lipids

Question 1

what are lipids commonly known as?

Answer 1

fats and oils

Question 2

what are lipids different from proteins?

Answer 2

they are not polymers made of long chains of monomers but instead are made of a variety of components all containing hydrocarbons.

Question 3

what is a hydrocarbon?

Answer 3

a molecule only containing hydrogen and carbon atoms

Question 4

name two types of lipids

Answer 4

triglycerides and phospholipids

Question 5

Structure of triglycerides?

Answer 5

one molecule of glycerol attached to fatty acid tails made of hydrocarbons.

Question 6

what are amino acid tails?

Answer 6

hydrophobic- repel water molecules

Question 7

lipids are …… in water?

Answer 7

insoluble

Question 8

two types of fatty acids? ( the r group)

Answer 8

saturated and unsaturated

Question 9

what does a saturated fatty acid have that an unsaturated one does not?

Answer 9

a double carbon bond

Question 10

the chains in unsaturated fatty acids cause there chains to ….?

Answer 10

kink

Question 11

test for lipids?

Answer 11

the emulsion test

Question 12

describe the emulsion test

Answer 12

add ethanol to sample
shake well for one min
pour solution into water
milky white emulsion = lipid present

Question 13

Triglycerides are formed by?

Answer 13

condensation reactions

Question 14

what type of bond forms in triglycerides?

Answer 14

ester bond

Question 15

how many times does the condensation reaction occur in triglycerides?

Answer 15

3

Question 16

where are phosphlipids found ?

Answer 16

cell membranes

Question 17

structure of phospholipid?

Answer 17

glycerol is attached to two fatty acid hydrophobic tails and one phosphate group( hydrophilic)

Question 18

what are tryglycerides used as?

Answer 18

energy storage molecules

Question 19

what are tryglycerides good for their function?( tails)

Answer 19

long hydrocarbon tails of the fatty acid contain lots of chemical energy- a load of energy is released when they are broken down.due to this they contain about twice as much energy per gram than carbs.

Question 20

what are tryglycerides good for their function? ( solubility)

Answer 20

they are insoluble in water so do not affect water potential and cause water to enter the cell via osmosis. They bundle together in cells as fatty acid tails are hydrophobic - the tails face inwards shielding themselves from water.

Question 21

phospholipids make a …… of cell membranes?

Answer 21

bilayer ( double layer)

Question 22

cell membranes control ?

Answer 22

what enters and leaves a cell

Question 23

phospholipid heads are ……? whereas their tails are ……….?

Answer 23

heads = hydrophilic 
tails= hydrophobic

Question 24

structure of phospholipid?

Answer 24

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Question 25

Phospholipid- bilayer is ?

Answer 25

hydrophobic (water soluble substances cannot pass through)