Multiple Choice QuestionsAssertion : Histamine is involved in allergic and inflammatory reactions.
Reason : Histamine is a vasodilator.
If both assertion and reason are true and reason is the correct explanation of assertion.
If both the assertion and reason are true but reason is not the correct explanation of assertion.
If assertion is true but reason is false.
If both the assertion and reason are false.
B.
If both the assertion and reason are true but reason is not the correct explanation of assertion.
Histamine is a derivative of the amino acid histidine produced by damaged cells of vertebrates. When released, it has the effect of dilating capillaries and lowering blood pressure. Histamine is involved in allergic and inflammatory reactions.
Which of the following would not give Fehling's test ?
Glucose
Sucrose
Fructose
Lactose
B.
Sucrose
Fehling's test is given only by reducing sugars. When Fehling's solution is added to any reducing sugar then a red precipitate is formed which shows that reduction has taken place. Sucrose does not give this test.
A nucleoside is
base + sugar
base + phosphate
sugar+ phosphate
base + sugar+ phosphate
A.
base + sugar
Base+ sugar form a nucleoside and base+ sugar + phosphate group combine together to give a nucleotide.
The vitamin nicotinamicle can be synthesized in our body from
tyrosine
tryptophan
valine
phenylalanine
B.
tryptophan
The amino acid tryptophan serves as a source material for the synthesis of nicotinamide which in turn forms two coenzymes NAD and NADP with metabolic roles.
Assertion : Wounds heal slowly due to vitamin C deficiency.
Reason : Vitamin C is essential for collagen formation
If both Assertion and Reason are true and Reason is the correct explantion of Assertion
If both Assertion and Reason are true and Reason is not the correct explanation of Assertion
If Assertion is true but Reason is false
If Assertion is false but Reason is true.
A.
If both Assertion and Reason are true and Reason is the correct explantion of Assertion
Wounds heal slowly due to vitamin deficiency. The best characterized function of vitamin C is the synthesis of collagen connective tissue protein at the level of hydroxylation of prolyl and lysyl residues of procollagen. Thus vitamin C is important for tissue healing.
Kuhne:
discovered parathyroid
coined the term enzyme
coined the term gene
discovered enzyme
B.
coined the term enzyme
The term enzyme was given by W. Kuhne in 1678. J.B. Sumner (1926) purified and crystallised urease enzyme and suggested that enzymes are proteins. J.H. Northrop and M. Kunitz (1930) prepared pure crystalline pepsin and trypsin and showed that these enzymes were also proteins.
Which is a typical example of 'feedback inhibition'?
Allosteric inhibition of hexokinase by glucose-6-phosphate
Reaction between succinic dehydrogenase and succinic acid
Cyanide and cytochrome reaction
Sulpha drugs and folic acid synthesizer bacteria
A.
Allosteric inhibition of hexokinase by glucose-6-phosphate
Feedback inhibition is a form of enzyme regulation whereby products prevent product formation by binding to an allosteric site and inhibiting enzyme activity.
Which of these are considered most essential in the origin of life?
Enzymes
Nucleic acids
Carbohydrates
Proteins
D.
Proteins
Out of all the four options, proteins are most essential in the origin of life.
Continuous bleeding from an injured part of body is due to deficiency of :
Vitamin A
Vitamin B
Vitamin K
Vitamin E
C.
Vitamin K
Vitamin K is essential for normal blood clotting. Its deficiency leads to slow rate of blood clotting, because formation of prothrombin in liver is adversely affected in absence of adequate amount of vitamin K.
An example of competitive inhibition of an enzyme is the inhibition of:
succinic dehydrogenase by malonic acid
cytochrome oxidase by cyanide
hexokinase by glucose-6-phosphate
carbonic anhydrase by carbon dioxide
A.
succinic dehydrogenase by malonic acid
In competitive inhibition, an inhibitor that resembles the normal substrate binds to the enzyme, usually at the active site and prevents the substrate from binding.
An example of competitive inhibition of an enzyme is the inhibition of succinic dehydrogenase by malonic acid. It is the simple type of competitive inhibition. A competitive inhibitor resembles the substrate and binds to the active site of the enzyme. The substrate is then prevented from binding to the same active site.
