Adenosine Triphosphate | Definition, Types & Examples
Definition of Adenosine Triphosphate (ATP):
What is Adenosine Triphosphate: ATP is a nucleoside, which serves as one of the essential energy carriers in the cell. It also plays a vital role in storing and transferring energy. ATP exists in both organic and inorganic forms. The organic structure of the molecule comprises adenine, ribose, phosphate groups, and the inorganic form comprises ATP with either two or three phosphates attached. The addition or removal of phosphate results in adenosine diphosphate (ADP) and adenosine monophosphate (AMP).
In ATP adenosine triphosphate, the energy released when ATP is hydrolyzed to ADP and AMP is used to fuel metabolic reactions and other cellular processes, such as the movement of proteins within cells, by active transport across plasma membranes and muscle contraction. ATP is constantly produced in cells through various cellular metabolism; however, when more energy is needed for a particular process, ATP could be broken down into ADP and AMP. This reaction yields 7.3 kcal/mol of energy, which drives endergonic reactions.
Aerobic metabolism is the primary source for ATP production in the cell since it involves the transfer of electrons from NADH and FADH 2 to molecular oxygen during oxidation/reduction reactions. This process results in the release of large amounts of energy stored as ATP. The enzymes that catalyze this process are collectively known as oxidative phosphorylation. The reduction of oxygen results in H+ ions, which pass through a proton membrane. This causes conformational changes in the electron transport chain enzymes, ultimately leading to ATP synthesis. During aerobic metabolism, it is estimated that 24 ATP molecules are produced per electron transferred.
Structure of Adenosine Triphosphate (ATP):
What are the components of Adenosine triphosphate ATP? ATP is a molecule that provides energy for any cell to conduct the chemical processes that make life possible? ATP is often called the “molecular unit of currency” because it readily releases its energy whenever needed.
As one macronutrient, ATP is vital for all living organisms, from the simplest single-celled creatures to humans. The human body produces approximately 70 grams of ATP per day, enough energy to drive a large truck about 13 miles. This process happens through several steps that convert energy derived from our food into ATP.
The function of Adenosine Triphosphate (ATP):
Functions are described below:
- The cell has 20 billion ATP molecules. However, ATP is needed for every activity you perform. These activities can be everything from walking to thinking to talking to writing.
- This is because ATP is the primary source of energy in the cell. Without it, a person would die within minutes because of a complete breakdown of metabolic processes.
- The human body is very efficient at creating ATP, but it still takes time for this energy-producing system to get started.
- The primary energy source during the first three minutes after exercise comes from creatine phosphate (CP). CP hands over its extra phosphate molecule to adenosine diphosphate (ADP), thus regenerating ATP. This is also why you can go back to doing exercise immediately after resting for a short period – the creatine phosphate already in your system means you don’t have to wait for new ATP molecules to be made.
- After three minutes, the next energy source comes from carbohydrate (sugar) metabolism. Glycogen is used to produce glucose, which is converted into ATP.
- This happens both in the cells of working muscles and in the liver. Excess glucose is stored as glycogen for later use. When you overeat carbohydrates at one time, say before a race or sports event, your body stores most of it as glycogen.
- Apart from its “energy currency” role in making muscle contractions and other vital cellular activities.
- ATP also helps send nerve signals across synapses involved in learning.
- ATP levels drop quickly when you think hard about a topic or problem, so extra energy is needed to boost the signal transmission.
- Researchers believe that the brain may release ATP to ensure that adequate supplies of this molecule are available at synaptic contacts.
- ATP is broken down into adenosine, which binds with receptors on nerve cells. This process appears to ease signals between brain cells and prompt communication across these synapses, thus aiding memory recall.
- Adenosine also has a calming effect on the brain, so its buildup makes people feel drowsy and ready for sleep.
- ATP can even help with bodyweight control because it is involved in regulating your appetite.
- Studies with animals suggest ATP may play a role in feeling full after eating, so if you have lots of in your system, you will stop eating before you feel full. This could be why people who exercise regularly often have more energy and lose weight without trying – more oxygen is being supplied to the cells of their body, which creates more ATP, resulting in a higher energy level.
- Playing computer games for as little as three minutes is enough to boost your brainpower and help you think faster. Adenosine triphosphate (ATP) levels in the brain rise after vigorous activity. The rise in brainpower occurs because the games activate a neurotransmitter called dopamine, released when you’re learning something new
Signal Transduction ATP
It is essential in all cellular activities. Its creation results from the body’s most basic yet most complex pathway for producing energy, called signal transduction.
When ATP levels are low, a chemical messenger called adenosine diphosphate (ADP) stimulates cells to make more ATP.
This process involves many molecules and cells working together. Here’s an overview of the steps involved:
- A substance (hormone or neurotransmitter) causes a receptor molecule on the surface of a cell to change shape slightly, thus allowing the entrance of calcium ions into the cell.
- The release of calcium ions makes a protein called calmodulin (CaM) change its shape, triggering a chemical reaction. The result is that proteins called kinases are activated.
- Kinases activate other enzymes that transfer phosphate groups to adenosine diphosphate (ADP), creating new phosphates and making adenosine triphosphate (ATP) molecules.
- The phosphate groups are released from ATP, which is now free to attach itself to other ADP molecules through the help of enzymes to create two new ADP molecules, thus “recycling” ADP. This process continuously repeats until the body needs no more energy.
Adenosine triphosphate example
cAMP, a chemical energy storage molecule, has been found in C. elegans and Drosophila.
GTP is also known as guanosine triphosphate, or simply GTP; the “tri” shows that it comprises three linked phosphate groups (similar to ATP).
GTP plays a crucial role in signal transduction processes, being a mediator of intracellular signaling via activation of G-protein-coupled receptors. GTP regulates signal transduction processes, such as chemokines and other cytokines, growth factors, neurotransmitters, receptors, ion channels, and membrane receptors for hormones or neurotransmitters. GTP is converted mainly to GDP by GTPase activating proteins (GAPs). Within the signal transduction cascade, activated receptors are often regulated by other downstream components that are modulated via receptor phosphorylation.