exam 2 chapter 8

Question 1

What is Palmitoleic acid?

Answer 1

16 carbons, 1 cis double bond

Question 2

What is Oleic acid

Answer 2

18 carbons, 1 cis double bond at Δ9

Question 3

What is Linoleic acid?

Answer 3

18 carbons, 2 cis double bonds at Δ9,12

Question 4

What is α-Linolenic acid?

Answer 4

18 carbons, 3 cis double bonds at Δ9,12,15

Question 5

What is γ-Linolenic acid?

Answer 5

18 carbons, 3 cis double bonds at Δ6,9,12

Question 6

What is Arachidonic acid?

Answer 6

20 carbons, 4 cis double bonds at Δ5,8,11,14

Question 7

What effect do cis double bonds have on fatty acids?

Answer 7

They create kinks, preventing tight packing and keeping fats liquid at room temperature.

Question 8

Which of these fatty acids has 20 carbons?

Answer 8

Arachidonic acid.

Question 9

Which fatty acids have 3 double bonds?

Answer 9

α-Linolenic acid and γ-Linolenic acid

Question 10

Which double bond position distinguishes γ-Linolenic from α-Linolenic acid?

Answer 10

γ-Linolenic has a Δ6 double bond instead of Δ9.

Question 11

What is the basic structure of fatty acids?

Answer 11

Alkyl chain terminated by a carboxylic acid group.

Question 12

What does “saturated” mean in fatty acids

Answer 12

No double bonds; chain is fully hydrogenated.

Question 13

How does unsaturation affect fatty acid chains?

Answer 13

Creates bends at double bonds → looser packing, more fluidity.

Question 14

What effect do trans fatty acids have on cholesterol?

Answer 14

Raise plasma LDL (bad) cholesterol.

Question 15

Where are trans fats found naturally and in processed foods?

Answer 15

Naturally in dairy/meat from ruminants; high in partially hydrogenated oils.

Question 16

What are triacylglycerols (triglycerides)?

Answer 16

Esters of glycerol with three fatty acids; main energy storage form.

Question 17

Why are triacylglycerols an efficient energy source?

Answer 17

Highly reduced → high energy; no water needed for storage; dense packing.

Question 18

How do polar bears get water from fat?

Answer 18

Oxidizing fat produces H₂O: fat + O₂ → CO₂ + H₂O.

Question 18

What is a simple triacylglycerol?

Answer 18

Triglyceride with all three fatty acids identical

Question 19

What is a glycerophospholipid?

Answer 19

1,2-diacylglycerol with a phosphate at C3 of glycerol.

Question 20

Where are unsaturated fatty acids usually located in glycerophospholipids?

Answer 20

At the 2-position.

Question 21

What does “prochiral” mean for glycerol?

Answer 21

Two ends can become distinguishable when substituted.

Question 22

How does olive variety affect fatty acid composition?

Answer 22

Different varieties have different percentages of palmitic and oleic acids.

Question 23

Olive oil example: Koroneiki (Greece) composition?

Answer 23

12.9% palmitic acid, 74.4% oleic acid.

Question 24

Olive oil example: Chemlali (Tunisia) composition

Answer 24

19.7% palmitic acid, 54.9% oleic acid.

Question 25

Parent compound of glycerophospholipids?

Answer 25

Phosphatidic acid.

Question 26

Basic structure of glycerophospholipids?

Answer 26

Glycerol backbone + 2 fatty acids + phosphate group.

Question 27

Primary function of glycerophospholipids?

Answer 27

Essential components of cell membranes and cellular structures.

Question 28

Backbone of sphingolipids?

Answer 28

Sphingosine (18-carbon alcohol).

Question 29

ceramide formation?

Answer 29

Sphingosine + fatty acid via amide linkage.

Question 30

Glycosphingolipid definition?

Answer 30

Ceramide with one or more sugars attached via β-glycosidic linkage.

Question 31

Cerebrosides?

Answer 31

Glycosphingolipids with a single sugar.

Question 32

Gangliosides?

Answer 32

Ceramides with ≥3 sugars, including sialic acid.

Question 33

Function of sphingolipids?

Answer 33

Found in biological membranes, contribute to structure and signaling.

Question 34

What are waxes?

Answer 34

Esters of long-chain alcohols and fatty acids.

Question 35

Key property of waxes?

Answer 35

Hydrophobic and water-repellent.

Question 36

Biological roles of waxes?

Answer 36

Coat animal skin/fur, plant leaves, bird feathers.

Question 37

Example of commercial wax?

Answer 37

Carnauba wax (polishes) and lanolin (cosmetics).

Question 38

Basic building block of terpenes?

Answer 38

Isoprene (2-methyl-1,3-butadiene).

Question 39

Monoterpenes?

Answer 39

2 isoprene units.

Question 40

Sesquiterpenes?

Answer 40

3 isoprene units.

Question 41

Diterpenes?

Answer 41

4 isoprene units.

Question 42

Biological relevance of terpenes?

Answer 42

Steroids (cholesterol, hormones) are terpene-derived.