Proteins are an essential part of our diet, and they play a vital role in many of the body's functions. They are made up of amino acids, which are small molecules that can be linked together to form long chains. There are 20 different amino acids that can be used to create proteins, and the sequence of these amino acids determines the structure and function of the protein.
Proteins can be classified into two main types: structural proteins and functional proteins. Structural proteins provide support and shape to cells and tissues, while functional proteins carry out various functions in the body, such as metabolism, cell signalling, and muscle contraction.
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In this article, we will take a closer look at the structure and function of proteins, and explore the different ways in which they are used in the body.
what are proteins made of
Proteins are essential molecules found in all living organisms.
- Building blocks: amino acids
- 20 different types of amino acids
- Sequence determines structure
- Two main types: structural and functional
- Structural: support and shape
- Functional: carry out body functions
- Essential for life
Proteins are involved in a wide range of biological processes, including metabolism, growth, and repair.
Building blocks: amino acids
Proteins are made up of smaller molecules called amino acids. There are 20 different types of amino acids that can be used to create proteins, and the sequence of these amino acids determines the structure and function of the protein.
Amino acids have a basic structure that consists of a central carbon atom bonded to an amino group, a carboxyl group, a hydrogen atom, and a side chain. The side chain is what distinguishes one amino acid from another. Side chains can be different sizes, shapes, and charges, which gives amino acids their unique properties.
Amino acids are linked together by peptide bonds to form long chains called polypeptide chains. These polypeptide chains can fold and twist into complex shapes, creating the different structures of proteins. The structure of a protein is essential for its function, as it determines how the protein interacts with other molecules.
Proteins are essential for life. They are involved in a wide range of biological processes, including metabolism, growth, and repair. They also play a role in cell signalling, immune function, and muscle contraction.
Proteins are obtained from the foods we eat. When we eat protein-rich foods, the proteins are broken down into amino acids in our digestive system. These amino acids are then absorbed into our bloodstream and used to build new proteins or repair damaged ones.
20 different types of amino acids
There are 20 different types of amino acids that are used to create proteins. These amino acids can be divided into two groups: essential amino acids and nonessential amino acids.
Essential amino acids cannot be made by the body, so they must be obtained from the foods we eat. The essential amino acids are:
- Histidine
- Isoleucine
- Leucine
- Lysine
- Methionine
- Phenylalanine
- Threonine
- Tryptophan
- Valine
Nonessential amino acids can be made by the body, so they do not need to be obtained from the foods we eat. However, they are still important for health and play a role in many bodily functions. The nonessential amino acids are:
- Alanine
- Arginine
- Asparagine
- Aspartic acid
- Cysteine
- Glutamic acid
- Glutamine
- Glycine
- Proline
- Serine
- Tyrosine
All 20 amino acids are important for health, and a deficiency in any one amino acid can lead to health problems. Eating a healthy diet that includes a variety of protein-rich foods is the best way to ensure that you are getting all of the amino acids that your body needs.
Amino acids are also classified as either polar or nonpolar. Polar amino acids have side chains that are attracted to water, while nonpolar amino acids have side chains that are repelled by water. This difference in polarity affects the structure and function of proteins.
Sequence determines structure
The sequence of amino acids in a protein determines its structure. This is because the side chains of amino acids interact with each other in specific ways, causing the protein to fold into a unique shape.
- Primary structure
The primary structure of a protein is the sequence of amino acids. This is the most basic level of protein structure.
- Secondary structure
The secondary structure of a protein is the way in which the polypeptide chain folds into a regular pattern. The most common secondary structures are alpha helices and beta sheets.
- Tertiary structure
The tertiary structure of a protein is the three-dimensional structure of the protein. This is the final, functional form of the protein.
- Quaternary structure
The quaternary structure of a protein is the structure of a protein complex, which is a group of two or more proteins that function together. Not all proteins have a quaternary structure.
The structure of a protein is essential for its function. For example, the active site of an enzyme is a specific region of the protein that is responsible for its catalytic activity. The structure of the active site is determined by the sequence of amino acids in the protein.
Two main types: structural and functional
Proteins can be divided into two main types: structural proteins and functional proteins.
- Structural proteins
Structural proteins provide support and shape to cells and tissues. They are typically fibrous proteins, which means that they are made up of long, coiled polypeptide chains. Examples of structural proteins include collagen, keratin, and elastin.
- Functional proteins
Functional proteins carry out various functions in the body, such as metabolism, cell signalling, and muscle contraction. They are typically globular proteins, which means that they are folded into a compact, spherical shape. Examples of functional proteins include enzymes, hormones, and antibodies.
Both structural proteins and functional proteins are essential for life. Structural proteins provide the scaffolding that holds cells and tissues together, while functional proteins carry out the chemical reactions that keep us alive.
Structural: support and shape
Structural proteins provide support and shape to cells and tissues. They are typically fibrous proteins, which means that they are made up of long, coiled polypeptide chains. These polypeptide chains can line up side by side to form strong, rope-like structures.
- Collagen
Collagen is the most abundant protein in the body. It is found in skin, bones, tendons, and ligaments. Collagen provides strength and flexibility to these tissues.
- Keratin
Keratin is a protein that is found in hair, nails, and skin. It is a tough, water-resistant protein that protects these tissues from damage.
- Elastin
Elastin is a protein that is found in blood vessels, lungs, and skin. It is a stretchy protein that allows these tissues to recoil after being stretched.
- Actin and myosin
Actin and myosin are proteins that are found in muscle tissue. They work together to cause muscle contraction.
Structural proteins are essential for the proper functioning of the body. They provide support and shape to cells and tissues, and they allow these tissues to withstand mechanical stress.
Functional: carry out body functions
Functional proteins carry out a wide range of functions in the body, including metabolism, cell signalling, and muscle contraction. They are typically globular proteins, which means that they are folded into a compact, spherical shape. This shape allows them to interact with other molecules in a specific way.
Some examples of functional proteins include:
- Enzymes: Enzymes are proteins that catalyze chemical reactions in the body. They speed up the rate of reactions that would otherwise be too slow to occur at body temperature.
- Hormones: Hormones are proteins that are produced by glands and travel through the bloodstream to target cells. They regulate a wide range of bodily functions, such as growth, reproduction, and metabolism.
- Antibodies: Antibodies are proteins that are produced by the immune system in response to infection. They bind to antigens, which are foreign substances, and help to destroy them.
- Transport proteins: Transport proteins move molecules across cell membranes. They are essential for the transport of nutrients, waste products, and other molecules into and out of cells.
Functional proteins are essential for life. They carry out the chemical reactions that keep us alive, regulate our bodily functions, and protect us from infection.
Proteins are essential for life. They play a role in almost every biological process, from building and repairing tissues to transporting oxygen and nutrients throughout the body. Without proteins, we would not be able to survive.
Essential for life
Proteins are essential for life. They play a role in almost every biological process, from building and repairing tissues to transporting oxygen and nutrients throughout the body. Without proteins, we would not be able to survive.
- Structural support
Proteins provide structural support to cells and tissues. They are found in the cell membrane, the nucleus, and the cytoplasm. Proteins also help to form muscles, bones, and tendons.
- Enzymes
Proteins are essential for metabolism. They act as enzymes, which are catalysts that speed up chemical reactions in the body. Enzymes are involved in a wide range of processes, including digestion, respiration, and DNA replication.
- Transport
Proteins help to transport molecules across cell membranes. They also transport oxygen and nutrients throughout the body.
- Immune function
Proteins are involved in the immune response. They help to identify and destroy foreign invaders, such as bacteria and viruses.
These are just a few of the many essential roles that proteins play in the body. Without proteins, life would not be possible.