Question

Most hunters know that meat from animals that have been run to death tastes sour. Suggest a reason for this observation.

Short answer

Lactic acid buildup from anaerobic respiration during intense activity makes the meat taste sour.

Step-by-step solution

- Understand the context

Recognize that the question pertains to the physiological processes in animals, specifically those related to muscle activity and metabolism during intense physical exertion.

- Muscle Activity during Intense Exercise

During intense exercise, muscles require more energy. Rapid energy production in muscles, primarily through anaerobic respiration, results in the production of lactic acid.

- Anaerobic Respiration

Anaerobic respiration occurs when oxygen supply is insufficient for the muscles' needs. This process converts glucose into lactic acid, providing energy quickly but leading to the accumulation of lactic acid in muscle tissues.

- Effect of Lactic Acid Accumulation

Lactic acid buildup lowers the pH of muscle tissue, making it more acidic. This acidity can affect the taste of meat, making it taste sour.

- Conclusion

The sour taste of meat from overexerted animals is due to the accumulation of lactic acid in muscle tissues, resulting from anaerobic respiration during strenuous activity.

Key concepts

Anaerobic respiration

Anaerobic respiration is a type of respiration that occurs without the presence of oxygen. When animals or humans engage in intense physical activity and their muscles demand more oxygen than what's available, the body switches from aerobic to anaerobic respiration.
This process is crucial because it allows the muscles to continue generating energy even in low-oxygen conditions.
Instead of using oxygen to break down glucose into carbon dioxide and water, anaerobic respiration converts glucose to lactic acid, producing energy quickly. This rapid energy production is beneficial for short bursts of intense effort, like sprinting or escaping predators.
However, this process results in the accumulation of lactic acid within muscle tissues.

Muscle metabolism

Muscle metabolism refers to the processes that provide energy for muscle contraction and other cellular functions within muscle tissues.
During periods of physical exertion, muscles require more energy than at rest.
To meet this increased demand, muscle cells break down glucose through glycolysis, eventually producing ATP (adenosine triphosphate), the energy currency of the cell.
In aerobic conditions, this ATP production involves a series of reactions in the mitochondria that require oxygen.
However, in the absence of sufficient oxygen, muscle cells switch to anaerobic metabolism, leading to the production of lactic acid.
While this process allows continued muscle function, the downside is the buildup of lactic acid, which contributes to muscle fatigue and stiffness.

Acidic pH in muscle tissue

The accumulation of lactic acid in muscles during anaerobic respiration affects the pH levels in muscle tissue, making it more acidic. Normal pH levels in muscle tissue are maintained around 7.0 to 7.2. When lactic acid accumulates, it dissociates into lactate and hydrogen ions, lowering the pH to more acidic levels, often below 7.0.
This change in pH can have several effects:

• First, it can interfere with muscle contraction and reduce muscle efficiency.


• Second, increase in acidity within the muscles can lead to the sour taste of meat, particularly noticeable when animals have been run to the point of exhaustion.


• Finally, the acidic environment can cause discomfort and damage to the muscle cells, leading to the sensation of muscle soreness experienced after intense physical activity.

Understanding these processes helps explain why meat from animals that have been run to death tends to taste sour, primarily due to the lactic acid buildup resulting from anaerobic respiration.