Lipids Flashcards
Are lipids polymers? and why?
- No because they do not have repeating units
What are the two main groups of lipids?
- Triglycerides and phospholipids
What bonds hold lipids together?
Ester bonds (RCOOH)
How are triglycerides formed?
Via the condensation reaction between one glycerol and 3 fatty acids
Can you draw a triglyceride?
Search if you got it right
Can you draw an ester bond?
hint: it only includes oxygen and carbon
Search if you got it right?
How many condensation reactions take place to form a triglyceride?
Three
What does mean R?
Variable group
what is the structure of phospholipids?
Glycerol, two fatty acids and a phosphate group
Can you draw a phospholipid
Search it up if you got it right
List the two types of fats?
Unsaturated and saturated
State the difference between saturated and unsaturated fats.
Saturated fats do not contain a single double bond between their carbon atoms. while unsaturated fats have at least one double bond between the carbon atoms.
What is the function of the high ratio of hydrocarbons in triglycerides?
to store twice as much energy as carbohydrates
why is oxidation useful in triglycerides?
to release water which is useful for desert animals
are triglycerides soluble or insoluble and how does it affect a cell
it is insoluble so it does not affect water potential and prevents osmosis
All fatty acids have the same basic structure but…
Their tails vary
why are triglycerides insoluble?
because they have hydrophobic tails
How does the tails in fatty acids vary?
in hydrocarbon tail and location
Are phospholipids soluble and why?
they are soluble due to their hydrophilic (water-loving heads) but their tails are hydrophobic (water-hating)
What is the function of phospholipids?
To form a bilayer in the cell membrane and serve as a selectively permeable membrane
How do phospholipids act as a membrane?
Hydrophobic tails prevent water-soluble substances from passing through
how is the bilayer formed?
hydrophilic heads face outwards and hydrophobic heads face inwards
What is formed when carbohydrates react with lipids
Glycolipids
which lipid has more hydrogens and why?
Triglycerides because they do not have double bonds between their carbon atoms
what makes phospholipids hydrophilic?
Phosphate group
What test is used for lipids
Emulsion test
Describe the emulsion test
- Add ethanol/ alcohol to the food sample and shake
- Add distilled water and gently shake
- The reaction is positive if the sample forms a white, milky, cloudy emulsion
why are hydrophobic tails insoluble?
Because they are non-polar
