Unit 1: Chemistry of Life - Flashcards

A comprehensive set of practice flashcards covering water properties, macromolecules, bond types, and nucleic and protein structure based on Unit 1 notes.

What property of water results from its polarity and hydrogen bonding and helps maintain body temperature in living organisms?

High specific heat capacity and high heat of vaporization, enabling temperature regulation and evaporative cooling.

Which elements are most prevalent in building biological macromolecules (carbohydrates, proteins, lipids, nucleic acids)?

Carbon, hydrogen, and oxygen.

Which macromolecule contains sulfur in some of its building blocks?

Proteins (sulfur is found in amino acids like cysteine and methionine).

Which macromolecules contain phosphorus?

Nucleic acids and phospholipids.

Which macromolecules contain nitrogen?

Proteins and nucleic acids.

What is dehydration synthesis in macromolecule formation?

A reaction where two monomers are joined by covalent bonds with the removal of a water molecule, forming a polymer.

What is hydrolysis in macromolecule breakdown?

A reaction where water is added to break covalent bonds, yielding smaller molecules or monomers.

What is the monomer of carbohydrates?

Monosaccharide.

What bond links carbohydrate monomers?

Glycosidic covalent bond.

Describe starch vs. cellulose in terms of glycosidic bonds and animal digestibility.

Starch has alpha-1,4 glycosidic bonds and is digestible by humans; cellulose has beta-1,4 glycosidic bonds and is not digestible by most animals.

Name two functions of carbohydrates.

Energy storage (e.g., starch) and structural support (e.g., cellulose in plants).

What is the monomer of lipids?

Lipids do not have a single monomer; they are composed of components such as glycerol and fatty acids. (Key concepts: saturated vs. unsaturated fatty acids.)

How do saturated and unsaturated fatty acids differ?

Saturated: only single bonds between carbons; Unsaturated: one or more double bonds causing kinks.

How does the level of saturation affect a lipid’s state at room temperature?

More unsaturation (more double bonds) generally makes fats more liquid at room temperature.

Name three examples of lipid macromolecules.

Fats (triglycerides), steroids (including cholesterol), phospholipids.

What are the primary functions of fats, steroids, cholesterol, and phospholipids?

Fats: energy storage and insulation; Steroids: hormones; Cholesterol: membrane stability; Phospholipids: form lipid bilayers.

Describe the general structure of a phospholipid.

Glycerol backbone with two fatty acid tails and a phosphate-containing head; amphipathic.

What is the monomer of nucleic acids?

Nucleotide (sugar, phosphate, and nitrogenous base).

What are the five nitrogenous bases in nucleic acids?

Adenine, thymine, cytosine, guanine, and uracil (RNA uses uracil instead of thymine).

Differentiate purines and pyrimidines.

Purines: adenine and guanine; Pyrimidines: cytosine, thymine, and uracil.

What ends define a nucleic acid and what functional group is at each end?

5' end has a phosphate; 3' end has a hydroxyl group.

In which direction are nucleic acids synthesized, and where are nucleotides added?

5' to 3' direction; nucleotides added to the 3' end.

What is the structure of DNA compared to RNA in terms of sugar, bases, and strands?

DNA: deoxyribose, thymine, double-stranded; RNA: ribose, uracil, single-stranded.

What are the complementary base pairings in DNA?

A pairs with T; C pairs with G.

What are the complementary base pairings in RNA?

A pairs with U; C pairs with G.

What type of bond holds base pairs together in DNA and RNA?

Hydrogen bonds.

What are the three components of a nucleotide monomer?

A five-carbon sugar (deoxyribose or ribose), a phosphate, and a nitrogenous base.

Name the five nitrogenous bases and indicate which are purines vs pyrimidines.

Purines: adenine (A) and guanine (G); Pyrimidines: cytosine (C), thymine (T), uracil (U).

What is the primary structure of a protein?

The linear sequence of amino acids connected by peptide bonds.

Which bond forms between the carboxyl group of one amino acid and the amino group of the next?

A peptide (covalent) bond.

What are the four levels of protein structure?

Primary, secondary, tertiary, and quaternary structures.

Describe the secondary structure of a protein.

Forms alpha helices and beta-pleated sheets via hydrogen bonding along the polypeptide backbone.

What drives the tertiary structure of a protein?

Involves R-group interactions: hydrogen bonds, hydrophobic interactions, ionic interactions, and disulfide bridges.

What is the quaternary structure of a protein?

Arrangement and interactions of multiple polypeptide units into a functional protein.

Which macromolecules contain nitrogen?

Proteins and nucleic acids.

Which macromolecules contain phosphorus?

Nucleic acids and phospholipids.

Which macromolecule contains sulfur?

Proteins.

What are the differences between DNA and RNA in terms of sugar, bases, and strands?

DNA: deoxyribose, thymine, double-stranded; RNA: ribose, uracil, single-stranded.

How are phospholipids oriented in a cell membrane?

Phospholipids form a bilayer with hydrophilic heads facing aqueous environments and hydrophobic tails facing inward.

Which end of a nucleic acid is the growing end during synthesis?

The 3' end (3'-OH) is the growing end; nucleotides are added to this end.