1.3 lipids

Question 1

2 groups

Answer 1

Triglycerides & phospholipids

Question 2

Triglycerides

Answer 2

Condensation of 1 molecule glycerol and 3 fatty acids

Question 3

Ester bond

Answer 3

Formed in condensation reaction between glycerol and a fatty acid (RCOOH)

Question 4

Triglyceride properties related to structure

Answer 4

Energy storage - high ratio of C-H bonds to C-C bonds. Long chains of hydrogen and carbon can be broken to form ATP

Metabolic water source - high ratio of H to O2 bonds

Insoluble - doesn’t affect water potential

Low mass

Question 5

Phospholipids

Answer 5

One of the fatty acids of a triglyceride is substituted by a phosphate-containing group

Question 6

Phospholipids properties related to structure

Answer 6

Form bilayer in cell membrane, allowing diffusion of non-polar/small molecules

Phosphate heads are hydrophilic so are attracted to water, orientate themselves towards water

Hydrophobic fatty acid orientate themselves away from water

Question 7

Saturated

Answer 7

No C=C double bonds in hydrocarbon chain; all carbons fully saturated with hydrogen

Question 8

Unsaturated

Answer 8

One or more C=C double bonds in hydrocarbon chain

Bend in structure due to double bond

Question 9

Test for lipids

Answer 9

1. Add ethanol and shake (dissolves lipids)
2. Add water
3. Positive: milky/cloudy white emulsion

Question 10

Glycolipids

Answer 10

Special type of fat that is found in cell membranes

One of the fatty acids found in a triglyceride is substituted by a sugar or chain of sugars

Question 11

Glycoproteins

Answer 11

Has sugar residues attached to its surface and always points towards tissue fluid (extracellular fluid)

Question 12

Similarities between phospholipids and triglycerides

Answer 12

Fatty acids

Glycerol

ester bonds

C,H,O (P has phosphorus)

Insoluble in water as non-polar

Question 13

How are lipids different to carbohydrates

Answer 13

More O2 in carbohydrates

Lipids have a large number of C-H bonds