Chapter 4: Carbon and Molecular Diversity of Life

Question 1

The 6 main elements in organic chemistry are…

Answer 1

Carbon, Hydrogen, Oxygen, Nitrogen, Sulfur and Phosphorous

Question 2

Define the outdated concept of “vitalism”

Answer 2

Vitalism was the widely held hypothesis that a life force outside the jurisdiction of physical and chemical laws, provided the foundation for the new discipline of organic chemistry. I.e., organic compounds could only be made through organic means and same for inorganic.

Question 3

Define valence

Answer 3

Valence is the numbers of bonds that an element can form with other atoms. This is typically counted by however many spaces it is away from the nearest noble gas on the PTE.

Question 4

Define “hydrocarbons”

Answer 4

Organic molecules consisting of only carbon and hydrogen. They are major components of fossil fuels and fats in animals

Question 5

Define “isomer”

Answer 5

Compounds that have the same number of atoms of the same elements but different structures and, thus, different properties.

Question 6

Define a “structural isomer”

Answer 6

An isomer that differs in the covalent arrangement of their atoms.

Examples in nature:
There are 18 variations of C^8H^18 but 366,000 possibilities for C^20H^42.

Question 7

Define “cis-trans isomers”

Answer 7

Within these, carbons have covalent bonds to the same atoms, but these atoms differ in their spatial arrangement due to the inflexibility of double bonds.

Question 8

Define “enantiometers”

Answer 8

Isomers that are mirror images of each other and that differ in shape due to the presence of an asymmetric Carbon, on that is attached to four different atoms or groups of atoms.

Example:
Ibuprofen and albuterol. When flipped, both are completely ineffective.

Question 9

Functional groups

Answer 9

Distinctive properties of an organic molecule depend on the arrangement of the skeleton as well as what other compounds it is attached to.

Example:
Estradiol (female hormone) and testosterone are exactly the same except the latter is attached to CH3 and O, instead of HO like the former.

Question 10

The seven most important chemical groups in biological processes:

Answer 10

Hydroxyl, carbonyl, carboxyl, amino, sulfhydryl, phosphate and methyl.

Question 11

Hydroxyl

Answer 11

–OH, a.k.a., alcohols

Example: C2H6O, ethanol

Function:
-Can form hydrogen bonds with water molecules, helping dissolve compounds such as sucrose. As such, it is a polar molecule.

Question 12

Carbonyl

Answer 12

C=O, a.k.a ketones and aldehydes

Example: Acetone, C3H6O

Function:
-Ketone and aldehyde groups are also founds in sugars, giving rise to two major groups of sugars: ketoses, (containing ketone groups) and aldoses (containing aldehyde groups).

Question 13

Carboxyl

Answer 13

COOH, separate as an O, C and OH- (O=C–OH)

Carboxylic acid

Example: Acetic acid, written as CH3CO2H or C2H4O2.

Function: -Acts as an acid, donating H+ b/c the covalent bond between O and H is polar.
-Found in cells in the ionized form with a charge of 1- and called a carboxylate ion.

Question 14

Amino

Answer 14

NH2 (H–N–H), a.k.a. amines

Example: Glycine, a compound that is both an amine and a carboxylic acid b/c it has both an amino groups and a carboxyl group; compounds with both groups are called amino acids

Function: -Acts as a base
-Found in cells in the ionized form with positive 1 charge.

Question 15

Sulfhydryl

Answer 15

SH (–SH), a.k.a. thiols

Example: -Cysteine, an important sulfur-containing amino acid

Function: -Helps in stabilizing protein structures
-Cross-linking cysteins in hair proteins maintains the patterns of hair (e.g., curly, wavy or straight.)

Question 16

Phosphate

Answer 16

OPO3^2-, a.k.a. organic phosphates
       O
        II
--O--P--O^-
        I
       O^-
Example: -Glycerol phosphate, which takes part in many important chemical reactions in cells.
-Provides the backbone for phospholipids, the most prevalent molecules in the cell membrane

Function: -Contributes negative charge to the molecule of which it is a part
-Molecules containing phosphate groups have the potential to react wit water, releasing energy.

Question 17

Methyl

Answer 17

CH3, a.k.a. methylated compounds

  H
   I
--C--H
   I
  H

Example: 5-Methyl cytosine, a component of DNA that has been modified by an addition of a methyl group

Function: -Addition of a methyl group to DNA or to DNA-bound molecules affects expression of the genes.
-Arrangements of methyl groups in male and female sex hormones affects their shape and function.

Question 18

ATP

Answer 18

Is not necessarily energy but is instead storing the potential to react with water, releasing energy that a cell can use.

Question 19

Asymmetric Carbon (Or chiral carbon)

Answer 19

Is a carbon atom that is attached to four different chemical groups.