Microbiology Quiz Chapter 4

1.

Here are some characteristics about prokaryotic and eukaryotic cells.

A.

Prokaryotic cells don't have their DNA enclosed within a nucleus
B.

Eukaryotes DNA is not associated with histones while prokaryotes DNA is consistently associated with those chromosomal proteins
C.

Archaea contain pseudomurein cell walls
D.

Prokaryotes divide by binary fission while eukaryotes divide by mitotic spindle
E.

Cell walls of prokaryotes contain many nutrients like polysaccharides
F.

B and E are false
G.

B, C and E are false
H.

None is false

Correct Answer
F. B and E are false

Explanation
The correct answer is B and E are false. This is because the statement in option B, "B, C and E are false," contradicts the given characteristics. The characteristics mentioned in the question clearly state that prokaryotic cells do not have their DNA enclosed within a nucleus and that the cell walls of prokaryotes contain many nutrients like polysaccharides. Therefore, option B is false. Similarly, option E, "None is false," is also incorrect as there are indeed false statements in the given characteristics.

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2.

We can find bacteria in multiple sizes, shapes with multiple functions as prokaryotic cells. Find which ones fit their nature. (can pick more than one)

A.

Bacteria that come in spheres and remain attached in chainlike patterns are called streptococci
B.

The basic shapes of bacteria are coccobacillus, tetrads and spirochete
C.

A rod-shaped bacterium is called bacillus
D.

Staphyloccoci are associated with grapelike clusters or broad sheets
E.

Cocci can be oval, elongated, round, or flattened on one side
F.

Some environmental conditions can alter the shape of a bacterium
G.

Spiral bacteria can be either straight or twisted
H.

A bacterium with an intermediate shape between a coccus and a bacillus is called coccobacillus

Correct Answer(s)
A. Bacteria that come in spheres and remain attached in chainlike patterns are called streptococci
C. A rod-shaped bacterium is called bacillus
D. Staphyloccoci are associated with grapelike clusters or broad sheets
E. Cocci can be oval, elongated, round, or flattened on one side
F. Some environmental conditions can alter the shape of a bacterium
H. A bacterium with an intermediate shape between a coccus and a bacillus is called coccobacillus

Explanation
The given answer correctly identifies the different shapes and characteristics of bacteria. Streptococci are spherical bacteria that remain attached in chainlike patterns. Bacillus refers to rod-shaped bacteria. Cocci can have various shapes such as oval, elongated, round, or flattened on one side. Staphylococci are associated with grapelike clusters or broad sheets. Environmental conditions can alter the shape of a bacterium. Coccobacillus is a bacterium with an intermediate shape between a coccus and a bacillus.

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3.

The main distinctions between prokaryotic and eukaryotic cells is the absence of organelles and the structure of cell walls and membranes.

A.

True
B.

False

Correct Answer
A. True

Explanation
The main distinctions between prokaryotic and eukaryotic cells are the absence of organelles and the structure of cell walls and membranes. Prokaryotic cells are simpler and lack membrane-bound organelles, such as mitochondria and nucleus, while eukaryotic cells have these organelles. Additionally, prokaryotic cells have a different structure of cell walls and membranes compared to eukaryotic cells. Therefore, the statement is true.

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4.

, external to the cell wall, it is composed of polysaccharide and/or polypeptide. Can be described as either a capsule or a slime layer. It is also a very important component of .

Correct Answer
Glycocalyx, biofilms
Glycocalyx, biofilm
glycocalyx, biofilm
glycocalyx, biofilms

Explanation
The correct answer is "Glycocalyx, biofilms". Glycocalyx is a structure external to the cell wall that is composed of polysaccharide and/or polypeptide. It can be described as either a capsule or a slime layer. Biofilms are a collection of microorganisms that are held together by the glycocalyx. The glycocalyx in biofilms is a very important component as it helps protect the microorganisms from environmental stresses and enhances their ability to adhere to surfaces.

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4

5.

All but one is true to glycocalyx's functions. Which are false? (can pick more than one)

A.

Slime layer can contribute to bacterial virulence
B.

Capsules can protect viruses from phagocytosis by the cells of the host.
C.

Can protect a cell against dehydration
D.

A glycocalyx's viscosity will enhance the movement of nutrients out of the cell
E.

None is false

Correct Answer(s)
A. Slime layer can contribute to bacterial virulence
B. Capsules can protect viruses from phagocytosis by the cells of the host.
D. A glycocalyx's viscosity will enhance the movement of nutrients out of the cell

Explanation
The false statements regarding glycocalyx's functions are: Slime layer can contribute to bacterial virulence, Capsules can protect viruses from phagocytosis by the cells of the host, and A glycocalyx's viscosity will enhance the movement of nutrients out of the cell.

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6.

The endosymbiotic theory explains that _ originates from _, meaning that larger bacterial cells lost their _ and engulfed smaller bacterial cells.

Correct Answer(s)
eukaryotes, prokaryotes, cell walls
eukaryotes, prokaryotes, cell wall

Explanation
The endosymbiotic theory explains that eukaryotes originate from prokaryotes, meaning that larger bacterial cells lost their cell walls and engulfed smaller bacterial cells.

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4

7.

Chose whatever is true about the movement of materials across membranes.

A.

Active processes mean the cell must uses ATP energy to move substances from area of low concentration to areas of high concentration (with the concentration gradient)
B.

Passive processes mean that substances cross the membrane from an area of high concentration to an area of low concentration without any use of ATP energy by the cell
C.

Simple diffusion, facilitated diffusion and osmosis are parts of active processes
D.

Simple diffusion and facilitated diffusion involve integral proteins
E.

Simple diffusion is used especially with the transportation of small molecules across their cell membrane
F.

Osmotic pressure is the pressure required to prevent the movement of pure water into a solution containing some solutes
G.

Osmosis is the net movement of solvent molecules across a selectively permeable membrane from an area with a high concentration of solvent molecules to an area of high concentration of solvent molecules
H.

Group translocation occurs exclusively in prokaryotes.
I.

When group translocation occurs, the substance is chemically altered during transport across the membrane, making the plasma membrane impermeable to the altered substance so it'll remain inside the cell.

Correct Answer(s)
B. Passive processes mean that substances cross the membrane from an area of high concentration to an area of low concentration without any use of ATP energy by the cell
E. Simple diffusion is used especially with the transportation of small molecules across their cell membrane
F. Osmotic pressure is the pressure required to prevent the movement of pure water into a solution containing some solutes
H. Group translocation occurs exclusively in prokaryotes.
I. When group translocation occurs, the substance is chemically altered during transport across the membrane, making the plasma membrane impermeable to the altered substance so it'll remain inside the cell.

Explanation
Passive processes involve the movement of substances across the membrane from an area of high concentration to an area of low concentration without the use of ATP energy by the cell. Simple diffusion is a type of passive process that is especially used for the transportation of small molecules across the cell membrane. Osmotic pressure refers to the pressure required to prevent the movement of pure water into a solution containing solutes. Group translocation is a process that occurs exclusively in prokaryotes, where the substance being transported is chemically altered during transport, making the plasma membrane impermeable to the altered substance, causing it to remain inside the cell.

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8.

Why are mycoplasmas resistant to antibiotics that interfere with cell wall synthesis?

A.

They are considered viruses
B.

They have no cell wall
C.

Since they are the smallest known bacteria, antibiotics can't affect them
D.

Their sterols containing plasma membranes protect them

Correct Answer
B. They have no cell wall

Explanation
Mycoplasmas are resistant to antibiotics that interfere with cell wall synthesis because they have no cell wall. Unlike other bacteria, mycoplasmas lack a rigid cell wall, making them naturally resistant to antibiotics that target this structure. Instead, they have a plasma membrane that contains sterols, which provides them with protection. This unique characteristic allows mycoplasmas to survive and thrive in various environments, including the presence of antibiotics that would typically inhibit bacterial growth by targeting the cell wall.

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Microbiology Quiz Chapter 4

Here are some characteristics about prokaryotic and eukaryotic cells.

We can find bacteria in multiple sizes, shapes with multiple functions as prokaryotic cells. Find which ones fit their nature. (can pick more than one)

The main distinctions between prokaryotic and eukaryotic cells is the absence of organelles and the structure of cell walls and membranes.

______, external to the cell wall, it is composed of polysaccharide and/or polypeptide. Can be described as either a capsule or a slime layer. It is also a very important component of ______.

All but one is true to glycocalyx's functions. Which are false? (can pick more than one)

The endosymbiotic theory explains that _______ originates from ___________, meaning that larger bacterial cells lost their _____ and engulfed smaller bacterial cells.

Chose whatever is true about the movement of materials across membranes.

Why are mycoplasmas resistant to antibiotics that interfere with cell wall synthesis?

, external to the cell wall, it is composed of polysaccharide and/or polypeptide. Can be described as either a capsule or a slime layer. It is also a very important component of .

The endosymbiotic theory explains that _ originates from _, meaning that larger bacterial cells lost their _ and engulfed smaller bacterial cells.