The readymade intramuscular stores of ATP-PC in human body are:
570 to 690 mM
Understanding Intramuscular ATP-PC Stores
The human body uses several energy systems to fuel muscle activity. For very short, high-intensity bursts of effort, the most immediate source of energy comes from the stored adenosine triphosphate (ATP) and phosphocreatine (PC), also known as phosphagen.
What are ATP and PC?
- ATP (Adenosine Triphosphate): This is the direct energy currency of the cell. When a muscle needs to contract, it breaks down ATP, releasing energy.
- PC (Phosphocreatine): This molecule acts as a rapidly available reserve of phosphate. When ATP is broken down during intense effort, PC quickly donates its phosphate group to adenosine diphosphate (ADP), regenerating ATP. This process is catalyzed by the enzyme creatine kinase.
The ATP-PC system is often called the 'readymade' or immediate energy system because it does not require oxygen and can regenerate ATP very rapidly, although its capacity is limited. The stores of ATP and PC within the muscle (intramuscular stores) are finite and can only sustain maximal effort for a few seconds.
Quantity of Readymade Intramuscular ATP-PC Stores
The question asks about the quantity of these readymade intramuscular stores (ATP + PC) in the human body, expressed in millimolar (mM) concentration. These stores represent the total amount of immediately available high-energy phosphates.
While typical physiological concentrations of ATP and PC in skeletal muscle are often cited in the range of a few mM for ATP and 20-30 mM for PC, leading to a total phosphagen pool of around 25-35 mM, the options provided suggest a much higher scale for what is considered the 'readymade intramuscular stores' in the context of this question. Based on the options, the expected value is in the hundreds of mM.
Let's look at the provided options:
- 570 to 690 mM
- 120 to 180 mM
- 450 to 510 mM
- 1000 to 1200 mM
Comparing the options, the range representing the readymade intramuscular stores of ATP-PC, as presented in this context, is stated to be 570 to 690 mM.
Summary of Energy Systems
The ATP-PC system is one of three main energy systems in the body. The others are glycolysis (breaking down carbohydrates) and the aerobic system (using oxygen to break down carbohydrates, fats, and proteins). The ATP-PC system is dominant for very short-duration, maximal-intensity exercise (like a sprint or a heavy lift).
| Energy System | Primary Fuel | Intensity | Duration | ATP Production Rate |
|---|---|---|---|---|
| ATP-PC System | ATP & PC | Very High | 0-10 seconds | Very Fast |
| Glycolysis (Anaerobic) | Glucose/Glycogen | High | 10-120 seconds | Fast |
| Aerobic System | Glucose, Fats, Proteins | Low to Moderate | > 120 seconds | Slow |
In conclusion, based on the options provided, the readymade intramuscular stores of ATP-PC in the human body are given as 570 to 690 mM.
Revision Table: Intramuscular ATP-PC
| Components | Adenosine Triphosphate (ATP) and Phosphocreatine (PC) |
| Location | Primarily in skeletal muscle |
| Function | Provides immediate energy for high-intensity, short-duration activities |
| System Name | ATP-PC System or Phosphagen System |
| Regeneration | PC regenerates ATP rapidly |
| Quantity (as per options) | 570 to 690 mM |
Additional Information: Factors Affecting ATP-PC Stores
The amount of ATP-PC stores in muscle can be influenced by several factors:
- Training: High-intensity interval training (HIIT) or sprint training can potentially increase the enzyme activity (like creatine kinase) and possibly the storage capacity of PC in muscles, although the increase in ATP stores is generally minimal.
- Diet: Creatine supplementation is known to significantly increase intramuscular PC stores (by 10-40%), which can enhance performance in short-duration, high-intensity exercise.
- Muscle Fiber Type: Fast-twitch muscle fibers (Type II) generally have higher concentrations of ATP and PC compared to slow-twitch fibers (Type I).
Understanding the ATP-PC system is crucial for optimizing training and performance in sports requiring explosive power and speed.
Important Questions from Exercise
- Which of the following is the most rapidly available source of energy within a muscle fibre?
- The forced vital capacity that can be expired in one second, is termed as
- Active isolated stretching is
Given below are two statements, one labelled as Assertion (A) and the other labelled as Reason (R). Read the statements and choose the correct answer using the code given below.
Assertion (A): In non-endurance athletes, that is, athletes engaged in high-resistance type of activities, the stroke volume capabilities are no different from those of their non-athletic counterparts.
Reason (R): In these non-endurance athletes, cardiac hypertrophy is characterized by a normal sized ventricular cavity and a thicker ventricular wall.
Given below are two statements, one labelled as Assertion (A) and the other labelled as Reason (R). Read the statements and choose the correct answer using the code given below.
Assertion (A): The complete breakdown of a fat molecule yields about 460 ATP molecules. Fatty acid metabolism is directly associated with oxygen uptake.
Reason (R): Numerous interconversions are possible among the various food nutrients. The exception is fatty acids that cannot be used for the synthesis of glucose.
