Lipids

Question 1

What is the common and defining feature of lipids?

Answer 1

Insolubility in water

Question 2

What are the main biological functions of lipids?

Answer 2

Energy storage
Structural components of cell membranes
Important signalling molecules

Question 3

What are the 5 common classes of lipids in eukaryotic cells?

Answer 3

Fatty acids
Triacylglycerols
Phospholipids
Glycolipids
Sterols

Question 4

What are fatty acids?

Answer 4

Carboxylic acids with hydrocarbon chains

Question 5

What affects the physical properties of fatty acids?

Answer 5

Degree of unsaturated bonds

Question 6

Are saturated or unsaturated fatty acids liquid at room temperature?

Answer 6

Saturated

Question 7

What are fatty acdis named by?

Answer 7

Length of the hydrocarbon chain and number and position of any carbon-carbon double bonds

Question 8

What are the essential fatty acids?

Answer 8

Polyunsaturated fatty acids that cannot be synthesised by humans and must be obtained from the diet e.g. omega-3 fatty acids and omega-6 fatty acids

Question 9

What are triaclyglycerols?

Answer 9

Composed of three fatty acids covalently joined to glycerol through ester linkages

Question 10

What do triacylglycerols do?

Answer 10

Provide stored energy and are stockpiled in adipocytes in humans

Question 11

What is the main role of phospholipids and glycolipids?

Answer 11

Structure

Question 12

What is the basic structure of phospholipids and glycolipids?

Answer 12

A backbone
At least one fatty acid
Something else

Question 13

What are the two backbones possible for phospholipids and glycolipids?

Answer 13

Glycerol
Sphingosine

Question 14

What are sphingolipids?

Answer 14

Phospholipids or glycolipids with a sphingosine backbone

Question 15

What are sterols?

Answer 15

Precursors to other biomolecules such as steroid hormones and bile acids

Question 16

What are sterols synthesised from?

Answer 16

Simple five carbon structures called isoprenes

Question 17

What is the family of cholesterol inhibitors and give an example of one?

Answer 17

Statins
Rosuvastatin

Question 18

What are the roles of cholesterol?

Answer 18

Production of sex hormones
Assists in bile production in liver
Building block for human tissues
Creating Vitamin D

Question 19

What is Niemann-Pick Disease?

Answer 19

Lysosomal storage disease characterised by a sphingomyelin metabolism disorder

Question 20

What causes Niemann-Pick Disease?

Answer 20

Rare autosomal recessive genetic defect in the gene encoding the enzyme sphingomyelinase resulting in a build up of sphingomyelin in the brain, spleen , liver and lungs

Question 21

What is the outcome for those with Niemann-Pick Disease?

Answer 21

Develops in infancy and leads to mental impairment and eventually death

Question 22

What is Tay-Sachs Disease?

Answer 22

Lysosomal storage disease due to mutations in the HEXA gene causing a build up of gangliosides in brain

Question 23

What does the HEXA gene do?

Answer 23

Encodes the hexosaminidase A enzymes which catalyses the degradation of gangliosides

Question 24

What is the outcome of a patient with Tay-Sachs Disease?

Answer 24

Progressive deterioration of nerve cells and of mental/physical capabilities that begins at ~6 months and usually results in death by age 4

Question 25

What causes Batten disease?

Answer 25

Build up of lipofuscins (deposits of fats and proteins) in tissues
CLN3 gene defect is the most common cause of this disease

Question 26

What are the usual symptoms of Batten Disease?

Answer 26

Visual problems and seizures and develop between the ages of 2 and 10

Question 27

What does the CLN3 gene do?

Answer 27

Encode for battenin which localises to lysosomes and endosomes but its function is unknown