Carbon and the Molecular Diversity of Life

Chapter 4

Figure 4.0 Protein

The Importance of Carbon

• A cell is compose of 70 – 95% water, but the remaining components of the cell are mainly carbon based.

• The unique chemistry of carbon gives us the large diversity of biological molecules that make life possible.

• Organic chemistry is the study of carbon compounds.

Figure 4.1 Abiotic synthesis of organic compounds under “early Earth” conditions

Carbon Atoms Are The Most Versatile Building Blocks of Molecules.

• Carbon has 6 electrons, with 2 in the fist shell, and 4 in the second.

• Carbon ‘want’ to complete its valence shell by sharing electrons with up to four other atoms.

• Each carbon atom is a point in the molecule where up to four branches can occur.

Figure 4.2 The shapes of three simple organic molecules

Figure 4.2x Shapes of Molecules

Figure 4.x1 Urea

Variation in carbon skeletons contributes to diversity of organic molecules.

• Carbon chains form the skeletons of most organic molecules.

• The skeletons vary in length, may be branched, or arranged in closed rings.

• Hydrocarbons consist of carbon and hydrogen.

Figure 4.4 Variations in carbon skeletons

Figure 4.4x Hydrocarbons: molecular models

Figure 4.5 The role of hydrocarbons in fats

Isomers

• Isomers have the same molecular formula but different structures and therefore different properties.

Figure 4.6 Three types of isomers

- Structural Isomers differ in the covalent arrangements of their atoms.

- Geometric isomers differ in their spatial arrangement.

- Enantiomers are mirror images.

Figure 4.6ax Structural isomers

Figure 4.7 The pharmacological importance of Enantiomers

Functional Groups

• Certain groups of atoms are frequently attached to skeletons of organic molecules.

• Each functional group has unique chemical properties.

• Functional groups are often added or removed from a molecule in chemical reactions.

– Modular

Figure 4.8 A comparison of functional groups of female (estradiol) and male (testosterone) sex hormones

Figure 4.8x1 Estrogen and testosterone

Table 4.1 Functional Groups of Organic Compounds

The hydroxyl group:

- A hydrogen atom bonded to an oxygen.

- compounds w/ hydroxyl groups are called alcohols.

- Polar

The carbonyl group:

- A carbon atom joined to an oxygen atom by a double bound.

- If at the end of a carbon skeleton, compound is called an aldehyde.

- If in the middle of the carbon skeleton, the compound is called a ketone.

The Carboxyl group:

- An oxygen double-bounded to a carbon atom that is also bonded to a hydroxyl group.

- Compounds w/ carboxyl groups are known as carboxylic acids.

- Polar

The amino group:

- A nitrogen atom bonded to two hydrogen atoms and to the carbon skeleton..

- compounds w/ amino groups are called amines.

- Polar

The sulfhydryl group:

- A sulfur atom bonded to a hydrogen atom.

- Resembles a hydroxyl group in shape.

- Compounds w/ -SH are called thiols.

- Form disulfide bonds to stabilize proteins.

- Polar

The phosphate group:

- Phosphate is an anion formed by dissociation of phosphoric acid (H3PO4).

- Can be covalently attached by one its oxygen atoms to the carbon skeleton.

- One function is to transfer energy between organic molecules.

- Polar

Carbon and the Molecular Diversity of Life

Chapter 4

Figure 4.0 Protein

The Importance of Carbon

• A cell is compose of 70 – 95% water, but the remaining components of the cell are mainly carbon based.

• The unique chemistry of carbon gives us the large diversity of biological molecules that make life possible.

• Organic chemistry is the study of carbon compounds.

Figure 4.1 Abiotic synthesis of organic compounds under “early Earth” conditions

Carbon Atoms Are The Most Versatile Building Blocks of Molecules.

• Carbon has 6 electrons, with 2 in the fist shell, and 4 in the second.

• Carbon ‘want’ to complete its valence shell by sharing electrons with up to four other atoms.

• Each carbon atom is a point in the molecule where up to four branches can occur.

Figure 4.2 The shapes of three simple organic molecules

Figure 4.2x Shapes of Molecules

Figure 4.x1 Urea

Variation in carbon skeletons contributes to diversity of organic molecules.

• Carbon chains form the skeletons of most organic molecules.

• The skeletons vary in length, may be branched, or arranged in closed rings.

• Hydrocarbons consist of carbon and hydrogen.

Figure 4.4 Variations in carbon skeletons

Figure 4.4x Hydrocarbons: molecular models

Figure 4.5 The role of hydrocarbons in fats

Isomers

• Isomers have the same molecular formula but different structures and therefore different properties.

Figure 4.6 Three types of isomers

Figure 4.6ax Structural isomers

Figure 4.7 The pharmacological importance of Enantiomers

Functional Groups

• Certain groups of atoms are frequently attached to skeletons of organic molecules.

• Each functional group has unique chemical properties.

• Functional groups are often added or removed from a molecule in chemical reactions.

– Modular

Figure 4.8 A comparison of functional groups of female (estradiol) and male (testosterone) sex hormones

Figure 4.8x1 Estrogen and testosterone

Table 4.1 Functional Groups of Organic Compounds

The Methyl Group

• A carbon atom with three hydrogen atoms covalently bonded to it.

• Often used to mark certain molecules.

• Very important in pharmacology.

The End