Biology Chapter on Energy and Macromolecules

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Questions and Answers

What are the building blocks of proteins?

Glycerol + Fatty acids

Monosaccharides

Nucleotides

Amino acids (correct)

Which type of energy is associated with objects in motion?

Potential energy

Kinetic energy (correct)

Chemical energy

Mechanical energy

According to the First Law of Thermodynamics, which of the following statements is true?

Energy cannot be transferred to new forms.

Energy increases in an isolated system.

Energy can be created but not destroyed.

Energy can only be transformed and transferred. (correct)

Which type of work is involved in muscle contraction?

Mechanical work Signup and view all the answers

What happens to energy during every transfer according to the Second Law of Thermodynamics?

Some energy is lost in an unusable form. Signup and view all the answers

Which of the following best defines potential energy?

Energy associated with the position or structure of matter. Signup and view all the answers

What is the primary function of chemical energy in cells?

To provide potential energy in molecular bonds. Signup and view all the answers

What role do carbohydrates play in energy metabolism?

They provide energy needed for cellular functions. Signup and view all the answers

What occurs during an exergonic reaction?

The products have less energy than the reactants. Signup and view all the answers

Which type of reaction requires energy input to synthesize large organic molecules?

Endergonic reactions Signup and view all the answers

What best describes catabolism?

The breakdown of molecules to release energy. Signup and view all the answers

During oxidation, what happens to an atom or molecule?

It loses electrons. Signup and view all the answers

What is the primary function of redox reactions in cells?

To transfer energy among molecules. Signup and view all the answers

Which statement is true regarding endergonic reactions?

They result in products with more free energy than reactants. Signup and view all the answers

Which of the following molecules is a product of catabolic reactions?

Amino acids Signup and view all the answers

What does a negative free energy change (ΔG < 0) indicate about a chemical reaction?

The reaction is spontaneous and releases energy. Signup and view all the answers

Study Notes

Food/Nutrients and Building Blocks

Macromolecules provide the building blocks for cells.
Food provides the energy needed for cellular processes.
Examples of food and their corresponding macromolecules:
- Bun: Carbohydrates
- Cheese: Protein and fats
- Patty: Protein and fats
- Tomatoes: DNA and RNA

Energy Flow

First Law of Thermodynamics: Energy is conserved, it can be transferred but not created or destroyed.
Second Law of Thermodynamics: Entropy (disorder) increases in an isolated system. Energy transfer leads to some energy loss as heat, resulting in increased entropy.

Why Do We Need Energy?

Chemical work: Combining molecules (e.g., glucose forming polysaccharides).
Transport work: Moving molecules across cell membranes (e.g., active transport).
Mechanical work: Cellular movements like muscle contraction and flagella rotation.

Types of Energy

Kinetic energy: Energy of motion (e.g., heat, light, walking).
Potential energy: Stored energy (e.g., a monkey on a tree, ions on one side of a membrane).
Chemical energy: Potential energy stored in chemical bonds. Released when bonds break.

Chemical Reactions and Energy

Molecules have potential energy stored in their chemical bonds.
Breaking bonds releases energy (exergonic reaction) with a negative free energy change (ΔG).
Forming bonds requires energy (endergonic reaction) with a positive free energy change (ΔG).

Metabolism

The sum of all chemical reactions in a cell.
Catabolism: Breaking down large molecules into smaller ones, releases energy (ΔG < 0).
Anabolism: Building up complex molecules from smaller ones, requires energy (ΔG > 0).

Oxidation-Reduction Reactions (Redox Reactions)

Oxidation: Removing electrons from a molecule, often releases energy.
Reduction: Gaining electrons, often requires energy.
Redox reactions transfer energy between molecules by the flow of electrons. Cells use redox reactions to transfer energy.

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Description

This quiz covers the essential concepts of macromolecules as building blocks of cells, energy flow according to the laws of thermodynamics, and the different types of energy relevant to biological systems. Understand how food provides energy and how various forms of work are performed at the cellular level.