Chapter 4 Microbiology

Describe each of the following flagellar arrangements: A. lophotrichous B. monotrichous C. peritrichous D. amphitrichous E. polar

A. tuft of flagella at one end B. single flagella at one end C. multiple flagella from all around D. two tufts of flagella from both ends E. can be tuft of flagella at one end, single flagella at one end, or two tufts of flagella from both ends

What group of microbes is characterized by cells that form filaments, reproduce by spores, and have peptidoglycan in their cell walls?

Actinomycetes

Which statement best describes what happens when a gram-negative bacterium is placed in distilled water and penicillin? a. No change will result; the solution is isotonic b. Water will move into the cell c. Water will move out of the cell d. The cell will undergo osmotic lysis e. Sucrose will move into the cell from an area of higher concentration to one of lower concentration

B. Water will move into the cell

The antibiotic amphotericin B disrupts plasma membranes by combining with sterols; it will affect all of the following cells EXCEPT: a. animal cells b. gram-negative bacterial cells c. fungal cells d. Mycoplasma cells e. plant cells

B. gram-negative bacterial cells

Which of the following pairs is mismatched? a. glycocalyx--adherence b. pili--reproduction c. cell wall--toxin d. cell wall--protection e. plasma membrane--transport

B. pili--reproduction

Which of the following statements best describes what happens to a cell exposed to polymyxins that destroy phospholipids? a. In an isotonic solution, nothing will happen b. In a hypotonic solution, the cell will lyse c. Water will move into the cell d. Intracellular contents will leak from the cell e. Any of the above might happen

D. Intracellular contents will leak from the cell

Which of the following pairs is mismatched? a. metachromatic granules--stored phosphates b. polysaccharide granules--stored starch c. lipid inclusions--poly-B-hydroxybutyric acid d. sulfur granules--energy reserve e. ribosomes--protein storage

E. Ribosomes--protein storage

Which of the following is false about fimbriae? a. They are composed of protein b. They may be used for attachment c. They are found on gram-negative cells d. They are composed of pilin e. They may be used for motility

E. They may be used for motility

Answer the following questions using the diagrams provided, which represent cross section of bacterial cell walls. A. Which diagram represent a gram-positive bacterium? How can you tell? B. Explain how the Gram stain works to distinguish these two types of cell walls C. Why does penicillin have no effect on most gram-negative cells? D. How do essential molecules enter cells through each wall? E. Which cell wall is toxic to humans?

A. Diagram A refers to a gram-positive bacterium because the lipopolysaccharide-phospholipid-lipoprotein layer is absent B. The gram-negative bacterium initially retains the violet stain, but it is released when the outer membrane is dissolved by the decolorizing agent. After the dye-iodine complex enters, it becomes trapped by the peptidoglycan of gram-positive cells. C. The outer layer of the gram-negative cells prevents penicillin from entering the cells D. Essential molecules diffuse through the gram-positive wall. Porins and specific channel proteins in the gram-negative outer membrane allow passage of small water-soluble molecules. E. Gram-negative

Which statement best describes what happens when a gram-positive bacterium is placed in an aqueous solution of lysozyme and 10% sucrose? a. No change will result; the solution is isotonic b. Water will move into the cell c. Water will move out of the cell d. The cell will undergo osmotic lysis e. Sucrose will move into the cell from an area of higher concentration to one of lower concentration

A. No change will result; the solution is isotonic

Match the characteristics of eukaryotic cells with their functions. Characteristics: A. Pericentriolar material B. Chloroplasts C. Golgi complex D. Lysosomes E. Mitochondria F. Peroxisomes G. Rough ER Functions: 1. Digestive enzyme storage 2. Oxidation of fatty acids 3. Microtubule formation 4. Photosynthesis 5. Protein synthesis 6. Respiration 7. Secretion

A. Pericentriolar material--> 3. Microtubule formation B. Chloroplasts--> 4. Photosynthesis C. Golgi complex--> 7. Secretion D. Lysosomes--> 1. Digestive enzyme storage E. Mitochondria--> 6. Respiration F. Peroxisomes--> 2. Oxidation of fatty acids G. Rough ER--> 5. Protein synthesis

You have isolated a motile, gram-positive cell with no visible nucleus. You can safely assume this cell has: a. ribosomes b. mitochondria c. an ER d. a Golgi complex e. All of the above

A. ribosomes

Why is an endospore called a resting structure? Of what advantage is an endospore to a bacterial cell?

An endospore is called a resting structure because it provides a method for one cell to "rest", or survive, as opposed to grow and reproduce. The protective endospore wall allows a bacterium to withstand adverse conditions in the environment.

Starch is readily metabolized by many cells, but a starch molecule is too large to cross the plasma membrane. How does a cell obtain the glucose molecules from a starch polymer? How does the cell transport these glucose molecules across the plasma membrane?

An extracellular enzyme (amylase) hydrolyzes starch into disaccharides (maltose) and monosaccharides (glucose). A carrier enzyme (maltase) hydrolyzes maltose and moves one glucose into the cell. Glucose can be transported by group translocation as glucose-6-phosphate.

Which statement best describes what happens when a gram-positive bacterium is placed in distilled water and penicillin? a. No change will result; the solution is isotonic b. Water will move into the cell c. Water will move out of the cell d. The cell will undergo osmotic lysis e. Sucrose will move into the cell from an area of higher concentration to one of lower concentration

D. The cell will undergo osmotic lysis

Which of the following is not a distinguishing characteristic of prokaryotic cells? a. They usually have a single, circular chromosome b. They have 70S ribosomes c. They have cell walls containing peptidoglycan d. Their DNA is not associated with histones e. They lack a plasma membrane

E. They lack a plasma membrane

Compare and contrast the following: A. simple diffusion and facilitated diffusion B. active transport and facilitated diffusion C. active transport and group translocation

A. Both allow materials to cross the plasma membrane from a high concentration to a low concentration without expending energy. Facilitated diffusion requires carrier proteins. B. Both requires enzymes to move materials across the plasma membrane. In active transport, energy is expended. c. Both move materials across the plasma membrane with an expenditure of energy. In group translocation, the substrate is changed after it crosses the membrane.

Endospore formation is called ______. It is initiated by ____. Formation of a new cell from an endospore is called ______. This process is triggered by ______.

a. sporogenesis b. certain adverse environmental conditions c. germination d. favorable growth conditions

Match the structures to their functions. Structures: A. Cell wall B. Endospore C. Fimbriae D. Flagella E. Glycocalyx F. Pili G. Plasma membrane H. Ribosomes Functions: 1. Attachement to surfaces 2. Cell wall formation 3. Motility 4. Protection from osmotic lysis 5. Protection from phagocytes 6. Resting 7. Protein synthesis 8. Selective permeability 9. Transfer of genetic material

A. Cell wall--> 4. Protection from osmotic lysis B. Endospore--> 6. Resting C. Fimbriae--> 1. Attachment to surfaces D. Flagella--> 3. Motility E. Glycocalyx--> 1. Attachment to surfaces & 5. Protection from phagocytes F. Pili--> 3. Motility & 9. Transfer of genetic material G. Plasma membrane--> 2. Cell wall formation & 8. Selective permeability H. Ribosomes--> 7. Protein synthesis