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TLS Online TPP Program

#Question id: 1373

Following statements are regarding to cholera toxins which can affect the junction’s activity.

a. Toxins produced by Vibrio cholerae, the enteric bacterium that causes cholera, alter the permeability barrier of the intestinal epithelium by altering the composition or activity of gap junctions.

b. Vibrio cholerae also releases a protease that disrupts tight junctions by degrading the extracellular domain of occludin.

c. Toxin-induced changes in tight-junction permeability (increased paracellular transport) and in protein-mediated ion pumping (decreased transcellular transport) can result in massive losses of internal body ions and water into the gastrointestinal tract, which in turn leads to diarrhea and potentially lethal dehydration.

d. Toxin-induced changes in tight-junction permeability (decreased paracellular transport) and in protein-mediated ion pumping (increased transcellular transport) can result in massive losses of internal body ions and water into the gastrointestinal tract, which in turn leads to diarrhea and potentially lethal dehydration.

Which of the following statements are correct?

#Unit 4. Cell Communication and Cell Signaling

  1. a, b and c

  2. a, b and d

  3. a only

  4. b only

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TLS Online TPP Program

#Question id: 14901

#Unit 6. System Physiology – Plant

cell walls are essential and are important features of plant cells that perform a number of essential functions. Which of the following are not the characteristics of a cell wall?
TLS Online TPP Program

#Question id: 14902

#Unit 6. System Physiology – Plant

Transpirational water flow in the xylem requires a mechanically strong wall that resists from,
TLS Online TPP Program

#Question id: 14903

#Unit 6. System Physiology – Plant

Cell walls of prokaryotes, fungi, algae, and plants differ from each other in chemical composition and molecular structure, yet they all serve three common functions:
a) regulating cell volume
b) determining cell shape
c) mechanically protecting the delicate protoplast against biochemical and physical assaults
d) used to make synthetic fibers
Which of the following common functions is correct?
TLS Online TPP Program

#Question id: 14904

#Unit 6. System Physiology – Plant

Cell walls commonly are classified into two major types. This classification is based not on structural or biochemical differences;
A) primary walls and
B) secondary walls
i) walls formed during cell growth
ii) walls that are formed after cell enlargement stops
iii) multilayered walls that are strengthened and waterproofed by lignin
iv) Usually they are thin and simple, but sometimes may be thick and multilayered, such as those found in collenchyma or in the epidermis
v) highly specialized in structure and composition, reflecting the differentiated state of the cell
Which of the following correctly represents features of primary and secondary walls?
TLS Online TPP Program

#Question id: 14905

#Unit 6. System Physiology – Plant

A thin layer called the middle lamella is found at the interface, middle lamella is typically enriched with acidic polysaccharides_____A______, which may be complexed with_______B__________.
TLS Online TPP Program

#Question id: 14906

#Unit 6. System Physiology – Plant

The specific linkages between sugar rings, including the specific carbons that are linked together and the configuration of the linkage, are important for the properties of the polysaccharide;
           
          I) Amylose                          a) β(1,3)-linkages                               
        II) Cellulose                          b) β (1,4)-linkages
         III) Callose                                   c) α(1,4)-linked
                                                             d) α (1,3)-linkages
Which of the following linkage combinations is correct linkages of the polysaccharides?