Wayground logo

Free Printable Worksheets

Font size

S
M
L
XL
Worksheets

Introductory Microbiology Exam 1

Total questions: 188

Worksheet time: 2hrs 34mins

Name
Class
Date
1.

Which of the following is NOT one of the three domains of life?

a)

Bacteria

b)

Archaea

c)

Protista

d)

Eukarya

2.

Which of the following have prokaryotic cells?

a)

Bacteria and Archaea

b)

Fungi and Protozoa

c)

Helminths and Animals

d)

Plants and Algae

3.

Which organelle is found in all prokaryotic cells?

a)

Nucleus

b)

Ribosome

c)

Mitochondria

d)

Golgi apparatus

4.

Which scientist disproved spontaneous generation using the swan-neck flask?

a)

Koch

b)

Lister

c)

Pasteur

d)

Fleming

5.

Koch’s postulates are used to:

a)

Identify cell structures

b)

Prove a microbe causes a disease

c)

Develop antibiotics

d)

Determine optimal growth temp

6.

Who emphasized hand-washing to prevent puerperal fever?

a)

Jenner

b)

Semmelweis

c)

Lister

d)

Ehrlich

7.

Who developed the smallpox vaccine?

a)

Fleming

b)

Jenner

c)

Pasteur

d)

Koch

8.

Which domain do fungi belong to?

a)

Bacteria

b)

Archaea

c)

Eukarya

d)

Protista

9.

Viruses are made of:

a)

DNA or RNA + protein coat

b)

Only proteins

c)

DNA + ribosomes

d)

Lipids + carbs

10.

Which microscope provides the highest resolution?

a)

Bright-field

b)

Dark-field

c)

Electron

d)

Phase-contrast

11.

Size of most bacteria?

a)

10–100 nm

b)

0.2–2 μm

c)

10–100 μm

d)

1–10 mm

12.

Stain for mycolic acids?

a)

Gram

b)

Ziehl-Neelsen acid-fast

c)

Endospore

d)

Negative

13.

13. Gram-positive bacteria stain what color?

a)

Red

b)

Blue

c)

Purple

d)

Colorless

14.

Which step in Gram stain is the decolorizer?

a)

Crystal violet

b)

Iodine

c)

Alcohol

d)

Safranin

15.

Unique to Gram-negative?

a)

Peptidoglycan

b)

Outer membrane w/ LPS

c)

Teichoic acid

d)

Cytoplasmic membrane

16.

Endotoxin Lipid A is part of?

a)

Peptidoglycan

b)

Capsule

c)

LPS

d)

Teichoic acid

17.

Shape of Vibrio cholerae?

a)

Rod

b)

Spiral

c)

Comma

d)

Sphere

18.

Structure for adhesion & biofilms?

a)

Capsule

b)

Fimbriae

c)

Endospore

d)

Flagella

19.

One flagellum at one end?

a)

Amphitrichous

b)

Monotrichous

c)

Lophotrichous

d)

Peritrichous

20.

NOT external structure?

a)

Flagella

b)

Capsule

c)

Ribosome

d)

Fimbriae

21.

Function of endospores?

a)

Reproduction

b)

Survival

c)

Nutrient storage

d)

Protein synthesis

22.

Endospore-forming genus?

a)

Staphylococcus

b)

Escherichia

c)

Bacillus

d)

Mycobacterium

23.

Mycolic acid bacteria?

a)

E. coli

b)

Bacillus subtilis

c)

Mycobacterium tuberculosis

d)

Staphylococcus aureus

24.

Ribosome function?

a)

Lipid synthesis

b)

ATP production

c)

Protein synthesis

d)

DNA replication

25.

Structure preventing phagocytosis?

a)

Capsule

b)

Endospore

c)

Pilus

d)

Flagella

26.

Growth phase with most division?

a)

Lag

b)

Exponential/log

c)

Stationary

d)

Death

27.

Converts superoxide → hydrogen peroxide?

a)

Catalase

b)

Superoxide dismutase

c)

Peroxidase

d)

DNA polymerase

28.

Breaks down H₂O₂ → water + oxygen?

a)

Catalase

b)

SOD

c)

Lipase

d)

Amylase

29.

Bacteria growing only with O₂?

a)

Obligate anaerobe

b)

Obligate aerobe

c)

Facultative anaerobe

d)

Aerotolerant anaerobe

30.

Media that inhibits some microbes but allows others?

a)

Complex

b)

Selective

c)

Differential

d)

Enrichment

31.

Differential media shows?

a)

Colony differences

b)

One species only

c)

Inhibits Gram+

d)

Enriches fastidious

32.

Process of one cell → two identical cells?

a)

Binary fission

b)

Photosynthesis

c)

Osmosis

d)

Meiosis

33.

Generation time of E. coli?

a)

20 min

b)

1 hr

c)

12 hr

d)

24 hr

34.

Most resistant to disinfectants?

a)

Enveloped viruses

b)

Prions

c)

Gram+

d)

Fungi

35.

Sterilizes by steam under pressure?

a)

Boiling

b)

Autoclaving

c)

Pasteurization

d)

Filtration

36.

Standard autoclave settings?

a)

100°C 10 min 5 psi

b)

121°C 15 min 15 psi

c)

134°C 5 min 20 psi

d)

60°C 30 min 10 psi

37.

Disinfectant used by Lister?

a)

Phenol

b)

Alcohol

c)

Iodine

d)

Silver nitrate

38.

Denatures proteins and membranes?

a)

Phenol

b)

ETO

c)

Silver nitrate

d)

Ozone

39.

Gaseous sterilant killing spores?

a)

Chlorine

b)

Ozone

c)

Ethylene oxide

d)

Iodine

40.

Radiation for medical supplies/food?

a)

UV

b)

Infrared

c)

Ionizing

d)

Microwaves

41.

Disadvantage of UV light?

a)

Free radicals

b)

Poor penetration

c)

Destroys DNA

d)

Mutations

42.

Most effective alcohol %?

a)

30%

b)

50%

c)

70%

d)

100%

43.

Sterilizes air in hospitals?

a)

UV

b)

HEPA filter

c)

Autoclaving

d)

Ozone

44.

Bond holding water molecules?

a)

Ionic

b)

Hydrogen

c)

Covalent

d)

Disulfide

45.

Monosaccharides form?

a)

Proteins

b)

Lipids

c)

Carbs

d)

Nucleic acids

46.

Amino acids contain?

a)

Carboxyl & amino

b)

Hydroxyl only

c)

Sulfhydryl only

d)

Phosphate

47.

Reaction building larger molecules?

a)

Hydrolysis

b)

Dehydration synthesis

c)

Oxidation

d)

Fermentation

48.

Main glycolysis product?

a)

Pyruvic acid

b)

Acetyl-CoA

c)

Lactic acid

d)

NADPH

49.

49. Net ATP from glycolysis?

a)

2

b)

4

c)

1

d)

0

50.

Process yielding most ATP/glucose?

a)

Glycolysis

b)

Fermentation

c)

Krebs cycle

d)

ETC

51.

List the three domains of life. Which contain prokaryotes? Which contain eukaryotes?

a)

Bacteria & Archaea = prokaryotes; Eukarya = eukaryotes.

b)

Bacteria & Eukarya = prokaryotes; Archaea = eukaryotes.

c)

Eukarya & Archaea = prokaryotes; Bacteria = eukaryotes.

d)

Bacteria, Archaea & Eukarya = all prokaryotes.

52.

Name three organelles found in eukaryotic cells but not in prokaryotic cells.

a)

Nucleus, mitochondria, ER, Golgi, lysosome.

b)

Ribosome, cell wall, plasma membrane.

c)

Cytoplasm, nucleoid, capsule.

d)

Flagella, pili, plasmid.

53.

What is Koch’s Postulates? List the four steps.

a)

(1) Pathogen present in all disease cases, (2) Isolate in pure culture, (3) Cause disease in healthy host, (4) Re-isolate.

b)

(1) Pathogen present in some disease cases, (2) Isolate in mixed culture, (3) Cause disease in immune host, (4) Do not re-isolate.

c)

(1) Pathogen absent in all disease cases, (2) Do not isolate, (3) Cause disease in healthy host, (4) Re-isolate from environment.

d)

(1) Pathogen present in all healthy cases, (2) Isolate in pure culture, (3) Cause disease in sick host, (4) Re-isolate from healthy host.

54.

Explain how Pasteur disproved spontaneous generation.

a)

Swan-neck flask → broth stayed sterile when air entered but microbes trapped.

b)

He boiled the broth and sealed the flask completely, preventing any air from entering.

c)

He added chemicals to the broth to kill all microbes, then left it open to the air.

d)

He used a microscope to show that all life comes from eggs.

55.

What is the difference between a simple stain and a differential stain? Give one example of each.

a)

Simple = 1 dye (methylene blue). Differential = multiple dyes to distinguish (Gram stain).

b)

Simple = multiple dyes (Gram stain). Differential = 1 dye (methylene blue).

c)

Simple = only used for animal cells. Differential = only used for plant cells.

d)

Simple = does not use any dye. Differential = uses only water.

56.

Why do we heat fix bacteria to a slide before staining?

a)

Kills bacteria, sticks them to slide, preserves shape.

b)

To make the bacteria change color.

c)

To dissolve the cell wall of bacteria.

d)

To sterilize the slide for reuse.

57.

Explain why Gram-positive bacteria retain crystal violet while Gram-negative do not.

a)

Gram+ = thick PG retains CV-I. Gram− = thin PG & outer membrane → dye lost.

b)

Gram+ = thin PG loses CV-I. Gram− = thick PG retains dye.

c)

Gram+ = outer membrane prevents dye loss. Gram− = no outer membrane.

d)

Gram+ = no peptidoglycan. Gram− = thick peptidoglycan retains dye.

58.

What is the Ziehl-Neelsen (acid-fast) stain used for? Which bacteria test positive?

a)

Detects Mycobacterium (TB, leprosy).

b)

Detects Streptococcus species.

c)

Detects Escherichia coli.

d)

Detects Staphylococcus aureus.

59.

Compare and contrast capsules and slime layers in bacteria.

a)

Capsule = organized, prevents phagocytosis. Slime = loose, helps adhesion & biofilm.

b)

Capsule = loose, helps adhesion. Slime = organized, prevents phagocytosis.

c)

Capsule = only in Gram-negative bacteria. Slime = only in Gram-positive bacteria.

d)

Capsule = aids in motility. Slime = aids in spore formation.

60.

What is the function of fimbriae? How do they differ from pili?

a)

Fimbriae = attachment. Pili = DNA transfer.

b)

Fimbriae = motility. Pili = protein synthesis.

c)

Fimbriae = energy production. Pili = cell wall formation.

d)

Fimbriae = DNA replication. Pili = nutrient absorption.

61.

Explain how flagella in prokaryotes differ from those in eukaryotes.

a)

Prokaryotic flagella = rotate. Eukaryotic flagella = whip-like, 9+2 tubules.

b)

Both prokaryotic and eukaryotic flagella have the same structure and movement.

c)

Prokaryotic flagella are made of microtubules, eukaryotic flagella are made of flagellin.

d)

Eukaryotic flagella rotate, prokaryotic flagella move in a whip-like fashion.

62.

Peptidoglycan is a structural component of the bacterial cell wall. What is its role?

a)

It provides rigidity and structural support to the bacterial cell wall.

b)

It acts as a genetic material in bacteria.

c)

It is responsible for energy production in bacteria.

d)

It helps in the movement of bacteria.

63.

Why are mycobacteria resistant to many disinfectants and slow-growing?

a)

Mycolic acids = waxy wall → slow growth, resistant to chemicals.

b)

They lack a cell wall, making them resistant to chemicals.

c)

They have a high metabolic rate, which slows their growth.

d)

They produce toxins that neutralize disinfectants.

64.

Describe the four phases of the bacterial growth curve.

a)

Lag = adjust. Log = rapid division. Stationary = growth = death. Death = decline.

b)

Lag = rapid division. Log = adjust. Stationary = decline. Death = growth.

c)

Lag = death. Log = stationary. Stationary = adjust. Death = rapid division.

d)

Lag = growth = death. Log = adjust. Stationary = rapid division. Death = decline.

65.

What is the function of catalase and superoxide dismutase? Why do obligate anaerobes lack these?

a)

Catalase = H2O2 → H2O + O2. SOD = converts O2- radicals → H2O2. Anaerobes lack them → oxygen toxic.

b)

Catalase = breaks down glucose. SOD = converts CO2 to O2. Anaerobes lack them → oxygen required.

c)

Catalase = synthesizes ATP. SOD = breaks down proteins. Anaerobes lack them → oxygen beneficial.

d)

Catalase = converts O2 to H2O2. SOD = converts H2O2 to O2. Anaerobes lack them → oxygen needed for growth.

66.

Define: a) Obligate aerobe b) Obligate anaerobe c) Facultative anaerobe d) Aerotolerant anaerobe.

a)

a) Requires oxygen for growth; b) Cannot survive in the presence of oxygen; c) Can grow with or without oxygen; d) Does not use oxygen but can tolerate its presence.

b)

a) Requires no oxygen for growth; b) Can only survive in oxygen; c) Can only grow in the absence of oxygen; d) Uses oxygen for growth.

c)

a) Can only grow in the absence of oxygen; b) Requires oxygen for growth; c) Can only survive in oxygen; d) Cannot tolerate oxygen at all.

d)

a) Can grow with or without oxygen; b) Uses oxygen for growth; c) Cannot survive in the presence of oxygen; d) Requires oxygen for growth.

67.

Explain the purpose of a streak plate.

a)

Isolate colonies from mixed culture.

b)

Measure the pH of a solution.

c)

Determine the boiling point of a liquid.

d)

Test for the presence of starch.

68.

What is a dilution count, and why is it used?

a)

Serial dilution + plating → estimate viable cell number.

b)

Direct microscopic count of all cells in a sample.

c)

Measuring turbidity to estimate total cell mass.

d)

Using PCR to quantify DNA content.

69.

Define selective media and differential media. Give one example of each.

a)

Selective = inhibits some, allows others (MacConkey). Differential = shows colony differences (blood agar).

b)

Selective = shows colony differences (blood agar). Differential = inhibits some, allows others (MacConkey).

c)

Selective = allows all bacteria to grow (nutrient agar). Differential = inhibits all bacteria (EMB agar).

d)

Selective = only for viruses (Sabouraud agar). Differential = only for fungi (MacConkey agar).

70.

What is a fastidious organism? How do we culture them?

a)

Needs special nutrients. Use enrichment media.

b)

Can grow on any medium. Use simple agar.

c)

Requires no nutrients. Grows in water only.

d)

Grows best in sunlight. Use phototrophic media.

71.

Compare the resistance of prions, endospores, and enveloped viruses.

a)

Prions are the most resistant, followed by endospores, and enveloped viruses are the least resistant.

b)

Enveloped viruses are the most resistant, followed by prions, and endospores are the least resistant.

c)

Endospores are the most resistant, followed by enveloped viruses, and prions are the least resistant.

d)

Enveloped viruses are the most resistant, followed by endospores, and prions are the least resistant.

72.

What are three mechanisms by which disinfectants kill microbes?

a)

Disrupt membranes, denature proteins, damage DNA.

b)

Increase cell wall thickness, enhance microbial growth, promote spore formation.

c)

Provide nutrients, stimulate cell division, repair cell membranes.

d)

Facilitate genetic exchange, increase resistance, promote biofilm formation.

73.

Describe how an autoclave works. Why better than boiling?

a)

121°C steam at 15 psi kills endospores. Boiling does not.

b)

Autoclaves use dry heat at 80°C, which is less effective than boiling.

c)

Autoclaves only use UV light to sterilize, which is similar to boiling.

d)

Autoclaves work at room temperature, making them equivalent to boiling.

74.

What is pasteurization, and how does it differ from sterilization?

a)

Pasteurization = reduce pathogens. Sterilization = complete kill.

b)

Pasteurization = complete kill. Sterilization = reduce pathogens.

c)

Pasteurization and sterilization are identical processes.

d)

Pasteurization = increase pathogens. Sterilization = reduce pathogens.

75.

Explain why refrigeration and freezing delay bacterial growth.

a)

Slow metabolism by lowering enzyme activity.

b)

Increase in bacterial reproduction rate.

c)

Enhance nutrient availability for bacteria.

d)

Raise the temperature to optimal growth levels.

76.

What are sulfa drugs? How do they interfere with metabolism?

a)

Competitive inhibitors of folic acid synthesis.

b)

Enzymes that break down proteins in the stomach.

c)

Hormones that regulate blood sugar levels.

d)

Antibodies that attack bacterial cell walls.

77.

Define cellular respiration. How does aerobic differ from anaerobic?

a)

ATP from glucose breakdown. Aerobic uses O2, anaerobic uses other acceptors.

b)

Cellular respiration is the process of photosynthesis. Aerobic and anaerobic both use sunlight.

c)

Cellular respiration only occurs in plants. Aerobic and anaerobic are identical.

d)

Cellular respiration is the breakdown of proteins. Aerobic uses water, anaerobic uses carbon dioxide.

78.

Explain how ATP is produced in the ETC. Why is oxygen important?

a)

Electron transport pumps H+ → ATP synthase. O2 = final acceptor → H2O.

b)

ATP is produced directly by glycolysis in the ETC. Oxygen is used to break down glucose.

c)

ATP is made by breaking down proteins in the ETC. Oxygen is not required.

d)

Electron transport pumps Na+ → ATP synthase. O2 is used to produce CO2.

79.

What is fermentation? List two products.

a)

Anaerobic pyruvate breakdown. Products: lactic acid, ethanol, acetic acid.

b)

Aerobic breakdown of glucose. Products: oxygen, water.

c)

Photosynthetic process. Products: glucose, oxygen.

d)

Protein synthesis process. Products: amino acids, peptides.

80.

How does UV radiation kill microbes? Why not reliable for thick materials?

a)

DNA damage (thymine dimers). Poor penetration.

b)

Disrupts cell membranes. Easily penetrates thick materials.

c)

Causes protein synthesis. Strong penetration in all materials.

d)

Induces cell wall formation. Penetrates deeply into tissues.

81.

Who discovered penicillin, revolutionizing the treatment of bacterial infections?

a)

Louis Pasteur

b)

Alexander Fleming

c)

Robert Koch

d)

Joseph Lister

82.

What was the major contribution of Rosalind Franklin to science?

a)

Structure of DNA

b)

Discovery of radioactivity

c)

Invention of the microscope

d)

Development of vaccines

83.

Why is Marie Curie considered important in scientific history?

a)

She pioneered research on radioactivity

b)

She developed antiseptic surgery

c)

She invented the stethoscope

d)

She discovered the electron

84.

Which type of flagella arrangement has flagella distributed all over the cell surface?

a)

Monotrichous

b)

Lophotrichous

c)

Amphitrichous

d)

Peritrichous

85.

What is the term for a bacterium with a tuft of flagella at one or both ends?

a)

Peritrichous

b)

Lophotrichous

c)

Atrichous

d)

Monotrichous

86.

A bacterium with a single flagellum at each end is called?

a)

Peritrichous

b)

Lophotrichous

c)

Amphitrichous

d)

Monotrichous

87.

Which component in the cell wall gives acid fast bacteria their characteristic staining property?

a)

Peptidoglycan

b)

Mycolic acid

c)

Lipopolysaccharide

d)

Teichoic acid

88.

Which of the following is an example of an acid fast bacterium?

a)

Streptococcus pneumoniae

b)

Escherichia coli

c)

Bacillus cereus

d)

Mycobacterium leprae

89.

Which of the following best describes an endospore?

a)

A reproductive structure in fungi

b)

A dormant, resistant bacterial cell

c)

A type of viral capsid

d)

A eukaryotic organelle

90.

Which bacterial genus is well known for producing endospores?

a)

Streptococcus

b)

Bacillus

c)

Escherichia

d)

Staphylococcus

91.

What is the primary function of an endospore?

a)

To aid in motility

b)

To survive harsh environmental conditions

c)

To facilitate conjugation

d)

To increase nutrient uptake

92.

What does 'generation time' refer to in microbiology?

a)

The time between inoculation and stationary phase

b)

The time it takes for a cell to divide and produce two daughter cells

c)

The time required for DNA replication

d)

The time needed for a colony to become visible

93.

Which factor does NOT affect the generation time of bacteria?

a)

Nutrient availability

b)

Color of the culture medium

c)

Temperature

d)

pH of the environment

94.

If a bacterial species has a generation time of 30 minutes, how many generations will occur in 3 hours?

a)

12

b)

6

c)

9

d)

3

95.

Which growth phase is characterized by adaptation to new environmental conditions without an increase in cell number?

a)

Lag phase

b)

Log phase

c)

Death phase

d)

Stationary phase

96.

During which phase does the rate of cell division equal the rate of cell death?

a)

Stationary phase

b)

Log phase

c)

Death phase

d)

Lag phase

97.

What typically causes the onset of the death phase in a bacterial growth curve?

a)

Increased oxygen levels

b)

Optimal temperature

c)

Accumulation of waste products

d)

Abundant nutrients

98.

Which pH range is optimal for the growth of neutrophiles?

a)

pH 1–3

b)

pH 12–14

c)

pH 6–8

d)

pH 9–11

99.

Neutrophiles are most commonly found in which type of environment?

a)

Neutral

b)

Highly acidic

c)

Saline

d)

Highly alkaline

100.

Which of the following is an example of a neutrophilic bacterium?

a)

Vibrio cholerae

b)

Helicobacter pylori

c)

Thermus aquaticus

d)

Escherichia coli

101.

Which of the following best describes an acidophile?

a)

An organism that requires high salt concentrations

b)

An organism that prefers alkaline conditions

c)

An organism that thrives in acidic environments

d)

An organism that grows best at high temperatures

102.

Acidophiles are most likely to be found in which of the following environments?

a)

Hot springs with low pH

b)

Frozen tundra

c)

Freshwater lakes

d)

Desert sand

103.

Which cellular adaptation helps acidophiles survive in acidic conditions?

a)

Thick peptidoglycan layer

b)

Enzymes stable at low pH

c)

High salt concentration in cytoplasm

d)

Photosynthetic pigments

104.

Which of the following is commonly used as a hospital disinfectant?

a)

Glucose solution

b)

Olive oil

c)

Distilled water

d)

Chlorine bleach

105.

What is the main purpose of using a disinfectant?

a)

To provide nutrients for bacteria

b)

To kill or inactivate pathogens on surfaces

c)

To increase microbial growth

d)

To stain cells for microscopy

106.

Which factor does NOT affect the effectiveness of a disinfectant?

a)

Color of the container

b)

Type of microorganism

c)

Contact time

d)

Concentration of the disinfectant

107.

Which method is used to sterilize heat-sensitive liquids?

a)

Boiling

b)

Dry heat

c)

Filtration

d)

Autoclaving

108.

Pasteurization is primarily used to:

a)

Completely sterilize food

b)

Reduce microbial load and kill pathogens

c)

Remove all toxins

d)

Freeze food

109.

Which of the following is NOT a method of sterilization?

a)

Autoclaving

b)

Pasteurization

c)

Dry heat oven

d)

Ethylene oxide gas

110.

Which component is found only in Gram-negative bacterial cell walls?

a)

Mycolic acid

b)

Thick peptidoglycan

c)

Lipopolysaccharide (LPS)

d)

Teichoic acid

111.

Gram-positive bacteria stain purple because of:

a)

High lipid content

b)

Thick peptidoglycan layer

c)

Presence of outer membrane

d)

Thin peptidoglycan layer

112.

Which is more susceptible to penicillin and why?

a)

Gram-negative, due to LPS

b)

Gram-positive, due to thick peptidoglycan

c)

Gram-positive, due to outer membrane

d)

Gram-negative, due to thin peptidoglycan

113.

Which component is unique to the outer membrane of Gram-negative bacteria?

a)

Lipopolysaccharide (LPS)

b)

Teichoic acid

c)

Peptidoglycan

d)

Mycolic acid

114.

Which of the following is a common Gram-negative bacterial pathogen?

a)

Staphylococcus aureus

b)

Bacillus subtilis

c)

Escherichia coli

d)

Streptococcus pyogenes

115.

Gram-negative bacteria are generally more resistant to antibiotics because of:

a)

Absence of cell wall

b)

Thicker peptidoglycan layer

c)

Presence of outer membrane

d)

Lack of ribosomes

116.

Which component is abundant in the cell wall of Gram-positive bacteria?

a)

Lipopolysaccharide

b)

Mycolic acid

c)

Outer membrane

d)

Teichoic acid

117.

Which of the following is a Gram-positive cocci?

a)

Staphylococcus aureus

b)

Pseudomonas aeruginosa

c)

Escherichia coli

d)

Neisseria gonorrhoeae

118.

Gram-positive bacteria are generally more susceptible to which class of antibiotics?

a)

Beta-lactams

b)

Polymyxins

c)

Macrolides

d)

Aminoglycosides

119.

What is the genetic material in most viruses?

a)

DNA or RNA

b)

Only DNA

c)

Only RNA

d)

Proteins

120.

Which structure allows a virus to attach to host cells?

a)

Capsid

b)

Envelope

c)

Spikes

d)

Ribosome

121.

Which of the following diseases is caused by a virus?

a)

Malaria

b)

Ringworm

c)

Influenza

d)

Tuberculosis

122.

Which of the following is an example of ionizing radiation?

a)

Visible light

b)

Gamma rays

c)

Ultraviolet light

d)

Microwaves

123.

What is the primary effect of ionizing radiation on microbial cells?

a)

Prevents nutrient uptake

b)

Damages DNA

c)

Disrupts cell wall synthesis

d)

Inhibits protein synthesis

124.

Which of the following is commonly sterilized using ionizing radiation?

a)

Disposable medical supplies

b)

Culture media

c)

Laboratory benches

d)

Glassware

125.

Which of the following is an example of non-ionizing radiation?

a)

Alpha particles

b)

X-rays

c)

Gamma rays

d)

Ultraviolet light

126.

Non-ionizing radiation is characterized by its inability to:

a)

Travel through a vacuum

b)

Remove tightly bound electrons from atoms

c)

Penetrate the skin

d)

Cause heating effects

127.

Which of the following devices commonly emits non-ionizing radiation?

a)

Microwave oven

b)

PET scanner

c)

Radioactive isotope

d)

CT scanner

128.

Which type of radiation is most likely to cause mutations in DNA?

a)

Visible light

b)

Infrared

c)

Ultraviolet

d)

Microwave

129.

Which of the following best describes the primary use of glutaraldehyde in microbiology laboratories?

a)

Disinfecting and sterilizing equipment

b)

Staining bacterial cells

c)

Enhancing bacterial growth

d)

Measuring pH of media

130.

Glutaraldehyde is classified as which type of chemical agent?

a)

High-level disinfectant

b)

Low-level disinfectant

c)

Intermediate-level disinfectant

d)

Antiseptic

131.

What is a major advantage of using glutaraldehyde over other disinfectants in microbiology?

a)

It requires no rinsing after use

b)

It is non-toxic to humans

c)

It can sterilize heat-sensitive instruments

d)

It is effective only against viruses

132.

What is the primary use of ethylene oxide in microbiology laboratories?

a)

Preparing culture media

b)

Measuring bacterial growth

c)

Sterilizing heat-sensitive equipment

d)

Staining bacterial cells

133.

Which of the following best describes the mechanism by which ethylene oxide sterilizes materials?

a)

Oxidizes cell wall components

b)

Alkylates DNA and proteins, preventing replication

c)

Denatures proteins by heat

d)

Disrupts cell membranes by dehydration

134.

Which type of items are most appropriately sterilized using ethylene oxide gas?

a)

Stainless steel autoclave trays

b)

Glass petri dishes

c)

Disposable plastic syringes

d)

Metal forceps

135.

Which pathway is used by bacteria to break down glucose in the absence of oxygen?

a)

Fermentation

b)

Transcription

c)

Photosynthesis

d)

Beta-oxidation

136.

What is the main function of the electron transport chain in microbial metabolism?

a)

DNA replication

b)

Cell wall formation

c)

ATP generation

d)

Protein synthesis

137.

Which molecule acts as the final electron acceptor in aerobic respiration in bacteria?

a)

Glucose

b)

Carbon dioxide

c)

Oxygen

d)

Nitrate

138.

What is the primary function of superoxide dismutase (SOD) in bacteria?

a)

Breaks down hydrogen peroxide into water and oxygen

b)

Facilitates DNA replication

c)

Converts superoxide radicals to hydrogen peroxide

d)

Hydrolyzes lipids

139.

Which type of bacteria is most likely to lack both SOD and catalase enzymes?

a)

Obligate anaerobes

b)

Facultative anaerobes

c)

Obligate aerobes

d)

Microaerophiles

140.

Which of the following correctly pairs the enzyme with the reactive oxygen species it detoxifies?

a)

Catalase – water

b)

SOD – hydrogen peroxide

c)

Catalase – superoxide radical

d)

SOD – superoxide radical

141.

What is the main purpose of using selective media in microbiology?

a)

To inhibit the growth of certain microbes while allowing others to grow

b)

To grow all types of bacteria equally

c)

To provide extra nutrients for fastidious organisms

d)

To observe colony color changes

142.

What is the main purpose of differential media in microbiology?

a)

To distinguish between different types of bacteria based on colony appearance

b)

To provide nutrients for all bacteria

c)

To enrich for fastidious organisms

d)

To inhibit unwanted microbes

143.

On blood agar, which result indicates hemolysis by bacteria?

a)

All of the above

b)

Clear zone around colonies

c)

No change in the medium

d)

Greenish discoloration around colonies

144.

Which type of media contains nutrients in exact amounts and chemical composition is known?

a)

Complex media

b)

Selective media

c)

Differential media

d)

Defined (synthetic) media

145.

Which of the following is an example of selective media?

a)

Blood agar

b)

Nutrient agar

c)

MacConkey agar

d)

Chocolate agar

146.

What is the main purpose of enrichment media in microbiology?

a)

To inhibit unwanted microbes

b)

To distinguish between different species

c)

To enhance the growth of specific microbes

d)

To provide a solid surface for growth

147.

What is the main function of ribosomes in a cell?

a)

DNA replication

b)

Lipid storage

c)

Energy production

d)

Protein synthesis

148.

Ribosomes are composed mainly of:

a)

RNA and proteins

b)

DNA and proteins

c)

Polysaccharides and RNA

d)

Lipids and carbohydrates

149.

Which of the following best describes the size of prokaryotic ribosomes?

a)

90S

b)

60S

c)

70S

d)

80S

150.

Where are ribosomes located in prokaryotic cells?

a)

Embedded in the cell wall

b)

Inside mitochondria

c)

Attached to the nuclear envelope

d)

Floating freely in the cytoplasm

151.

Which of the following best describes the structure of eukaryotic ribosomes?

a)

90S, composed of 70S and 20S subunits

b)

60S, composed of 40S and 20S subunits

c)

80S, composed of 60S and 40S subunits

d)

70S, composed of 50S and 30S subunits

152.

Where are ribosomes found in eukaryotic cells?

a)

Only in the nucleus

b)

Only in mitochondria

c)

Only on the plasma membrane

d)

Free in the cytoplasm and attached to the endoplasmic reticulum

153.

What is the first step in the Gram staining procedure?

a)

Application of safranin

b)

Application of crystal violet

c)

Application of alcohol

d)

Application of iodine

154.

Which reagent acts as the mordant in Gram staining?

a)

Saffron

b)

Iodine

c)

Crystal violet

d)

Alcohol

155.

What is the purpose of the alcohol step in Gram staining?

a)

To stain all cells purple

b)

To decolorize Gram-negative cells

c)

To act as a counterstain

d)

To fix the bacteria to the slide

156.

Which of the following best describes a bactericidal antibiotic?

a)

Inhibits bacterial growth without killing

b)

Prevents viral replication

c)

Kills bacteria directly

d)

Enhances host immune response

157.

Which statement is true regarding bacteriostatic agents?

a)

They kill bacteria instantly

b)

They inhibit bacterial protein synthesis, stopping growth

c)

They are only effective against viruses

d)

They destroy bacterial cell walls

158.

When is a bactericidal drug preferred over a bacteriostatic drug?

a)

For viral infections

b)

In immunocompromised patients

c)

In mild, self-limiting infections

d)

When treating fungal diseases

159.

Psychrophiles are microorganisms that grow best at which temperature range?

a)

20–30°C

b)

0–15°C

c)

37–45°C

d)

55–65°C

160.

Which of the following environments is most likely to harbor psychrophilic bacteria?

a)

Compost piles

b)

Hot springs

c)

Deep ocean waters

d)

Desert soil

161.

What adaptation helps psychrophiles survive in cold environments?

a)

High salt concentration in cytoplasm

b)

Thick peptidoglycan layer

c)

Enzymes with high activity at low temperatures

d)

Heat-stable enzymes

162.

Mesophiles grow best at which temperature range?

a)

0–15°C

b)

80–110°C

c)

20–40°C

d)

45–80°C

163.

Which of the following is a common example of a mesophilic bacterium?

a)

Psychrobacter cryohalolentis

b)

Thermus aquaticus

c)

Pyrococcus furiosus

d)

Escherichia coli

164.

Mesophiles are most likely to be found in which environment?

a)

Hot springs

b)

Polar ice caps

c)

Deep ocean vents

d)

Human body

165.

Which of the following best describes a thermophile?

a)

An organism that thrives at low temperatures

b)

An organism that thrives at high temperatures

c)

An organism that lives in acidic environments

d)

An organism that requires oxygen

166.

Thermophiles are most commonly found in which environment?

a)

Deep ocean trenches

b)

Desert sands

c)

Polar ice caps

d)

Hot springs

167.

What is the typical minimum temperature at which thermophiles can grow?

a)

100°C

b)

0°C

c)

40°C

d)

20°C

168.

Which environment is most suitable for hyperthermophiles?

a)

Deep ocean trenches

b)

Frozen lakes

c)

Hot springs

d)

Desert sand

169.

Hyperthermophiles are most commonly classified under which domain?

a)

Bacteria

b)

Archaea

c)

Protista

d)

Eukarya

170.

What is the typical minimum temperature for growth of hyperthermophiles?

a)

100°C

b)

80°C

c)

37°C

d)

20°C

171.

Halophiles are microorganisms that thrive in environments with:

a)

High salt concentration

b)

High temperature

c)

Low oxygen

d)

Low pH

172.

Which of the following is a well-known example of a halophilic microorganism?

a)

Streptococcus pneumoniae

b)

Bacillus subtilis

c)

Escherichia coli

d)

Halobacterium salinarum

173.

Halophiles are most commonly found in which type of environment?

a)

Acidic hot springs

b)

Freshwater lakes

c)

Desert sands

d)

Salt lakes and salt mines

174.

Barophiles are microorganisms that thrive in which type of environment?

a)

High pressure

b)

Low pH

c)

High salt

d)

High temperature

175.

Which of the following is a likely habitat for barophilic organisms?

a)

Hot springs

b)

Freshwater lakes

c)

Desert sands

d)

Deep-sea trenches

176.

Barophiles are also known as:

a)

Acidophiles

b)

Piezophiles

c)

Thermophiles

d)

Halophiles

177.

Which component is found in the cell wall of Gram-positive bacteria but not in Gram-negative bacteria?

a)

Outer membrane

b)

Lipopolysaccharide (LPS)

c)

Porins

d)

Teichoic acids

178.

What is the main structural difference between Gram-negative and Gram-positive bacterial cell walls?

a)

Gram-negative have a thick peptidoglycan layer

b)

Gram-positive have an outer membrane

c)

Gram-positive contain lipopolysaccharide (LPS)

d)

Gram-negative have a thin peptidoglycan layer and an outer membrane

179.

Which of the following is unique to the outer membrane of Gram-negative bacteria?

a)

Peptidoglycan

b)

Teichoic acids

c)

Lipopolysaccharide (LPS)

d)

Capsule

180.

Which process directly produces the most ATP during cellular respiration in bacteria?

a)

Fermentation

b)

Glycolysis

c)

Krebs cycle

d)

Electron transport chain

181.

What is the final electron acceptor in aerobic respiration in most microorganisms?

a)

Carbon dioxide

b)

Sulfate

c)

Nitrate

d)

Oxygen

182.

During fermentation, which of the following is regenerated to allow glycolysis to continue?

a)

ATP

b)

NAD+

c)

FADH2

d)

CO2

183.

Which molecule enters the Krebs cycle in microorganisms?

a)

Glucose

b)

Acetyl-CoA

c)

Pyruvate

d)

Lactic acid

184.

What is the main function of the Krebs cycle in microbial metabolism?

a)

Protein synthesis

b)

ATP production

c)

Cell wall synthesis

d)

DNA replication

185.

Which of the following is a product of the Krebs cycle in bacteria?

a)

Urea

b)

Carbon dioxide

c)

Glucose

d)

Oxygen

186.

Main function of the electron transport chain (ETC) in bacteria?

a)

Protein degradation

b)

Cell wall formation

c)

DNA replication

d)

ATP synthesis

187.

Final electron acceptor in aerobic bacterial ETC?

a)

Nitrate

b)

Carbon dioxide

c)

Oxygen

d)

Sulfate

188.

ETC is located in which part of prokaryotic cells?

a)

Nucleus

b)

Cytoplasm

c)

Cell wall

d)

Plasma membrane

Similar Resources on Wayground

Final Biomol

193 questions

Final Biomol

quiz

Worksheet

•

University

Circulatory and Respiratory System

190 questions

Circulatory and Respiratory System

quiz

Worksheet

•

University