Chapter 4: Carbon and the Molecular Diversity of Life

Merged flashcards from Chapter 4 of Pearson's Campbell Biology, Twelfth Edition.

Organic chemistry

The study of compounds that contain carbon, regardless of origin

Properties of carbon

• Can form four bonds, allowing it to make a wide variety of moleucles

  • This makes it responsible for the planet’s variety of organisms

Major elements of life

The elements:

• Carbon (C)

• Hydrogen (H)

• Oxygen (O)

• Nitrogen (N)

• Sulfur (S)

• Phosphorus (P)

Distributions are quite uniform from one organism to the other

Organic compounds

Compounds that contain carbon; these can range from small to colossal molecules

Electron configuration

How an atom’s electrons are arranged; the key to atomic bond types and numbers as part of their characteristics

Carbon

An atom with four valence electrons that can form four covalent bonds

• Molecules with multiple of these have a tetrahedral shape when joined to four other atoms

• Two of these together in a double bond allow other atoms to stay in the same plane

Valence

The number of unpaired electrons in the valence shell of an atom, determining the number of covalent bonds it can form

Carbon bonding partners

Most frequent are:

• Hydrogen

• Oxygen

• Nitrogen

Carbon molecule examples

• Carbon dioxide: CO₂

• Urea: CO(NH₂)₂

• Estradiol and Testosterone

Carbon chains

The skeletons of most organic molecules that vary in length, shape, double bond position, branches, and ring presence

Hydrocarbons

Organic molecules consisting of only carbon and hydrogen

• Many organic molecules, such as fats, have these as they can release a large amount of energy in some reactions

Isomers

Compounds with the same molecular formula (ratio) but different structures (arrangements) and properties, includes:

• Structural: Different covalent bonds and arrangements

• Cis-trans: Differing spatial arrangements, same covalent bonds

• Enantiomers: Mirror images

Structural isomers

Isomers with different covalent bonds and arrangements

Cis-trans isomers

Isomers with the same covalent bonds but differing spatial arragnements

Enantiomers

Isomers that are mirror images of each other

• Important in the pharmaceutical industry, as each pair may have different effects or not be effective at all, demonstrating molecular sensitivity

• Ibuprofen’s and albuterol’s versions are ineffective

Organic molecule properties

Depends on the carbon skeleton and chemical groups attached to it, giving it unique properties

Estradiol and testosterone

Steroids with a common carbon skeleton in the form of four fused rings, differing only in the chemical groups attached to the skeleton’s rings

Functional groups

The components of organic molecules most commonly involved in chemical reactions and molecular properties

Includes groups of:

• Hydroxyl

• Carbonyl

• Carboxyl

• Amino

• Sulfhydryl

• Phosphate

• Methyl

Hydroxyl

Functional group with the formula (—OH) or (HO—), also known as alcohol and included in ethanol

Carbonyl

Functional group with the formula (>C=O), also known as ketone or aldehyde and included in acetone or propanal

Carboxyl

Functional group with the formula (—COOH), also known as carboxylic acid or organic acid and included in acetic acid as well as its ionized form

Amino

Functional group with the formula (—NH₂), also known as amine and included in glycine as well as its ionized form

Sulfhydryl

Functional group with the formula (—SH) or (HS—), also known as thiol and included in cysteine

Phosphate

Funcational group with the formula (—OPO₃^2-), also known as organic phosphate and included in glycerol phosphate

Methyl

Functional group with the formula (—CH₃), also known as methylated compound and included in 5-Methylcytosine

Adenosine triphosphate (ATP)

An important organic phosphate, consisting of an organic molecule called adenosine attached to a string of three phosphate groups

• Reacts with water easily to release energy for cell utilization