Biology 1: Chemical Constituents of Cells

Front

What are the properties of water?

Back

1. Water is a universal solvent. 2. Water has high surface tension. 3. Water has high specific heat capacity. 4. Water has high heat of vaporization. 5. Water has low density in solid state. 6. Water has low viscosity.

Front

How does hydrogen bonding affect the properties of water?

Back

Hydrogen bonding allows water to form a stable structure, contributing to its high surface tension, high specific heat capacity, and its ability to act as a universal solvent.

Front

Define acids and provide an example.

Back

Acids are substances that donate hydrogen ions (H+). Example: Hydrochloric acid (HCl) dissociates into H+ and Cl-.

Front

Define bases and provide an example.

Back

Bases are substances that receive hydrogen ions (H+). Example: Ammonia (NH3) can accept H+ to form NH4+.

Front

What is a buffer?

Back

A buffer is a solution that resists changes in pH by reacting with added acids or bases. It typically consists of a weak acid and its conjugate base or a weak base and its conjugate acid.

Front

What is the primary structure of proteins?

Back

The primary structure of a protein is the linear sequence of amino acids linked by peptide bonds.

Front

What are the four levels of protein structure?

Back

1. Primary structure: Sequence of amino acids. 2. Secondary structure: Folding into α-helix or β-pleated sheets. 3. Tertiary structure: 3D folding due to interactions among side chains. 4. Quaternary structure: Association of multiple polypeptide chains.

Front

What is the role of hydrogen bonds in protein structure?

Back

Hydrogen bonds stabilize the secondary and tertiary structures of proteins by forming attractions between polar side chains.

Front

What is the difference between fibrous and globular proteins?

Back

Fibrous proteins have long, parallel chains and provide structural support (e.g., keratin, collagen). Globular proteins are compact and soluble in water, often functioning as enzymes or hormones (e.g., insulin, hemoglobin).

Front

What is the significance of water's high specific heat capacity?

Back

Water's high specific heat capacity allows it to absorb and release heat slowly, stabilizing temperatures in the environment and within organisms.