Lecture 10: Lipid Structure and Classification

Question 1

Lipids are non-polar and soluble in ____\_solvents but NOT ____\_

Answer 1

Lipids are non-polar and soluble in organic solvents but NOT water

Question 2

Function of lipids:

• _______\_ in biological membranes
• _______\_, predominantly in the form of triacylglycerols
• vitamins and hormones
• _______\_ aid in lipid solubilization
• signalling molecules

Answer 2

Function of lipids:

• structural components in biological membranes
• energy reserves, predominantly in the form of triacylglycerols
• vitamins and hormones
• bile acids aid in lipid solubilization
• signalling molecules

Question 3

Fatty acids are made of long hydrocarbon chains with terminal __________\_ group

Answer 3

Fatty acids are made of long hydrocarbon chains with terminal Carboxylate (COO-) group

Question 4

Fatty acid with 1 C-C Double bond

Answer 4

Monounsaturated (MUFA): Fatty acid with 1 C-C Double bond

Question 5

Fatty acid with 2 or more C-C Double bonds

Answer 5

Polyunsaturated (PUFA): Fatty acid with 2 or more C-C Double bonds

Question 6

FA Saturation is an important determinant of membrane ________

Answer 6

FA Saturation is an important determinant of membrane fluidity

Question 7

Humans cannot introduce double bonds into FA’s after __\_.

Answer 7

Humans cannot introduce double bonds into FA’s after C9.

Question 8

ARA and EPA are essential and must be consumed in diet. They serve as precursors for the synthesis of eicosanoids and are synthesized from ____\_and ____\_ acid respectively

Function as local signaling molecules and play important roles in ________

Answer 8

ARA and EPA are essential and must be consumed in diet. They serve as precursors for the synthesis of eicosanoids and are synthesized from Linoleic and Linolenic acid respectively

Function as local signaling molecules and play important roles in inflammation

Question 9

C-C double bonds in naturally occurring FA are ____\_

Answer 9

C-C double bonds in naturally occurring FA are cis

Question 10

The final carbon of a fatty acid chain is always known as: _____\_

Answer 10

Final carbon of a fatty acid chain is always known as Omega (w)

Question 11

Triacylglycerols (triglycerides):

Glycerol ______\_ to 3 Fatty Acids

Energy-dense stored in ____\_ tissue: insulation

Highly _____\_ form of carbon (38kj about 2x protein)

No solvation takes up less space

Answer 11

Triacylglycerols (triglycerides):

Glycerol Esterified to 3 Fatty Acids

Energy-dense stored in adipose tissue: insulation

Highly reduced form of carbon (38kj about 2x protein)

No solvation takes up less space

Question 12

_____\_ cleave ester bonds and release Fatty acids

Answer 12

Lipases cleave ester bonds and release Fatty acids

Question 13

2 fatty acids + glycerol= ______\_

Answer 13

2 fatty acids + glycerol= diacylglycerol

Question 14

Diacylglycerol + phosphate = _______

Simplest Glycero-Phospholipid (GPL)

Answer 14

diacylglycerol + phosphate = Phosphotidate

Simplest GlyceroPhospholipid (GPL)

Question 15

________\_ breakdown GlyceroPhospholipid (Example?)

Answer 15

Phospholipases breakdown GlyceroPhospholipid (ie. Snake venom: Lysolecithin, a breakdown product of this reaction, acts as a biological detergent and dissolves the membranes of red blood cells, causing them to rupture)

Question 16

GlyceroPhospholipids are _____\_ molecules:

Polar PO4 and alcohol head

Non-polar FA chains

Answer 16

GlyceroPhospholipids are amphiapathic molecules:

Polar PO4 and alcohol head

Non-polar FA chains

Question 17

Membrane permeability:

Hydrophobic moecules (O2, CO2, N2): ______\_

Ions (Na+, Ca2+, K+, H+): _____\_

H2O, glycerol: ______\_

Polar Molecules (Glucose Sucrose): _____\_

Answer 17

Membrane permeability:

Hydrophobic moecules (O2, CO2, N2): High

Ions (Na+, Ca2+, K+, H+): Low

H2O, glycerol: Med-High

Polar Molecules (Glucose Sucrose): Low

Question 18

__________ are particularly abundant in nerve cell membranes

Nerve impulse transmission

Cell-cell recognition

Molecular recognition( glycoprotein hormones and bacterial toxins)

Answer 18

Glycosphingolipids are particularly abundant in nerve cell membranes

Nerve impulse transmission

Cell-cell recognition

Molecular recognition( glycoprotein hormones and bacterial toxins)

Question 19

________: several fatal neurological disorders arising from genetic defects in glycosphingolipid metabolism

Answer 19

Sphingolipidoses: several fatal neurological disorders arising from genetic defects in glycosphingolipid metabolism

Question 20

_______\_: simplest form of glycol-sphingolipids

Answer 20

Ceramide: the simplest form of glycol-sphingolipids

Question 21

Cerebrosides: Ceramide + _____

Answer 21

Cerebrosides: Ceramide + 1 sugar

Question 22

Globosides: Ceramide+________

Answer 22

Globosides: Ceramide+ 2 or more sugars, not NANA

Question 23

Gangliosides: Ceramide + _____\_

Answer 23

Gangliosides: Ceramide + 3 or more sugars including NANA

Question 24

Lipids are predominantly hydrophobic molecules that can be esterified but cannot form _____

Answer 24

Lipids are predominantly hydrophobic molecules that can be esterified but cannot form Polymers

Question 25

Bilayer fluidity depends on the _____\_and saturation of its lipids and the presence of ____\_

Answer 25

Bilayer fluidity depends on the length and saturation of its lipids and the presence of cholesterol

Question 26

Glycolipids are abundant membrane lipids in cells of the ____\_

Answer 26

Glycolipids are abundant membrane lipids in cells of the CNS

Question 27

Cholesterol is an important lipid in regulating membrane fluidity and serves as a precursor for ___\_and ___\_

Answer 27

Cholesterol is an important lipid in regulating membrane fluidity is a precursor for hormones and bile salts