Biology Chapter 3

What do hydrocarbons consist of?

Molecules consisting of only carbon and hydrogen.

Define functional group.

A molecular group attached to a hydrocarbon that confers chemical properties or reactivities.

What is an isomer?

One of a group of molecules identical in atomic composition but different in structural arrangement.

List the four classes of biological macromolecules.

Carbohydrates, Lipids, Nucleic Acids, and Proteins.

What is a polymer?

A molecule composed of many similar or identical molecules.

What is a monomer?

Smallest chemical subunit of polymers.

What occurs during a dehydration reaction?

Two molecules join to form one larger molecule while splitting out a molecule of H2O.

What occurs during hydrolysis?

A molecule of water is added, breaking down a polymer into monomers.

Define organic chemistry.

The study of compounds that contain carbons and hydrogens.

How many covalent bonds can carbon form?

Four covalent bonds.

What variations can carbon chains have?

Varying in length, branching, double bond position, and presence of rings.

List the seven most important functional groups for life.

Hydroxyl, Carbonyl, Carboxyl, Amino, Sulfhydryl, Phosphate, Methyl.

What is the structure of the hydroxyl functional group?

-OH.

Describe the carbonyl functional group.

A carbon double bonded to an oxygen (C=O).

What is the carboxyl functional group?

A functional group consisting of COOH.

What comprises the amino functional group?

NH2.

What is the formula of the sulfhydryl group?

SH.

What does the phosphate functional group contain?

PO4.

Define isomer and provide an example.

Isomer is one of a group of molecules differing in structural arrangement; example: Pentane vs Isopentane.

What are structural isomers?

Isomers that differ in the arrangement of atoms.

What characterizes cis-trans isomers?

Differ in spatial arrangement due to double bonds.

Define enantiomers.

Mirror image molecules.

What are monosaccharides?

Single sugar molecules, e.g., glucose.

What are disaccharides?

Formed by the covalent bonding of two monosaccharides, e.g., sucrose.

Define polysaccharides.

Long chains of monosaccharides linked by dehydration synthesis.

What is starch used for?

Energy storage in plants.

Describe glycogen.

Storage polysaccharide in animals.

What is cellulose?

A component of tough walls of plant cells.

Compare DNA and RNA.

DNA: Double stranded, deoxyribose, stores genetic information. RNA: Single stranded, ribose, helps in gene expression.

Identify the nitrogenous bases in DNA.

Adenine (A), Cytosine (C), Guanine (G), Thymine (T).

What are the characteristic functions of proteins?

Enzymatic, Structural, Storage, Transport, hormonal, receptor, and defensive.

What is the structure of an amino acid?

Contains an amino group (NH2), central alpha carbon, hydrogen atom, and variable side chain.

Describe the primary structure of proteins.

Unique sequence of amino acids.

What is secondary structure of proteins?

Alpha helix and beta pleated sheets formed from hydrogen bonds.

What constitutes tertiary structure?

The overall 3D shape of a polypeptide due to various interactions.

Define quaternary structure.

Structure found in proteins composed of more than one polypeptide chain.

What are motifs in proteins?

Common elements of secondary structure useful for determining function.

What is a protein domain?

A functional group within a larger protein structure.

What do chaperonins do?

Help proteins fold correctly and prevent misfolding.

Define denaturation in proteins.

Loss of structure and function due to environmental conditions.

Why are lipids not considered true polymers?

They are not composed of repeating monomeric subunits.

Describe triglycerides.

Composed of 3 fatty acids joined to a glycerol.

Distinguish between saturated and unsaturated fats.

Saturated fats: no double bonds, solid at room temp. Unsaturated fats: contain double bonds.

What is the structure of phospholipids?

Glycerol with two fatty acid tails and a phosphate group.

Define amphipathic as it relates to lipids.

Contain both hydrophobic and hydrophilic regions.

What are micelles?

Spherical structures where phospholipids arrange with hydrophilic heads facing outward.

Identify the primary function of triglycerides.

Store energy.

What role do phospholipids serve in cells?

Form cellular membranes and provide structural integrity.

What are steroid functions?

Serve as precursors for hormones.