What Is ATP? How The Body Uses This Important Molecule

ATP is an energy-carrying molecule that powers cell functions such as muscle contraction, nerve impulses, and the production and release of chemicals. ATP is known as “the energy currency of life” or “the fuel of life,” because it’s the universal energy source for all living cells.

What Does ATP Do in the Body?

Adenosine triphosphate (ATP) is an essential building block of life. Every living organism has cells that rely on ATP for energy. Without it, cells would lack the fuel needed to perform vital functions.

Some ATP’s essential functions include:

• Neurotransmitter: ATP carries messages from one nerve cell (neuron) to another. ATP can be released by nerve cells in the body (peripheral neurons) as well as nerve cells in the central nervous system (brain and spinal cord). Its role as a neurotransmitter is to maintain homeostasis (equilibrium) throughout the body.
• Making genetic material: Your body needs ATP to make DNA and RNA. It needs the triphosphate in ATP to make RNA. For DNA, your body first converts ATP to deoxyribonucleotide (dATP) by removing an oxygen atom.
• Sending messages: ATP’s role in intracellular signaling is to release messengers, such as hormones, enzymes, lipid mediators, neurotransmitters, nitric oxide, growth factors, and reactive oxygen species. These messengers regulate the inner workings of cells.
• Muscle contraction: Your muscles can store a small amount of ATP. This ATP is used up rather quickly when you’re using your muscles, like when you’re exercising. Your body then makes more ATP and sends it to the muscles to sustain exercise levels.
• Protein synthesis: Most of the energy from a cell’s ATP is used to make proteins such as enzymes, antibodies, and structural proteins.
• Active transport: ATP powers the proteins that move substances across cell membranes.

What Is ATP’s Chemical Structure?

ATP consists of a nitrogen base (adenine) and a sugar molecule (ribose), which create adenosine, plus three phosphate molecules. If adenosine only has one phosphate molecule, it’s called adenosine monophosphate (AMP). If it has two phosphates, it’s called adenosine diphosphate (ADP).

How ATP Provides Energy to Your Cells

While adenosine is a fundamental part of ATP, it’s the phosphate groups that provide energy to cells and fuel cellular processes. The highest energy state for adenosine is when it forms ATP, which contains three phosphate groups.

Adenosine triphosphate (ATP) becomes adenosine diphosphate (ADP) when one of its three phosphate molecules breaks free and releases energy (“tri” means “three,” while “di” means “two”). This release of energy is what powers the cells.

Conversely, ADP becomes ATP when a phosphate molecule is added. As part of an ongoing energy cycle, ADP is constantly recycled back into ATP.

How ATP Is Made

The body uses molecules in fats, proteins, and carbohydrates from our diet to produce ATP, primarily through a process called hydrolysis.

After food is digested, it’s synthesized into glucose, which is a form of sugar. Glucose is the main source of fuel that your cells’ mitochondria use to convert caloric energy from food into ATP, which is an energy form that can be used by cells.

ATP is made via a process called cellular respiration that occurs in the mitochondria of a cell. Mitochondria are tiny subunits within a cell that specialize in extracting energy from the foods we eat and converting it into ATP.

Mitochondria can convert glucose into ATP via two different types of cellular respiration:

• Aerobic (with oxygen): Oxygen helps break down sugar into electron carriers that fuel the synthesis of ATP.
• Anaerobic (without oxygen): In the absence of oxygen, ATP can be made from lactic acid fermentation. This happens in both organisms that require oxygen and in other organisms, such as plants, algae, and some bacteria, which convert sunlight into energy that can be used by a cell via photosynthesis.

ATP Production During Exercise

The burning sensation you feel during high-intensity exercise is lactic acid, which is used to make ATP via anaerobic glycolysis.

During aerobic exercise, mitochondria have enough oxygen to make ATP aerobically. However, when you’re out of breath and your cells don’t have enough oxygen to perform cellular respiration aerobically, the process can still happen anaerobically, but it creates a temporary burning sensation in your skeletal muscles.

Do You Need ATP Supplements?

Eating a well-balanced diet and staying hydrated should give your body all the resources it needs to produce plenty of ATP. Although some athletes may slightly improve their performance by taking supplements or ergonomic aids designed to increase ATP production, it’s debatable whether oral adenosine triphosphate supplements actually increase energy.

How Is ATP Used in Medicine?

The clinical uses of ATP include pain management, anesthesia, cardiology, and surgery.

• Pain management: ATP administered through a vein (intravenously) can help control pain by acting on the A1 adenosine receptor. This initiates a signaling process, which can aid in relieving pain due to inflammation. In some cases, the effect can last for weeks.
• Anesthesia: Administered in low doses, ATP can reduce nerve pain (neuropathic pain), pain from a lack of blood flow (ischemic pain), and an increased sensitivity to pain (hyperalgesia) in a way comparable to morphine. This can reduce opioid use after surgery.
• Cardiology: ATP is safe for use in people with high blood pressure in the pulmonary artery (pulmonary hypertension). Pulmonary hypertension can lead to difficulty breathing and a reduced ability to perform everyday tasks. If left untreated, this condition can cause heart failure and early death.
• Surgery: ATP can also be used in surgery to cause low blood pressure (hypotension). This helps to reduce bleeding and provide a better view of the surgical site.