NASM Ch 8 Energy and Mechanical Work

mechanical work

The physical processes that move the body and keep it alive, such as muscle contraction.

sun

The only way new energy enters the earth’s ecosystem is from the

cellular and mechanical

sun. Plants convert the sun’s energy to food and food provides animals (including humans) with energy to perform _ functions

40%

the amount of energy released during metabolism is actually used for cellular work, such as a cell creating more molecules

60%

how much energy is used to produce heat?

gasoline for a car

what is the best memory trick for ATP?

adenine

a nitrogenous base

ribose

a sugar molecule

a nitrogenous base, sugar molecule, and three phosphate groups

what components is ATP made of?

When these chemical bonds are broken, energy from one of the phosphates is released for mechanical work (such as performing muscle contraction)

how does ATP get released?

ADP

when ATP is released, _ is then left free in the cell, waiting to be converted back to ATP when enough energy substrates from food or bodily stores are available

phosphorylation

The addition of a phosphate group to a molecule, such as in the transfer of a phosphate group to adenosine diphosphate to create adenosine triphosphate.

ATP-PC System

An energy system that provides energy very rapidly, for approximately 10–15 seconds, via anaerobic metabolism.

ATP-PC, glycolytic, and oxidative

the three metabolic pathways

anaerobic

Processes relating to the absence of oxygen.

ATP-PC

provides energy for primarily high-intensity, short-duration bouts of activity. This can be seen in strength and power forms of training in which very heavy loads are used with only a few repetitions or during short sprinting efforts

glycolysis

A metabolic process that occurs in the cytosol of a cell that converts glucose into pyruvate and adenosine triphosphate. Anaerobic glycolysis refers to when this process occurs in the absence of oxygen.

pyruvate and ATP

The process of glycolysis turns free blood glucose or stored glycogen into

cytoplasm of an animal cell

. Glycolysis takes place in the

glycolysis

a capacity of approximately 30 to 60 seconds of duration, which can be increased by several seconds through the use of high-intensity styles of training

60 minutes

For most people, those carbohydrate sources run out after around of sustained activity, which is why carbohydrate drinks or gels are helpful to keep the body performing at its best when an event lasts longer than _

further broken down, enters the oxidative system, and leads to the creation of additional ATP.

If there is oxygen available, the pyruvate is

converted into a molecule called lactate, which contributes to the “burn” felt during strenuous exercise as it accumulates in muscle tissue

If oxygen cannot be delivered fast enough, the pyruvate will be

oxidative phosphorylation

A series of reactions inside the mitochondria that uses oxygen to produce adenosine triphosphate.

aerobic

Processes relating to, involving, or requiring oxygen.

deamination

The breakdown of amino acids into substrates that can be used for energy metabolism.

ATP is needed faster than oxygen can be delivered by the cardiorespiratory system.

During high-intensity exercise, why does the body rely more on the ATP-PC system and glycolysis?

Pyruvate is quickly converted into lactate.

What happens to pyruvate during anaerobic exercise?

A free hydrogen ion (H+).

What is released when pyruvate is converted into lactate?

The accumulation of free hydrogen ions (H+), which lowers muscle pH.

What causes muscle acidosis during intense exercise?

A decrease in muscle pH caused by an accumulation of hydrogen ions during intense exercise.

What is acidosis?

They interfere with muscle contraction, contributing to pain and fatigue during intense exercise.

How do hydrogen ions contribute to muscle fatigue?

The combination of lactate and hydrogen ions produced during anaerobic glycolysis.

What is commonly referred to as "lactic acid"?

No. Lactate is recycled and reused rather than simply removed from the body.

Is lactate considered a true waste product?

The Cori cycle.

What metabolic process converts lactate back into glucose?

In the liver.

Where does the Cori cycle occur?

Lactate is converted back to pyruvate and then into glucose using ATP.

What happens to lactate during the Cori cycle?

It is released into the bloodstream to be used again for energy.

What happens to the glucose produced by the Cori cycle?

It recycles lactate into glucose and helps maintain the body's pH balance.

Why is the Cori cycle important?

The ATP-PC system and anaerobic glycolysis.

Which energy systems are primarily used during near-maximal exercise intensity?

Lactate + hydrogen ions (H+) → Glucose

Complete the pathway:
High-intensity exercise → Pyruvate → _____ + _____ → Cori cycle → _____ → Bloodstream

free fatty acids, the pyruvate created during glycolysis, and amino acids that have undergone deamination

what are the three substrates that are used in the oxidative system?

mitochondria

The parts of the cell that use nutrients to create energy for the cell; commonly known as the powerhouses of the cell.

electron transport chain (ETC)

A series of protein complexes that transfer protons and electrons received from the citric acid cycle through a series of reactions to create adenosine triphosphate.

acetyl coenzyme A

Produced by the breakdown of carbohydrates through glycolysis and by the fatty acids through beta-oxidation and is the precursor for these substrates to the citric acid cycle.

beta-oxidation

The first step in the process to break down fats via oxidative phosphorylation.

two, CAC and ETC

Oxidative phosphorylation uses a series of chemical reactions leading to the end result of creating ATP and carbon dioxide and includes how many sets of reactions?

CAC

aka Krebs cycle, which leads to the creation of a few ATP molecules and the waste product of carbon dioxide. Electrons are then freed for the next stage (ETC)

inner membrane, outer membrane, cristae, and matrix

the mitochondria contain what 4 parts?

oxidative system

what the body primarily relies on for the majority of low- to moderate-intensity activity

aerobic system

can sustain the body indefinitely, just at increasingly lower intensity levels

oxidative energy system’s ability to support higher intensity levels without having to preferentially activate the anaerobic processes.

As a person’s cardiorespiratory fitness improves (i.e., the ability to deliver oxygen to the cells), so does the

Krebs cycle

Whether carbohydrate, fat, or protein substrates are being used, they all must be broken down to the same substance (called acetyl coenzyme A), before they can enter the _

the electrons from this molecule and transports the negatively charged electrons along with positively charged hydrogen ions to the ETC

Acetyl CoA provides a common starting point for the enzymes used in the CAC, which removes

ADP to ATP

in the ETC, these electrons and hydrogens are stored inside the mitochondria and then used to provide the energy that converts

fat molecules

large, energy dense, and more complex than carbohydrates

fat metabolism

slower and cannot keep up with high-intensity energy demands

one fatty acid molecule

can net significantly more ATP than glucose

129 ATP

when one molecule of the fatty acid palmitate is fully metabolized, it yields

oxygen

using fat as an energy source always requires

number of mitochondria in the muscle cell and the amount of oxygen delivered by the blood

The rate at which a person can break down fat depends on the

more mitochondria

Athletes and well-conditioned people tend to have _ in their muscle cells

fat used to make ATP

Finally, if there is a lot of carbohydrate (glucose) available, the body will use some of that instead, which will decrease the total amount of

glucose

If oxidative phosphorylation is starting from a carbohydrate food source, it must first be broken down into this

pyruvate

If oxidative phosphorylation is starting from a carbohydrate food source, it must first be broken down into glucose and then converted to _ through glycolysis

aerobic metabolism of glucose

Essentially, not only is glycolysis its own anaerobic energy system, but it is also the first step in the

acetyl CoA and enters the CAC.

When there is enough oxygen present, pyruvate is not converted to lactate. Instead, it is further broken down to

35 and 40 ATP

the complete metabolism (anaerobic and aerobic) of a single glucose molecule produces between

also broken down and metabolized aerobically.

Additionally, if both carbohydrates and fats are depleted to the point that amino acids are being relied on directly for energy (e.g., during extreme starvation), they are

amino acids

are very rarely deaminated and converted to acetyl CoA directly for oxidative phosphorylation

glucose or ketone bodies via gluconeogenesis and ketogenesis. Those converted substrates then enter their respective carbohydrate- or fat-based metabolic pathways.

Most of the time, when amino acids are called on as an energy source, they are first converted to

removed the electrons from acetyl CoA.

The ETC is a vastly complex process that occurs in the inner mitochondrial membrane after the CAC has

stored hydrogen ions

In ETC, protein complexes create a gradient of _ that allow the electrons freed by the CAC to move through them

means the energy stored in the hydrogen (proton) gradient is captured and used by ATP synthase to make ATP.

In the electron transport chain (ETC), what does "harvested" mean?

ATP synthase uses the harvested energy from the hydrogen gradient, along with oxygen, to convert ADP into ATP and water. This allows the ETC to produce large amounts of ATP efficiently with very little waste.

What happens when ATP levels fall and ADP levels rise?

a few ATP, CO2 as a waste product, and free electrons.

The CAC (i.e., Krebs cycle) breaks down acetyl CoA, yielding

Free electrons enter the ETC and drive chemical reactions that produce large amounts of ATP, with water as the main waste product.

What is the role of free electrons in the electron transport chain (ETC)?