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What are Proteins?

Tip: This isn't the place to ask a question because the teacher can't reply.

Key Questions

  • Proteins are astonishing nutrients because they are so fundamental to our very architecture as humans. Our cells and organs, our muscles, our connective tissue, and even our bones could not hold together as the key body parts they are without the help of protein. This importance of protein to our very structure is only one function played by proteins, however. Proteins are equally important to our metabolism because all enzymes in our body that help trigger chemical reactions are proteins. Many of our most important regulatory hormones , like insulin, are also proteins. So are many of the key molecules in our immune system as are the major molecules used to carry nutrients around our body. Whether they are structural proteins, immunoproteins, hormonal proteins, transport proteins, or enzymes, proteins are of utmost importance to our health. The importance of protein to our life is reflected in the term itself: protein is derived from the Greek term protos, which means "taking first place."

    Proteins are made up of smaller molecules called amino acids that are strung together by chemical bonds like beads on a chain. To become an active, functional protein, this string of amino acids folds in on itself forming a twisted and entwined three-dimensional structure. Proteins come in many sizes . Some chains of amino acids are quite small, like the hormone insulin that is only 51 amino acids long. Most proteins, however, are larger. Most of proteins in your body contain between 200-400 amino acids.

  • Answer:

    There are only 20 in total used by humans, although there are many other types that different organisms use.


    Alanine - ala - A
    Arginine - arg - R
    Asparagine - asn - N
    Aspartic acid - asp - D
    Cysteine - cys - C (Only amino acid with a Sulfur atom)
    Glutamic acid - glu - E (Amino acid that codes of normal RBCs)
    Glycine - gly - G
    Histidine - his - H
    Isoleucine - ile - I
    Leucine - leu - L
    Lysine - lys - K
    Methionine - met - M (First amino acid to be produced at ribosome)
    Phenylalanine - phe - F
    Proline - pro - P
    Serine - ser - S
    Threonine - thr - T
    Tryptophan - trp - W
    Tyrosine - tyr - Y
    Valine - val - V (Amino acid that codes for sickle-cell anemia)

    There are two types of amino acids: right-handed and left-handed amino acids. They are isomers of each other. In general, only left-handed amino acids are used.

    Essential amino acids are those that the body cannot produce by itself, so it needs to consume those molecules from food to fulfill the requirement. The nine essential amino acids are histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine

    Credits: My Biology Textbook for AS and A Levels.

  • Proteins are hetero/homo polymers of specific amino acid sequences which then turned, twisted, or condensed in quaternery structure called proteins.

    Proteins play a vital role in any organism without which life on earth wouldn't be possible.

    There are majorly two types of proteins based on it's function:
    1 Structural proteins ;
    2 Functional proteins .

    Proteins situated in phospholipid bilayer called intergral/ transmembrane proteins are structural proteins.

    While functional proteins/enzymes like trypsin, peptidase, kinase etc. catalyses the reactions & maintain the metabolic activity.

    Also structural proteins like keratin can be found in nails & hairs which has a protection role.

    All enzymes are functional proteins.
    Even some amino acid derived hormones are proteins & are vital in lesser concentration.

    Also some proteins are coenzymes for specific enzymes.
    Some proteins are regulatory enzymes which controls the metabolic activity.

    Proteins located on the cell membrane have specific receptors for cell signaling & respond to external stimuli.

    Also our defence mechanism is also made of proteins like IgG, IgM etc.
    Also humoral defence possess proteins like interferons.

    Also there are transport proteins which transports compounds or organelles in & out cell.

    There would have been no life sans proteins.