Exam 1

Question 1

Which of the following statements about microbial cell structure is false?

A. Bacterial cells have ester-linked fatty acids in their phospholipid membranes and archaeal cells have ether-linked.

B. Bacteria have flagella and archaea have archella. These structures are powered via different mechanisms.

C. Bacterial and archaeal cells both contain peptidoglycan in their cell walls

D. Bacterial and archaeal cells contain ribosomes of the same size

Answer 1

Bacterial and archaeal cells both contain peptidoglycan in their cell walls

Question 2

Which of the following are true regarding bacterial endospores?
A. they contain a nucleoid

B. they represent a state of dormancy

C. they are a survival strategy

D. they are how bacterial cells reproduce

Answer 2

A. they contain a nucleoid

B. they represent a state of dormancy

C. they are a survival strategy

Question 3

Which of the following are true regarding virus structure?

A. All viruses are enveloped
B. Virus genomes are typically dsDNA
C. All viruses contain a nucleocapsid
D. Viruses can infect all cell types including fungi and archaea

Answer 3

C. All viruses contain a nucleocapsid
D. Viruses can infect all cell types including fungi and archaea

Question 4

The bacteriophage lysogenic cycle results in the release of new mature virion particles to the external environment.
True/ False

Answer 4

False

Question 5

Bacteriophage DNA that inserts itself into the bacterial genome is called a

Answer 5

prophage

Question 6

The bacterial cell envelope usually includes:

Answer 6

plasma membrane, cell wall, and an outer layer

Question 7

Which of the following is not a morphological type of bacterial cells?
A.Spirococci
B.Mycelium
C.Bacilli
D.Cocci

Answer 7

Spirococci

Question 8

The movement of bacterial cells towards or away from a chemical is referred to as

Answer 8

chemotaxis

Question 9

The three domains of life are:

Answer 9

Bacteria, Archaea, Eukarya

Question 10

The ____ stain is a procedure that categorizes bacterial cells based on the structure of peptidoglycan in their cell walls.

Answer 10

gram

Question 11

Viruses are acellular microorganisms that cannot synthesize their own proteins.
True/False

Answer 11

True

Question 12

Microorganisms are found in two out of the three domains of life
True/False

Answer 12

False

Question 13

Both bacterial and eukaryotic cells contain the 16S rRNA gene subunit.
True/False

Answer 13

False

Question 14

The criteria used to determine whether a microorganism causes disease is called

Answer 14

Koch’s Postulates

Question 15

Which molecule was likely the first to exist in the earliest cellular life on Earth?
A. Protein
B. Glucose
C. RNA
D. DNA

Answer 15

RNA

Question 16

Which of the following microorganisms is typically found in environments ranging from the gut to deep beneath the seafloor?
a) Bacteria
b) Fungi
c) Protista
d) Animalia

Answer 16

Bacteria

Question 17

What is one of the main advantages of using small-subunit rRNA for genetic studies?
a) It is very large and complex, making it hard to sequence.
b) It is present in all living organisms and has a conserved function.
c) It only exists in eukaryotic organisms.
d) It has no relation to genetic evolution.

Answer 17

b) It is present in all living organisms and has a conserved function.

Question 18

How are phylograms (evolutionary trees) constructed?
a) By measuring observable traits of organisms.
b) By calculating genetic distances based on small-subunit rRNA sequences.
c) By examining environmental factors.
d) By studying the physical size of organisms.

Answer 18

b) By calculating genetic distances based on small-subunit rRNA sequences.

Question 19

Which kingdom contains microorganisms such as yeast and mycorrhizae?
a) Animalia
b) Plantae
c) Fungi
d) Protista

Answer 19

Fungi

Question 20

Which of the following is NOT a kingdom within the domain Eukarya?
a) Protista
b) Plantae
c) Animalia
d) Monera

Answer 20

Monera

Question 21

What role do microorganisms play in the environment?
a) They only cause diseases in plants and animals.
b) They recycle essential elements and carry out photosynthesis.
c) They have no impact on the environment.
d) They only exist in specific habitats like deep-sea vents.

Answer 21

b) They recycle essential elements and carry out photosynthesis.

Question 22

Which of the following statements is true about the small-subunit rRNA in microorganisms?
a) It is only found in prokaryotes.
b) It is a molecular chronometer used to study genetic diversity.
c) It is not present in eukaryotes.
d) It is too large to be useful for sequencing.

Answer 22

b) It is a molecular chronometer used to study genetic diversity

Question 23

Which of the following is true about microorganisms?
a) They are typically larger than 1 mm in size.
b) They lack differentiated tissues.
c) All microorganisms are harmful to humans.
d) Microorganisms are only found in water.

Answer 23

b) They lack differentiated tissues.

Question 24

What is the most profound difference between eukaryotic cells and bacterial or archaeal cells?

a) The presence of ribosomes
b) The presence of a plasma membrane
c) The presence of a nucleus for DNA storage
d) The presence of a cell wall

Answer 24

c) The presence of a nucleus for DNA storage

Question 25

Which of the following is a characteristic of bacterial cell walls? a) Composed primarily of lipopolysaccharides b) Composed of peptidoglycan c) Have no structural function d) They are found inside the plasma membrane

Answer 25

B

Question 26

What type of bacteria stain purple in the Gram stain? a) Gram-negative bacteria b) Gram-positive bacteria c) Acid-fast bacteria d) Both Gram-negative and Gram-positive bacteria

Answer 26

B

Question 27

What structure outside the bacterial cell wall helps in attachment to solid surfaces? a) Pili b) Glycocalyx c) Capsule d) Plasmids

Answer 27

B

Question 28

How do bacterial flagella move? a) They rotate like a propeller, causing the cell to swim. b) They vibrate like a fan. c) They slide side to side. d) They move in a back-and-forth motion like a pendulum

Answer 28

A

Question 29

What is the function of the pili in archaea? a) To form biofilms b) To transport nutrients across the plasma membrane c) To move the cell d) To attach cells to surfaces

Answer 29

D

Question 30

What is the function of bacterial endospores? a) To facilitate the replication of DNA b) To allow the bacteria to survive in extreme environmental conditions c) To aid in bacterial motility d) To aid in nutrient uptake

Answer 30

B

Question 31

Which of the following is true about bacterial plasmids? a) Plasmids are always integrated into the bacterial chromosome. b) Plasmids are extrachromosomal, circular DNA molecules. c) Plasmids do not replicate independently of the chromosome. d) Plasmids are not inherited during cell division.

Answer 31

B

Question 32

What is the primary role of the nucleolus in eukaryotic cells? a) To store genetic information b) To direct assembly of rRNA and form ribosomal subunits c) To control protein synthesis d) To transport proteins out of the nucleus

Answer 32

B

Question 33

What is a characteristic of spirochete motility? a) They swim by undulating the entire cell. b) They move using flagella on the outside of the cell. c) They use cilia for movement. d) They exhibit jerky, intermittent motions.

Answer 33

A

Question 34

What is the structure surrounding the bacterial endospore called? a) Spore coat b) Cortex c) Exosporium d) Ribosome

Answer 34

C

Question 35

Which of the following is a unique feature of Gram-negative bacteria cell walls? a) Thick peptidoglycan layer b) No outer membrane c) Lipopolysaccharides in the outer membrane d) Teichoic acids

Answer 35

C

Question 36

Which of the following bacterial structures provides protection against environmental substances and helps maintain the cell envelope? a) Capsule b) Flagellum c) Pili d) S-layer

Answer 36

A

Question 37

What is the primary use of a bright-field microscope? a) To examine only unstained specimens b) To examine both stained and unstained specimens c) To examine only stained specimens d) To examine specimens using fluorescence

Answer 37

B

Question 38

The total magnification of a microscope is the product of which two lenses? a) Ocular lens and condenser lens b) Objective lens and condenser lens c) Ocular lens and objective lens d) Condenser lens and diaphragm

Answer 38

C

Question 39

What is the main factor that affects the resolution of a microscope? a) The brightness of the background b) The wavelength of light used c) The color of the specimen d) The type of objective lens

Answer 39

B

Question 40

Which of the following is true about microscope resolution? a) Shorter wavelengths result in lower resolution. b) The resolution limit for light microscopy is 0.2 μm. c) Longer wavelengths improve resolution. d) Resolution is not influenced by the aperture.

Answer 40

B

Question 41

What is the purpose of staining specimens before observing them under a microscope? a) To increase visibility and preserve the specimen for future research b) To reduce the size of the specimen c) To make the specimen invisible for better observation d) To accelerate the growth of microorganisms

Answer 41

A

Question 42

What type of dyes have negatively charged groups? a) Basic dyes b) Ionizable dyes c) Acid dyes d) Non-ionizable dyes

Answer 42

C

Question 43

What is the purpose of differential staining? a) To make cells appear larger b) To divide organisms into groups based on their staining properties c) To reduce the color contrast in specimens d) To stain only the background of the specimen

Answer 43

B

Question 44

Which of the following stains is commonly used in differential staining? a) Methylene blue b) Gram stain c) Eosin d) Crystal violet

Answer 44

B

Question 45

What does heat fixation do to a specimen? a) It preserves fine cellular structures and morphology. b) It destroys subcellular structures but preserves overall morphology. c) It enhances the fluorescence of the specimen. d) It makes cells more permeable to dyes.

Answer 45

B

Question 46

How does a fluorescence microscope produce an image? a) By using light that passes directly through the specimen b) By exciting the specimen with a wavelength of light and detecting emitted fluorescence c) By using dark-field illumination d) By examining the specimen under a low-power objective lens

Answer 46

B

Question 47

What is one potential positive role of viruses, aside from causing disease? A) Producing antibiotics B) Regulating bacterial microbiomes in the human gut C) Decreasing biodiversity in ecosystems D) Inhibiting cellular replication

Answer 47

B

Question 48

Which of the following is true about viruses? A) Viruses can reproduce outside a host cell B) Viruses are acellular and require a host cell to multiply C) Viruses are composed of only proteins D) Viruses have cellular organization like bacteria

Answer 48

B

Question 49

What is the structure that defines a mature virus particle? A) Nucleocapsid B) Ribosome C) Chloroplast D) Nucleus

Answer 49

A

Question 50

What type of viral capsid is shaped like hollow tubes with protein walls? A) Icosahedral capsid B) Complex capsid C) Helical capsid D) Binal capsid

Answer 50

C

Question 51

Which of the following viral genomes is most commonly found in cellular organisms? A) Single-stranded RNA B) Double-stranded RNA C) Double-stranded DNA D) Single-stranded DNA

Answer 51

C

Question 52

Which method of viral entry involves the virus’s envelope fusing with the host cell’s plasma membrane? A) Endocytosis B) Fusion C) Active transport D) Passive diffusion

Answer 52

B

Question 53

What is the name of the process in which a temperate phage remains within its host without destroying it? A) Lysis B) Lysogeny C) Translation D) Transcription

Answer 53

B

Question 54

Viroids are infectious agents that consist only of which substance? A) Protein B) DNA C) RNA D) Lipids

Answer 54

C

Question 55

What is a prion? A) A type of virus that infects plants B) An infectious agent made of only RNA C) A proteinaceous infectious particle that causes neurodegenerative diseases D) A virus that requires a helper virus for replication

Answer 55

C

Question 56

What is the purpose of a plaque assay in viral quantification? A) To identify the virus in a sample B) To measure the viral DNA concentration C) To count the number of virus particles based on the plaques they create D) To determine the host cell’s immune response

Answer 56

C

Question 57

What is a characteristic of satellites in viral biology? A) They can replicate without the help of a virus B) They encode their own replication enzymes C) They require a helper virus to replicate D) They are only found in animal viruses

Answer 57

C