Chapter 8 + Quiz Questions

Question 1

What are 3 structural characteristics of lipids?

Answer 1

1. Insolubility in water.
2. Lower molecular weight than other biomolecules.
3. Form aggregates rather than polymers.

Question 2

What are 3 functional characteristics of lipids?

Answer 2

1. Energy Storage
2. Structural Component of Membranes.
3. Active Roles

Question 3

What are the active roles lipids play?

Answer 3

Signaling, Enzyme Co-factors, Vitamins, Hormones, and Pigments

Question 4

What are fatty acids? (x3)

Answer 4

Hydrocarbon with carboxylic head
Differ in length and degree of saturation
Usually an even number of Cs (12-24)

Question 5

Assign the following terms with the amount of fatty acids (0, 1, +2): unsaturated, polyunsaturated, saturated.

Answer 5

Saturated = 0 double bonds
Unsaturated = 1 double bond
Polyunsaturated = +2

Question 6

Double bonds usually indicate a ____ configuration

Answer 6

cis

Question 7

Double bonds are usually separated by a _____ group

Answer 7

Methylene (CH2)

Question 8

What is the formula for determining fatty acid nomenclature?

Answer 8

carbons : XΔ^n. Where X is the amount of double bonds, and n is the lowest numbered carbon involved in a double bond. Carbon of the carboxyl group is the carbon 1

Question 9

Hydrocarbon tails of fatty acids associate through _____ and ___ ___ _____ interactions

Answer 9

hydrophobic, van der Waals

Question 10

In fatty acids, do long chains or short chains have stronger associations?

Answer 10

Long chains

Question 11

In fatty acids, do saturated chains or unsaturated chains have stronger associations?

Answer 11

Saturated

Question 12

The melting temperature of a fatty acid mixture reflects the ____ and ____ __ ______ of the hydrocarbon tails

Answer 12

length, degree of saturation

Question 13

Which has a greater influence on fatty acid associations: double bonds or length of the tail?

Answer 13

Double bonds

Question 14

Lipids occupy most of the intracellular space in _____

Answer 14

adipocytes

Question 15

What are adipocytes?

Answer 15

The energy storage cells in animal tissues

Question 16

Fatty acids required for energy are stored as ______

Answer 16

triacylglycerols

Question 17

What are triacylglycerols?

Answer 17

Three fatty acids linked to glycerol through ester linkages

Question 18

What is the difference between simple and complex triacylglycerols?

Answer 18

Simple: have the same three fatty acids at each position Complex: different fatty acids

Question 19

The ester linkage in triacylglycerols removes the polar carboxyl group to make a more _____ molecule

Answer 19

hydrophobic

Question 20

What are the characteristics of lipids that make them so effective as long-term energy storage molecules?

Answer 20

Low oxidation state and low hydration state

Question 21

Describe how having a low oxidation state helps lipids in being so effective as long-term energy storage molecules

Answer 21

Less oxygenated fuels burn more efficiently; triacylglycerols have lower oxygenation state than carbohydrates

Question 22

Describe how having a low hydration state helps lipids in being so effective as long-term energy storage molecules

Answer 22

Lipids are hydrophobic with limited interaction with water providing a more compact, dehydrated energy storage form

Question 23

What is saponification?

Answer 23

Treatment of fat with a strong base breaks the ester linkages to release free fatty acids.

Question 24

The amphipathic properties of free fatty acids make them effective in..?

Answer 24

solubilization of hydrophobic substances

Question 25

Fatty acids function as detergents and soaps through formation of ____ that capture hydrophobic molecules.

Answer 25

micelles

Question 26

What is a micelle?

Answer 26

A tiny particle that makes an upside-down cone shape, and is made of substances that are soluble in water and that come together to form a ball-like shape

Question 27

What is a wax?

Answer 27

Non-polar esters of long-chain fatty acids and long chain monohydroxylic alcohols

Question 28

Are waxes soluble in water?

Answer 28

Waxes are very water insoluble and have high melting temps (60-100 C)

Question 29

Membrane bilayers ____ _____ and ____ __ ______ of the intracellular environment

Answer 29

define cells, regulate the composition

Question 30

Formation of membranes is a ____ consequence of the properties of the molecules that compose them

Answer 30

spontaneous

Question 31

Membrane lipids can be classified based on their _______ or by their _________

Answer 31

backbone (glycerol vs sphingosine), polar head groups (phospho vs glyco)

Question 32

What are the most abundant lipids in membranes?

Answer 32

Glycerophospholipids

Question 33

What is the structure of a glycerophospholipid?

Answer 33

Glycerol backbone with a phosphate at the C3 position (Glycerol 3-phosphate).

Question 34

The _____ group is the point of attachment for a variety of polar head groups

Answer 34

phosphate

Question 35

The head groups in glycerophospholipids can carry what kind of charge: positive, negative, or neutral?

Answer 35

Can carry all of them

Question 36

True or False: different head groups are likely associated with specialized functions?

Answer 36

True

Question 37

Plant cells often contain _____: one or two galactose groups linked to C3 of diacylglycerol. Plants also contain _____

Answer 37

galactolipids, sulfolipids

Question 38

What are sphingolipids?

Answer 38

Derived from sphingosine, a long chain amino alcohol

Question 39

What is the structure of sphingolipids?

Answer 39

It is a single fatty acid linked by amide bonds to form ceramide, which is structurally similar to diacylglycerol

Question 40

What are 3 common sphingolipids?

Answer 40

Sphingomyelins, Cerebrosides, Gangliosides

Question 41

What is a Sphingomyelin?

Answer 41

Phosphocholine

Question 42

What is a Cerebroside?

Answer 42

Glycosphingolipid, which has a single sugar unit

Question 43

What is a Ganglioside?

Answer 43

Glycosphingolipid, which has multiple sugar units

Question 44

Different blood types (A, B, O) reflect different sugar patterns as the head groups of the _______

Answer 44

sphingolipids

Question 45

______ (extremophiles) live under conditions of high temp, pH and ionic strength making it a challenge to maintain membrane integrity

Answer 45

Archaebacteria

Question 46

The membrane lipids of these extremophiles often contain 3 factors:

Answer 46

1. Ethers linkages 2. Branch points within the hydrocarbon tails 3. Membrane spanning hydrocarbon tails composed from a single molecule.

Question 47

What are sterols and what is their structure?

Answer 47

Are structural membrane lipids, and contain four fused ring steroid nucleus: 3-six carbon rings and a 5-carbon D ring which is rigid and nearly planar

Question 48

True or False: sterols also serve as precursors for many biologically active products

Answer 48

True

Question 49

What are the functions of cholesterol?

Answer 49

Critical biological functions such as mediating membrane fluidity and as a precursor of steroid hormones and bile salts

Question 50

What are eicosanoids?

Answer 50

Paracrine hormones (act on cells near point of production), and are derivatives of C20 polyunsaturated fatty acids (arachidonic acid)

Question 51

What are the three classes of eicosanoids?

Answer 51

Prostaglandins, Thromboxanes, Leukotrienes

Question 52

What is the purpose of prostaglandins?

Answer 52

Constriction of blood vessels

Question 53

What is the purpose of thromboxane?

Answer 53

Involved in blood clot formation

Question 54

What is the purpose of leukotrienes?

Answer 54

Smooth-muscle contraction

Question 55

What are steroid hormones?

Answer 55

Hydrophobic oxidized sterol derivatives

Question 56

How are steroid hormones carried?

Answer 56

Through the blood stream by carrier proteins. From which they pass through the plasma membrane to bind receptors in the nucleus

Question 57

What are the consequences of steroid hormones?

Answer 57

Alter patterns of gene expression and metabolism

Question 58

What are the 4 lipid vitamins?

Answer 58

A, D, E, and K

Question 59

What is common to the vitamins and what is different?

Answer 59

They all contain rings, long aliphatic side chains, and are highly hydrophobic. But they differ in their functions

Question 60

What is the function of vitamin D?

Answer 60

Regulates Ca2+ uptake and deposition

Question 61

How can vitamin D be obtained?

Answer 61

From the diet or produces endogenously

Question 62

What is endogenous production for vitamin D?

Answer 62

Occurs in a series of reactions, one of which requires UV light

Question 63

What are the results of insufficient/excessive vitamin D?

Answer 63

Insufficient: skeletal defects (rickets) Excessive: calcification of soft tissues

Question 64

How is vitamin A obtained?

Answer 64

From liver, egg yolks, and milk products

Question 65

What are the three forms of vitamin A?

Answer 65

Alcohol(retinol), aldehyde, and retinoic acid

Question 66

What is aldehyde(retinal)?

Answer 66

A light sensitive compound with a role in vision

Question 67

What is vitamin E, and what is its purpose?

Answer 67

A reducing reagent that scavenges oxygen free radicals. It may prevent damage to fatty acids in membranes

Question 68

What is the result of vitamin E deficiency?

Answer 68

Scaly skin, muscular weakness, and sterility

Question 69

What is another name for vitamin E?

Answer 69

a-tocopherol

Question 70

What is the purpose of vitamin K?

Answer 70

Required for synthesis of blood coagulation proteins

Question 71

What are given to individuals who suffer excessive blood clotting?

Answer 71

Vitamin K analogs such as warfarin

Question 72

True or False: 18:0 is a saturated fatty acid?

Answer 72

True

Question 73

In sphingolipids, the fatty acid is linked to sphingosine through a(n) ______ bond

Answer 73

amide

Question 74

In triacylglycerol, fatty acids are linked to glycerol through..?

Answer 74

Ester linkages