Module 1 - Lipids Flashcards
What are lipids
Lipids are diverse group of compounds that are
insoluble in water but soluble in organic solvents
What are 3 things that lipids are used for?
The storage of energy, structural components of hormones and as signalling molecules.
What is triglyceride?
A type of lipid that contains one glycerol molecule and 3 fatty acid molecules formed through ester bonds.
What do lipids consist of
Lipids contain hydrogen, carbon and oxygen
What are 3 types of lipids that are formed?
Saturated = One consists of single covalent bonds Monounsaturated = One double covalent bond Polyunsaturated = More than one double covalent bond
What property does double bonds give lipids.
More than one double bond allows polyunsaturated lipids to bend which allows them to remain a liquid at room temperature.
What property do hydrogen and carbon atoms provide lipids?
Lipids contains lots of hydrogen and carbon meaning that a great deal of energy could be released.
What type of reaction occurs between glycerol and the 3 fatty acid molecules? Why?
A condensation reaction because 3 water molecules are produced
Give 2 properties of triglycerides.
They are non polar (hydrophobic) meaning that they do not dissolve in water, Large amount of carbon and hydrogen atoms meaning a great deal of energy can be released.
Where are lipids stored?
Adipose tissue
What are 2 important roles of adipose tissue?
Heat insulation: Within mammals, adipose tissue is under the skin to help prevent heat loss.
Protection: it is also around delicate organs in order to act as a cushion against impacts.
What cells are contained within adipose tissue?
Fat cells = adiphocyte.
What are phospholipids?
Phospholipids are major components of cell membranes
What is the structure of phospholipids?
Phospholipids contain a phosphate molecule and 2 fatty acid molecules.
What property does the phosphate group have in the structure of phospholipids?
Phosphate molecule is hydrophilic attracts water because it is the charged end of the molecule.
What properties do the fatty acid molecules have in phospholipids?
Non-polar long chain of hydrocarbons and hydrophobic (repels water).
What is the name of the test used to test for lipids?
An emulsion test
Describe the emulsion test.
Why does the emulsion form?
Get a clean test tube including a sample. Then add a sample of ethanol and mix well. Add some water and mix thoroughly. If a white cloudy emulsion appears then there a lipid is present. This emulsion forms because lipids are hydrophobic meaning they repel water and so the lipid globules will separate from the solution forming an emulsion.
How do phospholipids contribute to cell membrane structure?
Phospholipids orient their heads towards the polar molecules and tails in the interior of the cell membrane, thus forming a bilayer.
What are three functions that lipids serve in plants and/or animals?
Lipids serve in the storage of energy, as a structural component of hormones and, as a signalling molecule.
What is a phospholipids purpose in a cell membrane?
Forms a lipid bilayer. The hydrophobic tails repels water so in faces inwards and the hydrophilic head attracts water so faces outwards.
Explain two ways in which fatty acids are important in the formation of new cells
They can be used in respiration to provide energy for the formation of new cells
They can also be used to make phospholipids in membranes.
