Biology Chapter 8 and 9 Flashcards
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Questions and Answers

Define metabolism.

The totality of an organism's chemical reactions, consisting of catabolic and anabolic pathways, which manage the material and energy resources of the organism.

Which reactions release energy?

Catabolic

Which reactions consume energy?

Anabolic

Which reactions build up larger molecules?

<p>Anabolic</p> Signup and view all the answers

Which reactions break down molecules?

<p>Catabolic</p> Signup and view all the answers

Which reactions are considered 'uphill'?

<p>Anabolic</p> Signup and view all the answers

What type of reaction is photosynthesis?

<p>Anabolic</p> Signup and view all the answers

What type of reaction is cellular respiration?

<p>Catabolic</p> Signup and view all the answers

Which reactions require enzymes to catalyze reactions?

<p>Catabolic and anabolic</p> Signup and view all the answers

Contrast kinetic and potential energy.

<p>Kinetic energy is associated with the relative motion of objects, whereas potential energy refers to energy based on an object's position or structure.</p> Signup and view all the answers

Which type of energy does water have behind a dam? A mole of glucose?

<p>Water behind a dam has potential energy. A mole of glucose has chemical energy.</p> Signup and view all the answers

What is free energy and what is its symbol?

<p>Free energy is the portion of a system's energy that can perform work when temperature and pressure are uniform throughout. It is symbolized by G.</p> Signup and view all the answers

For an exergonic reaction, is ΔG negative or positive?

<p>ΔG is negative.</p> Signup and view all the answers

Is cellular respiration an endergonic reaction or exergonic reaction? What is ΔG for this reaction?

<p>Cellular respiration is an exergonic reaction. ΔG = -686 kcal/mol.</p> Signup and view all the answers

Is photosynthesis an endergonic or exergonic reaction? What is the energy source that drives it?

<p>Photosynthesis is an endergonic reaction, driven by sunlight.</p> Signup and view all the answers

To summarize, if energy is released, ΔG must be what?

<p>ΔG must be negative.</p> Signup and view all the answers

Name kinds of work that a cell does, give an example of each.

<p>Chemical work, transport work, mechanical work.</p> Signup and view all the answers

By what process will a molecule of ATP bond break?

<p>Hydrolysis.</p> Signup and view all the answers

Explain the name ATP by listing all the molecules that make it up.

<p>ATP contains the sugar ribose, nitrogenous base adenine, and a chain of three phosphate groups.</p> Signup and view all the answers

When the terminal phosphate bond is broken, a molecule of inorganic phosphate P is formed, and energy is ________.

<p>released</p> Signup and view all the answers

For this reaction: ATP-->ADP+P, ΔG = ________.

<p>-7.3 kcal/mol</p> Signup and view all the answers

Is this reaction endergonic or exergonic?

<p>Exergonic</p> Signup and view all the answers

What is energy coupling?

<p>In cellular metabolism, the use of energy released from an exergonic reaction to drive an endergonic reaction.</p> Signup and view all the answers

What is a catalyst?

<p>A chemical agent that selectively increases the rate of a reaction without being consumed.</p> Signup and view all the answers

What is activation energy?

<p>The amount of energy that reactants must absorb before a chemical reaction will start.</p> Signup and view all the answers

What is meant by induced fit? How is it shown in the picture of the enzyme reaction?

<p>Induced fit is the change in enzyme shape that allows it to bind more snugly to the substrate.</p> Signup and view all the answers

Explain how protein structure is involved in enzyme specificity.

<p>The specificity of an enzyme results from its shape, a consequence of its amino acid sequence.</p> Signup and view all the answers

Why can extremes of pH or very high temperatures affect enzyme activity?

<p>Proteins are sensitive to their environment, and extreme conditions can alter their three-dimensional structure.</p> Signup and view all the answers

Name a human enzyme that functions well in pH 2. Where is it found?

<p>Pepsin, found in the human stomach.</p> Signup and view all the answers

Distinguish between cofactors and coenzymes. Give examples of each.

<p>Cofactors are nonprotein molecules needed for enzyme function; coenzymes are organic molecules acting as cofactors.</p> Signup and view all the answers

Compare and contrast competitive inhibitors and noncompetitive inhibitors.

<p>Competitive inhibitors mimic substrate structure to reduce enzyme activity at the active site. Noncompetitive inhibitors bind elsewhere, changing enzyme shape.</p> Signup and view all the answers

What is allosteric regulation?

<p>Allosteric regulation is the binding of a regulatory molecule to a protein at one site, affecting its function at another site.</p> Signup and view all the answers

How is it somewhat like noncompetitive inhibition? How might it be different?

<p>It is like noncompetitive inhibition in that it may inhibit enzyme activity but can also stimulate it.</p> Signup and view all the answers

Explain the difference between an allosteric activator and an allosteric inhibitor.

<p>An allosteric activator stabilizes the shape with functional active sites, while an inhibitor stabilizes the inactive form.</p> Signup and view all the answers

Although it is not an enzyme, hemoglobin shows cooperativity in binding O2. Explain how hemoglobin works at the gills of a fish.

<p>Hemoglobin's binding of one oxygen molecule increases its affinity for others, facilitating oxygen uptake in high levels.</p> Signup and view all the answers

Study Notes

Metabolism

  • Metabolism encompasses the total chemical reactions in an organism, involving both catabolic and anabolic pathways to manage energy and materials.
  • Catabolic reactions release energy by breaking down larger molecules.
  • Anabolic reactions consume energy to build larger molecules.

Energy Types

  • Kinetic energy relates to the motion of objects; potential energy is stored due to an object's state or position.
  • Water behind a dam and glucose both contain potential energy, specifically chemical energy in glucose, which is relevant for biological reactions.

Free Energy

  • Free energy (G) is the energy available to perform work in a system at uniform temperature and pressure.
  • Exergonic reactions release energy, indicated by a negative ΔG; cellular respiration exemplifies this with a ΔG of -686 kcal/mol.
  • Photosynthesis, with an input of energy from light, is an endergonic reaction requiring 686 kcal to synthesize glucose.

Work in Cells

  • Cells perform various types of work including:
    • Chemical Work: Driving non-spontaneous reactions, e.g., polymer synthesis from monomers.
    • Transport Work: Pumping substances against concentration gradients, like Na+/K+ pumps.
    • Mechanical Work: Functions like cilia movement and muscle contractions.

ATP and Energy Release

  • ATP (adenosine triphosphate) consists of ribose sugar, adenine, and three phosphate groups.
  • Hydrolysis of ATP breaks the terminal phosphate bond, releasing around 7.3 kcal/mol of energy in an exergonic process.

Energy Coupling

  • Energy coupling involves using energy released from exergonic reactions to power endergonic reactions in cellular metabolism.

Enzymes and Catalysis

  • Enzymes are catalysts that speed up reactions without being consumed.
  • Activation energy is the necessary energy for reactants to initiate a chemical reaction.

Enzyme Function and Specificity

  • Induced fit describes the change in the enzyme's active site upon substrate binding, optimizing the reaction.
  • Enzyme specificity results from the unique 3D structure of proteins, ensuring a precise fit between enzyme and substrate.

Effects of Environment on Enzymes

  • Extreme pH or high temperatures can denature enzymes, altering their optimal shapes and functionality.

Cofactors and Coenzymes

  • Cofactors are non-protein molecules required for enzyme function; coenzymes are organic cofactors, often derived from vitamins.

Inhibitors and Regulation

  • Competitive inhibitors block the active site, while noncompetitive inhibitors bind elsewhere, altering the enzyme's shape.
  • Allosteric regulation involves the binding of regulatory molecules that can either enhance or inhibit enzyme activity.

Hemoglobin and Oxygen Affinity

  • Hemoglobin exhibits cooperative binding: the binding of oxygen to one subunit increases the affinity of remaining subunits, crucial for oxygen uptake in high-concentration areas like gills.

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Test your knowledge of key concepts from Biology chapters 8 and 9 with these flashcards. Focus on metabolism, energy reactions, and the definitions of catabolic and anabolic processes. Perfect for quick reviews and studying for exams.

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