A fatty acid is? What type of fats are they classified as?
a chain of usually 4 to 24 carbon atoms with a carboxyl group at one end and a methyl group at the other. Fatty acids and the fats made from them are classified as saturated or unsaturated.
A saturated fatty acid is?
has as much hydrogen as it can carry. No more could be added without exceeding four covalent bonds per carbon atom; thus it is “saturated” with hydrogen.
unsaturated fatty acids are?
Different to saturated fatty acids as some carbon atoms are joined by double covalent bonds. Each of these could potentially share one pair of electrons with another hydrogen atom instead of the adjacent carbon, so hydrogen could be added to this molecule.
Polyunsaturated fatty acids?
are those with many C=C bonds.
Can fatty acids be synthesised by the human body? Which ones can't?
Yes, most fatty acids can be synthesized by the human body, but a few, called essential fatty acids, must be obtained from the diet because we cannot synthesize them
A three carbon alcohol
A triglyceride is?
a molecule consisting of three fatty acids covalently bonded to a three-carbon alcohol called glycerol.
Once joined to glycerol, a fatty acid can no longer donate a proton to solution and is therefore no longer an acid. For this reason, triglycerides are also called neutral fats. Triglycerides are broken down by hydrolysis reactions, which split each of these bonds apart by the addition of water.
Triglycerides that are liquid at room temperature are also called ______?
A trans fat is?
a triglyceride containing one or more trans-fatty acids. In such fatty acids, there is at least one unsaturated C=C double bond. On each side of the C=C bond, the single covalent C—C bonds angle in opposite directions (trans means “across from”).
they resist enzymatic breakdown in the human body, remain in circulation longer, and have more tendency to deposit in the arteries than saturated and cis-unsaturated fats do. Therefore, they raise the risk of coronary heart disease (CHD).
cis-fatty acids are?
Same as trans fat except that the two C—C bonds adjacent to the C=C bond both angle in the same direction (cis means “on the same side”)
The primary function of fat is?
energy storage, but when concentrated in adipose tissue (body fat), it also provides thermal insulation and acts as a shock-absorbing cushion for vital organs.
similar to neutral fats except that in place of one fatty acid, they have a phosphate group which, in turn, is linked to other functional groups.
What is the dual nature of Phospholipids?
The two fatty acid “tails” of the molecule are hydrophobic, but the phosphate “head” is hydrophilic. Thus, phospholipids are said to be amphiphilic.
Together, the head and the two tails of a phospholipid give it a shape like a clothespin. The most important function of phospholipids is to serve as the structural foundation of cell membranes
Eicosanoids (eye-CO-sah-noyds) are?
are 20-carbon compounds derived from a fatty acid called arachidonic (ah-RACK-ih-DON-ic) acid. They function primarily as hormone like chemical signals between cells.
A steroid is
a lipid with 17 of its carbon atoms arranged in four rings. Cholestorol is a steroid, or the parent steroid from which the other steroids are synthesised.
Cholesterol is the? Name five steroids and explain how they differ
is the “parent” steroid from which the other steroids are synthesized.
The others include;
- bile acids
These differ from each other in the location of C=C bonds within the rings and in the functional groups attached to the rings.
We obtain dietary cholesterol from?
foods of animal origin; plants make only trace amounts of no dietary importance.
The average adult contains how much cholesterol?
200 g of cholesterol.
Cholesterol is a natural product of the body and is necessary for human health. How is it used by the body?
It is an important component of cell membranes and is required for proper nervous system function.
How much cholesterol comes from the diet and how much is internally synthesized? What organ primarily synthesises cholesterol?
Only about 15% of our cholesterol comes from the diet; the other 85% is internally synthesized, primarily by the liver.
Explain “good” and “bad” cholesterol?
Referring to droplets in the blood called lipoproteins, which are a complex of cholesterol, fat, phospholipids, and protein.
So-called bad cholesterol refers to low-density lipoprotein (LDL), which has a high ratio of lipid to protein and contributes to cardiovascular disease.
So-called good cholesterol refers to high-density lipoprotein (HDL), which has a lower ratio of lipid to protein and may help to prevent cardiovascular disease.
Even when food products are advertised as cholesterol-free, they may be high in saturated fat, which stimulates the body to produce more cholesterol.