Through which conversion is energy released?
A. ADP to ATP
B. ATP to ADP
C. NADP${}^{+}$to NADPH
D. $CO _2$ and $H _2 O$ to $C _6 H _{12} O _6$ and $O _2$
Answer (2)
The conversion that releases energy is from ATP to ADP. When ATP is broken down into ADP, it releases energy that cells use for various processes. Therefore, the correct option is B. ATP to ADP.
;
ATP converts to ADP and releases energy.
ADP converts to ATP and requires energy.
NADP + converts to NADPH and requires energy.
C O 2 and H 2 O converts to C 6 H 12 O 6 and O 2 and requires energy.
The conversion that releases energy is ATP to ADP. A TPt o A D P
Explanation
Problem Analysis We need to identify the conversion that releases energy from the given options.
ATP and Energy Release ATP (adenosine triphosphate) is the primary energy currency of cells. When ATP is converted to ADP (adenosine diphosphate), a phosphate group is removed, and energy is released in the process. This energy is then used to power various cellular activities.
Energy Requirements for Other Conversions The reverse process, converting ADP to ATP, requires energy input because it involves forming a bond to add a phosphate group. Similarly, converting NADP + to NADPH requires energy, as it involves the addition of electrons and a proton. The conversion of C O 2 and H 2 O to C 6 H 12 O 6 (glucose) and O 2 (photosynthesis) also requires energy, specifically light energy.
Conclusion Therefore, the conversion that releases energy is the breakdown of ATP to ADP.
Examples
Think of ATP as a fully charged battery. When you use the battery to power a device (like a flashlight), the battery discharges, releasing energy. Similarly, when ATP is converted to ADP, it releases energy that the cell can use to perform work, such as muscle contraction or protein synthesis. The ADP then becomes like a partially discharged battery, which needs to be recharged (converted back to ATP) using energy from food.
