Lipids Flashcards
Properties of Lipids
- Made up primarily of carbon, hydrogen and oxygen
- Lipids are hydrophobic
Why are lipids hydrophobic?
- They contain more relatively non-polar C-H bonds in comparison to O-H bonds which tend to be more polar
Functions of Lipids
- Energy storage in organisms
- Make up membrane structures
- They are chemical messengers
Classification of Lipids
- Fats
- Phospholipids
- Steroids
- Waxes
What are fats main function?
- Major storage depot for energy in the form of adipose tissues in many heterotrophs
What are fats made up of?
- Glycerol
- one, two, or three fatty acids
What is kJ?
Units for energy
How much energy storage does 1 gram of fat have?
38 kJ energy storage capacity in bonds
Saturated Fatty Acid
- number of carbons varies
- max number of hydrogens in the structure
Unsaturated Fatty Acid
- number of carbons varies
- hydrogen numbers are not maximized
- double bonds are made between carbon
What type of fat is healthier saturated or unsaturated?
Unsaturated fats
What is the linkage between a glycerol and a saturated fatty acid called?
An “ester linkage”
Reality of unsaturated fatty acids..
The molecule would appear bent wherever there are double bonds
Application of saturated fatty acids
- They contain many van Der Waals attractions between molecules
- This accounts for a straight condensed shape which allows saturated fatty acids to be solid at room temp
Example of a saturated fat
- animal fats such as lard
Application of unsaturated & polyunsaturated fatty acids
- Contain many double bonds which cause the molecules to fold up, therefore allowing fewer van Der Waals forces
- Accounts for the fact that unsaturated fats are usually liquid at room temp
Example of an unsaturated fat
vegetable oils
What is industrial hydrogenation
- Unsaturated fats can be covered into saturated or partially saturated fats by this process
What do phospholipids consist of?
- one glycerol
- 2 fatty acids
- one phosphate group
- made up of a polar head and two non-polar tails
What does amphipathic mean?
Polar and non-polar
What does the amphipathic nature of phospholipids cause?
It forms a bilayer or a single-layer micelle spontaneously in water
Phospholipid bilayers
- Phospholipids group together to form doubled-up sheets of phospholipids
Example of phospholipid bilayers
- The cell membrane and membrane-bound cell organelles
- These are semi-permeable structures that allow some substance to travel through them
Micelles
- single layers of phospholipids
- ex: soap bubbles
Vesicles
- made up of phospholipid bilayers
- Tiny transport bubbles found in cells
Steroid Functions
- Chemical messengers
- Important component of cell membranes
What are steroids?
- Compact hydrophobic molecules
- Made up of 4 hydrocarbon rings joined together, along with variable functional groups
Steroid molecular shape
- 3 hexagons
- 1 pentagon
- variable side groups
Cholesterol (steroid)
- Responsible for cell membrane structural integrity
- Too much in body is associated with atherosclerosis (caused by liver imbalance)
Male Hormone
testosterone (steroids)
Female Hormone
Estrogen (steroids)
Progesterone (steroids)
Androgenous hormone
Waxes molecular shape
- Lipids with long fatty acids attached with alcohols or carbon rings
Functions of waxes
- Used by plants as a waxy, protective coating on leaves and stems
- Ear wax in mammals
How to determine a trans fat by its molecular appearance?
- When the H’s are on opposite sides of an unsaturated fat they become a trans fat
