Lipids And Membranes

Question 1

The cellular oxidation of fatty acids to CO2 and H2O is

Answer 1

Highly exergonic (energy releasing)

Question 2

Fatty acids properties and functions (6)

Answer 2

• Major structural units of lipids
• aliphatic
• long chain
• mono carboxylic acids
• terminal carboxyl group
• 4- 36 carbons

Question 3

Saturated fatty acids naming

Answer 3

-anoic

Question 4

Unsaturated fatty acids with double bonds naming

Answer 4

-enoic

Question 5

Unsaturated fatty acids with triple bonds naming:

Answer 5

• ienoic

Question 6

Delta defines what?

Answer 6

The position of any double bond with a superscript numeral describing the location.

Question 7

cis-delta9 defines what?

Answer 7

There is a cis double bond between carbons 9 and 10.

Question 8

The quantitatively most common saturated fats in most organisms are: (2)

Answer 8

Palmitoleic and oleic.

Question 9

What organism contains more polyunsaturated fats than animals?

Answer 9

plants

Question 10

fat is solid at

Answer 10

at room temp

Question 11

oil is liquid at

Answer 11

room temp

Question 12

Lipids are generally ___ in water

Answer 12

insoluble

Question 13

some lipids have a part of which is hydrophobic and a part of the molecule which is hydrophilic; what is this called?

Answer 13

Amphipathic

Question 14

Lipids are classified as such (3)

Answer 14

• Energy storage
• membrane lipids cell structure
• Bilogically active lipids (hormones)

Question 15

What are Triglycerides?

Answer 15

Glycerol and the 3 fatty acids attached to the Glycerol.

Question 16

typical chain length of a fatty acid?

Answer 16

4-36 carbons

Question 17

palmitic acid

Answer 17

palm oil

Question 18

stearic acid

Answer 18

cow fat

Question 19

16:1 delta9 defines

Answer 19

16 carbon fat with one double bond at the 9 carbon position (palmitoleic acid)

Question 20

The more double bonds in a fatty acid the lower the

Answer 20

melting point

Question 21

EFA

Answer 21

Essential Fatty Acids

Question 22

TAGs

Answer 22

Triacylglycerols (TAG) are the simplest lipids. Note the other names for these: triglycerides, triacylglyceride fats, neutral fats.

Question 23

oxidation of unsaturated fats =

Answer 23

rancidity

Question 24

An ester is formed when

Answer 24

a fatty acid is oxidised into a resin or wax

Question 25

a lipid is classed a phospholipid if….

Answer 25

it contains a phosphate

Question 26

a lipid is classed a glycolipid if…..

Answer 26

it contains a glucose or a galactose

Question 27

if the poly-functional backbone group is glycerol, these are called

Answer 27

glycerophospholipids

Question 28

if the poly-functional backbone group is the long chain amino alcohol sphingosine, they are called

Answer 28

sphingolipids

Question 29

Sphingolipids structure and function

Answer 29

can be phospho- or glyco-lipids. They also have a polar head and two non-polar tails, but they contain sphingosine instead of glycerol. Firstly, sphingosine is the backbone of sphingolipids and it is made up of unbranched C18 alcohol with double bonds between C4 and C5, an amino group at C2 and hydroxyl groups at C1 and C3. Sphingolipids are involved with recognition events at the cell surface. They are responsible for our different blood groups

Question 30

Cholesterol structure/function (4)

Answer 30

• is the major sterol in animal tissue.
• It has a long hydrophobic side chain
• amphipathic
• has an important role as a component of cell membranes

Question 31

bi-layer structure of membranes are composed of

Answer 31

phospholipids

Question 32

Cholesterol or derivatives are molecules that do what in membranes?

Answer 32

rigid molecules that restrict the freedom of rotation of the hydrocarbon tails in their vicinity hence decreasing fluidity while they also prevent close packing that would restrict movement within the bilayer. By stopping too much movement or too little movement of the bilayer by the amount of sterol present these substances are able to regulate the fluid nature of the lipid portion

Question 33

integral or intrinsic proteins

Answer 33

proteins that are wholly within the membrane and are bound very tightly. They have both polar and nonpolar groups on their surfaces so they can bond with the hydrophobic tails and the polar heads of the phospholipids.

Question 34

Peripheral or extrinsic proteins

Answer 34

are exposed on only one surface of the membrane and are generally weakly held by hydrophilic interaction with the polar surface of the membrane. These proteins often serve a regulatory role. Hydrophillic portions.

Question 35

Simple diffusion through a membrane

Answer 35

the process by which substances pass from areas of high concentration to areas of low concentration. resonably difficult ecause of the change in character from polar to nonpolar to polar again as the membrane is crossed.

Question 36

Passive transport (facilitated diffusion) through a membrane

Answer 36

The movement of polar compounds and ions across membranes is made possible by protein carriers. These proteins act in a similar way to enzymes but the ‘substrate’ is only relocated; it is not converted into a ‘product’. called transporters or permeases.

Question 37

Active transport -

Answer 37

when a substance needs to be moved against a concentration gradient. To achieve this potassium ions are pumped into the cell and sodium ions are pumped out. Energy is needed to drive the pump and this is provided directly from ATP.

Question 38

Gated ion channels

Answer 38

They are like gates that open in the membrane and allow the unrestricted passage of selected ions for a very short time. They are used in transmission of electrical impulses in nerves. Require a electromagnestic gradient.

Question 39

the human diet is derived from what percentage of triglycerides?

Answer 39

30%

Question 40

Three different types of lipases have been identified in mammals that hydolyse triglycerides into glycerol and there constituent fatty acids.

Answer 40

• Pancreatic lipase
• Lipoprotein lipase
• Hormone sensitive lipase

Question 41

an enzyme secreted by the pancreas into the duodenum, which hydrolyses dietary triacylglycerols into di- and mono- acylglycerols and free fatty acids.

Answer 41

Pancreatic lipase

Question 42

an enzyme attached to the outer surface of cells lining capillaries adjacent to adipose tissue or skeletal muscle. These lipases catalyse the hydrolysis of triacylglycerols associated in lipoproteins (multimolecular aggregates of lipid and protein, designed to stabilise water-insoluble lipids in an aqueous environment, the bloodstream) to form glycerol and free fatty acids.

Answer 42

Lipoprotein lipase

Question 43

an enzyme found inside adipose tissue cells, which catalyses the hydrolysis of storage triacylglycerols to form free fatty acids and glycerol This enzyme is activated by hormones such as glucagon and adrenaline. Such hormone activation plays an important physiological role in fasting, to mobilise energy stores for use as a fuel.

Answer 43

Hormone-sensitive lipase

Question 44

β- oxidation and where it occurs

Answer 44

a three stage process of fatty acid metabolisation. The first of these stages is β- oxidation leading to the formation of acetyl-CoA. Through reactions involving dehydrogenation, hydration, and oxidation to a ketone we cleave two carbon units from the fatty acid chain.
- mitochondtion and peroxisomes.

Question 45

Lipid catabolism

Answer 45

enzymes break down triglycerides to fatty acids with lipases,