Lecture 5: Lipids Flashcards
What are three general characteristics of lipid molecules?
large
Structurally and functionally diverse
Hydrophobic (or at least partially)
List 3 classes of lipids.
1) phospholipids
2) triglycerides
3) steroids
Give 7 specific functions of lipids.
- Form biological membranes.
- Store chemical energy. (long term)
- Insulates the body and cushion vital organs.
- Act as signalling molecules. (ex signalling hormones)
- Aid in diverse processes in cells.
- Capture light energy.
- Water proofing body structures. (ex waxy cuticles of plants)
What are hydrocarbons?
organic molecules consisting of only C and H.
What makes lipids largely nonpolar and hydrophobic?
because of their major hydrocarbon component
Why are hydrocarbons hydrophobic and contain high energy? What type of energy are we talking about?
They contain high chemical energy because of the non polar bonds. (C-H & C-C)
the electrons are “on top of the hill”
Name the 7 type of lipids found in cells.
A. Fats
B. Phospholipids
C. Steroids
D. Glycolipids
E. Waxes
F. Vitamins
G. Photosynthetic Pigments
Fats:
1. How do they form?
2. Structure?
3. name three functions of fat in animals
4. Where do we find fat in animals?
5. II in plants, in what form?
- via dehydration reactions
2.fats consist of glycerol linked by ester linkages to three fatty acids - long term energy storage, insulation, protection (cushion and chemical barrier for vital organs)
- in adipocytes (fat cells) -> these cells (adipose cells) form up adipose tissues (fat storage)
- Rarely contain fats but more in the form of oils. Found in seeds (mostly), fruits and flower
Why is oil in plants mostly found in seeds?
Because it is where the nutrients are stored in a compact form to produce offsprings
Saturated vs Unsaturated fats
- composition
- structure
- solid or liquid at room temp
- structural formula of one fatty acid
Saturated fats are composed of saturated fatty acids.
Unsaturated fats are composed of unsaturated fatty acids. (at least one fatty acid is unsaturated)
What does saturation of fatty acids mean? What creates unsaturation?
Saturation of a fatty acid has to do with the number of H atoms bound to the carbon chain.
A. A saturated fatty acid is saturated (filled completely) with H.
B. An unsaturated fatty acid is NOT saturated with H.
Double bonds within the chain create unsaturated fatty acids.
Why do saturated fats contain more chemical energy than unsaturated fats?
more C-H bonds (store more energy)
Phospholipids:
- structure
- one most important function?
- another function
amphipatric -> formation of membranes
They are also involved in cell communication (cell signaling pathways).
Steroids:
- Structure
- three specific functions
- specific steroid for each function
What is another important function of cholesterol other than being a component of cell membrane?
precursor for:
1) steroid hormones
2) bile acids
Give a simple overview of:
1) glycolipids
2) waxes
3) lipid vitamins
4) photosynthetic pigments
What are biological membranes?
The plasma membrane and the cell’s internal compartments
What are biological membranes made of?
organelles
mitochondria
How do lipids travel around the body?
Lipids do not dissolve in the blood and are transported around the body as part of lipoprotein particles.
How do you identify lipoprotein particles?
based on their densities and diameters.
What is known as “bad cholesterol”?
Low-density lipoprotein (LDL)
What is known as “good cholesterol”?
High-density lipoprotein (HDL)
Role of HDL versus RDL
- LDL transports lipids from the liver to the rest of the body.
- HDL particles clears the blood by transporting lipids from cells back to the liver.
To what disease have High LDL been linked to?
cardiovascular disease such as atherosclerosis
Which type of diet raises LDL levels? What influences high LDL levels?
- A diet rich in saturated or trans fats can raise LDL levels.
- High LDL is not really influenced by the cholesterol in your diet but from the types of fats that you eat.
Why is the term Bad Cholesterol misleading?
Too much can cause plaques and blood clots which lead to strokes (no oxygen blood to brain) and heart attacks (no oxygen blood to heart)
What health benefits has been linked to high HDL?
protection from atherosclerosis.
How can you raise HDL levels?
An increase in unsaturated fats in your diet and other dietary/lifestyle changes
