BiochemistryLesson 1 of 1 in the course The Chemical Foundation of Life

Carbon Bonding, Isomers, Enantiomers, and Functional Groups

5 flashcards · 5 quiz questions · 5 match pairs · 5 fill-in sentences · English

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Summary

A carbon atom has atomic number 6, so it contains six protons and six electrons. Two electrons fill its inner shell, leaving four electrons in its outer shell. Carbon can share electrons with other atoms to form up to four covalent bonds, satisfying the octet rule and giving carbon unusual versatility as a molecular building block.

Methane, with the formula CH4CH_4, is a simple example. Its carbon atom shares one pair of electrons with each of four hydrogen atoms. These four bonds complete carbon's outer shell. In three dimensions, the atoms form a tetrahedron, so methane has tetrahedral geometry.

All flashcards

Why is carbon a useful backbone element for biological molecules?
Carbon can form up to four covalent bonds, including bonds with other carbon atoms, allowing it to build varied chains, branches, and rings.
What is a hydrocarbon?
An organic molecule composed entirely of carbon and hydrogen. Examples include methane, propane, and butane.
How do single, double, and triple carbon bonds affect molecular geometry?
Single bonds allow rotation, double bonds restrict rotation and create planar arrangements around the bond, and triple bonds create a linear arrangement.
What is the difference between structural and geometric isomers?
Structural isomers differ in how atoms are connected. Geometric isomers have the same basic connections but differ in the spatial arrangement of groups, often around a double bond.
How can cis and trans double bonds influence fats?
Cis bonds bend fatty acid chains and make tight packing harder, often resulting in oils. Trans bonds leave chains more linear and able to pack more tightly, contributing to solid fats.

Quiz questions

  1. What is the molecular geometry of methane?Answer: Tetrahedral
  2. What is a functional group in a biological molecule?Answer: A group of atoms that contributes characteristic chemical properties and reactivity.
  3. What remains when a carboxyl group releases a hydrogen ion from its COOH form?Answer: A negatively charged COO− group
  4. Which amino-acid forms predominate in proteins?Answer: L-forms
  5. How do hydrogen bonds contribute to biological molecules?Answer: They help macromolecules fold and maintain suitable shapes.

Based on Biology 2e by Mary Ann Clark, Matthew Douglas, Jung Choi (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.

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