Chapter Four Microbiology – Flashcards

Which of the following statements is INCORRECT regarding prokaryotic cells? They lack membrane-enclosed organelles. Their DNA is not enclosed within a membrane. They lack a plasma membrane. They reproduce by binary fission. They typically have a circular chromosome.

Which drawing in the figure is a tetrad? a b c d e

Which drawing in the figure possesses an axial filament? a b c d e

Which drawing in the figure is streptococci? a b c d e

How do spirochetes and spirilla differ? Spirochetes and spirilla are basically the same organisms and the terms can be used interchangeably. Spirochetes do not have a cell wall but spirilla do. Spirilla are found in chains of cells whereas spirochetes exist as individual cells. Spirilla have an external flagella but spirochetes have axial filaments. Spirochetes have a rigid, corkscrew shape while spirilla are helical and more flexible.

The cell walls of bacteria are responsible for the shape of the bacteria and the difference in the Gram stain reaction. True False

Functions of the glycocalyx include all of the following EXCEPT protection against dehydration. increased virulence. biofilm formation. binary fission. source of nutrition.

Which structure acts like an "invisibility cloak" and protects bacteria from being phagocytized? slime layer cell membrane capsule cell wall fimbriae

Which of the following terms best describes the cell in the figure? lophotrichous flagella amphitrichous flagella peritrichous flagella monotrichous flagellum axial filament

The difference between simple diffusion and facilitated diffusion is that facilitated diffusion requires ATP. requires transporter proteins. moves materials from a higher to a lower concentration. does not require ATP. moves materials from a lower to a higher concentration.

You have isolated a motile, gram-positive cell with no visible nucleus. You can safely assume that the cell has 9 pairs + 2 flagella. has a mitochondrion. has cilia. lives in an extreme environment. has a cell wall.

Fimbriae and pili differ in that pili are used for attachment to surfaces. pili are used for transfer of DNA and motility. there are only one or two pili per cell. pili are used to transfer DNA. pili are used for motility.

Which of the following statements about gram-negative cell walls is FALSE? They are sensitive to penicillin. Their Gram reaction is due to the outer membrane. They have an extra outer layer composed of lipoproteins, lipopolysaccharides, and phospholipids. They are toxic to humans. They protect the cell in a hypotonic environment.

The terms "run" and "tumble" are generally associated with clustering properties of certain rod-shaped bacteria. taxic movements of the cell in response to attractants or repellents. cell wall fluidity. cell membrane synthesis.

In the figure, which diagram of a cell wall is a gram-negative cell wall? a b both a and b neither a nor b The answer cannot be determined based on the information provided.

In the figure, which diagram of a cell wall possesses lipid A/endotoxin responsible for symptoms associated with infection? a b both a and b neither a nor b The answer cannot be determined based on the information provided.

In the figure, which diagram of a cell wall has a structure that protects against osmotic lysis? a b both a and b neither a nor b The answer cannot be determined based on the information provided.

In the figure, which diagram of a cell wall is decolorized by alcohol? a b both a and b neither a nor b The answer cannot be determined based on the information provided.

In the figure, which diagram of a cell wall is resistant to many antibiotics (e.g., penicillin)? a b both a and b neither a nor b The answer cannot be determined based on the information provided.

In the figure, which diagram of a cell wall contains teichoic acids? a b both a and b neither a nor b The answer cannot be determined based on the information provided.

Antibiotics that target the cell wall are an effective treatment against many pathogenic bacteria. True False

Spheroplasts, protoplasts, and mycoplasms are bacterial cells without cell walls. True False

If you observe rod-shaped red cells after the Gram stain, you can assume their cell walls contain endotoxin. True False

Which of the following is NOT a typical characteristic of most bacterial plasma membranes? contains proteins contains cholesterol is selectively permeable composed of a phospholipid bilayer site of energy production

Which of the following statements best describes what happens when a bacterial cell is placed in a solution containing 5% NaCl? Water will move out of the cell. Sucrose will move into the cell from a higher to a lower concentration. The cell will undergo osmotic lysis. Water will move into the cell. No change will result; the solution is isotonic.

In bacteria, photosynthetic pigments are found in cytoplasm. chromatophores. mesosomes. ribosomes. chloroplasts.

Which of the following is NOT part of the passive transport process? concentration gradient transporter proteins ATP plasma membrane aquaporins

Which statement regarding the structure or function of ribosomes is correct? The ribosomes in the prokaryote are slightly larger than those found in the eukaryotic endoplasmic reticulum. Ribosomes are the sites of lipid biosynthesis in both prokaryotes and eukaryotes. In eukaryotes, the ribosomes found in chloroplasts and mitochondria are 70S ribosomes, which are similar in size to prokaryotic ribosomes. Ribosomes are found both free-floating and attached to the rough endoplasmic reticulum in eukaryotes and in prokaryotes.

Which of the following is found in the cytoplasm of prokaryotic cells but is ABSENT from the cytoplasm of eukaryotic cells? DNA enzymes water a cytoskeleton

Which of the following statements accurately describes specific bacterial cell walls? In gram-negative bacteria, the thin layer of peptidoglycan is surrounded by an outer membrane made of phospholipids, lipopolysaccharides, and proteins. In bacteria with acid-fast cell walls, the carboxylic acid in the walls forms a layer outside a thin layer of hydrophilic polypeptides. Gram-negative bacterial cell walls contain teichoic acids, whereas the cell walls of gram-positive bacteria do not. The cell walls of gram-negative bacteria contain many more layers of peptidoglycan than those of gram-positive bacteria.

You are observing a Gram stain of spherical-shaped microorganisms that are linked in a chain and stain purple. How would you describe these bacteria using the correct terminology for the cell shape and arrangement? gram-positive streptococci gram-negative staphylococci gram-positive tetrads gram-positive coccobacilli

Endospores are a reproductive structure. True False

The DNA found in most bacterial cells is surrounded by a nuclear membrane. utilizes histones for chromosomal packaging. is found in multiple copies. is circular in structure. is linear in structure.

Which one of the following pairs is mismatched? lipid inclusions - energy reserve sulfur granules - energy reserve metachromatic granules - phosphate storage ribosomes - carbon storage gas vacuoles - flotation

Which of the following statements is correct about passive diffusion? It is a process in which molecules move from a region of lower concentration to one of higher concentration (or up a concentration gradient). It is a process in which molecules move from a region of higher concentration to a region of lower concentration (or down a concentration gradient). It involves movement of molecules down a concentration gradient and may require a transport protein. It may require a transport protein. It requires an expenditure of energy by the cell.

Where are phospholipids most likely found in a eukaryotic cell? surrounding flagella around organelles the plasma membrane the plasma membrane, around organelles, and surrounding flagella ribosomes

Where are phospholipids most likely found in a prokaryotic cell? flagella the plasma membrane the plasma membrane and around organelles ribosomes around organelles

Antibiotics that target cell wall synthesis ultimately cause bacterial cell death as a result of cell shrinkage. inhibition of molecular transport. plasmolysis. osmotic lysis. decreased synthesis of plasma membrane.

Which of the following statements is TRUE? A cell produces one endospore and keeps growing. A cell can produce many endospores. Endospores allow a cell to survive environmental changes by producing a dormant period with no growth. Endospores are easily stained in a Gram stain. Endospores are for reproduction.

Which of the following organelles most closely resembles a prokaryotic cell? mitochondrion vacuole nucleus Golgi complex cell wall