ATP and Energy - Online Tutor, Practice Problems & Exam Prep

The mitochondria, known as the powerhouse of the cell, are crucial for ATP (Adenosine Triphosphate) production. ATP stores energy from food catabolism and features high-energy phosphorus-oxygen bonds. Hydrolysis of ATP releases energy, converting it to ADP (Adenosine Diphosphate) and inorganic phosphate. This energy can drive unfavorable metabolic reactions, such as the conversion of glucose to glucose-6-phosphate, by coupling with ATP hydrolysis. Understanding these processes is essential for grasping cellular metabolism and energy transfer.

Structure of Mitochondria Concept 1

Now when it comes to ATP and energy, it's important to remember the structure of the mitochondria, which oftentimes you hear is the powerhouse of the cell. Now, the mitochondria is basically the energy-producing organelle where a majority of ATP is produced. Here, we're going to say that this is the site of the common metabolic pathway. In the mitochondria, we have what's called our cristae. Our cristae are folded inner membranes and they provide increased surface area for the production of ATP. If we were to take a look at this example of our mitochondria, we would say that our cristae will be represented by this portion where it's being highlighted. These are the folds of the inner membrane.

Next, we're going to say that inside of here, this gray portion would be our matrix of the mitochondria. Then we would say that this outside portion here would be our outer membrane, then we would say that this portion that's being touched would be our inner membrane. So remember, the membrane itself is just this portion. The cristae is just where it's folding. We have our outer membrane here, we have our inner membrane here. So what do we call the part that's in between that? Well, that's called our intermembrane space. Right? So these represent the most important portions of a typical mitochondria.

Structure of Mitochondria Example 1

This example question states, "Which structure in the mitochondrion contributes significantly to ATP synthesis?" So remember, we said that the cristae represent our inner folded membranes. They help to increase the surface area to help with the production of ATP. This is incredibly important for the generation of as much ATP as possible. So, out of all these options, it would have to be option B. The cristae help significantly in ATP synthesis by the folding of the membrane.

Adenosine Triphosphate (ATP) Concept 2

Now, ATP stands for Adenosine Triphosphate. We're going to say energy obtained from food catabolism is stored within these ATP molecules. ATP itself is a high energy compound that stores and transports energy. Now, here we're going to say that it has high energy Phosphorus-Oxygen bonds. We're going to say hydrolysis using water of ATP yields energy. If we take a look here, we have our ATP here. So, our ATP is made up of different things. We have our Adenine, our nitrogenous base here. We have our ribose, which is our sugar. And then we have three phosphates: 1, 2, 3. So, our Triphosphate. Remember that our Ribose and Adenine together are our adenosine, so together that's what they form. So this would be our adenosine triphosphate. That's why it's called ATP. Here, we're gonna use water. Water basically cuts one of these phosphate groups off. So, you'll notice that we no longer have three phosphate groups, we have only two. Tri means three, di means two, so this now becomes Adenosine Diphosphate or ADP. Now, the removal of this phosphate group creates P_i, which is inorganic phosphate. Inorganic because it doesn't have carbon connected to it. Also, by cutting off this phosphate, we're breaking that high-energy bond. Breaking it releases that energy that was in it. So, we have energy here being produced as a product. Now, here note that hydrolysis of ADP, so we could actually use water again if we wanted to to cut this high-energy bond and that will produce Adenosine Monophosphate or AMP. We're breaking again another high energy Phosphorus-Oxygen bond which would result in the release of energy again. So just remember, ATP is just a high energy molecule. We can cut through the use of water its PO bonds, its phosphorus oxygen bonds, to release an inorganic phosphate, but more importantly, energy.

Adenosine Triphosphate (ATP) Example 2

Which components make up the structure of ATP? Remember, ATP stands for Adenosine Triphosphate. The adenosine portion is made up of two things. It's made up of our nitrogenous base in the form of Adenine and the ribose sugar. And if we look, only A and B or A and C have those options. So B is out and D is out. So together those two components make the adenosine part of ATP. And why is it called TP? Well, triphosphate. There are three phosphate groups connected together. So here, it would not be one phosphate group, that would be adenosine monophosphate. So by elimination, C would have to be our answer. We're going to say here that ATP's components are Adenine, which is the nitrogenous base again, the ribose sugar, which is our sugar component, together they're the adenosine, and then we have our three phosphate groups. So C would be our final answer.

Hydrolysis of Adenosine Diphosphate yields:

• A. Ribose, inorganic phosphate, and energy.
• B. Adenosine Monophosphate, one inorganic phosphate, and chemical (potential) energy.
• C. Adenosine Monophosphate, three inorganic phosphates, and energy.
• D. Adenosine Monophosphate, one inorganic phosphate, and kinetic energy.

Coupled Reactions Concept 3

Now when it comes to ATP and energy, know that not every reaction in metabolic pathways is favorable. And some need to couple with favorable or exothermic reactions such as ATP hydrolysis, remember using water on ATP is hydrolysis. We have the releasing of an inorganic phosphate group, but more importantly, energy. The energy that we release, we can harness it and we're going to use this energy and serves as an energy source to basically drive unfavorable reactions. So if we take a look here, we're going to say this first reaction is unfavorable. In it, we have glucose and an inorganic phosphate group. Here, we're trying to add it to glucose to create glucose 6-phosphate. This reaction is highly unfavorable because there is not energy that helps to drive it. So what we do here to create a favorable reaction is first we do ATP hydrolysis. Remember, ATP hydrolysis would cut the high energy Phosphorus-Oxygen Bond to create Adenosine Diphosphate, Inorganic Phosphate, but more importantly energy. This energy that we make here, we can then harness it, couple it with this original equation. With this outside energy, we now have the energy source to help us connect the inorganic phosphate to our glucose molecule. And in this case, we can successfully make Glucose 6-Phosphate. So just remember, not all metabolic reactions are favorable. We sometimes have to couple them, we have to get energy from another place and then use it, harness it to help drive our initially unfavorable reaction.

Coupled Reactions Example 3

What role does ATP play? Alright. So ATP here, through hydrolysis, will release energy. This energy can be used to help drive this unfavorable reaction. Here we're going to say it's going to transfer energy to drive the endothermic reaction. So option A is the best answer.

Here, to act as a catalyst. No. It's not acting as a catalyst. It's acting as an energy source. Speed up the rate of the reaction. Well, here both options B and C are saying the same thing. Speeding up the rate of the reaction would mean it's acting as a catalyst, which is not what it's doing. A catalyst speeds up a reaction by lowering the energy of activation. It doesn't change an unfavorable reaction into a favorable one. That's why it doesn't work and it's not a good option.

Absorb energy from the surroundings? No. If we're cutting or cleaving a phosphorus-oxygen bond, we're releasing energy. Then we can use that energy to drive our next reaction. So here, option A is the correct answer.

An athlete is training for a marathon. Every mile that the athlete runs, an average of 117.5 kcal of energy is expanded. How many moles of ATP would the athlete burn during a full marathon (26.2 mi)? Use conversion factor: 1 mole ATP = 7.3 kcal.

• A. 22.47 moles ATP
• B. 4.22 x 105 moles ATP
• C. 22,473 moles ATP
• D. 421.7 moles ATP

Here’s what students ask on this topic:

What is the role of mitochondria in ATP production?

The mitochondria, often referred to as the powerhouse of the cell, play a crucial role in ATP production. They are the site of the common metabolic pathway where the majority of ATP is produced. The inner membrane of the mitochondria, known as the cristae, is folded to increase surface area, facilitating the production of ATP. The matrix, the space within the inner membrane, contains enzymes that aid in the production of ATP through processes like the Krebs cycle and oxidative phosphorylation. The energy obtained from food catabolism is stored in ATP molecules, which are then used to power various cellular functions.

How does ATP hydrolysis release energy?

ATP hydrolysis releases energy by breaking the high-energy phosphorus-oxygen bonds in ATP. ATP, or Adenosine Triphosphate, consists of adenine, ribose (a sugar), and three phosphate groups. When water (H₂O) is used to hydrolyze ATP, one of the phosphate groups is removed, converting ATP to ADP (Adenosine Diphosphate) and an inorganic phosphate (P_i). This reaction releases energy that can be harnessed for various cellular processes. The equation for ATP hydrolysis is:

${\text{ATP}}_{}+{\text{H}}_2\to {\text{ADP}}_{}+{\text{P}}_{}$_i+energy

What is the structure of ATP?

ATP, or Adenosine Triphosphate, is composed of three main components: adenine, ribose, and three phosphate groups. Adenine is a nitrogenous base, ribose is a five-carbon sugar, and the three phosphate groups are linked by high-energy phosphorus-oxygen bonds. The combination of adenine and ribose forms adenosine. The three phosphate groups are attached to the ribose, making it a triphosphate. The structure of ATP can be summarized as:

${\text{Adenine}}_{}+{\text{Ribose}}_{}+{\text{3}}_{Phosphate}$

How does ATP drive unfavorable metabolic reactions?

ATP drives unfavorable metabolic reactions by coupling its hydrolysis with these reactions. ATP hydrolysis releases energy by breaking a high-energy phosphorus-oxygen bond, converting ATP to ADP and an inorganic phosphate (P_i). This released energy can be harnessed to drive reactions that are otherwise energetically unfavorable. For example, the conversion of glucose to glucose-6-phosphate is an unfavorable reaction. By coupling it with ATP hydrolysis, the energy released from ATP can be used to add a phosphate group to glucose, making the overall reaction favorable. This process is essential for various cellular functions and metabolic pathways.

What happens during the hydrolysis of ADP?

During the hydrolysis of ADP (Adenosine Diphosphate), water (H₂O) is used to break one of the high-energy phosphorus-oxygen bonds, converting ADP to AMP (Adenosine Monophosphate) and an inorganic phosphate (P_i). This reaction releases energy, similar to the hydrolysis of ATP. The equation for ADP hydrolysis is:

${\text{ADP}}_{}+{\text{H}}_2\to {\text{AMP}}_{}+{\text{P}}_{}$_i+energy

This released energy can be used for various cellular processes, similar to the energy released from ATP hydrolysis.