Differences Between Carbohydrates, Proteins and Fats (Lipids)

Carbohydrates, proteins, and fats are the three macronutrients that the body needs for energy and to maintain its structure and systems.

Carbohydrates comprise carbon, hydrogen, and oxygen in a ratio of roughly one carbon atom to one water molecule. They are the body's primary source of energy and are broken down into glucose, which is used by cells for energy.

Proteins are made up of amino acids, which are the building blocks of all tissues in the body. They are essential for growth and repair of tissues, as well as for the immune system, hormones, enzymes, and transport.

Fats are made up of carbon, hydrogen, and oxygen atoms. The body uses them as a secondary source of energy, and they also help in the absorption of vitamins and minerals.

The body needs a balance of carbohydrates, proteins, and fats to function properly. The amount of each macronutrient that the body needs varies depending on age, sex, activity level, and overall health.

Carbohydrates

1. Carbohydrates are the primary products of photosynthesis. They are the most important energy-providing substrates for animals.
2. Most carbohydrates contain only three elements, viz., carbon, hydrogen, and oxygen.
3. The simplest carbohydrates are monosaccharides. This may be hexose, pentose or triose sugars.
4. Hexose sugars are mainly three isomers namely glucose, fructose, and galactose.
5. Pentose sugars are mainly ribose and deoxyribose sugars in RNA and DNA.
6. Triose sugars are formed during metabolism like glyceraldehyde.
7. Three common disaccharides are: Maltose (Glucose + glucose), Sucrose (Glucose + Fructose) and Lactose (Glucose + Galactose)
8. Sucrose is the cane sugar found in sugarcane. Sucrose does not reduce Cu⁺⁺ to Cu⁺.
9. Maltose or malt sugar is formed during the germination of starch seeds.
10. Lactose or milk sugar is found in milk.
11. Compared to cows, buffalo, and goats, lactose is highest in human milk.
12. Starch common in plants and glycogen in animals are two food storage polysaccharides.
13. Starch is abundant in rice, wheat, legumes, potato, and bananas.
14. Our food mainly contains carbohydrates.
15. Rice and potato are good sources of carbohydrates.

Proteins

1. Proteins are among the most important macromolecules of organisms.
2. After water, proteins form the major (14%) part of living protoplasm. Of the dry weight of protoplasm, 75% is the protein.
3. Proteins are very complex organic molecules containing carbon, hydrogen, oxygen, and nitrogen and less commonly sulfur, phosphorus, iodine, and iron.
4. The term 'Protein' was coined by Berzelium and Mulder.
5. Fischer and Hofmeister discovered that on complete hydrolysis all protein molecules break down into simpler amino acids.
6. The basic unit or smallest structural units of proteins are called amino acids. Amino acids are linked together in a long chain to form protein.
7. The anhydrobiosis of proteins is called peptide bonds. A peptide bond is formed between the carboxyl group of one amino acid and the amino group of adjacent.
8. Proteins in our body may be circulated in the form of amino acids. The excess amino acids cannot be stored in the body.
9. Although about 300 amino acids occur in nature, only 20 of these enter into the composition of proteins.
10. Amino acids that cannot be synthesized in the body are called essential.
11. Essential amino acids are those which are taken from food, not synthesized in the body.
12. Other amino acids may be synthesized in the body, particularly from carbohydrate metabolites. They need not be supplied in the diet and are called non-essential or dispensable amino acids.
13. Proteins that contain most of the essential amino acids are termed first class, while those that do not, are called second class.
14. Animal proteins are mostly first class and plant proteins are second class proteins.
15. Casein is a protein that forms part of the food for the young animal. The best source of casein is milk.
16. Many children in our country suffer from malnutrition, a protein deficiency disease known as Kwashiorkor disease. This can be prevented by giving food rich in protein.
17. A person suffering from Kwashiorkor should have more meat, butter, milk, and eggs in his diet.
18. Glutelins are large globular proteins present in wheat or rice.
19. Haemoglobin and cytochromes are two chromoproteins.

Fats (Lipids)

1. Fats are esters of fatty acids with glycerol.
2. Each molecule of glycerol can react with three molecules of fatty acids.
3. Depending on the number of fatty acids that are attached to the glycerol molecule, the esters are called mono-, di- or triglycerides.
4. Fats that are generally liquid at room temperature are called oils.
5. Fatty acids most commonly involved in fat formation are Palmitic, stearic, and oleic acids.
6. Fatty acids are called saturated if they do not have any double bond between the carbons of molecular chains, eg., palmitic acid (16C) and stearic acid (18C)
7. Unsaturated fatty acids have one or more double bonds between the carbons of the chain, eg., oleic acid with one double bond.
8. Essential fatty acids are polyunsaturated fatty acids (with more than one double bond) that cannot be synthesized in the animal body and must be supplied with food to avoid their deficiency.
9. Linoleic, linolenic and arachidonic acids are essential fatty acids for man.
10. Excess intake of saturated fats like butter, ghee, and hydrogenated vegetable fats enhances blood cholesterol.
11. High amounts of fats, particularly saturated fats, and cholesterol should be avoided by sedentary, old, or obese persons and patients of heart disorders and high blood pressure.
12. Too much use of fats should be avoided during the summer months.
13. Fat yields twice as many calories per gram as carbohydrates.
14. Fats are richly found in adipose tissues.
15. Obesity can be controlled by reducing the intake of calories from fats and carbohydrates.