Exam 2 Flashcards
Our model organism, E. coli, is which of the following:
Chemoorganotroph
Peptidoglycan synthesis occurs where within the cell?
- cytoplasm
- cell membrane
- cell wall
- cytoplasm and cell membrane
- cytoplasm and cell wall
- all of the above
ALL of the above
How does penicillin inhibit cell division?
Penicillin mimics the pentapeptide and covalently binds transpeptidase preventing the addition of peptidoglycan
What is the structure of peptidoglycan monomers?
N-acteylglucosamine -> N-acteylmuramic acid -> pentapeptide crosslinker
What is the condensed chromosome of a bacterium called?
Nucleoid
Which of the following is an accumulation of extracellular material visible by microscopy?
capsule
The rfa genes are involved in the synthesis of what molecule?
Lipopolysaccharide
What microbial product is important for biofilm formation?
Slime Layer
Which of the following best describes a bacterium’s movement?
Zig-Zag or circular random walk
What type of export pathway is used to form the flagella filament?
Type III
Which of the following is NOT a component of the bacterial flagella/chemotaxis?
Axoneme
In E. coli, smooth directional swimming is associated with…
CCW flagellar rotation
How do bacteria know when to change direction?
Stimulus of MCPs
Superoxide dismutase are enzymes that dissipates superoxide to hydrogen peroxide and oxygen and are present in aerobic organisms.
True
Which of the following secretion systems autotransport their cargo.
Type V
Which of the following statement is true for Aerobic bacteria:
oxygen serves as the terminal electron acceptor
Following is NOT true for Mesophilic bacteria
Maximum temperature at which bacterial can grow is >80 °C
Which of the following transport mechanisms does not utilize energy?
Facilitated Diffusion
Which of the following transport mechanisms modifies the transported material?
Group Transport
The F0-F1 ATPase is an example of what type of transporter?
Ion driven
Catalase are the enzymes:
All the statements are true
How do Gram-positive bacteria secrete material?
Sec Pathway
Clostridium tetani and botulism neurotoxin (BoNT) of Clostridium botulinum both are A-B toxin composed of heavy chain (B subunit) and light chain (A-subunit). Both TeNT and BoNT inhibit neuroexocytosis.
True
Which of the following is not an example of Neurotoxin
Cholera toxin
A-B toxins act as autotransporters. What class of toxin are these?
Exotoxins
Which of the following is True about injected Toxins
They are secreted directly into the host cytoplasm by Type II and VI systems
Which is an incorrect statement about Toxins
toxins are beneficial for the host
Which of the below-mentioned statements are not correct about Cholera Toxin.
It increases absorption of Na+
Bacteria use quorom sensing for what purpose?
To communicate with other bacteria in the area to work together
Pore forming Toxins secreted by bacteria kills the host cell by:
by forming pores in the cell membranes
Which of the following is NOT true about Anthrax toxin from Bacillus anthracis
It is an endotoxin
Which of the following statements are true about Gliding Motility
All are true (select all)
except Type IV Pilli
The growth of aerotolerant organisms is frequently enhanced by culture on media containing blood or other natural materials but contain catalase or peroxidase
True
Complete LPS molecule is made up of
o-antigen core polysaccharide disaccharide diphosphate fatty acids (a, b, c and d)
Select TRUE statements about Gram-Negative Bacteria
outer cell membrane
LPS represent one of the most important features of gram-negative cells
presence of LPS causes septic shock
(a, b, c)
Teichoic and Lipoteichoic acids are found in Gram-Negative bacteria
False
Capsule does not have well-defined boundaries and is not visible by Microscopy
False
Swarming Motility is a
rapid and coordinated movement of a bacterial population across a solid or semi-solid surface
Coordinated quorum sensing
Involves periodic morphological changes at 1-2 hr intervals
Swarming motility are produced from relatively short and sparsely flagellated cells
(ALL of the above)
