The Molecular Diversity of Life and Macromolecules

Flashcards cover key concepts from the lecture notes on carbon-based life, macromolecules, and the structure and function of carbohydrates, lipids, proteins, and nucleic acids.

What is the valence of carbon and how many covalent bonds can it form?

Carbon has a valence of 4 and can form four covalent bonds with other atoms.

What are hydrocarbons?

Organic molecules consisting only of carbon and hydrogen.

Name the four major classes of biological macromolecules.

Lipids, carbohydrates, proteins, and nucleic acids.

What is the general formula for carbohydrates and the most common monosaccharide?

Generally CH2O)n; glucose is the most common monosaccharide.

What is a monosaccharide?

A simple sugar; glucose is a common example.

How are disaccharides formed?

Two monosaccharides joined by a glycosidic linkage via dehydration synthesis.

What are polysaccharides and give examples?

Polymers of sugars; examples include starch, cellulose, glycogen, and chitin.

What is a glycosidic linkage?

A bond formed between two monosaccharides during dehydration synthesis.

What is the major function of carbohydrates?

Serve as fuel and building material; provide short-term energy storage (glucose) and structural roles.

What is a triglyceride (fat) composed of?

Glycerol backbone with three fatty acids linked by ester bonds.

What distinguishes saturated fatty acids?

Have the maximum number of hydrogen atoms (no double bonds); fats from saturated fatty acids are solid at room temperature.

What distinguishes unsaturated fatty acids?

Have one or more double bonds that cause kinks; fats from unsaturated fatty acids are liquids (oils) at room temperature.

What is the major function of fats?

Long-term energy storage.

What are phospholipids and their role in membranes?

Glycerol with two fatty acids and a phosphate group; hydrophobic tails and hydrophilic head; form the phospholipid bilayer of cell membranes.

What is cholesterol?

A steroid and component of animal cell membranes; high levels can contribute to cardiovascular disease.

What are the four levels of protein structure?

Primary, secondary, tertiary, and quaternary structures.

What determines a protein’s properties and function?

The amino acid sequence (primary structure) and the interactions among R groups that drive folding into higher-level structures.

What are the properties of amino acid R groups?

R groups can be nonpolar (hydrophobic), polar (hydrophilic), or electrically charged (acidic or basic).

What is denaturation?

The loss of a protein’s native structure due to changes in pH, temperature, or salt concentration, leading to loss of function.

What are nucleic acids and their two main types?

Nucleic acids store and transmit hereditary information; the two main types are DNA and RNA.

What is a nucleotide made of?

A sugar, a phosphate group, and a nitrogenous base.

What is complementary base pairing in DNA and RNA?

In DNA, A pairs with T and G pairs with C; in RNA, A pairs with U and G pairs with C.

What is the antiparallel arrangement in DNA?

The two DNA strands run in opposite directions (5'→3' and 3'→5').