Practice Quizzes Lectures 5-8 Flashcards
1
Q
The building of complex organic molecules from simpler ones is called:
A
anabolism.
2
Q
Inhibitors that fill the enzyme’s active site and compete with the normal substrate are:
A
competitive.
3
Q
Enzymes increase the speed of a chemical reaction by:
A
lowering the energy of activation
4
Q
Many apoenzymes are inactive by themselves and must be activated by:
A
cofactors and/or coenzymes.
5
Q
The addition of phosphate to a chemical compound is called
A
phosphorylation.
6
Q
A molecule that undergoes reduction:
A
gains one or more electrons
7
Q
What process does the aerobic electron transport chain perform?
A
oxidative phosphorylation
8
Q
The energy from catabolic reactions is used to produce:
A
ATP
9
Q
What are the overall (net) products of glycolysis?
A
2 pyruvic acid, 2 ATP, 2 NADH
10
Q
In prokaryotes, how many ATP molecules are produced from the breakdown of one glucose via aerobic respiration?
A
38
11
Q
In anaerobic respiration, the final electron acceptor is:
A
an inorganic molecule other than oxygen.
12
Q
In fermentation,
A
the final electron acceptor is organic.
13
Q
The process whereby cells completely break down glucose to CO2 and water for energy is:
A
cellular respiration
14
Q
The final acceptor molecule in the electron transport system is:
A
oxygen
15
Q
Which of the following processes produces 2 ATP, 6 NADH, and 2 FADH2 after 2 turns?
A
citric acid (Krebs) cycle
16
Q
The anaerobic process where oxygen is not available to cells and lactic acid is formed is:
A
fermentation
17
Q
Most of the ATP in aerobic respiration is produced directly from membrane hydrogen gradients created by:
A
the electron transport chain
18
Q
Which of these reactions ends with pyruvic acid?
A
glycolysis
19
Q
In yeast fermentation:
A
alcohol and carbon dioxide are given off
20
Q
After two complete turns of the citric acid (Krebs) cycle, the results are:
A
4 molecules of CO2 and 2 ATP molecules
21
Q
In a eukaryotic cell, the electron transport chain functions within the:
A
mitochondrion
22
Q
A redox reaction can easily be explained as:
A
transferring electrons between reactants
23
Q
Enzymes:
These are all correct.
speed up metabolic reactions
give energy to metabolic reactions
act as a buffer in metabolic reactions
destroy foreign bodies
A
speed up metabolic reactions
24
Q
The substance that an enzyme works upon is called a:
A
substrate
25
An enzyme's specificity for a particular substrate is due to:
the shapes of the substrate and active site
26
Enzymes belong to which group of organic molecules?
proteins
27
In the below image, which letter represents the product
of the reaction?
A reactions going in, B is doing something in the cell, C is something is going out
C
28
The site on an enzyme surface where a reactant (substrate) fits is called the:
active site
29
Which of the following is most likely to denature an enzyme?
Extreme change in pH
30
The type of enzyme inhibition shown in the below image is best described as:
Picture shows an inhibitor that that made an active site distorted so a substrate cannot bind to it
noncompetitive
31
What is the most common electron carrier in biological systems?
NAD
32
The NADH molecules formed during the Krebs cycle are ________.
oxidized when electrons are passed to the electron transport chain
33
When Streptococcus ferments glucose,
lactic acid is produced
34
The metabolic byproducts of yeast fermentation are:
CO2 and ethanol
35
The optimum pH for MOST bacteria is near:
7
36
A psychrophile has an optimal growth temperature of about:
15˚ C.
37
Organisms that require high salt concentrations for growth are called:
obligate halophiles.
38
Addition of salts preserves foods because they:
increase osmotic pressure.
39
An organism that uses oxygen when present but can grow without oxygen is called a(n):
facultative anaerobe.
40
Which organism is killed by atmospheric oxygen?
obligate anaerobe
41
Toxic hydrogen peroxide in some bacteria can be broken down into water and oxygen by the enzyme:
Catalase
42
Generation time can best be defined as:
the time it takes for a cell to divide.
43
Bacterial growth is usually graphed using ______ scales.
logarithmic (semi-logarithmic)
44
In which growth phase is there intense activity preparing for population growth, but no increase in population?
lag phase
45
Which of the following is NOT a possible reason why exponential growth stops?
bacteria becoming dormant
46
In the stationary phase,
the number of microbial deaths is equal to the number of new cells formed.
47
Which type of medium suppresses the growth of unwanted bacteria and encourages growth of desired microbes?
selective media
48
Microbes that are introduced into a culture medium to initiate growth are called a(n):
inoculum.
49
What is added to a medium when it is desirable to grow bacteria on a solid medium?
agar
50
A culture medium made of extracts from yeasts, meat, or plants is a _______ medium.
Complex
51
A spectrophotometer can be used to measure:
turbidity.
52
The method in which a measured volume of bacterial suspension is placed within a defined area on a microscope slide is called the:
direct microscope count
53
Which process is used to ensure that plates contain 30 to 300 colonies when counted?
serial dilution
54
Starting with one bacterial cell, how many cells would you have after 10 generations?
1024
55
Your lab instructor hands you a culture and tells you that there are two different types of bacteria growing in it: Pseudomonas and Staphylococcus. If you wanted to grow just Staphylococcus colonies, you would need to use a(n):
selective medium
56
Your friend complains to you that her soup tastes spoiled, even though she refrigerated it right after she made it last week. The most likely culprits are:
psychrotrophs.
57
Two different cultures of the same bacteria were grown at the same temperature, but one was placed in a regular incubator while the other was grown in an anaerobic jar. After incubation, the culture in the anaerobic jar showed moderate growth while that in the incubator showed heavy growth. What can you conclude about the species being studied?
It’s a facultative anaerobe
58
The phase of the bacterial growth curve in which newly inoculated cells are adjusting to their new environment (i.e., they are metabolizing but not actively dividing) is the:
lag phase.
59
Which of the following does not contribute to the initiation of the stationary phase of bacterial growth?
The generation time of the dividing organisms
60
Aunt Melba brought out her famous chicken salad at the start of the annual barn dance, but insisted nobody eat any until the end of the dance, 3 hours later. However, as soon at the bowl was set down, little cousin Joey dipped his finger in for a taste and inoculated the salad with 500 Salmonella cells. It takes about 10,000 Salmonella cells to cause illness. Assuming a generation time of 30 minutes, will the person who gets the contaminated scoop of chicken salad after the dance become sick?
yes
61
I find a gallon of milk at the back of my fridge and realize it is past its expiration date. I take a 1 mL sample and perform a serial dilution, then inoculate a series of growth plates. After incubation, I count 47 colonies on the growth plate labeled “1:10,000 dilution.” Thus, my original sample contained:
4.7 x 10 to the 5 power bacteria per mL
62
Nitrogen is required for the production of what category of molecules?
Nucleotides
63
An experiment began with 5 cells and ended with 160 cells. How many generations did the cells go through?
32
64
In making a 1:10 dilution, you would mix ___ ml of your bacterial suspension with ___ ml of sterile culture medium.
1; 9
65
The removal or destruction of ALL forms of microbial life Is called:
sterilization
66
The destruction of vegetative pathogens (but not endospores) is called:
disinfection.
67
What treatment is intended to lower microbial counts on eating and drinking utensils to safe public health levels?
sanitization
68
The absence of significant contamination is referred to as:
asepsis.
69
Commercial sterilization is a limited heat treatment to destroy:
Clostridium botulinum endospores
70
Which of the following best describes the rate of microbial death when treated with antimicrobial chemicals?
Cells in a population die at a constant rate.
71
MOST disinfectants work better in _______ solutions.
warm
72
Damage to which structure causes cellular contents to leak into the surrounding medium?
plasma membrane
73
In hospitals, the presence of ________ in blood, vomit, and feces influences the selection of disinfectants.
organic matter
74
If a population of 100,000 microbes has been treated with antimicrobials for 2 minutes and 90% of the population dies per minute, how many microbes remain after 2 minutes?
1000
75
To sterilize heat-sensitive solutions such as culture media, enzymes, and vaccines, one should use:
filtration.
76
Which method kills microorganisms primarily by the coagulation of proteins (denaturation)?
moist heat
77
Direct flaming is one of the simplest methods of:
dry heat sterilization.
78
The lowest temperature at which ALL of the microorganisms in a particular liquid suspension will be killed in 10 minutes is called the:
thermal death point.
79
Which of the following have little value as antiseptics, but are used to mechanically remove microbes?
soaps
80
Which method of evaluating disinfectants is the currently used standard?
use-dilution test
81
Which of the following injure(s) plasma membranes and was/were first used by Lister to control surgical infections?
phenolics
82
The recommended optimum concentration of ethanol to use as a biocide is:
70%
83
Which of the following is/are NOT used to preserve foods?
biguanides
84
Which of the following include the cationic detergents?
quats
85
One of the few liquid chemical disinfectants that can be considered a sterilizing agent and is also used for embalming is:
glutaraldehyde.
86
Peracetic acid is a liquid chemical sporicide that is a type of:
peroxygen.
87
Which agents exert antimicrobial activity via oligodynamic action
heavy metals
88
What chemical is used to prevent spoilage in wine?
sulfur dioxide
89
What chemical selectively inhibits iron-containing enzymes of Clostridium botulinum?
sodium nitrite
90
Assume that you are responsible for decontaminating materials in a large hospital. How would you sterilize used disposable syringes?
ethylene oxide
91
Which of the following is mismatched?
radiation – directly affects cell membranes
bisphenols – disrupt cell membranes
fungicide – kills Saccharomyces
chlorine – oxidizing agent
chlorhexidine – used in surgical hand scrubs
radiation – directly affects cell membranes
92
Physical and chemical antimicrobial agents can target all but which of the following?
Capsule formation
93
What germicidal chemical is used to prepare skin and mucous membranes for surgery and injections, is included in surgical handscrubs, is used to treat burns, and is used to disinfect equipment and surfaces?
Iodine
94
A disk-diffusion test using Pseudomonas aeruginosa gave the following results:
Disinfectant Zone of inhibition (mm)
Dettol 3
Sanisol 16
Teflex 8
Accel 1
Which compound was the least effective against Pseudomonas aeruginosa?
Accel
95
A disk-diffusion test using Pseudomonas aeruginosa gave the following results:
Disinfectant Zone of inhibition (mm)
Dettol 3
Sanisol 16
Teflex 8
Accel 1
which compound was bactericidal?
Cannot be determined based on the information provided.
96
Which of the following statements about UV light is FALSE?
UV light is sometimes used in water treatment systems.
A wavelength of approximately 254 nm is most efficient for disinfection purposes.
It damages the nucleic acids of cells.
It is not a deeply penetrating form of radiation.
It has no negative effects on human cells.
It has no negative effects on human cells.
97
A segment of DNA that codes for a functional product is a(n):
gene.
98
Which process converts one parental double-stranded DNA molecule to two identical ‘offspring’ molecules?
replication
99
In DNA replication, the newly added nucleotide is joined to the growing DNA strand by:
DNA polymerase.
100
DNA polymerase adds nucleotides ONLY to the _______ end of a DNA strand.
3’
101
What carries the coded information for making specific proteins from DNA to ribosomes?
mRNA
102
Which molecules recognize specific codons and transport amino acids?
tRNA
103
A group of three nucleotides on mRNA is called a(n):
codon.
104
Transcription begins when RNA polymerase binds to the DNA at the:
promoter.
105
Of the 64 codons, how many are sense codons
61
106
What is the process that turns on the transcription of a gene or genes?
induction
107
Ionizing radiation causes:
DNA strand breaks.
108
What is the MOST common type of mutation involving single base pairs?
base substitution
109
Mutations in which one or a few nucleotide pairs are deleted or inserted in the DNA are called:
frameshift mutations
110
The process of bacteria passing their genes to other microbes of the same generation is known as:
horizontal gene transfer
111
Transformation is the transfer of DNA from a donor to a recipient cell:
as naked DNA in solution.
112
The process in which bacterial DNA is transferred from a donor cell to a recipient cell inside a bacteriophage is called:
transduction.
113
What are the small segments of DNA that can move from one region of a DNA molecule to another?
transposons
114
How does an organism’s phenotype differ from its genotype?
Phenotype is physical differences, genotype is genetic
115
Which of the following terms contains the most DNA?
genome
116
Replication
Copies the sequence in a DNA molecule to create more DNA (uses DNA polymerase)
117
Transcription
Uses the sequence in a DNA gene to create an mRNA molecule (uses RNA polymerase)
118
Translation
Uses the sequence in an mRNA molecule to create a protein
119
DNA polymerase
The enzyme that adds the nucleotides to the growing strand during replication
120
RNA polymerase
The enzyme that adds the nucleotides to a growing mRNA molecule during transcription
121
Helicase
The enzyme that separates the two halves of the DNA molecule during replication by breaking hydrogen bonds
122
Primase
The enzyme that tells DNA polymerase where to start copying during replication
123
Ligase
The enzyme that makes sure that the copied DNA is a continuous molecule with no breaks
124
Transcription of the sequence TACCGA would produce which of the following?
A-U-G-G-C-U
125
The three steps in each PCR cycle are:
denaturation, annealing, extension
126
If an mRNA molecule is 126 nucleotides in length, how many amino acids will be in the protein after translation? (Assume that the entire mRNA molecule is translated.)
42
127
All of the following are true of base substitutions except:
Mutations rarely involve base substitutions.
A base substitution may cause no change in the protein encoded by the affected gene.
A base substitution may be beneficial if the affected gene encodes an enzyme with enhanced activity.
A base substitution can result in the production of a shortened protein.
Base substitutions may be caused by radiation or chemical mutagens.
Mutations rarely involve base substitutions.
128
Which of the following is true about transduction?
Segments of DNA move from one region of DNA to another.
A virus is required for transfer of genetic material.
Recombination does not occur.
Naked DNA is passed from bacterium to bacterium.
Bacteria-bacteria contact is required.
A virus is required for transfer of genetic material.
129
An enzyme that copies DNA to make a molecule of RNA is:
RNA polymerase.
130
A point mutation that changes a codon specifying an amino acid into a stop codon is called a _______ mutation.
nonsense
131
A section of DNA that codes for a protein is, by definition, a:
a gene
132
Every three base code on DNA (a codon) codes for a single:
amino acid
133
Following the transcription of DNA, the resultant mRNA is processed and the ______ are removed.
introns
134
In complementary base pairing of the DNA molecule, adenine always combines with:
thymine
135
In replication DNA serves as a template for the synthesis of:
more DNA
136
Mutations can be caused by:
All of the choices are correct.
exposure to environmental substances
errors in the replication process
base substitutions
All of the choices are correct.
137
Nucleotides are composed of:
phosphate, sugar, base
138
Protein synthesis in eukaryotes is similar to the process in prokaryotes in that both eukaryotes and prokaryotes
Use codons to arrange amino acids
139
The automated laboratory procedure that can create millions of copies a single gene is:
PCR
140
The bases in DNA are joined by weak hydrogen bonds; this association is called:
complementary base pairing
141
Translation takes place:
on ribosomes
142
What did Frederick Griffith's experiments with laboratory mice demonstrate?
Bacteria could be transformed by DNA from other cells.
143
Which method of DNA transfer requires direct contact between two bacterial cells?
Conjugation.
144
Which of the following is NOT true about mRNA?
It forms a double-stranded helix.
It contains the sugar ribose.
It is single-stranded.
It is found in the cytoplasm.
It contains adenine, guanine, uracil, cytosine.
It forms a double-stranded helix.
145
Which type of RNA carries the instructions from a template strand of DNA in the nucleus out to the ribosomes in the cytoplasm?
mRNA
