lipids

Question 1

contain

Answer 1

carbon, hydrogen, oxygen

Question 2

2 types of lipids

Answer 2

triglycerides, phospholipids

Question 3

Lipids are not

Answer 3

polymers as they are not chains of repeated units

Question 4

Lipids in water

Answer 4

insoluble in water as they are non-polar but soluble in organic solvents

Question 5

diff to carbo

Answer 5

more O2 in carbo

lipids have a large number of C-H bonds

Question 6

triglycerides

Answer 6

common type of lipid

made of molecule of glycerol joined in a condensation reaction to 3 fatty acids

ester bond

Question 7

molecules formed in a triglyceride formation

no different types of molecules formed in this

Answer 7

4-1 triglyceride & 3 molecules of water

2 types - water & triglyceride

Question 8

fatty acids info

Answer 8

• vary in length whether C=C bond present
• R grouping in the fatty acid is varibale
• some are saturated fatty acids with no C=C
• some are unsaturated fatty acids with C=C , less hydrogen bonds
• the double bond influences the properties of the molecule (such as MP &BP)

Question 9

how are the two ends of a fatty acid molecule different

Answer 9

one end had a carboxylic -COOH and other has CH3 methyl end

Question 10

difference between mono and poly unsaturated fatty acid

Answer 10

mono - 1 C=C

poly - 2+ C=C

Question 11

HDL

Answer 11

high density lipoproteins (good)

Question 12

LDL

Answer 12

low density lipoproteins (bad)

picks up bad CHL to arteries

Question 13

phospholipids

Answer 13

special types of fat that are the main constituent of cell membranes

one of the fatty acids found in a triglyceride is substituted by a phosphate group

Question 14

how is phospholipid diff to triglyceride

Answer 14

P - 2 fatty acids T - 3 fatty acids
P - has a phosphate group T -doesnt

phospholipids form monolayer, tri dont

Question 15

how is phospholipid similar to triglyceride

Answer 15

fatty acids,
glycerol,
ester bonds,
C, H, O (P has phosphorus)
insoluble in water

Question 16

phosphate in water

Answer 16

hydrophilic (polar) which means that it will orientate itself towards water

Question 17

fatty acids water

Answer 17

hydrophobic (non-polar) which means they will orientate itself away from water

Question 18

fluid mosaic model

Answer 18

used to describe membrane structure

Question 19

glycolipids

Answer 19

special types of fat that are also found in cell membranes

one of the fatty acids found in a triglyceride is substituted by a sugar or chain or sugars

Question 20

glycoproteins

Answer 20

have sugar residues attached to their surface and always point towards the tissue fluid (extracellular fluid)

Question 21

glycolipids and glycoproteins

Answer 21

are important in the process of recognition and how the immue system distiguishes between ‘self’ and ‘non-self’ and in cell adhesion.

Question 22

lipids solubility

Answer 22

all lipids will disolve in organic solvents, but are insoluble in water

this is important as it means that they don’t interfere with the many reactions which go in the aqueous solution inside the cytoplasm of the cell

Question 23

lipid function

Answer 23

energy store - lipids provide more energy per gram than carbohydrates

insulation - fats are insulators

protection - fat is packed around major organs

waterproofing - due to insolubility in water

cell membranes

Question 24

how is the structure of a phospholipid linked to its main function

Answer 24

• hydrophilic phosphate (head) and hydrophobic fatty acid (tails) allows it to form a bilayer in membranes
• controls what goes in and out of cells as any small and lipid-soluble (non-polar) molecules can pass through this bilayer

Question 25

test for lipids

Answer 25

emulsion test

add 2cm3 food sample
add 2cm3 ethanol, mix
add 2cm3 distilled water

pos: cloudy white emulsion
neg: retains original colour

Question 26

How triglyceride structure relates to its properties

Answer 26

Energy storage - High ratio of carbon-hydrogen bonds to carbon-carbon bonds
Long chains of hydrogen and carbon can be broken to form ATP

Metabolic water source- high ratio of hydrogen to oxygen atoms

Insoluble- doesn’t affect water potential

Low mass