Question

Which of the following statements is correct with re. to the effect of temperature on rate of respiration? (a) Rate of respiration increases with an increak, temperature from \(0^{\circ} \mathrm{C}\) to \(30^{\circ} \mathrm{C}\). (b) Rate of respiration doubles for every \(10^{\circ} \mathrm{C}\) temperature, thus temperature co-efficient (Q.1] respiration is 2 . (c) At very high temperatures such as \(50^{\circ} \mathrm{C}\) or mcere, \(a:\) respiration decreases due to enzymatic degradán (d) All of these.

Short answer

The correct statement is (d) All of these.

Step-by-step solution

Understanding the effect of temperature on respiration

Bodily functions, including respiration, are affected by temperature changes. A moderate increase in temperature generally enhances the rate of respiration due to increased enzymatic activity. However, there is an upper limit to this.

Analyzing each statement

(a) This statement is correct; the rate of respiration typically increases with a temperature increase from 0°C to 30°C. (b) The general rule of thumb is that the rate of a chemical reaction, including respiration, can double for every 10°C increase in temperature, known as Q10 coefficient, usually approximately 2 for respiration. (c) At very high temperatures, enzymes, which facilitate respiration, can denature, which decreases the rate of respiration.

Concluding the correct statement

Considering the effects of temperature on enzymes and the fact that the rate of respiration alters within different temperature ranges, all given statements are correct regarding the effect of temperature on the rate of respiration.

Key concepts

Rate of Respiration

The rate of respiration is a crucial biological parameter that illustrates the intensity at which organisms convert nutrients into energy. It’s an indicator of metabolic activity and plays an integral role in the maintenance of life processes.

As temperature increases from a low point, say from freezing point at 0°C to a more temperate 30°C, metabolic processes, including respiration, tend to become more efficient. This is because biochemical reactions accelerate as the substrates and enzymes gain kinetic energy, facilitating more frequent and successful collisions between them. Therefore, within this temperature range, the rate of respiration increases, which is consistent with the observation in statement (a) of our exercise.

However, it’s important to note that the relationship between temperature and the rate of respiration is not linear. Beyond a certain optimal temperature, the rate will plateau and eventually decline, highlighting the delicate balance organisms must maintain to optimize their metabolic processes.

In essence, while a moderate increment in temperature can enhance respiration rates, this effect only holds true up to the point where the increasing temperature maintains enzyme stability and function.

Q10 Coefficient

The Q10 coefficient is a dimensionless number that quantifies the rate of increase in biological or chemical processes with a 10°C rise in temperature. Specifically, a Q10 value of 2 means that the given process will double its rate as the temperature increases by 10°C.

This coefficient is especially useful in understanding how temperature affects processes like respiration. In the context of our exercise, statement (b) speaks to this phenomenon, suggesting that respiration rate conforms to this rule of thumb, a concept widely observed in biochemical reactions.

The practical application of the Q10 coefficient helps in predicting the changes in metabolic rates due to temperature fluctuations. While different processes have different Q10 values, many enzymes involved in respiration have a Q10 value close to 2, which means they are highly sensitive to temperature changes within certain ranges. This sensitivity is a critical aspect of thermal adaptation in organisms.

To calculate the Q10 coefficient for a process, the formula is given by:
\[\begin{equation} Q10 = \frac{R2}{R1}^{\frac{10}{T2-T1}} \end{equation}\]where \( R1 \) and \( R2 \) represent the rates of respiration at temperatures \( T1 \) and \( T2 \) respectively. Understanding the Q10 coefficient aids in grasping the intricacies of biological temperature response.

Enzyme Activity

Enzymes are biological catalysts that accelerate the rate of reactions within cells; without them, vital processes like respiration would occur too slowly to sustain life. Enzyme activity is highly dependent on several factors, such as pH and temperature.

As temperatures rise from low to moderate levels, enzyme activity generally increases due to enhanced kinetic energy, leading to more effective collisions between enzymes and their substrates. This enhancement aligns with statement (a) from the exercise, highlighting that respiration increases between 0°C and 30°C.

However, beyond an enzyme's optimal temperature, activity begins to decline, often dramatically. High temperatures, typically around 50°C or above, can lead to the denaturation of enzymes. When this happens, the enzyme's structure, particularly the active site, changes such that it can no longer bind to its substrate effectively, which can lead to a decrease or cessation in enzymatic activity, as mentioned in statement (c) of the exercise.

This decline is often irreversible, as the proteins are unfolded to a state where their function is compromised. Understanding enzyme kinetics is essential for grasping why living organisms have a preferred temperature range within which they operate most efficiently, as this directly affects enzyme activity and, consequently, the rate of respiration.