Oxidation of water to form molecular oxygen is very difficult: The photosynthetic oxygen-evolving complex is the only known biochemical system that carries out this reaction which essential cofactor are involved in the water-oxidizing process?

#Question id: 31408

#Unit 5. Developmental Biology

#Question id: 28316

#Unit 5. Developmental Biology

Equatorial region in the mammalian fertilization sperm is___

#Question id: 4746

#Unit 8. Inheritance Biology

Two independent pure line varieties having deep red and brown phenotype in their seed coat were cross, the all f1 progeny is deep red. The F2 progeny obtain from selfing show deep red and brown in ratio of 15:1. Which of the following observation is correct?

#Question id: 32212

#Unit 1. Molecules and their Interaction Relevant to Biology

#Question id: 1373

#Unit 4. Cell Communication and Cell Signaling

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?