lipids (triglycerides, phospholipids and steroids) Flashcards
What are lipids?
Lipids are composed mainly of C, H and O atoms however some also contain phosphorus and nitrogen atoms
Are lipids hydrophobic or hydrophilic and what does this mean?
Most lipids are hydrophobic meaning they are not soluble in water
What are the three main classes of lipids found in humans/animals?
triglycerides (fats and oils)
phospholipids
steroids
What are triglycerides?
Triglycerides ar made up only of C, H and O atoms. They have a “backbone” of a glycerol molecule to which 3 fatty acid molecules are linked
What are the 2 main types of fatty acids?
Saturated and unsaturated
Saturated fats contain mainly C-C single bonds, whereas unsaturated fats contain one or more C=C double bonds along each fatty acids chain.
describe the differences between fats and oils
Fats tend to be animal in origin compared to oils which are usually plant/vegetable origin.
Fats are solid at room temp while oils are liquid at room temp
Fats are a higher saturated fatty acid while oils are more unsaturated fatty acids
How are triglycerides digested in the intestine?
Digested by hydrolysis (by an enzyme called lipase) into a monoglyceride and two fatty acids
What is the function of triglycerides?
protection from knocks and bumps
insulation
highly concentrated energy source that can be stored for use later
What is a phospholipid?
Phospholipids are made up of C, H and O atoms but also contain phosphorus and often nitrogen. Similar to triglycerides however only have 2 fatty acids attached to the glycerol and in the third position they contain a group of atoms which includes phosphorus and nitrogen. This part of the molecule is polar (water-soluble, hydrophilic). The fatty acids are non-polar (NOT water-soluble, hydrophobic)
What is the function of a phospholipid?
used by cells in production of cell membranes. The main structural component of the cell membrane is a double layer of phospholipid molecules known as the phospholipid bilayer.
What is a steroid?
Made up of C, H and O atoms. Compared to triglycerides and phospholipids where the C atoms are arranged in chain, in steroids the C atoms are arranged in rings
What is the function of steroids?
growth, development, sexual differentiation and reproduction
define hydrolysis
Hydrolysis is a chemical change in which a large molecule is broken down into smaller molecules by reaction with water
define a polymer
A giant molecule made up of lots of repeated small molecules (monomers) bonded together
