Molecular Building Blocks

Question 1

What are macromolecules? Give examples:

Answer 1

Simple molecules can form complex large molecules
Sugars, lipids, amino acids

Question 2

State the properties of water:

Answer 2

• Universal solvent - dissolve ionic and polar compounds
• Polar molecule
• Hydrogen bonding with O,N,F
• Maximum density at 4 degrees celsius
• Doesn’t react with non polar molecules, lipids and aromatic compounds due to hydrophobic properties.

Question 3

Carbohydrate general formula and types:

Answer 3

Cn(H20)y
Monosaccharides, Disaccharides, Oligosaccharides & Polysaccharides

Question 4

Give example of Monosaccharides and Disaccharides

Answer 4

• Glucose + galactose = lactose
• Glucose + fructose = sucrose
• Glucose + glucose = maltose

Question 5

How do monosaccharides exist as cyclic structure?

Answer 5

By the reaction of the aldehyde or ketone groups with a hydroxyl group of the same molecule, monosaccharides generally exist as ring structures.

Question 6

What bonds can form with monosaccharides?

Answer 6

Monosaccharide react w/ OH or NH group - form glycosidic bond between disaccharides
O-glycosidic bonds: (oxygen i.e hydroxyl) form disaccharides, oligosaccharides and polysaccharides
N-glycosidic bonds: (nitrogen i.e amine) are found in nucleotides and DNA

Question 7

What’s an oligosaccharide?

Answer 7

Made of 3-12 units of MS. They are the product of digestion of polysaccharides.

Question 8

What is a polysaccharide?

Answer 8

Thousands of MS joined by glycosidic bonds

Question 9

Name 3 types of PS and describe them:

Answer 9

1. Starch - storage in plants, made of amylose (a- glucose 1,4) and amylopectin (a-glucose 1,4 and alpha 1,6 glycosidic bonds)
2. Proteoglycans - long, unbranched polysaccharides radiating from a core protein, in animals
3. Glycogen - storage in animals, branched formed of glucose residues. Linkage is both alpha 1,4 and alpha 1,6.

Question 10

What is a lipid and what does the structure look like?

Answer 10

Triglycerides - 3 fatty acids bound to glycerol.
Straight carbon chains (mostly 16-20) with a methyl group (CH3) and a carboxyl group (C=OOH) at the ends.

Question 10

What is a lipid and what does the structure look like?

Answer 10

Triglycerides - 3 fatty acids bound to glycerol.
Straight carbon chains 16-20 with a methyl group (CH3) and a carboxyl group (C=OOH) at the ends.

Question 11

State the properties of a lipid:

Answer 11

• Can be saturated or unsaturated
• Melting point decreases as unsaturation increases.
• Usually hydrophobic, no oxygen in main chain.
• In unsaturated fatty acids, the double bonds are commonly cis and spaced at 3C intervals

Question 12

What is a nucleotide made from?

Answer 12

• Phosphate
• Sugar - ribose or deoxyribose
• Nitrogenous base - AT CG in DNA or AU CG in RNA

Question 13

What are the bonds between the different parts of the nucleotide called?

Answer 13

Between phosphate and sugar - Phosphodiester bonds
Between sugar and base - N-glycosidic bond
Between bases - Hydrogen bond

Question 14

How many amino acids are there?

Answer 14

20

Question 15

What is the structure of an amino acid?

Answer 15

Central carbon has - NH3 amine group, side chain R group, COOH carboxyl group

Question 16

What determines the charge and what can it affect?

Answer 16

All three chains. Amine, carboxyl and R group
Changes pH of solution

Question 17

Which groups on an amino acid have charge and what are they?

Answer 17

COO-
NH3+
R group may have a charge too