Flashcards in 2: Lipids Deck (24):
What are lipids?
carbon compounds made by living organisms that are mostly or entirely hydrophobic
Name the 3 main types of lipid.
Describe 'triglycerides'. Give 2 general examples.
- made from 3 fatty acids and 1 glycerol by condensation reactions so they have 3 hydrocarbon tales
- fats and oils
- 2 fatty acid tails linked to glycerol, with a phosphate group instead of the third fatty acid
- phospholipids are partly hydrophobic and form the basis of membranes
Describe 'steroids'. Give 4 examples of steroids.
- all types of steroids have similar structure
- 4 fused rings in their molecule
- cholesterol, progesterone, estrogen, testosterone
How can molecules be identified as lipids?
- if they have 2 or 3 hydrocarbon chains
- if they have the quadruple ring structure (steroids)
Draw a molecular structure of a glycerol molecule. (p22)
How are hydrocarbon chains often shown in molecular diagrams?
as a zigzag line (see p22)
How are rings of carbon atoms often shown in molecular diagrams?
hexagons or pentagons (see p22)
Draw the molecular structure of a triglyceride. (p22)
Draw the molecular structure of a phospholipid. (p22)
Draw the molecular structure of a testosterone (p22).
How many parts to a fatty acid are there? What are they?
- two parts
- carboxyl group (acid) and an unbranched hydrocarbon chain (fatty)
Draw a molecular diagram of a carboxyl group. Draw a molecular diagram of a hydrocarbon chain. (p22)
What is the fast way of showing the molecular structure of a hydrocarbon chain?
- CH2 - (CH2)n - CH3
What two factors vary in a chain of hydrocarbons?
- the number of carbon atoms in the hydrocarbon chain
- the bonding of the carbon atoms to each other and to hydrogens
What does 'saturated' mean when talking about fatty acids?
all carbon atoms in the chain are connected by single covalent bonds = the number of hydrogen atoms bonded to the carbons cannot be increased
What does 'unsaturated' mean when talking about fatty acids?
contain one or more double bonds between carbon atoms in the hydrocarbon chain = more hydrogen could be bonded to the carbons if a double bond was replaced by a single bond
Draw an unsaturated fatty acid. (p22)
What does 'monounsaturated' mean when talking about fatty acids?
only one double bond (between carbon atoms in hydrocarbon chain)
What does 'polyunsaturated' mean when talking about fatty acids?
two or more double bonds (between carbon atoms in hydrocarbon chain)
What does the position of the nearest double bond to the the CH3 terminal determine?
- third bond from terminal = omega-3 fatty acid
- sixth bond from terminal = omega-6 fatty acid
What does 'cis unsaturated' mean when talking about fatty acids?
hydrogen atoms are bonded to carbon atoms on the same side of a double bond