Week 8/25

Question 1

Organelle

Answer 1

any specialized membrane bounded structure within a eukaryotic cell.

Question 2

Configuration

Answer 2

the arrangement of atoms around a chiral center.

A change in configuration does require breaking and re-making the bonds between the atoms and the chiral center.

Question 3

Conformation

Answer 3

the arrangement of atoms in space.

A change in conformation does not require breaking and re-making chemical bonds, although many changes in conformation occurs with the breaking and re-making the bonds between the atoms and the chiral center.

Question 4

Isomers

Answer 4

two different chemical compounds which have the same chemical composition but are physically distinct and separable.

There are two different types: chemical and stereo.

Question 5

Anomer

Answer 5

a chiral center which is not initially present in a molecule and which is created by intramolecular bonding

Question 6

Epimers

Answer 6

two stereoisomers which differ in only one chiral center

Question 7

Enantiomers

Answer 7

two stereoisomers in which all chiral centers are switched.

For example, D-glucose and L-glucose are enantiomers and are mirror images of each other.

Question 8

Diastereomers

Answer 8

stereoisomers which contain more than one chiral center but are not mirror images of each other

Question 9

Chemical isomers

Answer 9

two different molecules which have the same chemical composition.

For example, 2-methyl propane and n-butane are chemical isomers.

Question 10

Buffer

Answer 10

a solution of a weak acid or base which is present in acid-base pair which resists changes in pH when another acid or base is added

Question 11

pH

Answer 11

a negative of the logarithm of the hydronium ion concentration = -log[H+]

Question 12

pKa

Answer 12

the negative of the logarithm of the acid dissociation constant.

It is a measure of how strong (easily lose a proton) an acid functional group might be. The lower the value, the stronger the acid.

Question 13

Chiral center

Answer 13

a single atom or a group of atoms when the attached groups are interchanged, the two molecules are not superimposable.

Not that a helical arrangement of atoms, which themselves do not have chiral centers, create a chiral center. It is typically four different groups attached to the same carbon [chiral] atoms and is capable of rotating the plane of polarized light and thereby is optically active.

Question 14

Macromolecules

Answer 14

Large molecules (>10,000 daltons) usually composed of similar or identical parts (monomers or residues)

Question 15

Amino acid

Answer 15

A biomolecule amino group, a carboxylic acid group, a proton and another functional group attached to the same carbon = an alpha amino carboxylic acid.

The last functional group is usually named the “R-group”

Question 16

Carbohydrates

Answer 16

Polyhydroxyl ketones or polyhydroyxl aldehydes and their derivatives.

The name is derived as the hydrate of carbon based on the general formula (C(H2O))n

Question 17

Lipids

Answer 17

Bio molecules which are insoluble or slightly soluble in water and usually extractable by organic [nonpolar] solvents.

This category of biomolecules is the most diverse of the four.

Question 18

Nucleic acid

Answer 18

Biopolymers consisting of nitrogenous bases which are linked to ribose or deoxyribose linked by phosphodiester bonds.