1.3 Lipids Flashcards
What are the 3 elements that make up lipids
- Carbon
- Hydrogen
- Oxygen
What are lipids insoluble in
Water
What are lipids soluble in
Organic solvents like ethanol
What are the 7 functions of lipids
- Thermal insulation
- Protection
- Buoyancy
- Source of metabolic water
- Waterproofing
- Energy store
- Cell membrane structure
What is denser lipids or water
Water is denser than lipids
What waterproof organisms’ layers come from lipids
-Skin
- Leaf cuticle
- Fur
- Feather
What type of tissue creates thermal insulation, lipids
Adipose tissue
What 2 things in the cell membrane are lipids
- Phospholipid bilayer
- Cholesterol
What are the 2 types of lipid structure
- Simple
- Compound
In a simple lipid, what are the 2 components
- Glycerol
- Fatty acids
In a compound lipid, what are the components
- Glycerol
- Fatty acids
- Another group/ molecule/ compound
What is an example of a simple lipid
Triglyceride
What is an example of a compound lipid
Phospholipid
What is the chemical formula for glycerol
C3H8O3
What is the general formula for fatty acids
CH3(CH2)nCOOH
In fatty acids, which part of the general formula is the variable/ R group
The elements in a bracket e.g. (CH2)n
In fatty acids, which part of the general formula is the carboxyl group
COOH
In a fatty acid how is the carboxyl group bonded
HO-C=O
In lipid structure, what bond is formed by a condensation reaction
Ester bond
Does an ester bond contain an oxygen bridge
Yes
Are lipids polymers, and why
Not polymers because they aren’t made from the same repeated units
How do the hydrocarbon tail and the fatty acid tail differ in lipids
The hydrocarbon tail only contains carbon and hydrogen so doesn’t have a carboxyl group (COOH) whereas the fatty acid tail does contain the carboxyl group
Why are some fatty acids saturated
- A saturated fatty acid is fully saturated with hydrogen because there are no carbon to carbon double bonds
Why are some fatty acids unsaturated
- An unsaturated fatty acid isn’t fully saturated with hydrogen because there is at least one carbon to carbon double bond
Name an example of a saturated fat
Butter
Name an example of an unsaturated fat
Oil
Where do saturated fats usually come from
Animals
Where do unsaturated fats usually come from
Plants
At room temp, what state are saturated fats
Solid
At room temp, what state are unsaturated fats
Liquid
What does a high increase of saturated fats increase your risk of
Heart disease
What is a respiratory substrate
A molecule that can release energy which is used to create ATP
How do animals get their energy from a respiratory substrate
By breaking it down in the presence of oxygen, oxidising it
When you oxidies a lipid respiratory substrate, where does the energy come from
The breaking of the C-C and C-H bondds
Why do you get twice the energy yield from using lipids instead of carbohydrates as a respiratory substrate
Because there are more C-C and C-H bonds in lipids due to the hydrocarbon tail
Are phospholipids, a compound or simple lipid
Compound lipid
What are the 2 components of a phospholipid
- x2 Hydrophobic tails
- x1 Hydrophilic head
What is the head made of in a triglyceride
Glycerol
What is the head made of in a phospholipid
- Glycerol
- Phosphate
How many tails does a triglyceride have
3
How many tails does a phospholipid have
2
Why do fats form good waterproofing layers
They’re insoluble in water
What is the structure of a tiglyceride
- 1 Glycerol
- 3 fatty acids
What chemical group does glycerol belong to
Alcohol
What are the 2 different types of fatty acids
- Saturated
- Unsaturated
In a triglyceride, what is the name of the covalent bond that forms between a fatty acid and glycerol
Ester bond
What type of reaction takes place when ester bonds form
Condensation reaction
Name the biochemical test that is used to show the presence of lipids
Emulsion test
Describe how you would use a microscope to find the mean diameter of triglyercide droplet on a slide
- Measure with eyepiece graticule / scale;
- Calibrate with stage micrometer / scale on slide / object of known size
- Repeats and calculate the mean;
Explain why phospholipids can form a bilayer but triglycerides cannot (3 marks)
- Phospholipids both hydrophobic and hydrophilic
- Triglycerides only hydrophobic
- Hydrophilic group attracts to water
Describe how a triglyceride molecule is formed (3 marks)
- One glycerol and three fatty acids;
- Condensation (reactions) and removal of
three molecules of water; - Ester bond(s) (formed);
