ATP-ADP Cycle PDF

**ATP-ADP CYCLE** **Introduction:** Adenosine triphosphate (ATP) is the energy currency used throughout the cell. ATP provides energy for the cell to do work, such as mechanical work, transport substances across the membrane, and perform various chemical reactions. ATP is composed of phosphate gro...

**ATP-ADP CYCLE** **Introduction:** Adenosine triphosphate (ATP) is the energy currency used throughout the cell. ATP provides energy for the cell to do work, such as mechanical work, transport substances across the membrane, and perform various chemical reactions. ATP is composed of phosphate groups, ribose, and adenine. In the structure of ATP, there are three phosphate groups attached to adenosine. The last two bonds on the phosphate groups contain especially high energy and are therefore very useful for doing work within living cells. The bonds that hold phosphate groups are easily broken by hydrolysis which results in the release of energy. *Fig. 1a. Adenosine triphosphate (ATP) to adenosine diphosphate (ADP) transformation* **Adenosine Triphosphate (ATP)** - - - - - - - - **Hydrolysis of ATP** - - - - - -  *Fig. 1.b. The Hydrolysis of ATP* **How the Hydrolysis of ATP Perform Work** - - - *Fig. 1.c. Phosphorylation (ADP to ATP) and dephosphorylation (ATP to ADP)* **The Regeneration of ATP** - - - - - - -  *Fig. 1.d. The ATP cycle* **The Importance of Chlorophyll and Other Pigments** **Terminology:** **CHROMATOGRAPHY -** is a separation technique used to identify various components of mixtures based on the differences in their structure and/or composition. **PIGMENTS -** are substances that absorb visible light. Different pigments absorb light of different wavelengths. Light, as it encounters an object, is either reflected, transmitted, or absorbed. Visible light, with a wavelength of 380--750nm, is the segment in the entire range of the electromagnetic spectrum that is most important to life on earth. It is detected as various colors by the human eye. The color that is not absorbed by pigments of objects is transmitted or reflected and that is the color of the object that we see. *Fig. 1.e. The Electromagnetic Spectrum* Pigments are the means by which plants capture the sun's energy to be used in photosynthesis. However, since each pigment absorbs only a narrow range of wavelengths, there is usually a need to produce several kinds of pigments of different colors to capture more of the sun's energy. **CHLOROPHYLL -** is the greenish pigment found in the thylakoid membrane inside the chloroplast of a plant cell. Chlorophyll absorbs blue and red light while it transmits and reflects green light. This is why leaves appear green. There are several kinds of chlorophyll. Among these, chlorophyll plays the most important role in photosynthesis. It directly participates in converting solar energy to chemical energy. Other pigments in the chloroplast play the part of accessory pigments. These pigments can absorb light and transfer the energy to chlorophyll a. One of these accessory pigments is chlorophyll b. Some carotenoids also contribute energy to chlorophyll a. Other carotenoids, however, serve as protection for chlorophyll by dissipating excessive energy that will otherwise be destructive to chlorophyll. **Structure of chlorophyll** - - **How does photoexcitation of chlorophyll happen?** 1. 2. 3.  *Fig. 1.f. The Photoexcitation of Chlorophyll* **PHOTOSYSTEM -** A photosystem is an aggregate of pigments and proteins in the thylakoid membrane responsible for the absorption of photons and the transfer of energy and electrons. It is composed of: - - **There are two types of photosystems:** - - **PERFORMANCE ACTIVITY** 1. 2. 3.