Tag: body defense system

Questions Related to body defense system

Which of the following is scientific explanation of depression?

  1. An increased level of sugar in the blood leads to depression.

  2. Low levels of noradrenaline, a neurotransmitter in the blood lead to depression.

  3. Release of extra gastric juice in the stomach lead to depression.

  4. Sleep incducing drugs lead to depression.


Correct Option: B
Explanation:

Noradrenaline is a neurotransmitter that plays a role in mood swings. Low levels of noradrenaline lower the signal-sending activity and make the person suffers from depression. 

Drugs which bind strongly to the active site of an enzyme and do not depend upon the concentration of natural substrate are called as:

  1. competitive inhibitors

  2. non-competitive inhibitors

  3. $\beta$-blockers

  4. $\alpha$-blockers


Correct Option: A
Explanation:

Competitive inhibitors are the interruption of a chemical pathway owing to one chemical substance inhibiting the effect of another by competing with it for binding or bonding.

These drugs bind to active sites and do not depend on the concentration of natural substrate.

Which of the following statements is not true about enzyme inhibitors?

  1. Inhibit the catalytic activity of the enzyme.

  2. Prevent the binding of substrate.

  3. Generally a strong covalent bond is formed between an inhibitor and an enzymes.

  4. Inhibitors can be competitive or non-competitive.


Correct Option: C
Explanation:

Generally a weak bond such as H-bonding, van der Waals interaction etc. is formed between an inhibitor and an enzyme.

Noradrenaline is one of the example of :

  1. anti-depressant

  2. anti-Histamine

  3. neurotransmitter

  4. antacid


Correct Option: C
Explanation:

Solution:- (C) Neutrotransmitter

Noradrenaline is one of the example of Neurotransmitter

What is the source of receptor proteins?

  1. Interior of a cell

  2. Cell wall

  3. Out of cell wall

  4. Fixed in the cell membrane partially inside and partially projected outward


Correct Option: D
Explanation:

The source of receptor proteins is fixed in the cell wall, partly inside and partly projected out of the cell wall.
This is so that chemical messengers can interact with the outside portion of receptor protein, which transfers the signal to interior of cell via the receptor protein.
Hence, signal is transferred from outside the cell to inside without the messenger having to cross the cell membrane.

Drugs which supplement (or) substitute for chemical messengers are :

  1. antagonists

  2. agonists

  3. blocking chemicals

  4. all


Correct Option: B
Explanation:

An agonist is a chemical that binds to some receptor of a cell and triggers a response by that cell. Agonists often mimic the action of a naturally occurring substance. Whereas an agonist causes an action, an antagonist blocks the action of the agonist and an inverse agonist causes an action opposite to that of the agonist. So agonist drugs copy the action of the chemical messengers thereby substituting them.

Which of the following statements is not true about enzyme inhibitors?

  1. Inhibit the catalytic activity of the enzyme.

  2. Prevent the binding of substrate.

  3. Generally, a strong covalent bond is formed between an inhibitor and an enzyme.

  4. Inhibitors can be competitive or non-competitive.


Correct Option: C
Explanation:
Enzyme inhibitors bind reversibly and irreversibly.
They bind reversibly with non-covalent bond, whereas, they bind irreversibly with covalent bond where they change the key amino acid residues needed for enzymatic activity.
Hence, option C is correct.

Which site of an enzyme is called allosteric site?

  1. which binds to the cell wall

  2. where drugs bind to an enzyme

  3. which is not the active site, where some drugs bind to an enzyme

  4. none of these


Correct Option: C
Explanation:

 The allosteric site is the site, which is not the active site, where some drugs bind to an enzyme. Due to this, the shape of the enzyme changes, it becomes difficult for the substrate to recognize the active site of the enzyme. This represents non-competitive inhibition.

Assertion: There is a scientific explanation for the feeling of depression.

Reason:  In people who are depressed, the mood-regulating neurotransmitters fail to function normally, so that the signal is either depleted or disrupted before passing to the next nerve cell. In all depressions, it is likely that the transmission of serotonin is reduced or disrupted.

Choose the correct options.
  1. Both Assertion and Reason are correct

  2. Assertion is correct but Reason is incorrect

  3. Both Assertion and Reason are incorrect

  4. Assertion is incorrect but reason is correct


Correct Option: A
Explanation:

Neurotransmitters are chemicals that carry signals from one part of the brain to the next. There are many neurotransmitters, serving different purposes, however, three important ones that affect a person's mood are serotonin, noradrenaline and dopamine. 


In normal brain function, neurotransmitters jump from one nerve cell to the next, with the signal being as strong in the second and subsequent cells as it was in the first. However, in people who are depressed, the mood-regulating neurotransmitters fail to function normally, so that the signal is either depleted or disrupted before passing to the next nerve cell. 

In all depressions, it is likely that the transmission of serotonin is reduced or disrupted.

Hence, option A is correct.

The bond formed between an enzyme and an inhibitor:

  1. can be broken easily

  2. cannot be broken easily

  3. is a weak bond

  4. none of the above


Correct Option: B
Explanation:
If the bond formed between an enzyme and an inhibitor is a strong covalent bond, it cannot be broken easily. Then the enzyme is blocked permanently and the body degrades the enzyme-inhibitor complex and synthesizes the new enzyme.