Biology Chapter: Acidity, Enzymes, and Water

Study Notes

Acidity and pH Levels

A solution with a pH of 2 is 1,000 times more acidic than one with a pH of 5, demonstrating the logarithmic nature of the pH scale.

Enzyme Characteristics

The mechanism of enzyme action is commonly described by the "lock and key" model.
Enzymes are proteins that can denature (lose structure and functionality) at high temperatures.
Enzymes often require vitamins and minerals as cofactors for optimal activity.
They generally are not degraded during the reactions they catalyze.

Properties of Water

Water is a molecule with significant cohesion due to hydrogen bonding.
The covalent bonds in water are polar, leading to strong intermolecular attractions.
Water and lipids do not mix because of the polarity difference; water is polar while lipids are nonpolar.
Contrary to some claims, there is strong attraction between water molecules.

Characteristics of Water

Water has high specific heat, high heat of vaporization, strong cohesion, and is less dense than ice, which allows ice to float.
Water is known as a universal solvent due to its ability to dissolve many substances.

pH of Blood

The pH of human blood is normally around 7.4 and is known to resist drastic changes.
It is highest at birth and gradually decreases to a minimum level over time.

Carbohydrates

Insulin is not a carbohydrate; it is a peptide hormone.
Glycerol is not a polysaccharide; it is a sugar alcohol used in lipids.
Polysaccharides include cellulose, glycogen, chitin, and starch.

Biological Molecules

Nucleotides make up nucleic acids (DNA/RNA), not proteins.
Proteins, lipids, and carbohydrates each have distinct building blocks; carbohydrates are not made of amino acids but of sugars.

Isotopes

Isotopes are variants of elements that differ in the number of neutrons, affecting atomic mass, but not chemical reactivity.

Enzyme Functionality

Enzymes are organic catalysts that lower the activation energy for chemical reactions.
They are affected by both temperature and pH changes, which can alter their activity.

Storage Polysaccharides

Starch is the primary storage polysaccharide found in plants, while glycogen serves this purpose in animals.

Protein Structure

The tertiary level of protein structure relates most directly to a protein's overall shape and function.

Medical Uses of Radioisotopes

The radioisotope I-131 is utilized primarily in medical diagnoses and treatment related to the thyroid gland.

Description

Explore the fascinating concepts of acidity and pH levels, enzymatic action, and the unique properties of water. This quiz covers key characteristics of enzymes and water's behavior in biological systems. Test your knowledge on these essential topics in biology.