lipids

Question 1

Why are lipids good for energy?

Answer 1

• low mass to energy ratio
• insoluble (don’t effect water potential, don’t diffuse out of cell)

Question 2

What bonds the fatty acids and the glycerol?

Answer 2

Ester bonds formed by condensation

Question 3

Saturated vs unsaturated in organisms and explanation

Answer 3

Humans use saturated fatty acids usually as the molecules are more closely packed so they’re solid at room temp. but the heat of the body can melt them so animals can afford to pack them more tightly and still be able to use them, whereas plants can’t so need to use unsaturated fas.

Question 4

Roles of lipids

Answer 4

• energy source
• waterproofing
• thermal and electrical insulating
• protection around organs like kidneys (shock absorbance)

Question 5

Use of phospholipids in cell membrane

Answer 5

Due to polar nature, form a bilayer which acts as a barrier to anything water soluble. Also can form glycolipids which are neccesary in the role of recognition on the cell surface.

Question 6

Emulsion test for lipids

Answer 6

• oil in test tube
• add ethanol and shake thoroughly to fully dissolve the oil
• add distilled water and shake gently to mix
• milky white emulsion for positive result

Question 7

Structure of fatty acids

Answer 7

R—COOH