Biology Chapter 2 Quiz

Atomic Structure and Bonding

• Atoms consist of protons, neutrons, and electrons; not composed of chemical bonds.
• Electrons occupy the space surrounding the nucleus of an atom.
• The atom retains the chemical properties of an element; smallest unit of carbon is a carbon atom.
• An element is a substance composed of one type of atom.
• All matter comprises atoms, which group to form molecules.

Types of Chemical Bonds

• Covalent bonds: electrons shared between atoms, e.g., in water (H₂O).
• Ionic bonds form between oppositely charged particles, creating compounds.
• A covalent bond occurs when two atoms share a pair of electrons.
• Polar molecules have regions with slight positive and negative charges; nonpolar molecules lack these regions.

Properties of Water

• Water is a polar molecule crucial for life; it exhibits unique properties such as high heat retention and cohesion between molecules, exhibiting hydrogen bonds.
• Oil (nonpolar) does not mix with water (polar) due to differing polarity.

pH and Solutions

• Acidic solutions have a pH less than 7; hydronium ions (H⁺) and hydroxide ions (OH⁻) can react to form water.
• Biomolecules can be categorized based on their functions; carbohydrates, lipids, proteins, and nucleic acids are essential macromolecules.

Macromolecules and Biomolecules

• Carbohydrates serve as energy sources; polysaccharides are complex carbohydrates.
• Lipids are key for energy storage and are insoluble in water; examples include oils and fats.
• Proteins consist of long chains of amino acids; their functionality is determined by their structure.
• Nucleic acids (DNA, RNA) store and transmit genetic information.

Enzymes and Chemical Reactions

• Enzymes lower the activation energy required for reactions, facilitating metabolic processes.
• Substrates are the molecules upon which enzymes act, and enzymes bind substrates at their active sites.

Conservation Laws

• The law of conservation of mass states that mass is neither created nor destroyed in chemical reactions; the mass of products equals the mass of reactants.
• Energy cannot be created or destroyed, only transformed; this principle governs all chemical reactions.

Importance of Molecular Structure

• Amino acids' unique properties come from their side groups, impacting protein structures and functions.
• DNA's double helix structure is stabilized by hydrogen bonds between nucleotide bases.

Summary of Key Terms

• Covalent bond: shared electrons between atoms.
• Ionic bond: attraction between oppositely charged ions.
• Hydrophilic: water-attracting; hydrophobic: water-repelling.
• Peptide bond: link between amino acids in proteins.
• pH: scale to measure acidity or alkalinity; key range is 0-14.

Test your understanding of the unique properties of water and the fundamentals of acids and bases with this quiz. Delve into concepts such as pH levels, hydronium ions, and the classification of biomolecules. Perfect for reinforcing key biological principles in your studies.