Medical Microbiology - Ch 3 - Exam 1

A typical bacterial cell is 2 micrometers (2μm) in diameter. How many millimeters (mm) in diameter? A) 200 mm B) 20 mm C) 0.02 mm D) 0.002 mm

0.002 mm

How does the plasma membrane of bacteria and archaea differ? A) Bacteria have phospholipids built from branched fatty acids. B) Archaea have phospholipids built from linear fatty acids. C) Bacteria build only lipid monolayers. D) Archaea have phospholipids built from branched fatty acids. E) Archaea build only lipid monolayers.

Archaea have phospholipids built from branched fatty acids.

Why aren't Archaea discussed as much as bacteria? A) Archaea are only found in a few limited environments. B) Archaea infections are easy to treat. C) Archaea haven't been linked to human diseases. D) Archaea are not part of the human microbiome. E) Archaea only live in extreme environments.

Archaea haven't been linked to human diseases.

How does the cell wall of bacteria and archaea differ? A) Bacteria use peptidoglycan. B) Archaea use peptidoglycan. C) Bacteria use pseudopeptidoglycan. D) Archaea have little diversity in the makeup of their cell walls. E) Bacteria have a lot of diversity in the makeup of their cell walls.

Bacteria use peptidoglycan.

Which of the following is true about endospores? A) Endospores are metabolically active structures. B) Endospores are highly resistant to environmental stress such as heat, drying, freezing, and radiation. C) Endospores are only viable for a short time. D) Endospores are considered reproductive structures.

Endospores are highly resistant to environmental stress such as heat, drying, freezing, and radiation.

Which of the following statements is false? A) Archaea and Bacteria are prokaryotic domains. B) Both Archaea and Bacteria are unicellular. C) Eukaryotic cells evolved from prokaryotic cells. D) Eukaryotes have a much simpler genetic makeup than prokaryotic cells.

Eukaryotes have a much simpler genetic makeup than prokaryotic cells.

A capsule is a well-organized glycocalyx that causes increased phagocytosis by host immune cells during an infection. A) True B) False

False

A capsule is one type of glycocalyx that is fairly unorganized and loosely associated with the cell wall. A) True B) False

False

Bacterial DNA can be found in the nucleus of the cell. A) True B) False

False

Binary fission is more complicated than mitosis. A) True B) False

False

Prokaryotic cells that move in response to oxygen levels are said to display chemotaxis. A) True B) False

False

Why are Gram-negative bacteria more resistant than Gram-positive bacteria to damage by certain chemical agents like lysozyme?

Gram-negative bacteria have an outer membrane as part of their cell wall.

Why is the acid-fast stain clinically useful? A) It confirms the results of the Gram stain. B) It confirms that a single dose of antibiotics is enough to kill the bacteria. C) It identifies the causative agent of strep throat and Scarlet fever. D) It identifies the causative agent of leprosy and tuberculosis.

It identifies the causative agent of leprosy and tuberculosis.

How are L-forms different than Mycoplasma bacteria? A) L-forms have never had a cell wall. B) L-forms live inside plant cells. C) L-forms live inside animal cells. D) L-forms are resistant to certain environmental stresses such as boiling and autoclaving. E) L-forms are susceptible to antibiotics that target the cell wall.

L-forms are resistant to certain environmental stresses such as boiling and autoclaving.

Why is it so difficult to kill acid-fast bacteria? A) The acid in the bacteria denatures most antibiotics before they can work. B) The bacteria are able to quickly break down several types of antibiotics before the concentration can reach dangerous levels. C) Mycolic acid in the cell wall makes it very difficult for antimicrobial drugs to enter cells. D) The bacteria are very motile and can travel to areas with a lower concentration of hazardous chemicals. E) They form endospores that are highly resistant to antibiotics.

Mycolic acid in the cell wall makes it very difficult for antimicrobial drugs to enter cells.

Why are most prokaryotic cells small? A) Nutrient diffusion is most efficient for smaller cells. B) Intracellular inclusions demand that cell size be small. C) Storage bodies within a cell enable cells to be small so they need fewer nutrients. D) A low surface area-to-volume ratio helps smaller cells divide easier. E) A high surface area-to-volume ratio helps smaller cells divide easier.

Nutrient diffusion is most efficient for smaller cells.

Which of the following is true about ribosomes? A) Antibiotics often take advantage of functional differences between prokaryotic and eukaryotic ribosomes. B) Ribosomes are organelles made of RNA and carbohydrates. C) Prokaryotic ribosomes have a lower overall mass and diameter than eukaryotic ribosomes. D) Ribosomes build amino acids by linking together nucleic acids.

Prokaryotic ribosomes have a lower overall mass and diameter than eukaryotic ribosomes.

Which of the following is false about the bacterial cytoskeleton? A) The bacterial cytoskeleton is composed of long protein filaments. B) The bacterial cytoskeleton acts as scaffolding to organize cell division. C) The bacterial cytoskeleton directs the construction of the rigid cell wall. D) The bacterial cytoskeleton contains actin and tubulin proteins.

The bacterial cytoskeleton contains actin and tubulin proteins.

What happens when you place a bacterial cell into a hypertonic solution? A) The cell will undergo plasmolysis. B) The cell will lyse. C) There will be no effect on the cell. D) The cell will burst. E) The cell will swell.

The cell will undergo plasmolysis.

Penicillin (an antibiotic that prevents peptidoglycan from forming during cell division) is added to a bacterial culture, and after several hours the bacteria are placed in a hypotonic environment. What is the likely outcome? A) The cells will lyse due to a weakened cell wall. B) The cells will undergo plasmolysis. C) Water will be drawn into the cells, but the cell wall will prevent them from lysing. D) The cells will continue to grow normally, because the hypotonic solution will prevent penicillin from working.

The cells will lyse due to a weakened cell wall.

A clinical microbiologist is studying a suspected E. coli UTI in a patient. After obtaining a sample from the patient and immediately performing a Gram stain, the bacterial cells were determined to be Gram-negative with a filamentous shape. However, after culturing the sample for 24 hours, the cells were observed to be Gram-negative bacillus-shaped cells. What is the most likely explanation for these results? A) The bacterial species mutated from a filamentous to a bacillus-shaped bacterial species. B) The sample was contaminated during culturing. C) The organism is pleomorphic and displays different characteristics when grown in a lab than during an infection. D) The Gram staining procedure was defective.

The organism is pleomorphic and displays different characteristics when grown in a lab than during an infection.

Bacteria that have flagella at both poles of the cell are described as amphitrichous. A) True B) False

True

Bacteria that have periplasmic flagella always have a spirochete shape. A) True B) False

True

Gram-positive bacteria stain purple when the Gram stain is complete. A) True B) False

True

Spirochetes move in a corkscrew-rotary motion due to a specialized periplasmic flagellum. A) True B) False

True

Which of the following is incorrect when E. coli cause a UTI? A) Within the first few hours of invading host tissues, E. coli cells triple in size. B) When inside host cells, E. coli exist as nonmotile rods. C) As the infection progresses, E. coli pass through a stage where they appear as cocci. D) When infection has been established, the E. coli return to being motile rods that swim away from biofilms to perpetuate infections.

Within the first few hours of invading host tissues, E. coli cells triple in size.

How can cells increase the fluidity of their plasma membrane? A) move to colder temperatures B) a lower proportion of unsaturated fats in the fatty acid portion of phospholipids C) fewer phospholipids in the plasma membrane D) a higher proportion of unsaturated fats in the fatty acid portion of phospholipids E) remove double bonds in the hydrocarbon backbone

a higher proportion of unsaturated fats in the fatty acid portion of phospholipids

Periplasmic flagella are unlike most flagella because they A) move their flagella in a counter-clockwise direction. B) move their flagella in a clockwise direction. C) are located in the space between the plasma membrane and the peptidoglycan. D) have fibers that stick into the cytoplasm for a better hold. E) are located in the space between the peptidoglycan and the outer membrane.

are located in the space between the peptidoglycan and the outer membrane

Membrane proteins perform all of the following functions except A) transporters. B) anchors. C) receptors. D) blocking cell division

blocking cell division

Most prokaryotic cells reproduce A) sexually. B) by mitosis. C) by meiosis. D) by binary fission. E) extremely quickly.

by binary fission.

Cell shape is determined by which of the following? A) the way cells move through their media B) cell wall and cytoskeleton components C) the way cells divide D) whether or not the species is pathogenic

cell wall and cytoskeleton components

In which of the following environments do Gram-positive not have a survival advantage over Gram-negative bacteria? A) exposure to penicillin-based drugs B) dry environment C) mechanical crushing D) needing to adhere to a host

exposure to penicillin-based drugs

Which type of cellular transport uses transport proteins and moves substances from an area of high concentration to an area of low concentration? A) simple diffusion B) facilitated diffusion C) primary active transport D) secondary active transport E) phosphotransferase system

facilitated diffusion

Short, bristle-like structures that extrude from the cell surface are called A) fimbriae. B) pili. C) flagella. D) cilia. E) mating bridges.

fimbriae

What is the function of a carboxysome? A) fix carbon B) store energy C) store carbon D) protect against oxygen radicals E) acts as a magnetic compass to guide bacteria

fix carbon

Which of the following structures do not help the bacteria adhere to surfaces? A) flagella B) fimbriae C) pili D) slime layer

flagella

Which of the following is an example of an inclusion body? A) ribosomes B) magnetosomes C) lysosomes D) endosomes

magnetosomes

In order to maintain a fluid plasma membrane in cold conditions, bacteria commonly have A) more short unsaturated fatty acids in their phospholipids. B) more long saturated fatty acids in their phospholipids. C) more cholesterol in their phospholipids. D) less concentrated phospholipids. E) more concentrated phospholipids.

more short unsaturated fatty acids in their phospholipids.

The genetic material of bacteria can be found in the A) nucleus. B) nucleolus. C) nucleoid. D) nucleosome. E) cytoskeleton.

nucleoid

Which of the following does not enable bacterial endospores to be heat resistant? A) spore coat B) exosporium C) low water content D) peptidoglycan

peptidoglycan

Bacteria that have flagella distributed all over the cell surface are described as (having) A) monotrichous. B) lophotrichous. C) amphitrichous. D) peritrichous. E) periplasmic flagella.

peritrichous

Which of the following structures allow bacteria to transfer genetic information through conjugation? A) fimbriae B) pili C) glycocalyx D) slime layer

pili

Bacterial cells that have the ability to take on different cell shapes are known as A) chemotactic. B) pyloric. C) pleomorphic. D) pallidic. E) biphasic.

pleomorphic

Which of the following arrangements is sometimes referred to as having a beads-on-a-string appearance? A) diplococci B) streptococci C) staphylococci D) palisade

streptococci

What term most correctly describes when energy released by the flow of an ion from high to low concentration fuels the transport of an unrelated substance from low to high concentration but in the same direction? A) primary active transport B) tertiary active transport C) symport D) antiport E) phosphotransferase system

symport

Which of the following cell shapes look like a comma? A) bacilli B) spirochetes C) stella D) vibrio

vibrio