2.1.2 Biological molecules Flashcards
How is water a solvent?
Dissolves polar molecules
How is water a transport medium?
Capillary action due to cohesion and adhesion
What is cohesion between?
Water molecules
What is adhesion between?
Water molecules and vessel wall
What makes water a coolent?
High latent heat of evaporation (high boiling point)
Why is ice less dense than water?
Due to hydrogen bonding
What molecules do carbohydrates contain?
C, H, O
Examples of monosaccharides?
- Glucose
- Fructose
- Galactose
- Ribose
Examples of polysaccharides?
- Glycogen
- Cellulose
- Starch
What units make up the disaccharide sucrose and which bond is involved?
- Fructose + glucose
- 1,6-glycosidic
What units make up the disaccharide lactose and which bond is involved?
- Galactose + glucose
- 1,4-glycosidic bond
Where is the OH in α-glucose?
Below carbon-1
Where is the OH in β-glucose
Above carbon-1
Why is glucose soluble in water?
Polar molecule due to hydrogen bonds that form between OH and water
What reaction MAKES glycosidic bonds
Condensation reaction (removal of water)
What units make up the disaccharide maltose and which bond is involved?
- α-glucose + α-glucose
- 1,4-glycosidic bond
What % of amylose is present in starch?
20-30%
What % of amylopectin is present in starch?
70-80%
What is the structure of amylose?
Linear chain of glucose units joined by α-1,4-glycosidic bonds
What is the structure of amylopectin?
Branched chain of glucose units joined by α-1,6-glycosidic bonds and α-1,4-glycosidic bonds
Why is it important for amylose and amylopectin to be able to coil into a spiral shape?
Makes it compact and less soluble
What is the structure of glycogen?
Branched chain of glucose units joined by α-1,6-glycosidic bonds and α-1,4-glycosidic bonds (more than amylopectin)
Where is glycogen normally found?
Liver and muscle cells
What reaction BREAKS glycosidic bonds?
Hydrolysis reaction (addition of water)
What is the structure of cellulose?
Straight chain containing repeating units of β-glucose that alternate so OH groups are next to each other. Forms 1,4-glycosidic bonds
What makes cellulose suitable to be the cell wall of plants?
High tensile strength
Insoluble
Flexible
What molecules do lipids contain?
C, H, O
Why are lipids insoluble in water?
Non polar and hydrophobic fatty acids
What are triglycerides made up of?
Glycerol + 3 fatty acids
What bond forms between glycerol and fatty acids?
Ester bond (condensation reaction)
What state are saturated fats normally?
Solids
What state are unsaturated fats normally?
Liquids (oils)
What do phospholipids contain?
Hydrophilic phosphate head (PO43-)
Hydrophobic fatty acid tails
Which parts of a phospholipid are hydrophobic and hydrophilic?
- Hydrophobic - fatty acid tail
- Hydrophilic - phosphate head
Functions of phospholipids when interacting with water?
- Surfactant
- Cell membrane bilayer