After the drought of 1977, researchers hypothesized that on the Galápagos Island Daphne Major, medium ground finches with large, deep beaks survived better than those with smaller beaks because they could more easily crack and eat the tough Tribulus cistoides fruits. A tourist company sets up reliable feeding stations with a variety of bird seeds (different types and sizes) so that tourists can get a better look at the finches. Which of these events is now most likely to occur to finch beaks on this island?

#Question id: 10284

#Unit 6. System Physiology – Plant

Allosteric regulation of enzyme multisubunit or multiactive site shows cooperativity with the sigmoidal graph between substerate conc. v/s Activity,

a) Cell contain NADH, FADH2 and ATP, that inhibits the allosteric enzyme activity by lowering the affinity with its substate, graph shifts towards B from control

 b) A- shows low ATP, the Km for fructose 6-phosphate is relatively low, the affinity of the enzyme with its substate is relatively high

 c) Haemoglobin, Phosphofructokinase, Phosphate dehydrogenase complex, α-ketoglutarate dehydrogenase complex, these all enzymes shows characteristics of sigmoidal graph

 d) When ATP is high, Km for fructose 6-phosphate is greatly increased- this activity shown by B in the graph

 e) fructose 2,6-bisphosphate binds to its allosteric site on PFK-1, it increases the enzyme’s affinity for its substrate fructose 6-phosphate and reduces its affinity for the allosteric inhibitors ATP and citrate- shown in graph by A

 Which of the following  combination of the enzyme activity with its substate correctly shown;

#Question id: 10283

#Unit 6. System Physiology – Plant

How to Phosphofructokinase-1 (PFK-1) and Fructose 1,6-Bisphosphatase are reciprocally regulated ?

a) ATP inhibits PFK-1 by binding to an allosteric site and lowering the affinity of the enzyme for its substrate fructose 6-phosphate

b) citrate is also an allosteric regulator of PFK-1, high citrate concentration increases the inhibitory effect of ATP

c) FBPase-1, is strongly inhibited (allosterically) by AMP; when the cell’s supply of ATP is low (corresponding to high AMP), the ATP-requiring synthesis of glucose slows

d) AMP inhibits PFK-1 by binding to an allosteric site and lowering the affinity of the enzyme for its substrate fructose 6-phosphate

Which of the following statements of regulation of enzyme is correct?

#Question id: 10280

#Unit 6. System Physiology – Plant

The enzyme of glycolytic pathway that forms fructose 1,6-bisphosphate is called phosphofructokinase-1 (PFK-1), which statements can’t distinguish it from a second enzyme (PFK-2) Phosphofructokinase-2.

#Question id: 10278

#Unit 6. System Physiology – Plant

The type of ATP synthesis, traditionally referred to as substrate-level phosphorylation involves the direct transfer of a phosphate group, which reactions perform substrate-level phosphorylation?

a) Conversion of Glyceraldehyde 3-phosphate to 1,3-Bisphosphoglycerate

b) Conversion of Phosphoenol pyruvate to pyruvate

c) Conversion of Fructose 6-phosphate to Fructose 1,6-bisphosphate

d) Conversion of 1,3-Bisphosphoglycerate to 3-Phosphoglycerate

Find the correct one.

#Question id: 10277

#Unit 6. System Physiology – Plant

Each of the nine glycolytic intermediates between glucose and pyruvate is phosphorylated. The phosphoryl groups seem to have many functions such as,

a) The plasma membrane generally lacks transporters for phosphorylated sugars, the phosphorylated glycolytic intermediates cannot leave the cell

b) After the initial phosphorylation, further energy is necessary to retain phosphorylated intermediates in the cell, despite the large difference in their intracellular and extracellular concentrations

c) Phosphoryl groups are essential components in the enzymatic conservation of metabolic energy, Energy released in the breakage of phosphoanhydride bonds is partially conserved in the formation of phosphate esters such as glucose 6-phosphate

d) Binding energy resulting from the binding of phosphate groups to the active sites of enzymes lowers the activation energy and increases the specificity of the enzymatic reactions

which of the following functions shows Importance of Phosphorylated Intermediates?

#Question id: 10275

#Unit 6. System Physiology – Plant

In the initial phase of glycolysis, each hexose unit is phosphorylated twice and then split, producing two molecules of triose phosphate, in these reactions included irreversible reaction. How much irreversible reaction is performed in the glycolytic pathway through in this series of reactions?