Which of the following is not a classified form of conjugated proteins?
(a) Lipoproteins
(b) Glycoproteins
(c) Metalloproteins
(d) Complete proteins
Sol: (d) Complete proteins
A. Lipoproteins
Lipoproteins are complex particles that transport fats (lipids) throughout the body in the bloodstream. They are made up of a combination of proteins, cholesterol, and triglycerides, and are classified based on their density and size.
There are several different types of lipoproteins, including:
- Low-density lipoprotein (LDL) – often referred to as “bad” cholesterol, LDL is responsible for transporting cholesterol from the liver to the rest of the body. High levels of LDL in the blood can increase the risk of heart disease.
- High-density lipoprotein (HDL) – often referred to as “good” cholesterol, HDL helps to remove excess cholesterol from the body and can lower the risk of heart disease.
- Very low-density lipoprotein (VLDL) – VLDL is responsible for transporting triglycerides from the liver to the rest of the body.
Lipoproteins are important for maintaining the balance of lipids in the body and for maintaining overall health. However, imbalances in lipoprotein levels can increase the risk of various health problems, including heart disease, stroke, and diabetes.
B. Glycoproteins
Glycoproteins are a type of protein that contains one or more carbohydrate groups attached to the protein molecule. These carbohydrate groups, also known as glycans, are composed of simple sugars such as glucose, galactose, and mannose. Glycoproteins are found in many tissues and bodily fluids, including blood, urine, and mucus. They play a variety of roles in the body, including structural support, signaling, and immune defense.
Glycoproteins are synthesized in cells by the addition of glycans to proteins. This process is called glycosylation and is important for the proper folding and function of proteins. Glycoproteins are classified based on the type of glycans they contain, the number of glycans per protein, and the position of the glycans on the protein.
There are several different types of glycoproteins, including mucins, lectins, and antibodies. Mucins are a type of glycoprotein found in mucus and other secretions. They help to lubricate and protect surfaces such as the lining of the respiratory and digestive tracts. Lectins are glycoproteins that bind to specific sugars and are involved in cell recognition and adhesion. Antibodies, also known as immunoglobulins, are glycoproteins produced by the immune system to recognize and neutralize foreign substances such as viruses and bacteria.
Glycoproteins are important for many physiological processes in the body and have been the subject of much scientific research. They have been studied for their roles in cancer, diabetes, and other diseases, as well as their potential use as therapeutics and diagnostic agents.
C. Metalloproteins
Metalloproteins are proteins that contain one or more metal ions as part of their structure. The metal ions can be either essential for the protein’s function or play a structural role. Metalloproteins are found in all domains of life and perform a wide variety of functions, including catalyzing chemical reactions, transporting ions and molecules, and binding and releasing ligands.
There are several types of metalloproteins, including metalloenzymes, which use metal ions as catalysts to carry out chemical reactions, and metallochaperones, which help transport metal ions within cells. Some examples of metalloproteins include hemoglobin, which transports oxygen in the blood; cytochrome c, which is involved in the production of energy in cells; and superoxide dismutase, which helps protect cells from oxidative damage.
The metal ions in metalloproteins can be either inorganic or organic. Inorganic metal ions, such as iron, zinc, and copper, are more common in metalloproteins, while organic metal ions, such as cobalt, are less common. The metal ions in metalloproteins can also be bound to the protein through various coordination bonds, such as covalent bonds or ionic bonds. The type and number of bonds that form between the metal ions and the protein can affect the stability and function of the metalloprotein.
D. Complete proteins
Complete proteins are proteins that contain all nine essential amino acids in adequate amounts. Essential amino acids are amino acids that the body cannot synthesize on its own and must be obtained from the diet. They are called “essential” because they are essential for human health and must be obtained from the diet.
There are 20 amino acids that are used by the body to build proteins, and nine of them are considered essential because the body cannot make them from other amino acids. These nine essential amino acids are: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine.
Complete proteins are typically found in animal-derived foods, such as meat, poultry, fish, eggs, and dairy products. Some plant-based sources of complete proteins include quinoa, soy, and hemp. It is possible to get all of the essential amino acids from a plant-based diet, but it may require careful planning and a variety of foods to ensure that all of the essential amino acids are consumed.