Mastering Micro Biology Chapter 4

List some characteristics of Prokaryotic Cells

-70S ribosomes -Circular chromosomes, not enclosed w/in a nuclear envelope -Peptidoglycan-containing cell wall -Flagella that rotate, composed of flagellin

In the figure, which diagram of a cell wall contains teichoic acids?

A

List some characteristics of Eukaryotic Cells

-80S ribosomes -Mitochondria -Endoplasmic reticulum -Linear chromosomes enclosed within a nuclear envelope -Flagella that wave, composed of micrtubules -Cellulose of chitin-containing cell wall -Golgi apparatus -Lysosomes

What are some antibacterial strategies that would likely be selectively toxic for bacteria?

-Interfering with translation at 70S ribosomes -Inhibition of fimbriae synthesis -Inhibition of peptidoglycan synthesis (Those structures of processes that are unique to bacterial (prokaryotic) cells make excellent targets for antibacterial drugs. These include the peptidoglycan of the bacterial cell wall, the 70s bacterial ribosome, and potentially the bacterial fimbriae. Lysosomes and microtubules are found in eukaryotic cells and would not be appropriate targets for antibacterial drugs.)

List some attributes of Gram-positive bacterial cell walls

-Single lipid bilayer membrane -teichoic acids -thick layer of peptidoglycan

List some attributes of Gram-negative bacterial cell walls

-dual lipid bilayer membranes -thin layer of peptidoglycan -lipopolysaccharides -periplasmic space

Which of the following scenarios is an example of bacterial motility? A. A bacterium traveling through the air from a sneeze B. A bacterium being removed from the skin during hand washing C. A bacterium moving towards a food source

C. A bacterium moving towards a food source

In a hypertonic solution, a bacterial cell will typically

plasmolyze.

The difference between simple diffusion and facilitated diffusion is that facilitated diffusion

requires transporter proteins.

One of the ways smooth endoplasmic reticulum (ER) differs from rough endoplasmic reticulum is that rough ER is covered by

ribosomes (Ribosomes dock on the rough ER, and proteins are completed inside the rough ER)

Which membrane transport mechanism requires ATP?

Active transport

Which drawing in the figure possesses an axial filament?

A

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

A. In eukaryotes, the ribosomes found in chloroplasts and mitochondria are 70S ribosomes, which are similar in size to prokaryotic ribosomes. (The fact that prokaryotic ribosomes and the ribosomes in mitochondria and chloroplasts are the same size provides evidence for the endosymbiosis theory)

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

A. They are sensitive to penicillin.

Which of the following is NOT part of the passive transport process?

ATP

Where in a cell is ATP made?

ATP is made in mitochondria.

Function of the fimbriae

Attachment to other bacteria and to surfaces

In the figure, which diagram of a cell wall contains porins?

B

In the figure, which diagram of a cell wall is a gram-negative cell wall?

B

In the figure, which diagram of a cell wall is decolorized by alcohol?

B

In the figure, which diagram of a cell wall is resistant to many antibiotics (e.g., penicillin)?

B

In the figure, which diagram of a cell wall possesses lipid A/endotoxin responsible for symptoms associated with infection?

B

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

B. It involves movement of molecules down a concentration gradient and may require a transport protein.

Which of the following pairs is mismatched? A. Golgi complex secretion B. centrosome food storage C. mitochondria ATP production D. lysosome digestive enzymes E. endoplasmic reticulum internal transport

B. centrosome food storage

Which of the following is NOT a functionally analogous pair? A.mitochondria - prokaryotic plasma membrane B. cilia - pili C. 9+2 flagella - bacterial flagella D. chloroplasts - thylakoids E. nucleus -nucleiod region

B. cilia - pili

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

C. In gram-negative bacteria, the thin layer of peptidoglycan is surrounded by an outer membrane made of phospholipids, lipopolysaccharides, and proteins. (The difference in peptidoglycan thickness and the outer membrane distinguishes gram-positive from gram-negative bacteria)

Sequence the path of a solute from the external environment to the cytoplasm of a prokaryotic cell.

Capsule --> cell wall --> plasma membrane

Function of the pilus

Conduit for transfer of DNA from one cell to another

Function of the nucleoid

Containing DNA/genetic information of the cell

What are the structures that are found in ALL bacterial cells?

Cytoplasm, Plasma membrane, Ribosomes, and Nucleoid (Capsules, fimbriae, pili, flagella, and even the cell wall are not found in all bacteria.)

Which drawing in the figure is streptococci?

D

Which of the following facts does NOT provide evidence for the endosymbiotic theory? A. The same antibiotics that inhibit protein synthesis in prokaryotes also inhibit protein synthesis within mitochondria and chloroplasts. B. Mitochondria and chloroplasts contain circular DNA, similar to the DNA in prokaryotes. C. The ribosomes contained within mitochondria and chloroplasts are very similar to prokaryotic ribosomes. D. Prokaryotes contain peptidoglycan in their cell walls.

D. Prokaryotes contain peptidoglycan in their cell walls. (This is not evidence supporting the endosymbiotic theory; rather, it highlights a difference between bacteria and mitochondria and chloroplasts)

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

D. Water will move out of the cell.

Each of the following statements concerning the gram-positive cell wall is true EXCEPT A. it maintains the shape of the cell. B. it is sensitive to lysozyme. C. it contains teichoic acids. D. it protects the cell in a hypertonic environment. E. it is sensitive to penicillin.

D. it protects the cell in a hypertonic environment.

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

DNA (The DNA in eukaryotes is found within the nucleus, not in the cytoplasm)

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

E. Endospores allow a cell to survive environmental changes by producing a dormant period with no growth.

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

E. They lack a plasma membrane.

T/F: A cell wall is a requirement for all living bacteria.

FALSE

T/F: Endospores are a reproductive structure.

FALSE

T/F: Many enzymes in both prokaryotic and eukaryotic cells are compartmentalized within organelles.

FALSE

T/F: The composition of the cell wall allows for the expansion and contraction of the cell wall in response to the gain or loss of water from the cell.

FALSE

T/F: Bacterial flagella have a biological motor that spins within the cell wall and is powered by ATP. This allows the flagella to spin in a whiplike motion to propel the bacterium.

FALSE (The biological motor that spins the flagella for bacterial propulsion is powered by the electron imbalance across the membrane that generates a gradient that the cell can harness for energy via proton motive force)

Which bacterial structures are likely to be antigens, to which host antibodies bind, marking the invader for phagocytosis

Flagella, Capsule, Fimbriae, and Cell Wall (Surface components (capsule, cell wall, fimbriae, flagella) are more likely to be "visible" to the host as antigens. Components in the cell's interior (ribosomes, nucleoid, plasmid), are not as likely to serve as useful antigens for the host since they are sequestered within the bacterial cell. Even though they may be antigenic, antibodies against them will not be able to tag the SURFACE of a bacterial cell.)

Which one of the following organisms has a cell wall? fungi mycoplasmas protoplasts L forms animal cells

Fungi

What is the advantage to spirochetes of the corkscrew movement provided by axial filaments?

It allows the cells to move more easily through viscous human tissues and fluids, such as mucus.

Key differences between Gram-positive and Gram-negative cell walls

It is the thickness of the peptidoglycan layer that determines the staining reaction. The outer membrane and more specifically the lipoopolysaccharide (LPS) is responsible for some of the toxic properties of gram negative bacteria.

A strain of Streptococcus pneumoniae is no longer able to synthesize its capsular polysaccharide. What is a likely outcome?

It will be readily phagocytized upon entering the host (The presence of a polysaccharide capsule is a well-known virulence factor of Streptococcus pneumoniae. Encapsulated strains typically produce smooth glistening, mucoid-appearing colonies. Non-encapsulated strains produce flat, dry colonies. Inoculating mice with these two strains readily demonstrates the virulence of the encapsulated strains, and the lack of virulence of the non-encapsulated strains.)

A strain of Neisseria gonorrhoeae has been genetically altered and can no longer produce fimbriae. What is a likely outcome?

It will be unable to adhere to host tissue and establish infection (Fimbriae are an important virulence factor of Neisseria gonorroheae. These delicate structures support adhesins which enable Neisseria gonorrohoeae strains to adhere to the tissues of a host and establish infection)

Function of the plasma membrane

Location of respiratory enzymes

Function of the capsule

Protection from phagocytosis

Function of the cell wall

Protection of cell from osmotic lysis

Function of ribosomes

Protein synthesis

Where are lipids made in the cell?

Smooth ER

T/F: Antibiotics that target the cell wall are an effective treatment against many pathogenic bacteria.

TRUE

T/F: If you observe rod-shaped red cells after the Gram stain, you can assume their cell walls contain endotoxin.

TRUE

T/F: The cell walls of bacteria are responsible for the shape of the bacteria and the difference in the Gram stain reaction.

TRUE

How do axial filaments differ from regular bacterial flagella?

The axial filament is located between the cell membrane and the outer membrane.

What will happen if a bacterial cell is pretreated with a lysozyme solution, then placed in distilled water?

The cell will undergo osmotic lysis.

Which type of solution would cause a bacterium with a weak or damaged cell wall to burst as water moves into the cell?

a hypotonic solution (A hypotonic solution has a lower solute concentration than the inside of the cell; therefore, water would move into the cell, which might cause a weak or damaged cell to rupture.)

By which of the mechanism can a cell transport a substance from a lower to a higher concentration?

active transport

Which structure acts like an "invisibility cloak" and protects bacteria from being phagocytized?

capsule

Which of the following is NOT characteristic of the glycocalyx found in bacteria?

creates a slimy, slippery coating that prevents bacteria from attaching to surfaces (This is not characteristic of the glycocalyx. In fact, the glycocalyx enables the bacteria to attach to surfaces and create biofilms)

The structural framework in a cell is the

cytoskeleton (The cytoskeleton is the structural framework in a cell ("cyto" refers to cell and "skeleton" refers to a structural framework))

Axial filaments are composed of

endoflagella.

Which of the following is part of the endomembrane system?

golgi apparatus (The endomembrane system includes the ER, the Golgi apparatus, lysosomes, and vesicles. It manufactures, processes, and transports lipids and proteins. The Golgi apparatus processes and packages proteins)

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-positive cells stain purple, and the term "streptococci" indicates a chain of spherical-shaped cells)

You have isolated a motile, gram-positive cell with no visible nucleus. You can safely assume that the cell

has a cell wall.

The DNA found in most bacterial cells

is circular in structure.

Which of the following organelles breaks down worn-out organelles?

lysosomes (Lysosomes contain digestive enzymes and break down worn-out organelles)

What carries instructions for making proteins from the nucleus into the cytoplasm?

mRNA (The "m" in mRNA stands for "messenger"; mRNA is the messenger that carries genetic instructions from the nucleus to the cytoplasm)

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

mitochondrion

Function of the Flagella

motility

Where is the genetic information of the cell stored?

nucleus (DNA is the genetic information of the cell, and it is stored in the nucleus)

Antibiotics that target cell wall synthesis ultimately cause bacterial cell death as a result of

osmotic lysis.

Amino acids and fatty acids are oxidized in which organelles?

peroxisome (Peroxisomes contain the enzymes oxidase and catalase, which are used in the oxidation of many substances.)

Fimbriae and pili differ in that

pili are used for transfer of DNA and motility.

What structure acts as a selective barrier, regulating the traffic of materials into and out of the cell?

plasma membrane (The plasma membrane surrounds the cell and regulates the movement of materials into and out of the cell)

What is the composition of the peptidoglycan layers found in the cell wall of bacteria?

short amino acid chains, NAG, NAM, and some lipid proteins

Axial filaments are found on

spirochetes

Where are phospholipids most likely found in a prokaryotic cell?

the plasma membrane

Which of the following eukaryotic organelles is correctly matched with its function? mitochondrion--protein synthesis flagellum--protection vacuole--storage of materials glycocalyx--transport

vacuole--storage of materials ( Vacuoles provide storage for many important cellular substances)