Energy Concepts in Physics

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Questions and Answers

What type of energy is exhibited by a space station orbiting Earth?

kinetic energy

'Conservation of energy' refers to the fact that _____.

energy cannot be created or destroyed but can be converted from one form to another

Chemical energy is a form of _____ energy.

potential

What process in the body converts the chemical energy found in glucose into the chemical energy found in ATP?

cellular respiration Signup and view all the answers

What are the by-products of cellular respiration?

heat, carbon dioxide, and water Signup and view all the answers

In general, enzymes are what kinds of molecules?

proteins Signup and view all the answers

Enzymes work by _____.

reducing activation energy (EA) Signup and view all the answers

What is an enzyme?

is an organic catalyst Signup and view all the answers

What name is given to the reactants in an enzymatically catalyzed reaction?

substrate Signup and view all the answers

As a result of its involvement in a reaction, an enzyme _____.

is unchanged Signup and view all the answers

What is the correct label for 'A' in a given diagram?

energy of activation Signup and view all the answers

The Haber process is typically carried out at what temperature?

approximately 500 Signup and view all the answers

What happens to the rate of the forward reaction if the temperature is lowered to 100?

The reaction rate would decrease. Signup and view all the answers

What would happen to the rate of the forward reaction if the concentration of nitrogen were decreased?

The reaction rate would decrease. Signup and view all the answers

Which of the following would increase the rate of the reverse reaction?

increasing the concentration of ammonia Signup and view all the answers

What will happen to the rates of the forward and reverse reactions when a catalyst is added?

Both forward and reverse rates increase. Signup and view all the answers

What is the term for the least product formed in a reaction?

uncatalyzed reaction Signup and view all the answers

What is an enzyme considered when it loses its native conformation?

denatured Signup and view all the answers

What is an enzyme considered because it speeds up chemical reactions without being used up?

catalyst Signup and view all the answers

What term describes the ability of an enzyme to recognize the shape of a particular molecule?

specific Signup and view all the answers

What binds to an enzyme and plays a role in catalysis?

cofactor Signup and view all the answers

What is formed when the enzyme and the substrate are properly aligned?

enzyme-substrate (ES) complex Signup and view all the answers

Where does a substrate bind to an enzyme?

active site Signup and view all the answers

How is a reactant often referred to in a catalyzed reaction?

substrate Signup and view all the answers

Select the highest energy form of adenosine from the following images.

ATP adenosine triphosphate, contains most phosphate groups Signup and view all the answers

Which part of the adenosine triphosphate molecule is released when it is hydrolyzed to provide energy?

lambda-phosphate (the terminal phosphate) Signup and view all the answers

In this reaction, what can be said about the products?

the products have less potential energy than the reactants and heat has been released to the environment Signup and view all the answers

The reaction A --> B + C + heat is released in a(n) _____ reaction.

exergonic Signup and view all the answers

What type of reaction occurs spontaneously?

exergonic Signup and view all the answers

Which of these reactions requires a net input of energy from its surroundings?

endergonic Signup and view all the answers

In cells, what is usually the immediate source of energy for an endergonic reaction?

ATP Signup and view all the answers

What is the fate of the phosphate group that is removed when ATP is converted to ADP?

It is acquired by a reactant in an endergonic reaction. Signup and view all the answers

What does an increase in enzyme concentration do in a reaction?

Increase the rate of the reaction. Signup and view all the answers

What must occur in order for the aminoacyl-tRNA synthetase to attach a particular amino acid to the tRNA molecule?

The binding of the first two molecules must cause a 3-dimensional change that opens another active site on the enzyme. Signup and view all the answers

How does a noncompetitive inhibitor decrease the rate of an enzyme reaction?

by changing the shape of an enzyme Signup and view all the answers

What does the binding of a product to an enzyme at a position remote from its active site do?

decreases the activity of the enzyme. Signup and view all the answers

How do living organisms increase in complexity as they grow in relation to the second law of thermodynamics?

As a consequence of growing, organisms create more disorder in their environment than the decrease in entropy associated with their growth. Signup and view all the answers

How is the ATPase acting if it is transporting calcium ions against the concentration gradient?

ATPase activity must be pumping calcium from the cytosol to the SR against the concentration gradient. Signup and view all the answers

Study Notes

Energy Concepts

Kinetic energy is the energy an object possesses due to its motion, exemplified by a space station in orbit.
"Conservation of energy" states that energy cannot be created or destroyed, only transformed from one form to another.
Chemical energy is a type of potential energy stored in molecular bonds.

Biological Processes

Cellular respiration converts chemical energy from glucose into ATP, the energy currency of cells.
By-products of cellular respiration include heat, carbon dioxide, and water.

Enzyme Functionality

Enzymes are proteins that act as organic catalysts, speeding up chemical reactions by reducing activation energy.
They remain unchanged after reactions, engaging with substrates at their active sites, forming an enzyme-substrate complex.

Reaction Dynamics

The reactants in an enzymatic reaction are referred to as substrates, and their rate can be affected by various factors including temperature, concentration, and presence of inhibitors.
Adding a catalyst increases both forward and reverse reaction rates without being consumed.

Thermodynamics of Reactions

Exergonic reactions release energy, occur spontaneously, and result in products with lower potential energy than reactants.
Endergonic reactions require energy input, are nonspontaneous, and are typically driven by ATP.

Energy Transfers

ATP undergoes hydrolysis to release energy, specifically losing the terminal phosphate group.
Energy coupling allows the energy released from exergonic reactions to drive endergonic processes.

Enzyme Inhibition

Competitive inhibitors, like malonic acid, compete with substrates for enzyme binding, reducing reaction rates.
Noncompetitive inhibitors alter an enzyme's shape, decreasing its activity without competing for the active site.

Regulation and Feedback Mechanisms

Allosteric inhibitors bind to enzymes at sites other than the active site, modulating their activity.
Feedback regulation in enzymatic pathways helps control product synthesis, as seen when a product binds and deactivates an enzyme in the pathway.

Thermodynamics and Organism Growth

While living organisms increase in complexity (decreasing their own entropy), they contribute to greater disorder in their environment, in line with the second law of thermodynamics.

ATPases and Calcium Transport

ATP-driven pumps, known as ATPases, transport ions such as calcium across membranes against their concentration gradient, maintaining low intracellular calcium levels crucial for cellular functions.

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Description

This quiz explores key concepts related to energy, including kinetic energy, conservation of energy, and chemical energy forms. It challenges your understanding of how energy is defined and transformed within various systems. Perfect for students learning about physics and energy principles.