Lipids

Question 1

Give 2 function of terpenes

Answer 1

Disease resistance, signalling

Question 2

Why do most fatty acids have an even number of carbons?

Answer 2

Due to the mode of synthesis - putting together couples of carbons

Question 3

There are rarely more than _double bonds in an unsaturated fat

Answer 3

4

Question 4

Unsaturated fats usually have their double bonds on carbons _

Answer 4

9, 12, 15

Question 5

Simple triacylglycerols have __ fatty acids

Answer 5

3 of the same units of

Question 6

Which type of cells specialise in fat storage?

Answer 6

Adipocytes

Question 7

White fat cells store _

Answer 7

A single droplet of fat and oil

Question 8

Brown fat cells store _

Answer 8

Multiple membrane bound droplets of fat/oils

Question 9

Which type of fat cell increases in number as a person gains weight?

Answer 9

White adipocytes

Question 10

How do plants use triacylglycerols?

Answer 10

They are stored in seeds for use as an energy source after germination

Question 11

Triacontanol is _

Answer 11

an example of an alcohol which reacts with fatty acids

Question 12

The esterification between triacontanol and palmitic acid produces _

Answer 12

Beeswax

Question 13

Compare melting point of waxes to triacylglycerol

Answer 13

Waxes have higher melting points

Question 14

Alcohols that react with fatty acids tend to have _

Answer 14

Long R groups

Question 15

How do you form a soap?

Answer 15

By heating triacyclglycerols with an alkali, like sodium hydroxide

Question 16

What happens during saponification?

Answer 16

Ester linkages are broken between fatty acids and glycerol,

Fatty acids form salt with the cations of an alkali

Question 17

What are micelles?

Answer 17

Aggregates of salt molecules, which form a spherical structure with hydrophilic carboxyl groups on the surface, and hydrocarbon chains embedded within

Question 18

Glycerophospholipid structure:

Answer 18

Like a triacylglycerol, but one fatty avid is replaced with a hydrophilic group known as the ‘head’

Question 19

What kind of bond links the ‘head’ to the rest of the molecule in glycerophospholipids?

Answer 19

Phosphodiester bond

Question 20

A cerebroside is_

Answer 20

A sphingolipid with a simple sugar head group

Question 21

A ganglioside is _

Answer 21

A sphingolipid with a complex sugar head group

Question 22

The components of a sphingolipid are _

Answer 22

Sphingosine, with a hydrophilic group ‘head’ and a fatty acid chain on second carbon

Question 23

What is the most diverse type of natural product?

Answer 23

Terpenes

Question 24

What 2 factors give terpenes diversity

Answer 24

Varying lengths of chains, vast range of structural derivatives

Question 25

Hemiterpenes have

Answer 25

one isoprene unit

Question 26

Monoterpenes have

Answer 26

two isoprene units

Question 27

the secreted resins of birch and spruce are largely composed of

Answer 27

diterpenes, with four isoprene units

Question 28

Rubber is a _terpene with _ units

Answer 28

Poly | tens of thousands of isoprene

Question 29

What process forms cross links between individual chains of rubber molecules. What does effect does it have on properties?

Answer 29

Vulcanization Confers mechanical stability Improves elasticity

Question 30

What compounds are formed from the cyclization of squalene (a triterpene composed of 6 isoprene units)?

Answer 30

Sterols

Question 31

The core structure of sterols is _

Answer 31

Four fused carbon rings, three with 6 carbons, and one with 5 carbons

Question 32

What is the plant equivalent of cholesterol?

Answer 32

Stigmasterol

Question 33

Bile acids like cholic acid, are sterols with _

Answer 33

Hydrophilic R groups

Question 34

Derivatives of cholic acid are synthesized in the liver and then secreted in to the small intestine where they _

Answer 34

Emulsify fats, aiding digestion

Question 35

Steroids are derivatives of

Answer 35

Sterols

Question 36

What is the difference between the core structure of steroid and sterols

Answer 36

Steroids may have a variety of functional groups at a site at which sterols only have a hydroxyl group

Question 37

What compounds are derived from arachidonic acid?

Answer 37

Eicosanoids

Question 38

give 2 procceses which eicosanoids are involved in

Answer 38

reproduction, pain response

Question 39

Paracetamol and aspirin function by

Answer 39

prevent formation of specific eicosanoids

Question 40

Why are eicosanoids not true hormones?

Answer 40

Because they stay within the tissues in which they are secreted

Question 41

Prostaglandins and thromboxanes are examples of _

Answer 41

Eicosanoids

Question 42

Which vitamin is esssential for the syntheiss of photoreceptors in the eye?

Answer 42

Vitamin A

Question 43

Which lipid vitamin is needed for correct functioning of blood clotting response?

Answer 43

Vitamin K

Question 44

Which lipid vitamin is involved in prevention of oxidative damage in cells

Answer 44

Vitamin E

Question 45

What determines the structre that an amphiphilic compounds will take in aqueous solution

Answer 45

The number of hydrophobic tails

Question 46

What 3 types of lipids are in biological membranes?

Answer 46

Glycerophospholipids, sphingolipids and sterols

Question 47

What property of membranes allows them to take different shapes?

Answer 47

Flexibility, can stretch 2-4% without breaking

Question 48

What are the restrictions on movement for a lipid within a memmbrane?

Answer 48

It cannot easily move across to the other side. It can readily move along its layer - fluid mosaic

Question 49

Lipids with longer hydrophobic tails form _ associations, and _ fluid membranes

Answer 49

closer | less

Question 50

Lipids with kinks from _ associations and _ fluid membranes

Answer 50

looser | more

Question 51

Membranes are more protein by _

Answer 51

Weight

Question 52

Membranes are more fat by _

Answer 52

Number of molecules

Question 53

Which membrane proteins can only be removed by disruption?

Answer 53

Integral membrane prot

Question 54

Which membrane proteins can be removed wtihout disruption?

Answer 54

Peripheral membrane proteins

Question 55

How are integral membrane proteins removed experimentally?

Answer 55

Using detergent, which resembles and functions like soap, using micelles

Question 56

Give two types of transmembrane protein structures

Answer 56

Barrel-like structures made of beta sheets | Alpha-helical shapes spanning the membrane`

Question 57

The internal face of transmembrane proteins often forms attachments with

Answer 57

Peripheral membrane proteins

Question 58

What are lipid-linked proteins?

Answer 58

Peripheral membrane proteins which are linked to membrane lipids

Question 59

What are lipid rafts?

Answer 59

Stable domains within which proteins can co-locate and function together

Question 60

What can be said about fluidity of areas which function as lipid-rafts?

Answer 60

They are usually less fluid due to tighter associations between hydrophobic tails

Question 61

Why are sterols common in lipid rafts?

Answer 61

They fit neatly between two glycerophospholipids

Question 62

Compounds that can't cross the membrane still influence events within the cell through _

Answer 62

Signal transduction

Question 63

Give an example of signal transduction

Answer 63

Growth factors binding to proteins, inducing cell division

Question 64

Carbohydrates on surface of membrane are held in place by _

Answer 64

attachment to lipids and proteins

Question 65

Carbohydrate coating of cell membranes plays a role in

Answer 65

cell-cell recognition and provides protection

Question 66

What molecules are able to cross membranes freely?

Answer 66

Water, gases like oxygen, nitrogen and carbon dioxide | Urea, ethanol (small molecules)

Question 67

How does the GLUT1 transporter function?

Answer 67

Glucose binds to extracellular surface, causing a conformational change which allows glucose to flow down its gradient within the channel of the protein

Question 68

What are the two sources of energy for transport

Answer 68

Hydrolysis of ATP | Coupling to the movmement of a molecule down its gradient

Question 69

Give an example of a symporter

Answer 69

Na+ glucose transporter

Question 70

what does the mammalian Na+ glucose transporter do?

Answer 70

It couples the diffusion of sodium ions in to intestinal cells from gut cells with the intake of glucose

Question 71

Give an example of an antiporter

Answer 71

Na+/Ca2+ exhange protein

Question 72

What does the sodium/calcium exchange protein do?

Answer 72

Uses the enerrgy from the diffusion of 3 sodium ions to power the export of a single calcium ion

Question 73

Give the two types of ATP dependent pumps

Answer 73

ABC (ATP-binding cassette) | P-type

Question 74

How do p-type transporters function?

Answer 74

The released phosphate group form ATP forms a transient attachment with the transport protein

Question 75

Na/K ATPase moves _ pottasium ions _ and __ sodium ions _ for 1ATP

Answer 75

2 in | 3 out