Tag: cell membrane

Questions Related to cell membrane

Types of chemoreceptors involved in respiration regulation is

bio-chemistry cell membrane regulation of respiration transport of respiratory gases buffer and its role

  1. Central chemoreceptors

  2. Peripheral chemoreceptors

  3. Spinal chemoreceptors

  4. Both A and B

Show answer
Correct Option: D
Explanation:
Central and peripheral chemoreceptors involve in the regulation of respiration. They detect reduction and elevation in the concentration level of oxygen, carbon dioxide and pH in the body.
So the correct answer is 'Both A and B'.

In response to a decrease in blood pH, the respiratory center sends nervous impulses to

bio-chemistry cell membrane regulation of respiration transport of respiratory gases buffer and its role

  1. Increase breathing rate

  2. Decrease breathing rate

  3. Increase heart beat

  4. None of th above

Show answer
Correct Option: A
Explanation:
Respiratory centre is located in the medulla oblongata and pons. They control the rate and depth of respiratory movements of the diaphragm. The increase in CO$ _2$ level in the blood lowers the pH of the blood which in response cause respiratory center to send impulses to breath fast and increase breathing rate.
So the correct answer is 'Increase breathing rate'.

Central chemoreceptors are found in

bio-chemistry cell membrane regulation of respiration transport of respiratory gases buffer and its role

  1. Pons

  2. Medulla

  3. Spinal cord

  4. Cerebrum

Show answer
Correct Option: B
Explanation:
Central chemoreceptors are located on the ventrolateral medullary surface in the central nervous system. There receptors act to detect the changes in pH of their environment by detecting alteration in the concentration of O$ _2$ and CO$ _2$ of nearby cerebrospinal fluid. The decrease in CO$ _2$ causes the blood to become more acidic while it's increase makes the blood alkaline
So, the correct answer is 'Medulla'.

Central chemoreceptors are sensitive to the

bio-chemistry cell membrane regulation of respiration transport of respiratory gases buffer and its role

  1. pH of their environment

  2. Level of oxygen

  3. High blood pressure

  4. Level of sugar in blood

Show answer
Correct Option: A
Explanation:
Central chemoreceptors are located on the ventrolateral medullary surface in the central nervous system. There receptors act to detect the changes in pH of their environment by detecting alteration in the concentration of O$ _2$ and CO$ _2$ of nearby cerebrospinal fluid. The decrease in CO$ _2$ causes the blood to become more acidic while it's increase makes the blood alkaline.
So, the correct answer is 'pH of their environment'.

In a $PCR$, which of the following components is not required?

bio-chemistry cell membrane regulation of respiration transport of respiratory gases buffer and its role

  1. Nucleotide precursors

  2. A primer containing $3'-OH'$

  3. DNA helicase to separate the strands

  4. DNA polymerase to catalyse the reaction

Show answer
Correct Option: A
Explanation:

A common laboratory technique used to make many copies (millions or billions) of a particular region of DNA is called Polymerase Chain Reaction(PCR). It requires a primer, DNA helicases, DNA polymerases, etc.,

So, the correct option is ‘ Nucleotide precursors’.

Receptors associated with aortic arch and carotid artery can recognise changes in (i) and (ii) concentration and send necessary signals to (iii) for remedial actions.

bio-chemistry cell membrane regulation of respiration transport of respiratory gases buffer and its role

  1. (i) $O _{2}$ (ii) $CO _{2}$ (iii)pneumotaxic centre

  2. (i) $CO _{2}$ (ii) $H^+$ (iii) rhythm centre

  3. (i) $CO _{2}$ (ii) $H^+$ (iii) apneustic centre

  4. (i) $O _{2}$ (ii) $H^+$ (iii)pneumotaxic centre

Show answer
Correct Option: B
Explanation:

Receptors associated with aortic arch and carotid artery can recognise a change in $CO _{2}$ and $H^+$ concentration and send necessary signals to the rhythm centre (medulla oblongata) that controls the rate of breathing.

So, the correct answer is (B).

Sterols are not fats but solid alcohols. These are put as lipids because they form

bio-chemistry lipids derived lipids biomolecules: chemical constituents of living cells cell membrane

  1. Fats and fatty acids

  2. Triglycerides

  3. Cholesterol

  4. Ester and fatty acids

Show answer
Correct Option: C

Cholesterol is a precursor for each  of the following except

bio-chemistry lipids derived lipids biomolecules: chemical constituents of living cells cell membrane

  1. bile salts

  2. Vitamins D

  3. insulin

  4. steroids

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Correct Option: A

At physiological temperature, sterols in biological membranes

bio-chemistry lipids derived lipids biomolecules: chemical constituents of living cells cell membrane

  1. Increase their fluidity

  2. Decrease their fluidity

  3. Increase their permeability to water

  4. Decrease their permeability to water

Show answer
Correct Option: A
Explanation:

Biological membranes are made up of lipid bilayer. These sterols affects the fluidity and rigidity of the membrane. At physiological temperature, sterols in biological membranes increase their fluidity but makes them more stronger and rigid. Environmental conditions like higher temperatures or unsaturated fatty disrupts close packing of lipids. This results in increase in the fluidity of the membrane. The membranes become more permeable to water. However, at lower temperatures, membranes become rigid. 

So the correct option is 'Increase their fluidity'.

Which of the following is a precursor of vitamins and steroid hormones

bio-chemistry lipids derived lipids biomolecules: chemical constituents of living cells cell membrane

  1. Lipids

  2. Cholesterol

  3. Lipoic acid

  4. None of the above

Show answer
Correct Option: B
Explanation:

Cholesterol acts as precursor of Vitamin D and steroid hormones like estrogen, testesterone

So, the correct answer is 'Cholesterol'