The ability of a population of fibroblasts to migrate along the surface of a tissue culture dish depends on adhesion between the cell surface and the extracellular matrix molecules coating the dish. The dish is coated with laminin, and the only cell-surface protein capable of binding laminin is a cell-adhesion protein called an integrin. Integrins are integral plasma-membrane proteins that function as heterodimers. Under these conditions the rate at which a fibroblast can migrate along the laminin coated culture dish is proportional to the strength of adhesion between the cell and the laminin substrate. The table below lists the rate of cell migration observed for fibroblasts genetically engineered to generate the indicated phenotypes. One explanation for the effect of overexpression of the cytoplasmic domain of the integrin beta subunit is that this domain normally functions to bind a cytoplasmic factor necessary for integrin function. Which of the following would be the most informative experiment to identify the cytoplasmic factor?

#Question id: 10146

#Unit 6. System Physiology – Plant

Light-dependent ion movements modulate enzymes of the Calvin–Benson cycle such as : rubisco, fructose 1,6-bisphosphatase, sedoheptulose 1,7-bisphosphatase, and phosphoribulokinase what will happen Upon illumination;

#Question id: 10147

#Unit 6. System Physiology – Plant

Which of the following enzymes is regulated by supramolecular assembly ?

#Question id: 10148

#Unit 6. System Physiology – Plant

How light controls the assembly of chloroplast enzymes into supramolecular complexes?

a.) Light regulates the stability of the ternary complex through the ferredoxin–thioredoxin system

b.) Reduced thioredoxin cleaves the disulfide bonds of both phosphoribulokinase and CP12, releasing glyceraldehyde-3-phosphate dehydrogenase and phosphoribulokinase in the catalytically active conformations

c.) Oxidised thioredoxin cleaves the disulfide bonds of both phosphoglyceratekinase and CP12, releasing glyceraldehyde-3-phosphate dehydrogenase and phosphoglyceratekinase in the catalytically active conformations

d.) thioredoxin system oxidised the disulfide bonds and reduces the assembly of between chloroplast enzymes and CP12 and converted into the catalytically active conformations

Which of the following statement is correct?

#Question id: 10149

#Unit 6. System Physiology – Plant

Formation of supramolecular complexes with regulatory proteins how effects on the catalytic activity of chloroplast enzymes in the dark as well as in the light?

a.) glyceraldehyde-3-phosphate dehydrogenase binds noncovalently with phosphoribulokinase and CP12 form a ternary complex, wherein glyceraldehyde-3-phosphate dehydrogenase and phosphoribulokinase are catalytically inactive in the dark condition

b.) The A2B2 glyceraldehyde-3-phosphate dehydrogenase can form the A8B8 oligomer, Under dark conditions

c.) Reduced thioredoxin cleaves the disulfide bonds of CP12 and phosphoribulokinase, due to the reduction separates the components of the ternary complex releasing the active phosphoribulokinase and the active A4B4-glyceraldehyde 3-phosphate dehydrogenase under the light condition

d.) Reduced thioredoxin (Trx) cleaves the disulfide bond in subunit B of A8B8-glyceraldehyde-3-phosphate dehydrogenase, the reduction converts the active oligomer into the inactive A2B2-glyceraldehyde3-phosphate dehydrogenase under the light condition

Which of the following combination about catalytic activity in dark and the light is true?

#Question id: 10150

#Unit 6. System Physiology – Plant

Light controls the assembly of chloroplast enzymes into supramolecular complexes one of the enzyme such as Glyceraldehyde-3-P dehydrogenase, this enzyme acivity is dependent on

#Question id: 10151

#Unit 6. System Physiology – Plant

Light regulates the stability of the ternary complex through the ferredoxin–thioredoxin system Regulation of chloroplast phosphoribulokinase and glyceraldehyde-3-phosphate dehydrogenase. Chloroplasts contain two isoforms of glyceraldehyde3-phosphate dehydrogenases, named A4 and A2B2. Which of the following statement about isoform of glyceraldehyde3-phosphate dehydrogenases is False?