Campbell Biology - Chapter 4: Carbon and the Molecular Diversity of Life

Flashcards covering key concepts from Campbell Biology Chapter 4: Carbon and the Molecular Diversity of Life, including organic chemistry, Miller's origin-of-life experiments, carbon valence and bonding, isomerism, functional groups, and ATP chemistry.

What is the definition of organic chemistry?

Organic chemistry is the study of compounds that contain carbon, regardless of their origin.

What did Stanley Miller's 1953 experiment demonstrate regarding the origin of life?

It demonstrated the abiotic synthesis of organic compounds under simulated conditions of early Earth, supporting the hypothesis that organic building blocks could form spontaneously.

What are the six major chemical elements of life that show uniform overall percentages across all living organisms?

Carbon, hydrogen, oxygen, nitrogen, sulfur, and phosphorus ($\text{C}$, $\text{H}$, $\text{O}$, $\text{N}$, $\text{S}$, and $\text{P}$).

What electron shell configuration gives carbon atom its central role in forming diverse complex molecules?

A neutral carbon atom has $6$ protons, $6$ neutrons, $2$ electrons in its $1\text{st}$ shell, and $4$ valence electrons in its $2\text{nd}$ shell, allowing it to form $4$ covalent bonds.

What molecular shape is formed around a carbon atom when it forms four single covalent bonds with other atoms?

A tetrahedral shape.

How does a double bond between two carbon atoms affect the geometric layout of the attached atoms?

It forces all atoms joined to those double-bonded carbons to lie within the same plane.

What is valence, and how many covalent bonds can hydrogen, oxygen, nitrogen, and carbon form?

Valence is the number of covalent bonds an atom can form (equal to unpaired valence electrons): hydrogen has a valence of $1$, oxygen $2$, nitrogen $3$, and carbon $4$.

What four structural variations can carbon skeletons display?

Variation in carbon skeleton length, branching (unbranched vs. branched), double bond position, and the presence of rings.

What are hydrocarbons, and why do fat molecules store substantial energy?

Hydrocarbons are organic molecules consisting solely of carbon and hydrogen. Fat molecules contain long hydrocarbon tails that release large amounts of energy during chemical reactions.

How do structural isomers, cis-trans isomers, and enantiomers differ from one another?

Structural isomers differ in the covalent arrangements of their atoms; cis-trans isomers have identical covalent bonds but differ in spatial arrangements around double bonds; enantiomers are non-superimposable mirror images of each other.

In pharmaceutical applications, which specific enantiomers of Ibuprofen and Albuterol are biologically effective?

$\text{S-Ibuprofen}$ (reduces inflammation and pain) and $\text{R-Albuterol}$ (relaxes bronchial muscles in asthma patients).

How do the steroid sex hormones estradiol and testosterone differ structurally?

Both share a common four-fused-ring carbon skeleton, but estradiol has a hydroxyl group ($\text{-OH}$) attached to its phenol ring, while testosterone has a carbonyl group ($\text{=O}$) and an additional methyl group ($\text{-CH}_3$).

Which functional group contains an oxygen double-bonded to a carbon atom ($\text{>C=O}$), and how are its subcategories named based on location?

The carbonyl group; it is classified as a ketone if located within a carbon skeleton and an aldehyde if located at the end of a carbon skeleton.

Which functional group acts as an acid by donating a hydrogen ion ($\text{H}^+$)?

The carboxyl group ($\text{-COOH}$).

Which functional group acts as a base by picking up a hydrogen ion ($\text{H}^+$) from the surrounding solution?

The amino group ($\text{-NH}_2$).

What role do sulfhydryl groups ($\text{-SH}$) play in protein structure?

Two sulfhydryl groups can react to form a covalent cross-link (disulfide bridge) that stabilizes overall protein structure.

What is the molecular structure of adenosine triphosphate (ATP)?

ATP consists of an organic molecule called adenosine connected to a linear chain of three phosphate groups ($\text{-OPO}_3^{2-}$).

What chemical reaction equation represents the release of energy from ATP in cellular processes?

$$\text{ATP} + \text{H}_2\text{O} \rightarrow \text{ADP} + \text{P}_i + \text{Energy}$$

In E. T. Parker et al.'s analysis of Stanley Miller's 1958 $H_2S$-rich spark discharge experiment, what were the molar ratios of Alanine, Serine, and Methionine relative to Glycine?

Glycine has a molar ratio of $1.0$, Alanine is $1.1$, Serine is $3.0 \times 10^{-2}$, and Methionine is $1.8 \times 10^{-3}$.

What note did Stanley Miller record in his laboratory notebook regarding Run #22 on March 24, 1958?

He noted starting the spark at $5:30\text{ P.M.}$ on Monday March 24, 1958, and observed that 'after a few minutes there was yellowing of the solution but no green.'