Lipids

Question 1

Lipids

Answer 1

Molecules that are found in fats and oils

Question 2

Fats

Answer 2

Solid lipids

Question 3

Oils

Answer 3

Liquid fats

Question 4

Functions of lipids in our diet

Answer 4

A source of energy for respiration

Question 5

Functions of lipids as tissue in our body

Answer 5

Adipose tissue/ fat on body:
Stores energy
Insulates the body
Protects the organs from injury

Question 6

Functions of lipids in our cells

Answer 6

Part of membrane structures around cells and mitochondria

Question 7

Categories of lipids

Answer 7

Triglycerides
Phospholipids

Question 8

Triglyceride structure molecule

Answer 8

Molecule of glycerol
Bonded to 3 fatty acids

Question 9

Fatty acid molecules

Answer 9

Contains carboxylic acid group at one end
Then long chain of carbons surrounded by hydrogen

Question 10

Saturated fatty acids

Answer 10

Contains only single bonds between the carbon atoms on the long chain

Question 11

Unsaturated fatty acid

Answer 11

Contains at least one double covalent carbon to carbon bond in the carbon chain

Question 12

Monounsaturated fatty acid

Answer 12

Contains only 1 double covalent bond in the carbon chain

Question 13

Polyunsaturated fatty acid

Answer 13

Contains 2 or more double covalent bond double covalent bond in the carbon chain

Question 14

Glycerol structure

Answer 14

3 carbon atoms bonded to 3 hydroxyl groups each
Rest is bonded to hydrogen

Question 15

How does 1 glycerol and 3 fatty acids bond together

Answer 15

The 3 OH groups in the acid group of each fatty acid
And the 3 OH groups of the glycerol form an ester bond (oxygen linking each molecule together) and water

Question 16

Esterification

Answer 16

Forming ester bonds between glycerol and fatty acids
Through condensation = releases water

Question 17

How are triglycerides digested?

Answer 17

Lipase enzymes break ester bonds which release the 3 fatty acids and glycerol
Requires water = hydrolysis

Question 18

Features of triglycerides

Answer 18

Insoluble in water (hydrophobic)
Large amounts of energy release

Question 19

Why are triglycerides hydrophobic?

Answer 19

Because it is non polar so won’t dissolve in the polar molecule water

Question 20

Why are triglycerides good stores of energy?

Answer 20

Contains many carbon to hydrogen bonds
Which when broken release a lot of energy

Question 21

Phospholipid structure

Answer 21

Glycerol molecule
Attached to 2 fatty acid molecules (ester bond)
Remaining carbon in the glycerol attaches to phosphate group forming a phosphodiester bond

Question 22

Phosphate group

Answer 22

PO₄³⁻
Is negatively charged

Question 23

Is the phosphate group polar?

Answer 23

Yes because there’s an uneven distribution of electrons in its bonding
And negatively charged

Question 24

Why is the phosphate group hydrophilic?

Answer 24

Because it is a polar molecule so attracts other polar molecules (water)

Question 25

Simple way to show phospholipid

Answer 25

Circle with 2 lines coming out of it
Circle = polar hydrophilic head (phosphate) and glycerol bonded to the acid group in fatty acids
Lines = non polar hydrophobic fatty acids

Question 26

Are fatty acids hydrophobic

Answer 26

Yes because it contains no oxygen to hydrogen bonds therefore not a polar molecule

Question 27

Phospholipids properties

Answer 27

Contains hydrophobic region (fatty acidsl)
Contains hydrophilic region (phosphate group and glycerol)

Question 28

When phospholipid is put in water

Answer 28

The polar hydrophilic phosphate heads position themselves to interact with them
And the hydrophobic tails cluster away from water molecules

Question 29

Phospholipid bilayer

Answer 29

Structure formed when phospholipids face themselves where the hydrophilic head interacts with water molecules and hydrophobic tails face away

Question 30

Phospholipid bilayer use

Answer 30

Forms membranes around cells and inside cells