Microbiology Ch 3

The movement of bacteria in response to chemicals in their environment is called

A) chemotaxis. B) phototaxis. C) chemokinesis. D) aerotaxis. E) chemomobility.

The process in which water moves through a selectively permeable membrane in the direction of higher solute concentration is called

A) diffusion. B) facilitated diffusion. C) osmosis. D) active transport. E) filtration.

Which of the following is similar to confocal microscopy, but uses lower energy light?

A) electron microscopy B) light microscopy C) multiphoton microscopy D) cryo-electron microscopy E) None of these

A resistant dormancy structure produced by some bacteria in response to adverse conditions, and that germinates when conditions become favorable is called a(n)

A) endospore. B) sporangium. C) vegetative cell. D) plasmid. E) porin.

A lipopolysaccharide molecule that is released from the outer membrane of Gram-negative bacteria cell walls and causes the symptoms of the bacterial infection is called:

A) porin B) endotoxin C) exotoxin D) plasmid E) peptidoglycan

Many bacterial throat infections are aggravated by the fact that the bacteria can attach to throat cells. Drugs can be developed that reduce the ability of bacteria to stick to surfaces. Which of the following structures would most likely be affected by these drugs?

A) storage granules B) plasmid C) cell membrane D) flagella E) fimbriae

The chromosome of prokaryotes is located in which of the following regions?

A) the nucleus B) the nucleoid C) the plasmid D) the periplasmic space E) the capsule

Gram-positive bacteria

Bacteria that have a thick peptido glycan cell wall, and no outer membrane. They stain very darkly (purple) in Gram stain.

Gram-negative bacteria

Bacteria that have a thin peptidoglycan cell wall covered by an outer plasma membrane. They stain very lightly (pink) in Gram stain. Gram-negative bacteria are typically more resistant to antibiotics than Gram-positive bacteria.

Plasmid

Extrachromosomal DNA molecule; found in many bacteria. Replicates independently of the chromosome.

Pili

Hair like projections that allow bacteria cells to stick to surfaces; some types involved in a mechanism of DNA transfer.

Transport Systems

Mechanism used to transport nutrients and other small molecules across the cytoplasmic membrane.

The ability of a microscope to differentiate between two close objects or points is referred to as

Resolution

Ribosome

Structure intimately involved in protein synthesis.

Flagellum

Structure that provides mechanism for motility.

Peptidoglycan

a macromolecule that provides rigidity to cell wall and is found only in bacteria.

Endospore

dormant bacterial cell able to survive for long periods of time during extreme environmental conditions

Lipopolysaccharide

molecule that makes up the outer layer of the outer membrane of Gram negative bacteria

Chemotaxis

movement of a cell or organism toward or away from a chemical stimulus

When observing live organisms, the specimen is best prepared as a wetmount.

A) True B) False

Which of the following will occur if a prokaryotic cell is placed in a solution that has a higher concentration of solutes (that cannot readily diffuse across the plasma membrane) than does the cytoplasm of the cell?

A) Water will move into the cell, pushing the cell membrane against the cell wall. B) Water will leave the cell causing the cell membrane to be pulled away from the cell wall. C) Water leaving the cell will equal the volume of water entering the cell; no net change in cell pressure will occur. D) Channels would open and the solute would equalize in concentration on both sides of the membrane. E) Both water and solute will move across the cell membrane until equilibrium is reached.

Chemicals that deplete ATP in a cell are most likely to affect which of the following cell transport systems?

A) active transport B) passive transport C) facilitated diffusion D) diffusion E) osmosis

Transport processes that require the input of energy by the cell to move molecules against a concentration gradient are called

A) active transport. B) facilitated diffusion. C) diffusion. D) transporters. E) passive transport.

Mitochondria and bacteria are morphologically very similar. One sure way of telling the difference between the two is by analyzing differences in the

A) cell membrane. B) ribosomes. C) nucleus. D) DNA. E) None of these choices are correct.

Capsule

A Gelatinous outer layer enclosing some microorganisms.

Periplasm

A gel-like region between the outer surface of the cytoplasmic membrane and the inner surface of the lipopolysaccharide layer of gram-negative Bacteria.

Cytoplasmic membrane

A phopholipid bilayer embedded with proteins that surrounds the cytoplasm and defines the boundary of the cell.

Which of the following statements about the outer membrane of Gram-negative cell walls is FALSE?

A) The outside leaflet is largely composed of lipopolysaccharides. B) The outer membrane contains porins that allow passage of molecules and ions directly into the periplasm or cytoplasm. C) The outer membrane acts as a protective barrier to many toxic compounds. D) The Lipid A part of the lipopolysaccharide molecule is toxic to humans. E) None of these choices are correct.

Which of the following statements about plasmids is FALSE?

A) They are extrachromosomal pieces of DNA. B) A single cell can carry only one type of plasmid. C) The cell ordinarily does not require the plasmid for survival. D) Plasmids may be advantageous to the cell. E) Plasmids can be transferred to other bacteria.

Aquaporins are pore-forming membrane lipids that specifically allow water molecules to pass through.

A) True B) False

Which of the following structures do bacteria use for attachment to surfaces or to each other?(return)1. capsule(return)2. lipopolysaccharide(return)3. flagella(return)4. pili(return)5. fimbria

A) 1,2 B) 1,2,5 C) 1,2,3,4 D) 1,4,5 E) 1,2,3,4,5

You are given a prepared slide and are told that it is a streptobacillus. Without even looking at the slide under the microscope, you know which of the following? 1. The bacteria are linked together in chains. 2. The bacteria are spherical in shape. 3. The bacteria are in grape-like clusters. 4. The bacteria are rod-shaped. 5. The bacteria are Gram-negative.

A) 1,2. B) 1,4. C) 2,3. D) 2,4. E) 1,4,5.

Which of the following is/are characteristic(s) of Gram-positive cell walls? 1. multiple overlapping layers of peptidoglycan; 2. teichoic acid; 3. an outer membrane outside of the peptidoglycan; 4. lipid A

A) 1. B) 1,2. C) 1,2,3. D) 2,3. E) 1,2,3,4.

If your microscope has a 10X ocular lens and you are using the 40X objective lens, what is the total magnification?

A) 100X B) 1000X C) 50X D) 400X E) The magnification cannot be determined

Bacteria of the genus Mycobacterium are difficult to stain because of the waxy material associated with their unique cell walls. Which of the following stains is used to stain Mycobacterium?

A) Gram stain B) acid-fast stain C) counterstain D) endospore stain E) simple stain

What action does penicillin have that makes it effective in treating many types of bacterial infections?

A) It interferes with DNA transcription. B) It interferes with peptidoglycan synthesis. C) It breaks down the cell wall. D) It blocks the electron transport system. E) It directly damages the plasma membrane.

Which of the following statements about Gram-staining is FALSE?

A) It separates bacteria into two major groups, Gram-negative and Gram-positive. B) Bacteria stain differently based on differences in their cell wall composition. C) The primary stain will stain both Gram-positive and Gram-negative bacteria purple. D) After staining is complete, Gram-positive bacteria will appear purple and Gram-negative bacteria will appear red. E) None of these choices are correct.

Which of the following statements about prokaryote structure is FALSE?

A) Most prokaryotes possess a cell wall made of peptidoglycan. B) Prokaryotes possess a single chromosome inside a nucleus. C) Some prokaryotes possess flagella for motility. D) Cytoplasmic ribosomes are used for protein synthesis. E) All prokaryotes possess a plasma membrane.

Which of the following statements about prokaryote structure is FALSE?

A) Most prokaryotes possess a cell wall made of peptidoglycan. B) Prokaryotes typically possess a single chromosome. C) Some prokaryotes possess flagella for motility. D) Cytoplasmic ribosomes are used for protein synthesis. E) Few prokaryotes possess a plasma membrane.

Which of the following statements about the cell membrane is FALSE?

A) Phospholipid molecules are arranged with the hydrophobic tails facing each other in the middle of the membrane. B) Phospholipids in the cell membrane are arranged so that the collective hydrophilic parts of the molecules line both the outside and inside (cytoplasmic) facing interfaces of the cell. C) Proteins are freely movable within the membrane. D) The membrane is impermeable to all molecules except water. E) None of these choices are correct.

When a bacterial cell is placed in a hypotonic solution, which will happen?

A) Solutes will flow into the cell. B) Water will flow out of the cell. C) The water will not move. D) Water will flow into the cell. E) None of these choices are correct.

The differential interference contrast microscope causes the image of the specimen to appear three-dimensional.

A) True B) False