Energy and Cellular Respiration

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Questions and Answers

What is the primary role of energy in living organisms?

To synthesize new molecules (correct)

To create oxygen

To regulate temperature

To store information

What happens to glucose during cellular respiration?

It is stored as fat

It is converted to oxygen

It is broken down to form ATP (correct)

It is transformed into starch

Which of the following describes kinetic energy?

Energy that cannot be converted

Energy related to the position of an object

Energy that is stored for future use

Energy that can be harnessed when there is motion (correct)

In the context of the plasma membrane, what does the sodium ion concentration gradient represent?

Potential energy due to stored ions Signup and view all the answers

What type of energy is involved in the movement of blood by the heart?

Mechanical Energy Signup and view all the answers

Which of the following is related to the energy of electromagnetic waves?

Radiant Energy Signup and view all the answers

Which type of energy is exemplified by water at the top of a dam?

Potential energy Signup and view all the answers

What occurs when sodium ions move from an area of high concentration to an area of lower concentration?

They acquire kinetic energy Signup and view all the answers

Which form of energy is responsible for the vibrations that stimulate sensory receptors for hearing?

Sound Energy Signup and view all the answers

What is the best definition of energy?

The capacity to do work Signup and view all the answers

What is the result of higher frequencies of electromagnetic waves?

Increased mutation of DNA Signup and view all the answers

Which of the following is a form of potential energy?

Chemical energy Signup and view all the answers

Which type of light is detected by retinal cells for vision?

Visible Light Signup and view all the answers

What role do cells play when they protect themselves from higher frequency electromagnetic waves?

They produce melanin Signup and view all the answers

What is the frequency range capable of entering the body and potentially damaging DNA?

400 nm to 740 nm Signup and view all the answers

In what form of energy does the eagle convert its potential energy while flying?

Kinetic Energy Signup and view all the answers

What is the primary use of chemical energy in the body?

For mechanical movements and cellular activities Signup and view all the answers

Which of the following molecules is primarily responsible for long-term energy storage in adipose tissue?

Triglycerides Signup and view all the answers

What type of energy is stored in the chemical bonds of molecules?

Chemical energy Signup and view all the answers

Which molecule is produced continuously and used immediately in cells?

ATP Signup and view all the answers

What type of energy is manifested in muscle contractions during physical movement?

Mechanical energy Signup and view all the answers

What is the role of Na+ ions in the context of kinetic energy?

Exhibit kinetic energy while moving down a concentration gradient Signup and view all the answers

Which of the following statements about protein energy storage is correct?

Proteins can be utilized as fuel molecules but primarily serve other critical functions. Signup and view all the answers

Which of the following is an example of electric energy in the body?

Movement of ions across a plasma membrane Signup and view all the answers

What is the primary substrate used by glycogen synthase in the synthesis of glycogen?

Glucose Signup and view all the answers

At what temperature do human enzymes generally exhibit optimal activity?

95°F - 104°F Signup and view all the answers

How does a moderate fever affect enzyme activity?

It can enhance enzyme activity Signup and view all the answers

What happens to enzymes at severe increases in temperature?

They undergo denaturation Signup and view all the answers

What is the effect of cooler temperatures on the 3-D shape of enzymes?

Enzymes become more rigid Signup and view all the answers

What pH condition is generally optimal for enzyme activity?

Neutral to slightly alkaline solutions Signup and view all the answers

Which factor primarily affects the intramolecular interactions within enzymes as temperature increases?

Energy of molecular motion Signup and view all the answers

What is the optimal temperature range for maintaining protein flexibility in human enzymes?

35°C - 40°C Signup and view all the answers

What is the primary source of energy for the formation of ATP?

Energy from exergonic reactions Signup and view all the answers

Which molecule is produced alongside ATP during the formation process?

ADP Signup and view all the answers

What is the state of ATP in terms of its presence within the cell?

Present in a few seconds' worth Signup and view all the answers

How do enzymes affect activation energy in chemical reactions?

Decrease the activation energy of reactions Signup and view all the answers

Which statement correctly describes how reversible reactions behave?

They reach equilibrium with no net change in concentrations. Signup and view all the answers

What is the role of catalysts in cellular reactions?

They increase the rate of product formation. Signup and view all the answers

What happens if the temperature increases significantly within a cell?

Proteins may denature and lose function. Signup and view all the answers

Which of the following correctly defines activation energy?

The energy required to initiate a reaction Signup and view all the answers

What characterizes exergonic reactions in terms of energy?

They release energy and have a net decrease in potential energy. Signup and view all the answers

Which of the following is an example of an endergonic reaction?

Photosynthesis of plants Signup and view all the answers

In the context of energy changes, what occurs during endergonic reactions?

Energy is supplied and products have higher energy than reactants. Signup and view all the answers

What is true about the reactants in an exergonic reaction?

They have more energy than the products. Signup and view all the answers

When graphing an exergonic reaction, what trend would be observed?

The energy releases steadily with more products formed. Signup and view all the answers

Endergonic reactions primarily require energy for what purpose?

To synthesize complex molecules from simpler ones. Signup and view all the answers

Which statement accurately describes the energy changes in decomposition reactions?

They are exergonic with energy released. Signup and view all the answers

What distinguishes endergonic reactions from other types of chemical reactions?

They require energy input for the formation of products. Signup and view all the answers

Study Notes

Energy, Chemical Reactions, and Cellular Respiration

Living organisms require energy
Energy is needed for various bodily functions, including:
- Powering muscles
- Pumping blood
- Absorbing nutrients
- Exchanging respiratory gases
- Synthesizing new molecules
- Establishing cellular ion concentrations
Glucose is broken down through metabolic pathways to form ATP, the energy currency of cells

Energy: States of Energy

Energy is the capacity to do work, invisible except for its effects on matter
Energy exists in two states:
- Potential energy: stored energy (energy of position)
- Kinetic energy: energy of motion
Energy can be converted from one state to another (e.g., potential energy of water at the top of a dam to kinetic energy as it falls)

Potential energy and the plasma membrane

Concentration gradient of sodium ions across the plasma membrane of a cell represents potential energy (analogous to water at the top of a dam)
When sodium ions move from high to low concentration, they convert potential energy into kinetic energy, which can be used to do work

Energy: Forms of Energy

Chemical Energy (A Form of Potential Energy):
- Stored in chemical bonds of molecules
- Most important energy form in the body
- Used for movement, molecule synthesis, establishing concentration gradients
- Released when bonds are broken
Molecules in Chemical Energy Storage:
- Triglycerides: long-term energy storage in adipose tissue
- Glycogen: energy storage in liver and muscle
- ATP: stored in all cells, continuously produced, and used immediately
- Proteins: can be used as a fuel, but has more important functions

Kinetic Energy Forms

Electric energy: movement of charged particles (e.g., electricity or ion movement across a neuron's plasma membrane)
Mechanical energy: exhibited by objects in motion (e.g., muscle contraction for walking).
Sound energy: molecule compression caused by vibrating objects (e.g., sound waves causing eardrum vibration)
Radiant energy: energy of electromagnetic waves (e.g., various wavelengths and frequencies, including visible light)

Energy: Laws of Thermodynamics

First Law of Thermodynamics: Energy can neither be created nor destroyed; it only changes form
Second Law of Thermodynamics: When energy is transformed, some energy is inevitably lost as heat; the amount of usable energy decreases. (e.g. , conversion of chemical energy to mechanical energy results in waste heat).

Chemical Reactions: Chemical Equations

Metabolism: All chemical reactions in the body.
Chemical Reactions: Occur when chemical bonds in existing molecules are broken and new bonds are formed.
Chemical Equations: summary of changes in reactions.

Chemical Reactions: Components of Chemical Equations

Reactants: substances present before the reaction; written on the left side of the equation
Products: substances formed by the reaction; written on the right side of the equation
Reactions are typically presented as A+B -> C (with A and B being reactants and C being the product). Arrows indicate direction, and a balanced equation represents equal numbers of elements on both sides of the reaction

Chemical Reactions: Classification of Chemical Reactions

Catabolism: Decomposition reactions (break down of molecules)
Anabolism: Synthesis reactions (building up of molecules).
Metabolism: Collective term for all chemical reactions in the body

Chemical Reactions: Classification Based on Changes in Chemical Energy

Exergonic reactions: reactants have more energy than products; energy is released (e.g., decomposition reactions).
Endergonic reactions: reactants have less energy than products; energy is absorbed or supplied (e.g., synthesis reactions).
ATP Cycling: continuous formation and breakdown of ATP; ATP provides energy for energy-requiring processes.

Chemical Reactions: Reaction Rates and Activation Energy

Activation energy (Ea): energy needed to start a reaction (break existing chemical bonds).
Catalysts (enzymes): proteins that reduce activation energy (speed up chemical reactions), without being consumed in the reaction.

Enzymes: Function of Enzymes

Enzymes are catalysts that speed up normal chemical activities by decreasing the activation energy of cellular reactions
Enzymes only facilitate reactions that would already occur
Enzymes increase the rate of product formation.
Chemical reactions without enzymes are "uncatalyzed", while reactions with enzymes are "catalyzed"

Enzymes: Structure and Location

Most enzymes are globular proteins, with unique 3D structures.
Active site: Region of the enzyme that accommodates and binds the reaction substrate, temporarily forming an enzyme-substrate complex.
Specificity of enzyme shape: Permits binding of a specific substrate, catalyzing a specific reaction.

Enzymes: Mechanism of Enzyme Action

Enzyme catalysis: Substrate enters the active site, forming an enzyme-substrate complex.
Induced fit: Enzyme changes shape slightly for a closer fit with the substrate.
Stressing chemical bonds: Shape change stresses bonds in the substrate, allowing them to break and new bonds to form, creating the product.
Release of products and repeat: Products are released, and the enzyme is free to repeat the process.

Enzymes: Enzymes and Reaction Rates

Effect of Temperature:
- Enzymes have optimal temperatures for function in human bodies (typically between 95-104°F).
- Moderate increases in temperature result in more enzyme efficiency.
- High temperatures cause denaturation (loss of function)
Effect of pH: Enzymes function best at a specific pH range, typically between 6-8.
- Changes in pH disrupt electrostatic interactions important for enzyme shape and function.
- Extreme pH changes cause protein denaturation.

Clinical View: Lactose Intolerance

Caused by a deficiency in the enzyme lactase, which is needed to break down lactose.
Symptoms include abdominal upset.
Treated with lactase enzymes or by avoiding milk products

Let's Graph It!

Create two graphs measuring changes in energy over time for a given reaction:
- One graph showing the reaction of energy supplied or released over time for various products
- A second graph showing the cumulative amount of heat generated (or given off) during the reaction

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Description

Explore the essential concepts of energy, chemical reactions, and cellular respiration in living organisms. This quiz covers energy states, the conversion of glucose to ATP, and the role of potential energy in cellular functions. Test your understanding of how energy powers various bodily functions and supports life.