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Shared characteristic of all lipids
- water insoluble
- high energy content (more than carbohydrates)
- main component of cell membranes
why are lipids not considered macromolecules but are still part of the essential biomolecules?
- lipids are distinct biomolecules because of its interactions with water
- not considered a macromolecule because it is not a polymer (not made up of repeating units)
some lipid functions
how are lipids used as insulation?
fat deposits that surround the vital organs protects as well as helps prevent heat loss.
types of lipids
- fatty acids
Steroid carbon skeletons
4 infused rings, and differ in chemical groups
an example of steroids
What are fatty acids composed of and describe the functional groups
- fatty acids are long hydrocarbon chains with a carboxylic acid group attached at the end.
- The hydrocarbon chain is nonpolar, therefore hydrophobic.
describe the phospholipid structure, chemical groups, and function.
- Phospholipids are made up of two fatty acids, attached to a glycerol, with a phosphate head, and a choline attached.
- Head: phosphate group + choline + glycerol
- Tail: 2 fatty acid (1 saturated and 1 unsaturated)
- amphiphatic: having a hydrophilic (head) and hydrophobic (tails) end,
- phospholipids form the basis for cell membranes, creating a phospholipid bilayer. Forms spontaneously, without requiring energy
Fatty acids tend to form what kind of structure
- fatty acids form micelles, which are spheres made up of a single layer of amphiphatic molecules. The tails are facing inwards and the polar end face outward toward the water.
- Aids in digesting of fat soluble vitamins, fatty acids, cholesterol
Steroids include what?
a type of lipid that includes sex hormones and cholesterol
Steroids have 4 infused carbon rings.
Importance of cholesterol and where is it located
Cholesterol is found in the cell membrane of animal cells, produced by the liver. They are the bases for steroid hormones.
What are LDL and HDL and how do they impact human health?
- LDL (low density lipoprotein): "bad cholesterol" high levels of LDL are associated with increased risk of atherosclerosis (thickening of arteries). They act as carrier molecules, by transporting cholesterol into the blood stream
- HDL (high density lipoprotein): "good cholesterol", transports cholesterol from cells to the liver where it is converted into bile salts and eliminated. High levels aid in decreased risk of cardiovascular disease.
What are lipoproteins?
molecules made up of lipids and proteins, they aid in transporting steroids throughout the bloodstream. Their hydrophilic exteriors allows them to move through the aqueous blood environment
What is it about the chemical bonds of fat and water molecules that prevents them from mixing well?
fats are composed of non polar components, making them insoluble when placed in water.
Why does a phospholipid bilayer naturally form when phospholipids are placed in water?
The phosphate end of the phospholipid is polar and is naturally attracted to water. The fatty aid tails are nonpolar and repel water. When the phospholipid is placed in water, they align in a way so that the nonpolar fatty acids are touching leaving the polar phospholipid head exposed to water. The resulting structure spontaneously forms.
Fat is a another name for
The structure of a triclyglycerol
- the glycerol is attached to 3 fatty acids, usually 16-18 carbons long
- The bond between the glycerol and fatty acid is ester linkage
what are the two types of fatty acids
- saturated: all C atoms have H bonded to it. tends to be solid at room temperature.
- unsaturated: a lipid with one or more double bonds (cis-bond). tends to be liquid at room temperature
What are trans fats, how does it form, where is it found, and what impact does it have on the human health?
- unsaturated fatty acids with a trans-bond rather than a cis bond.
- Not naturally found in nature, produced by hydrogenation which reduces the number of double bonds.
- The structure is straight, similar to a saturated fatty acid.
- They are produced to increase the shelf life of certain foods, and are semi-solid at room temperature.
- High intake of trans fats increases LDL levels and lowers HDL levels which are associated with heart disease
How is can the structure of fat molecules relate to the function of energy storage?
because lipids produce twice as much energy as carbohydrates like starch, they serve as the ideal biological molecules to store large amounts of energy for the long term.
what is an adipose tissue?
fat storing cells, they must be replenished by fat molecules.
What is LDL
- LDL is short for low density lipoproteins, they act as carrier molecules that transport cholesterol throughout the bloodstream.
- "bad cholesterol"
What is the impact of LDL on human health?
- LDL transfers cholesterol from the liver to body.
- a high concentration of LDL would lead to increased risk of atherosclerosis, the thickening of the arteries.
What is HDL?
- HDL is short for high density lipoproteins, and act as carrier molecules that transport cholesterol throughout the blood stream
- "good cholesterol"
What is the impact of HDL on human health?
- HDL transfers cholesterol from the body to the liver
- high concentrations of HDL has been shown to decrease the risk of heart disease
- anti inflammatory properties
- They allow the body control amount of cholesterol by carrier them to the liver where it is converted to bile and is then eliminated.
When animals use the energy stored in fats, what gets depleted the adipose cells or fat molecules?
What are the two essential fatty acids that humans cannot produce?
omega -3 and omega 6
What is the impact and function of Omega 3 and Omega 6 on human health?
They are found in fish and leafy vegetables, and are necessary raw material for other biomolecules
What is the function of triaclyglycerols and where is it stored?
- Triaclyglycerols circulate within the human bloodstream within lipoproteins
- When the body needs energy they are broken down to release fatty acids.
- They are stored within adipose cells
How do lipids help animals hibernate?
Lipids are compact and energy rich molecules. During hibernation, animals are in a state of inactivity and serve as energy sources when food is scarce during the winter, allowing animals to sustain biological functions.