Carbon Chemistry, Functional Groups, Macromolecules, and Lipids

Practice flashcards reviewing carbon bonding, biological macromolecules, chemical functional groups, and lipid classifications based on the lecture material.

What fundamental bonding property of carbon allows it to form a massive diversity of organic molecules?

Carbon has $4$ valence electrons, allowing it to form $4$ covalent bonds with other atoms or silent hydrogens.

What are isomers?

Molecules that share the exact same chemical formula as each other, but have different physical structures.

How are the four main biological macromolecules classified based on whether they are polymers and their respective monomers?

Proteins are polymers (monomer: amino acid), nucleic acids are polymers (monomer: nucleotide), carbohydrates can be monomers (e.g., glucose) or polymers (e.g., starch), and lipids are not polymers.

How do dehydration synthesis (condensation) reactions differ from hydrolysis reactions?

Dehydration synthesis builds larger polymers by forming new covalent bonds and removing a water molecule ($H_2O$), while hydrolysis breaks covalent bonds to convert larger molecules into smaller ones.

What is a functional group, and what are the specific properties and common locations of the amino group?

Functional groups are groups of atoms that provide consistent properties (polarity, acidity, basicity). The amino group ($\text{-NH}_2$) is polar, positively charged at cellular pH, behaves as a base, hydrophilic, and is found in amino acids and proteins.

What are the chemical properties and common locations of the amide functional group?

The amide group is polar and hydrophilic, and it is commonly found in proteins.

What are the primary functions of proteins, nucleic acids, carbohydrates, and lipids in living systems?

Proteins act as workhouses (enzymes, structural support, transport); nucleic acids serve as the blueprint for life (encoding/transmitting genetic info); carbohydrates provide structure and fuel; lipids form cell membranes, store fuel, and act as chemical signals.

What elemental composition and stoichiometric ratio define carbohydrates?

Carbohydrates contain only carbon, hydrogen, and oxygen ($C$, $H$, and $O$) in a $1:2:1$ ratio ($CH_2O$).

Which functional groups represented in this summary chart are negatively charged at the pH of a cell?

Carboxyl ($\text{-COOH}$) and Phosphate ($\text{-OPO}_3\text{H}_2$) are both negatively charged at cellular pH and behave as acids or hydrophilic charged groups.

What are the properties, chemical formula, and common biological locations of the carboxyl group?

Formula $\text{-COOH}$; it is polar, negatively charged at cellular pH, behaves as an acid, is hydrophilic, and is found in fatty acids, amino acids, and proteins.

How do carbonyl ($>C=O$) and hydroxyl ($\text{-OH}$) functional groups compare in terms of polarity and biological locations?

Both are polar and hydrophilic. Carbonyl ($>C=O$) is found in carbohydrates and proteins; hydroxyl ($\text{-OH}$) is found in carbohydrates, proteins, and nucleic acids.

What are the chemical characteristics and functions of sulfhydryl ($\text{-SH}$) and methyl ($\text{-CH}_3$) groups?

Sulfhydryl ($\text{-SH}$) is polar and forms $S-S$ disulfide bonds (found in cysteine and proteins); methyl ($\text{-CH}_3$) is nonpolar (found in amino acids, proteins, and nucleic acids).

What are the chemical properties, formula, and occurrences of the phosphate group?

Formula $\text{-OPO}_3\text{H}_2$; it is polar, negatively charged at cellular pH, hydrophilic, and found in phospholipids, nucleic acids, and ATP.

What are neutral lipids, and how are triglycerides synthesized?

Neutral lipids store energy, are uncharged, and are insoluble in $H_2O$ (fats are semisolid and oils are liquid at biological temp). Triglycerides are formed by dehydration synthesis between one glycerol molecule and $3$ fatty acids.

How are fatty acids classified based on the number of double bonds present in their hydrocarbon chains?

Saturated (no double bonds), monounsaturated ($1$ double bond), and polyunsaturated ($>1$ double bond).