BIOL 131 Chapter 2: Chemistry of Life

What is the basic structure of an atom?

An atom consists of a nucleus formed of protons and neutrons, with electrons orbiting the nucleus.

What elements make up 96% of the human body by weight?

Oxygen, carbon, hydrogen, and nitrogen.

What distinguishes isotopes from regular atoms?

Isotopes have differing numbers of neutrons.

What is a radioisotope?

A radioisotope is an isotope that emits radiation.

What is the difference between a molecule and a compound?

A molecule is formed from two or more atoms, while a compound is formed from atoms of two or more different elements.

What does a molecular formula indicate?

It indicates the types of elements and the number of atoms of each element in a molecule.

What is the function of an ionic bond?

An ionic bond is the attraction between two ions with opposite electrical charges.

What is the difference between polar and nonpolar covalent bonds?

Polar covalent bonds share electrons unequally, while nonpolar covalent bonds share electrons equally.

What is a hydrogen bond?

A weak attraction between a slightly positive hydrogen atom and a slightly negative atom.

What are the four types of chemical reactions?

Synthesis, decomposition, exchange, and reversible reactions.

What is the role of water in the human body?

Water is the most abundant inorganic substance and serves as a solvent for living systems.

What are electrolytes?

Electrolytes are substances that ionize in water and can conduct electricity.

How does an acid behave in an aqueous solution?

An acid releases hydrogen ions (H+).

What is the pH scale used for?

The pH scale measures the relative concentrations of hydrogen ions (H+) and hydroxide ions (OH-) in a solution.

What is the function of buffers in the body?

Buffers maintain the pH of a solution relatively constant by absorbing or releasing H+ ions.

What are carbohydrates composed of?

Carbohydrates are composed of carbon, hydrogen, and oxygen in a 1:2:1 ratio.

What are the building blocks of proteins?

Amino acids are the building blocks of proteins.

What is the role of enzymes in chemical reactions?

Enzymes catalyze chemical reactions, speeding them up.

What is adenosine triphosphate (ATP)?

ATP is a modified nucleotide that temporarily holds energy in high-energy phosphate bonds.

What distinguishes organic molecules from inorganic substances?

Organic molecules contain both carbon and hydrogen, while inorganic substances do not.

What are the two types of nucleic acids?

Deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).

What is the function of DNA?

DNA determines hereditary traits and controls cellular functions.

What is the function of RNA?

RNA works with DNA in the synthesis of proteins.

What are triglycerides?

Triglycerides are fats consisting of three fatty acids bonded to glycerol.

What is the difference between saturated and unsaturated fats?

Saturated fats have no double bonds in their fatty acids, while unsaturated fats have one or more double bonds.

What are phospholipids?

Phospholipids consist of two fatty acids and a phosphate group bonded to glycerol.