Tag: respiratory quotient-basic

Questions Related to respiratory quotient-basic

Respiratory quotient is 

  1. More than one for organic acids.

  2. Less than one for proteins.

  3. Equal to zero for CAM plants at night.

  4. All of the above.


Correct Option: D
Explanation:

The respiratory quotient (R.Q) is the ratio of $CO _2$ produced to $O _2$ consumed, while food is being metabolized.
RQ = $CO _2$ eliminated / $O _2$ consumed
R.Q for proteins is less than 1 since, amount of $CO _2$ evolved is lesser than amount of $O _2$ consumed.
When organic acids are broken down as respiratory substrates under aerobic conditions the R.Q is more than one. Organic acids contain more oxygen than carbohydrates and therefore require less oxygen for their oxidation.
R.Q is equal to zero for CAM plants at night time since, no $CO _2$ is evolved and $O _2$ is continuously consumed.
Thus, option D is correct.

R. Q in anaerobic respiration is 

  1. 0

  2. ${\propto }$

  3. 1

  4. > 1


Correct Option: B
Explanation:

The respiratory quotient (RQ) is the ratio of $CO _2$ produced to $O _2$ consumed, while food is being metabolized.
RQ = $CO _2$ eliminated / $O _2$ consumed.
The value of RQ is infinity during anaerobic respiration, because $CO _2$ is produced but $O _2$ is not utilized. Thus, option B is correct and other options are incorrect.

${Q _{10}}$ is

  1. Respiratory coefficient

  2. Photosynthetic coefficient

  3. Photosynthetic yield

  4. Temperature coefficient


Correct Option: D
Explanation:

The respiratory quotient (or RQ or respiratory coefficient), is a dimensionless number used in calculations of basal metabolic rate (BMR), when estimated from carbon dioxide production.
RQ = CO$ _{2}$ eliminated / O$ _{2}$ consumed. Thus, option A is incorrect. Photosynthetic coefficient is the specific light spectrum at which chlorophyll absorbs light. Thus, option B is wrong. Photosynthetic yield is the quantity of the end product of the photosynthesis. Thus, option C is wrong. The temperature coefficient (Q$ _{10}$) represents the factor by which the rate (R) of a reaction increases for every 10-degree rise in the temperature (T). The rate (R) may represent any measure of the progress of a process. Thus option D is correct.

In CAM the R.Q  will be 

  1. Zero

  2. 1

  3. More than one

  4. Less than one


Correct Option: A
Explanation:

CAM plants open their stomata only at night and absorbs $CO _2$, which then converted into malate by acidification. During night time oxygen is absorbed continuously but no $CO _2$ is evolved. There fore R.Q in night is zero. During day time, malate gets converted to $CO _2$ and $C _3$ photosynthesis occurs. During day time amount of $CO _2$ evolved is equal to the amount of $O _2$ absorbed. So, R.Q at day time is 1. So, in CAM plants, R.Q will be zero at night. Thus, option A is correct and other options are incorrect.

Protein rich pulses have R.Q. will be

  1. One

  2. More than one

  3. Less than one

  4. None of the above


Correct Option: C
Explanation:

The respiratory quotient (R.Q) is the ratio of $CO _2$ produced to $O _2$ consumed, while food is being metabolized.
RQ = $CO _2$ eliminated / $O _2$ consumed
R.Q for proteins is less than 1. Because, amount of $O _2$ consumed is higher than amount of $CO _2$ eliminated. So, protein rich pulses have R.Q less than 1. Thus, option C is correct and other options are incorrect.

R.Q of the succulents can be

  1. 0

  2. 1

  3. 0.7

  4. Both (A) and (B)


Correct Option: D
Explanation:

CAM plants open their stomata only at night and absorbs $CO _2$, which then converted into malate by acidification. During night time oxygen is absorbed continuously but no $CO _2$ is evolved. There fore R.Q in night is zero. During day time, malate gets converted to $CO _2$ and $C _3$ photosynthesis occurs. During day time amount of $CO _2$ evolved is equal to the amount of $O _2$ absorbed. So, R.Q at day time is 1. Since succulents are CAM plants, their R.Q at night is zero and day is 1. Thus, option D is correct and other options are incorrect.

In succulent plants R.Q. is less than one because of

  1. Complete oxidation

  2. Complete reduction

  3. Incomplete reduction

  4. Incomplete oxidation


Correct Option: D
Explanation:

In succulent plants, the stomata are open during night and during this time plants absorb carbon dioxide. During day time stomata are closed and no carbon dioxide is evolved. These plants respire during night time, when they can take oxygen through open stomata. The volume of carbon dioxide is less than typical aerobic respiration. In fact during night time, these plants fix carbon dioxide into organic acids. The respiratory substrates are incompletely oxidised and thus, respiratory quotient is less than one.

In Opuntia ,the R.Q. will be

  1. Equal to 1.

  2. Less than 1.

  3. More than 1.

  4. Equal to 0.


Correct Option: D
Explanation:

Respiratory quotient (RQ) is defined as the ratio between volume of carbon dioxide released to volume of oxygen absorbed. Opuntia is a succulent plant. Succulents open their stomata in night, when atmospheric carbon dioxide is fixed temporarily into organic acids like oxaloacetate and malate. During daytime the stomata are closed and organic acids are decarboxylated to release carbon dioxide which is used in the synthetic processes of photosynthesis. As there is no net evolution of carbon dioxide, the value of RQ is zero in succulents like Opuntia.

The value of R.Q. for proteins is

  1. Equal to one.

  2. More than one.

  3. Less than one.

  4. Infinite.


Correct Option: C
Explanation:

During aerobic respiration, $O _2$ is consumed and $CO _2$ is released. The ratio of the volume of $CO _2$ evolved to the volume of $O _2$ consumed in respiration is called the respiratory quotient (R.Q) or respiratory ratio. The respiratory quotient depends upon the type of respiratory substrate used during respiration. When carbohydrates are used as substrate and are completely oxidised, the RQ will be 1, because equal amounts of $CO _2$ and $O _2$ are evolved and consumed, respectively. When fats are used in respiration, the RQ is less than 1. When proteins are respiratory substrates the ratio would be about 0.9.

What causes R. Q. to vary?

  1. Respiratory substrates

  2. Light and $O _2$

  3. Respiratory products

  4. Temperature


Correct Option: A
Explanation:

During aerobic respiration, $O _2$ is consumed and $CO _2$ is released. The ratio of the volume of $CO _2$ evolved to the volume of $O _2$ consumed in respiration is called the respiratory quotient  (RQ) or respiratory ratio. The respiratory quotient depends upon the type of respiratory substrate used during respiration. When carbohydrates are used as substrate and are completely oxidised, the RQ will be 1, because equal amounts of $CO _2$ and $O _2$ are evolved and consumed, respectively. When fats are used in respiration, the RQ is less than 1. When proteins are respiratory substrates the ratio would be about 0.9.