Biological molecules

Question 1

What is the structure of amino acids?

Answer 1

Amino acids are molecules that contain a side chain (R), a carboxylic acid, and an amino group at the alpha carbon

Question 2

What is the relative configuration shared by all amino acids?

Answer 2

The L configuration

Question 3

What property leads to an “S” configuration?

Answer 3

Chirality

Question 4

Define amphoteric

Answer 4

Have both acidic and basic components.

The R group can be acidic, basic or neutral

Question 5

What are zwitterions?

Answer 5

Also known as dipolar ions. When a molecule has a negatively charged ionic group and a positively charged ionic group

Question 6

What is the isoelectric point?

Answer 6

The pH at which a given amino acid will be neutral. This will be the average of the two pKa values of an amino acid (depending on the dissociated group):
Isoelectric point = pl = (pKa1 + pKa2)/2

Question 7

Peptide bonds are also known as what?

Answer 7

Amide bonds.

Derived form the amino group of one amino acid and the acid group of another. Molecule of water released when bond forms (condensation). Bond can be broken by adding water molecule (hydrolysis)

Question 8

What are the two ways to classify sugars?

Answer 8

1. Classify the molecule based on the type of carbonyl group it contains (e.g. aldehyde is aldose, ketone is ketose).
2. By the number of carbons in the molecule (6 carbons are hexose, 5 carbons are pentose)

Question 9

Most naturally occurring aldoses have what configuration?

Answer 9

D configuration

Question 10

What is a disaccharide?

Answer 10

A molecule made up of two monosacharides, joined by a glycosidic bond between the hemiacetal carbon of one molecule and the hydroxyl group of another.

Condensation reaction joins them together; one water molecule released

Question 11

Can sugars undergo oxidation?

Answer 11

Yes

Question 12

Name 5 common polysaccharides

Answer 12

1. Starch (plant energy storage)
2. Cellulose (plant structural component)
3. Glycocalyx (associated with the plasma membrane)
4. Glycogen (animal energy storage in the form of glucose)
5. Chitin (structural component found in shells or arthropods)

Question 13

What are lipids?

Answer 13

A class of organic molecules containing many different types of substances, such as fatty acids, fats, waxes, tricyl glycerols, terpenes and steroids

Question 14

Whats the difference between oils and fats?

Answer 14

Generally it’s that fats are solid at room temperature and oils are liquid

Question 15

What’s the difference between saturated and unsaturated fatty acids?

Answer 15

Saturated fatty acids have no multiple bonds and unsaturated fatty acids have double or triple bonds (?).

Common fatty acids include palmitic acid, stearic acid and oleic acid