sequence
4. they are the largest molecules known
5. none of the above

10. Catalysts are important to biological chemistry because

1. they spread up chemical reactions
2. they are not altered by the chemical reactions
3. they permit the reactions of life to occur at temperatures where life can exist
4. they are always proteins
5. none of the above

11. The protein portion of an enzyme is termed the

1. holoenzyme
2. apoenzyme
3. coenzyme
4. retroenzyme
5. none of the above

12. Enzymes function by

1. decreasing the free energy of a reaction
2. lowering the energy of activation
3. increasing the free energy of a reaction
4. increasing the energy of activation
5. none of the above

13. The removal of hydrogen from an organic molecule would be classed as a _______ reaction

1. reduction
2. dehydration synthesis
3. oxidation
4. peptide bond synthesis
5. none of the above

14. A molecule which is oxidized

1. gains energy
2. looses energy
3. may gain or lose energy
4. undergoes no energy transformation
5. none of the above

15. Photosynthesis can best be defined as

1. the conversion of carbon dioxide into glucose
2. carbon dioxide fixation
3. the conversion of radiant energy into chemical energy
4. the generation of oxygen
5. all of the above

16. Bacterial photosynthesis differs from that of eukaryotes and cyanobacteria in that

1. bacterial chlorophyll is different
2. water is never the hydrogen source
3. oxygen is not liberated
4. all of the above
5. none of the above

17. Chemoorganothrophs obtain energy by

1. oxidation of inorganic compounds
2. oxidation of organic compounds
3. photosynthesis
4. a and b
5. b and c

18. DNA is a major significance to living things because

1. it is the largest molecule known
2. it is self replicating
3. it contains all of the genetic information
4. it contains four different nucleotides
5. all of the above

19. RNA differs for DNA in that

1. it is single stranded
2. contains uracil instead of thymine
3. it contains the sugar ribose
4. it is much smaller
5. all of the above

20. What would be the opposite strand for the DNA segment below?

A-T-C-T

1. A-T-C-T
2. T-C-G-C
3. U-G-U-G
4. T-A-G-A
5. None of the above

21. The codon of the triplet code word TTT would be

1. UUU
2. AAA
3. TTT
4. GGG
5. CCC

22. The anti-codon is contained in

1. rRNA
2. mRNA
3. tRNA
4. uDNA
5. aRNA

23. The anticodon of the triplet code word GGG would be

1. GGG
2. UUU
3. CCC
4. AAA
5. TTT

24. The copying of the genetic code from DNA into a RNA strand is known as

1. translation
2. transcription
3. transfusion
4. confusion
5. none of the above

25. The bacterium known as Serratia marcesens normally produces a bright red pigment. Specimens which have been bombarded by X-rays produce colonies which are colorless. Which sequence of events would most likely lead to this condition?

1. normal DNA –normal RNA – defective protein
2. normal DNA – defective RNA –defective protein
3. normal DNA – normal RNA –normal protein
4. defective DNA –defective RNA – defective protein
5. defective DNA- defective RNA –normal protein

26. That segment of the DNA which codes for a protein is termed a (an)

1. polypeptide
2. polynucleotide
3. gene
4. peptide determining section
5. none of the above

27. The transference of bacterial genes via an infecting virus is termed

1. transduction
2. transformation
3. conjugation
4. viral conversion
5. none of the above

28. Viral conversion is a medical significance because

1. viruses always cause diseases in humans
2. viruses inactive soil bacteria
3. conversion leads to pathogenic on the part of the bacteria
4. conversion prevents bacteria from invading the body
5. none of the above

29. The uptake of DNA from the medium by certain bacteria is termed

1. transduction
2. transformation
3. conjugation
4. viral conversion
5. none of the above

30. F+ cells are those

1. which contain the fertility plasmid (episome)
2. which lack the fertility plasmid
3. which cannot conjugate with another cell
4. that have been converted by viruses
5. none of the above

31. A small circular strand of DNA which replicates independently of the bacterial chromosome is termed

1. extrachromosomal genetic material
2. a plasmid
3. a conjugant
4. a gene
5. none of the above

32. Hfr refers to

1. high frequency recombination
2. those cells which have plasmids which have become incorporated into their DNA
3. cells which cannot conjugate
4. a and b
5. a and c

33. A permanent alteration in the nucleotide sequence is termed a (an)

1. accident
2. transformation
3. transduction
4. gene
5. mutation

34. Which of the following are traits which show variation in bacteria

1. colony shape
2. nutritional requirements
3. virulence
4. antigenic characteristics
5. all of the above

35. During the lag phase of population growth in bacteria

1. the numbers are not increasing significantly
2. the organisms are synthesizing molecules necessary for reproduction
3. cells are increasing in size
4. all of the above
5. none of the above

36. During the log phase of population growth

1. cells are dividing slowly
2. cells are dying fast as they reproduce
3. cells are dividing at the maximum rate
4. cells are dying faster than dividing
5. none of the above

37. The reason that hay will last for years without decay is because

1. the pH level is too low
2. the pH level is to high
3. the moisture level is too low
4. the moisture level is too high
5. none of the above

38. A given species of bacteria is known to require 100 different nutrients 99 of these are in optimum quantities but one is limited. You would expect that population growth would be

1. maximum, because the one limited nutrient is insignificant with 99 percent
2. maximum, because the single limited nutrient was probably not important
3. limited, because even one missing essential nutrient will limit growth
4. limited, because any organism which requires a total of 100 nutrients
5. none of the above

39. The major sources of toxic substances which inhibit the growth of microorganisms are

1. metabolic waste products
2. agents utilized by humans to inhibit growth (disinfectants, etc)
3. volcanic eruptions
4. water purification plants
5. a and b only

40. An organism which grew best at 25 degrees C. would be classified as a

1. Psychrophil
2. Necrophil
3. Thermophil
4. Mesophil
5. None of the above

41. Obligate aerobes are those organisms which

1. must have oxygen
2. can use oxygen but do not require it
3. do not use oxygen but are not destroyed by it
4. are destroyed by oxygen
5. none of the above

42. Osmosis may be defined as

1. the movement of water across a selective membrane from an area of low water concentration to an area of high concentration
2. the movement of water from an area of high water concentration to an area of low water concentration
3. the movement of water from an area of low water concentration to an area of high water concentration
4. the movement of water across a selective membrane from an area of high water concentration to an area of low water concentration
5. none of the above

Microbiology 2420 - EXAM 2B

Choose the best answer for each question.

1. A large molecule, made up of repeating subunits, best defines

1. hydrolysis
2. dehydration synthesis
3. dehydration
4. polymer
5. monomer

2. In dehydration synthesis, one of the products is always

1. a macromolecule
2. water
3. a polymer
4. monomer
5. none of the above

3. Dehydration synthesis is significant to living things because

1. it utilizes much of the water
2. it is the method by which virally all of their macromolecules are formed
3. it produces a large quantity of water for their use
4. it requires energy
5. none of the above

4. Hydrogen bonds form between hydrogen and

1. oxygen
2. nitrogen
3. chlorine
4. sulfur
5. more than one is correct

5. Hydrogen bonds are significant because they

1. greatly strengthen macromolecules
2. require a great deal of energy to form
3. give macromolecules their proper 3D shape
4. are essential for polymer formation
5. yield a great deal of energy when broken

6. Carbohydrates are composed of

1. carbon, hydrogen, & oxygen
2. carbon, hydrogen, oxygen & nitrogen
3. carbon, hydrogen, oxygen & sulfur
4. carbon, hydrogen, oxygen, nitrogen, sulfur & phosphorous
5. none of the above

7. Sucrose (table sugar) is an example of a (n)

1. polysaccharids
2. monosaccharide
3. disacchaide
4. anasaccharide
5. neutral fat

8. Carbohydrates function

1. as fuel molecules
2. in energy storage
3. as components of cell walls
4. as components of proteins
5. more than one is correct

9. Fats are composed of

1. glycerol and monosaccharides
2. glycerol and fatty acids
3. fatty acids and monosacchrides
4. fatty acids and disaccarides
5. glycercol and disaccarides

10. Which of the following is not a lipid?

1. fats
2. oils
3. waxes
4. sterols
5. amino acids

11. In addition to carbon, hydrogen, oxygen, and nitrogen, most proteins usually contain

1. phosphorous
2. iodine
3. sulfur
4. chloride
5. none of the above

12. Each of the 20 different amino acids is given its individuality by its

1. alpha amino group
2. alpha carbon
3. alpha carboxyl group
4. alpha hydrogen
5. R group

13. The peptide bond is a dehydration bond that forms between

1. nitrogen and sulfur
2. nitrogen and oxygen
3. carbon and oxygen
4. carbon and nitrogen
5. carbon and sulfur

14. The biological activity of proteins is a function of their

1. primary structure
2. secondary structure
3. tertiary structure
4. quaternary structure
5. C and D are correct

15. The nucleic acids are made up of repeating subunits termed

1. amino acids
2. monosaccharides
3. ATP
4. Nucleotides
5. none of the above

16. Enzymes function as

1. energy sources
2. substrates for dehydration synthesis
3. biological catalysts
4. vitamins
5. cofactors

17. Vitamins often function as

1. enzymes
2. holoenzyems
3. apoenzymes
4. coenzymes
5. more than one is correct

18. Enzymes function by

1. increasing the energy of activation of a reaction
2. increasing the free energy of a reaction
3. reducing the energy of activation of a reaction
4. reducing the free energy of a reaction
5. increasing entropy

19. The shape of the active stie of an enzyme is a function of the

1. kind of coenzyme present
2. tertiary and quaternary structure of the apoenzyme
3. class of enzyme
4. size of the enzyme
5. none of the above

20. Enzyme that catalyst internal rearrangements of molecules are termed

1. isomerase
2. hydrolases
3. ligases
4. lysases
5. transferases

21. Reduction is defined as

1. a loss of electrons
2. a gain of electrons
3. the formation of water
4. the internal change in shape of a macromolecule due to hydrogen
5. a loss of energy

22. Biological oxidation usually involve

1. addition of hydrogen
2. removal of hydrogen
3. removal of oxygen
4. addition of nitrogen
5. removal of nitrogen

23. Which of the following systems contain the least amount of entropy?

1. waterfall
2. rock
3. sweater
4. ball point pen
5. ameba

24. In accordance with the second law of thermodynamics, highly organized structure such as living things are highly unstable and should run down. Living things seem to be in a balance condition until death. This apparent contradiction of the second law is because:

1. living things don’t obey the 2^nd law
2. thermodynamics doesn’t apply to living things
3. the 1^st law takes precedence the 2^nd law
4. living systems are not closed systems

25. The laws of thermodynamics make it essential that living systems

1. keep moving
2. take in energy on a continuos basis
3. lose energy on a continuos basis
4. be energy independent
5. ingest large quantities of water

26. Those reactions that occur with in a cell and which result in the breakdown of complex molecules yielding energy constitute tha branch of metabolic known as

1. anabolism
2. catabolism
3. catastrophe
4. embolism
5. anachronism

27. The carbon is organic compounds is oxidized sequentially releasing energy. This energy is then utilized immediately for

1. protein synthesis
2. DNA replication
3. Cell division
4. ATP synthesis
5. RNA synthesis

28. Anaerobic respiration differs from aerobic respiration in that

1. it is fermentation
2. nitrate replaces oxygen as the final electron (hydrogen) acceptor
3. oxygen is the final electron acceptor
4. CO2 is not an endproduct
5. More than the above is correct

29. Fermentation is significant to human beings in that it

1. Allows microorganisms to generate ATP in the absence of oxygen
2. is not as efficient as is aerobic respiration
3. results in the production of a wide variety of useful
4. can occur in the total absence of oxygen
5. more than one is correct

30. At the end of glycolysis,

1. 2 ATP have been generated
2. pyruvic acid has been formed
3. 4 electrons (hydrogen) have been transferred
4. 2 NAD have been utilized
5. more than one is correct

31. For every glucose molecule, how many CO2 molecule are formed during the Kreb’s cycle?

1. 1
2. 2
3. 4
4. 6
5. none of the above

32. The 1^st hydrogen acceptor of the electron transport system is

1. FAD
2. NAD
3. Oxygen
4. Nitrate
5. Cytochochromes

33. The greatest amount of ATP is produced during

1. glycolysis
2. the conversation of pyruvic acid is not acetly CoA
3. the krebs cycle
4. the ETS
5. DNA replication

34. The starting point for most fermentation is

1. Pyruvic acid
2. FAD
3. Acetyl CoA
4. NAD
5. Cirtic acid

35. During the oxidation of fats, fatty acids are broken down into

1. pyruivic acid
2. acetyl CoA
3. glycerol
4. glucose
5. glutamic acid

36. Before proteins can be oxidized, the amino acids must first be

1. energized
2. deaminated
3. decarboxylated
4. dehydrogenated
5. deemphsizes

37. The conversion of CO2 into organic compounds is termed

1. cellular respiration
2. fermentation
3. CO2 fixation
4. CO2 disintegration
5. Deamination

38. Certain bacteria can oxidize inorganic compounds, releasing their energy, and converting it into ATP. This ATP is then utilized for

1. cellular respiration
2. fermentation
3. glycolysis
4. krebs’ cycle
5. none of the above

39. Eucaryotic-cyanobacterial photosynthesis differs form bacterial in that

1. the chorolphils are different
2. bacterial does not produce oxygen as a byproduct
3. the source of hydrogen for CO2 fixation is different
4. eucaryotic-cyanobacterial photosynthesis is more common]
5. more than one of the above is correct

40. An organism which derives its energy of the oxidation of inorganic compounds would be treated a (n)

1. chemorganotrophen
2. ingestor
3. saprophte
4. chemolithotroph
5. phototroph

41. The two strands of the DNA molecules are said to be antiparallel. This means that the strand

1. run in the same direction
2. veer away from each other forming a V shaped arrangement
3. run in the opposite direction
4. form loops around each other
5. are in a double helix

42. A segment of a DNA strand has the following sequence of nucleotides

The complementary strand would be:

1. T – A - A - G – C
2. T - C – C – A – G
3. A – T – T – G – C
4. T – A – A – C – G
5. NONE FO THE ABOVE

43. RNA differs for DNA in that is:

1. is single stranded
2. contains uracil in place of thymine
3. contains the sugar ribose
4. is much smaller than DNA]
5. more than one is correct

44. Which of the following is a genetic code word?

1. CCCC
2. CCCA
3. CC
4. CAC
5. More than one of the above is correct

45. The information contained in the DNA molecule gets to the ribose via

1. rRNA
2. mRNA
3. tRNA
4. hormones
5. gRNA

46. The anticodon is contained in

1. DNA
2. mRNA
3. rRNA
4. tRNA
5. gRNA

47. The triplet code word in the DNA molecule is ATA. The codon for this word would be

1. TAT
2. ATA
3. UAU
4. AUA
5. CAC

48. The triplet code word in the DNA molecule is AAA. The anticodon would be

1. TTT
2. UUU
3. AAA
4. CCC
5. GGG

49. For each peptide bond formed, ______ ATP are required.

1. 1
2. 2
3. 3
4. 4
5. 5

50. The correct sequence for information flow for trait expression would be

1. DNA – tRNA – mRNA – enzyme – reaction – trait.
2. reaction – DNA – mRNA – enzyme – trait.
3. mRNA – DNA – enzyme – reaction – trait.
4. DNA – RNA – enzyme – reaction – trait.
5. RNA – DNA – trait – enzyme – reaction.

51. Which of the following is not a genetically controlled trait in microorganism?

1. shape
2. size
3. virulence
4. colony shape & color
5. all of the above are genetically controlled

52. The movement of bacterial DNA form one cell to another by means of viral vector best defines

1. transduction
2. transformation
3. viral conversion
4. conjugation
5. meiosis

53. A small, circular, extrachromosomal strand of DNA best describes a (n)

1. nucleus
2. operon
3. enzyme
4. conjugate
5. none of the above

54. Hfr cells result from

1. transformation
2. viral conversion
3. conjugation
4. transduction
5. genetic engineering

55. In the operon, the operator is:

1. a series of nucleotides which serves as a switch to turn the structural genes on
2. a gene located a short distance from the operon that produces a repressor substance
3. a substance which turns the system on
4. the attachment point for RNA polymerase
5. none of the above

56. Repressible operons

1. are turned on by inducing substances
2. remain off most of the time
3. remain on until specifically turned off
4. lack promotors
5. lack structural genes

57. In genetic engineering, the plasmid is opened up by

1. donor DNA
2. ligases
3. endonucleases
4. isomerase
5. tranferases

58. IN a typical population growth curve, the phase that is entered into immediately following inoculation into fresh medium is the

1. log phase
2. stationary phase
3. death phase
4. lad phase
5. growth phase

59. All microorganisms require

1. organic substance
2. vitamins
3. moisture
4. low acidity
5. more than one of the above is correct

60. If a particular species requires 100 nutrients for growth, the nutrient which will limit the growth fo the population will be the one which

1. is required in the greatest amount
2. is not soluble in H2O
3. requires more than one enzyme for processing
4. is in shortest supply

61. A major source of toxic substances for microorganisms is

1. end products of metabolism
2. pollutants
3. substances deliberately introduced by humans
4. other microorganisms
5. more than one is correct

62. An organism which grows best at 4 degrees C. would be termed a (n)

1. mesophil
2. theromphil
3. acidophil
4. psychrophil
5. neutrophil

63. An organism which grows best with small quantities of oxygen would be classed as a (an)

1. obligate aerobe
2. facultative aerobe
3. obligate anaerobe
4. microaerophil
5. psychrophil

64. Improperly canned food is potentially dangerous because

1. it contains oxygen which supports many bacteria
2. it is anaerobic and therefore makes a good growth medium for toxin producing anaerobes
3. viruses may grow in it
4. rickettsias may grow in it
5. more than one of the above is correct

65. Two solutions are separated by a selectively permeable membrane. Solution A contains 10% sugar and solution B contains 12% sugar. Water will move in which direction

1. from solution B to A
2. from solution A to B
3. in neither direction because the concentration difference is so small
4. in neither direction due to the small concentration difference
5. none of the above

66. A solution which is hypotonic to a cell would contain

1. less water than the cell
2. more water than the cell
3. an equal amount of water as the cell
4. the same types of dissolved substances as the cell
5. more than one of the above is correct

67. A Gram positive bacterium is placed into a hypotonic solution. You would expect that it would

1. swell and burst
2. shrink or shrivel
3. excrete water
4. remain unchanged
5. initially it would swell, but following rupture it would shrink

68. Which of the following pH values would be the most acid?

1. 14
2. 13
3. 12.
4. 11
5. 10

69. The reason that organisms are pH sensitive is

1. hydrogen is an essential element
2. biological oxidation require removal of hydrogen
3. enzyme activity is pH sensitive
4. pH effects the osmotic pressure
5. none of the above

70. Which of the following radiation would be lethal to microorganisms

1. UV
2. X-ray
3. Gamma rays
4. Neutrons
5. More than one of the above is correct

71. Which of the following are part of the peptidoglycan molecule?

1. NAM
2. NAG
3. Amino acids
4. Fructose-6-phosphate
5. More than one of the above is correct

72. Allosteric changes are a major means of regulating enzyme activity by

1. inducible operons
2. repressible operons
3. feedback inhibition
4. environmental fine tuning
5. none of the above

73. A compound that decreased enzyme activity by tying up the activity site would be classified as a (n)

1. competitive inhibitor
2. noncompetitive inhibitor
3. allosteric effector
4. inducible operon
5. repressor substance