B1aL7 Cholesterol and Salt

Key Words

Cholesterol - a waxy material made from fats, used as a base for many hormones.

High density lipoproteins (HDL) - carry cholesterol back from the cells to the liver

Low density lipoproteins (LDL) - take cholesterol from the liver to the cells.

Saturated fats - fats that have all single bonds in their hydrocarbon chains.
Heart disease - conditions that cause the heart to fail to pump blood properly.

Lipoprotein - a combination of fat and protein, which enable fats to be carried about by the blood

Plaque - deposits that build up in the arteries

Unsaturated fats - fats that have at least one double bond in the hydrocarbon chain.

Test Yourself

Homework
Chemistry GCSE
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Grade E

Fast food is any food that has been prepared and is ready to eat immediately on purchase.  Street vendors sell fast food the world over.  Not all of this is bad.

However, a lot of fast food is sold in the Western world is not good:

  • It is fried and has a very high fat content;

  • The frying oil tends to be based on trans-fats, which are associated with health problems;

  • The ingredients are cheap and often poor quality;

  • There is a high salt content;

  • Many additives are present.

A few fast food outlets have poor standards of hygiene, and a number have been the source of food poisoning.

Also highly processed food that can be heated up in the microwave to make instant meals can lead to health problems due to high fat, salt, and sugar content, and the presence of additives.

Junk food is even worse; it has little or no nutritional value.

Another problem is that fast food or junk food can be addictive, with it taking much more food for the body to feel satisfied.

 

Grade C

Cholesterol is a waxy material from which many steroid hormones are made.

The picture shows that it is quite a big molecule.  It is made by the liver from fats that have been transported to the liver from either fat cells, or the intestines.  Cholesterol is an essential part of the body's chemistry.  It is insoluble in water, so cannot be carried as it is in the blood.  Instead it is incorporated into lipoproteins, big protein molecules that combine with fatty materials.

The cholesterol is carried from the liver to the cells by low density lipoproteins (LDL).  A high level of LDL is a risk factor for heart attacks, hence LDL are called "bad" lipoproteins.

Cholesterol is carried back from the cells to the liver by high density lipoproteins (HDL).  HDL are referred to as "good" lipoproteins.

Cholesterol can be deposited on the walls of arteries as plaques.  This can harden the arterial walls.   If vital arteries are blocked up, then this can lead to serious problems such as thromboses.  If the artery is in the heart, heart disease can result.  Heart attacks can be treated, but can also be fatal.

Too much salt is also bad for you.  It can cause high blood pressure, which can, in turn, lead to heart attacks.

Grade A

Cholesterol is found in many foods.  Eggs are particularly rich in cholesterol.  If too much is taken in, the levels of LDL tend to be high.  Cholesterol then is deposited on arterial walls.  The liver breaks down cholesterol, and it is released in the bile salts.

The presence of unsaturated fats makes the liver produce more cholesterol to compensate.

A high proportion of HDLs to LDLs is good for a healthy heart.  Monounsaturated and polyunsaturated oils are found in vegetable oils.  These oils help to reduce cholesterol levels in the blood.  They also increase the proportion of HDL to LDL.

However, saturated fats tend to increase the proportion of LDL to HDL.