7A & 8

Front 1

Ultraviolet light (UV) causes irreversible breaks in DNA strands.

Back 1

False

Front 2

Which of the following is an example of microbial control?

-Sue washes off the vegetables before serving them in a meal.

-Mary microwaves food before putting it on the table.

-Sue uses bleach to clean the kitchen counters.

-Mary places leftovers in the refrigerator after the meal.

Back 2

-Sue washes off the vegetables before serving them in a meal.

-Sue uses bleach to clean the kitchen counters.

-Mary places leftovers in the refrigerator after the meal.

Front 3

What was the MOST likely source of the family’s botulism food poisoning?

Back 3

The family consumed botulism toxin in the canned green beans.

Front 4

Botulism food poisoning is a preventable illness if special precautions are taken during food preparation. In this case, what could Sue have done to prevent the outbreak of botulism?

Back 4

-Sue noticed that the pressure cooker was malfunctioning during the canning process. She should have fixed the instrument, borrowed a properly working one, or purchased a new pressure cooker.

-Sue could have boiled the food for at least 10 minutes before serving it to her family members.

Front 5

Which of the following best explains why the pressure cooker is so important in the canning process?

Back 5

A pressure cooker utilizes steam to create a higher-pressure environment that allows the food to cook at higher temperatures than normal. The higher temperatures kill most contaminating microbes and endospores and therefore effectively sterilize the food.

Front 6

Use of moist heat can control microbial growth in many circumstances, but heat-sensitive items and those susceptible to moisture cannot be sterilized in this manner. Which of the following correctly describes a method of physical control used to control microbial growth on or in such items?

Back 6

Filtration is the passage of a liquid or a gas through a screenlike material with pores small enough to retain microorganisms. A vacuum is typically used to force the liquid through the mesh, and then the sterile liquid or gas is collected in a sterile container on the other side.

Nonionizing radiation, such as UV light, has a wavelength longer than that of ionizing radiation. The wavelengths of UV light are absorbed by cellular DNA in organisms directly exposed to the light.

Front 7

Sodium nitrate and sodium nitrite are added to many meat products, such as ham, bacon, hot dogs, and sausage. These additives help to prevent the growth of Clostridium botulinum by inhibiting certain iron-containing enzymes of the organism. This is an example of chemical food preservation. Which of the following correctly describes a method of chemical control used to control microbial growth?

Back 7

Surface-active agents, or surfactants, decrease surface tension among molecules of a liquid.

Phenolics exert antimicrobial activity by injuring lipid-containing plasma membranes, which causes the cellular components to leak out of the cell.

Alcohols exert their action by denaturing proteins and dissolving lipids.

Front 8

Autoclaving is the most effective method of moist heat sterilization.

Back 8

True

Front 9

The thermal death time is the time needed to kill all the bacteria in a particular culture at a certain temperature.

Back 9

True

Front 10

Which concentration of ethanol is the most effective bactericide?

Back 10

70%

Front 11

An agent used to reduce the number of bacteria on a toilet would most accurately be called a(n)

Back 11

disinfectant.

Front 12

The pH of the medium has no effect on the activity of the disinfectant being applied.

Back 12

False

Front 13

Desiccation is a reliable form of sterilization.

Back 13

False

Front 14

The preservation of beef jerky from microbial growth relies on which method of microbial control?

Back 14

desiccation

Front 15

If you were preparing nutrient agar at home and did not have an autoclave, what could you use to sterilize the nutrient agar?

Back 15

pressure cooker at 121°C for 15 minutes

Front 16

Which of the following is a limitation of the autoclave?

Back 16

It cannot be used with heat-labile materials.

Front 17

Which of the following substances is used for surgical hand scrubs?

Back 17

chlorhexidine

Front 18

All of the following are methods of food preservation EXCEPT

Back 18

microwaves.

Front 19

All of the following factors contribute to hospital-acquired infections EXCEPT

Back 19

All of these factors may contribute to hospital-acquired infection.

Front 20

Which of the following does NOT achieve sterilization?

Back 20

pasteurization

Front 21

Which of the following treatments is the most effective for controlling microbial growth?

Back 21

They are equivalent treatments.

Front 22

Which of the following disinfectants acts by disrupting the plasma membrane?

Back 22

bisphenols

Front 23

Disinfection of water is achieved by all of the following EXCEPT

Back 23

peracetic acid.

Front 24

All of the following are effective for destroying prions EXCEPT

Back 24

boiling.

Front 25

What characteristic of DNA allows two connected DNA polymerases to synthesize both the leading and lagging strands?

Back 25

DNA is flexible.

Front 26

What is the function of the connector proteins?

Back 26

They link the leading strand DNA polymerase and the lagging strand DNA polymerase together.

Front 27

Which DNA strand is synthesized continuously?

Back 27

Leading strand

Front 28

Which of the following are terms associated with Okazaki fragments?

Back 28

Lagging strand, DNA ligase, and discontinuous

Front 29

Why is the DNA synthesis of the lagging strand considered discontinuous?

Back 29

The synthesis is moving in the opposite direction from the replication fork.

Front 30

Transcription produces which of the following?

Back 30

mRNA, tRNA, and rRNA are all produced by transcription.

Front 31

According to the animation, which of the following makes mRNA from the information stored in a DNA template?

Back 31

RNA polymerase

Front 32

Ribosomes contain which of the following?

Back 32

rRNA

Front 33

Which of the following is involved in bringing amino acids to the ribosomes?

Back 33

tRNA

Front 34

Which of the following can be translated into protein?

Back 34

mRNA

Front 35

During the initiation step of translation, the fMet charged tRNA assembles in which site of the ribosome?

Back 35

P site

Front 36

How does the ribosome know if the entering charged tRNA is correct?

Back 36

The anticodon on the tRNA base pairs to the codon on the mRNA.

Front 37

Where would one find an uncharged tRNA molecule in a ribosome?

Back 37

In the P and E sites

Front 38

What kind of bond is formed when two amino acids join together?

Back 38

A peptide bond

Front 39

How is translation terminated?

Back 39

When a protein called a release factor enters and binds to the A site

Front 40

What are the products of semiconservative replication for a double-stranded DNA molecule?

Back 40

Two double-stranded DNA molecules, each consisting of one parental strand and one daughter strand.

Front 41

Why is DNA replication essential for a cell?

Back 41

An organism must copy its DNA to pass genetic information to its offspring.

Front 42

What is the function of the parental DNA in replication?

Back 42

It serves as the template for DNA replication.

Front 43

As shown in the animation, the start codon also codes for which amino acid?

Back 43

Methionine

Front 44

How many codons code for the amino acid arginine?

Back 44

Six

Front 45

GAU codes for

Back 45

aspartic acid.

Front 46

Which of the following amino acids is coded by only one codon?

Back 46

Trp

Front 47

What would happen if the mRNA codon that coded for Cys was mutated in the third position from a U to an A?

Back 47

A stop codon would be introduced prematurely.

Front 48

What is the initial target of RNA polymerase?

Back 48

The promoter

Front 49

RNA polymerase is guided by the

Back 49

template strand of DNA.

Front 50

RNA that has hydrogen bonded to itself forms a

Back 50

stem loop.

Front 51

How would one increase the concentration of a particular polypeptide in a cell?

Back 51

Increase the level of transcription

Front 52

During elongation, how is the RNA synthesized?

Back 52

5’ to 3’

Front 53

Which enzyme breaks the hydrogen bonds during replication?

Back 53

DNA helicase

Front 54

How do stabilizing proteins work on the DNA?

Back 54

They bind to the single-stranded DNA.

Front 55

In which direction does the replication fork move?

Back 55

It moves ahead of the newly synthesized DNA.

Front 56

What ensures that the single strands of DNA do not come back together?

Back 56

Stabilizing proteins

Front 57

What results from the process of translation?

Back 57

A polypeptide

Front 58

How is bacterial translation different from eukaryotic translation?

Back 58

Bacteria can begin translation before transcription has terminated.

Front 59

According to the animation, ribosomes move along the mRNA in which direction?

Back 59

5’ to 3’

Front 60

Which of the following genetic elements is transcribed into a single mRNA?

Back 60

The structural genes

Front 61

Which operons are always transcribed unless deactivated?

Back 61

Repressible operons

Front 62

Which operons are never transcribed unless activated?

Back 62

Inducible operons

Front 63

According to the animation, where on the DNA strand does a repressor bind?

Back 63

The operator

Front 64

What is considered to be the average natural mutation rate that occurs during DNA replication?

Back 64

One in every billion nucleotides replicated.

Front 65

A mutation that affects the genotype of the organism but not the phenotype is called a

Back 65

silent mutation.

Front 66

A base insertion or deletion in the translated region of the gene may lead to

Back 66

frameshift mutation.

Front 67

A base substitution that changes a codon coding for an amino acid to a stop codon is called a

Back 67

nonsense mutation.

Front 68

How frequently do silent mutations occur?

Back 68

One out of every three mutations

Front 69

In the figure, if base 4 is thymine, what is base 4'?

Back 69

adenine

Front 70

Genetic change in bacteria can be brought about by

Back 70

All of the answers are correct.

Front 71

Which of the following build(s) new strands of DNA?

Back 71

DNA polymerases

Front 72

Which statement about DNA replication is CORRECT?

Back 72

The leading strand is built continuously, and the lagging strand is built in pieces.

Front 73

During DNA replication, which nucleotide will bind to an A nucleotide in the parental DNA?

Back 73

T

Front 74

The molecule that seals the gaps between the pieces of DNA in the lagging strand is

Back 74

DNA ligase.

Front 75

Which statement about DNA replication is FALSE?

Back 75

DNA ligase adds nucleotides to the lagging strand.

Front 76

The damage caused by ultraviolet radiation is

Back 76

cut out and replaced.