Colour Reactions of Proteins

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Questions and Answers

What type of bonds are involved in the quaternary structure of proteins?

Disulfide bonds

Covalent bonds

Peptide bonds

Hydrogen bonds, hydrophobic interactions, and ionic bonds (correct)

What is the primary function of haemoglobin, an example of an oligomeric protein?

Transportation of oxygen (correct)

Cellular signaling

Storage of amino acids

Regulation of metabolism

What is the classification of proteins based on their composition?

Structural, enzymatic, and transport proteins

Complete, incomplete, and conditional proteins

Simple, conjugated, and derived proteins (correct)

Primary, secondary, and tertiary proteins

Which of the following is an example of a conjugated protein?

Glycoprotein Signup and view all the answers

What is the function of structural proteins?

To provide structure and support to cells and tissues Signup and view all the answers

Which of the following proteins is classified as a complete protein?

Egg albumin Signup and view all the answers

What is the classification of proteins based on their function?

Structural, enzymatic, transport, and hormonal proteins Signup and view all the answers

What is the term for proteins that are obtained by degradation of simple or conjugated proteins?

Derived proteins Signup and view all the answers

What is the purpose of the Biuret reaction in biological solutions?

To detect the presence of proteins in biological solutions Signup and view all the answers

What is the function of Glutathione in preventing oxidation of sulfhydryl groups?

It prevents oxidation of sulfhydryl groups to disulfide groups Signup and view all the answers

What is the role of Glutathione in the transport of amino acids?

It involves in the transport of amino acids in the intestines and kidney tubules via γ-glutamyl cycle Signup and view all the answers

What is the function of Tryotropin releasing hormone (TRH)?

It stimulates the pituitary gland to release tyrotropic hormone Signup and view all the answers

What is the function of Angiotensin II?

It has hypertensive effects and stimulates the release of aldosterone Signup and view all the answers

What is the function of Glutathione peroxidase?

It scavenges free radicals and peroxides Signup and view all the answers

What is the function of Enkephalins?

They inhibit the sense of pain in the brain Signup and view all the answers

What is the function of Vasopressin?

It stimulates water retention by the kidneys Signup and view all the answers

What percentage of cellular dry weight do proteins make up?

50% Signup and view all the answers

What is the origin of the word 'protein'?

From the Greek word 'proteios', meaning holding first place Signup and view all the answers

What is the primary function of clotting factor proteins?

Blood clotting Signup and view all the answers

What is the name of the Swedish chemist who suggested the name 'proteins'?

Berzelius Signup and view all the answers

What are the five major elements that make up proteins?

Carbon, Oxygen, Nitrogen, Hydrogen, Sulfur Signup and view all the answers

What is the term for the classification of proteins based on their structures?

Primary, secondary, tertiary, and quaternary structure Signup and view all the answers

What is the role of enzymes in the body?

To catalyze biochemical reactions Signup and view all the answers

What is the term for proteins that provide structural support and strength to cells?

Structural proteins Signup and view all the answers

Study Notes

Colour Reactions of Proteins

Biuret reaction is a common method to detect proteins in biological solutions, producing a purple colour when biuret is treated with dilute copper sulphate in an alkaline medium.

Biologically Important Peptides

Glutathione is a coenzyme for certain enzymes, prevents oxidation of sulfhydryl groups of proteins, participates in the formation of correct disulfide bonds in proteins, and maintains RBC membrane structure and integrity.
Glutathione also protects haemoglobin from oxidation, is involved in the transport of amino acids, and participates in detoxification processes.
Other biologically important peptides include:
- Tryotropin releasing hormone (TRH), produced in the hypothalamus, stimulates the pituitary gland to release thyrotropic hormone.
- Oxytocin, secreted by the posterior pituitary gland, is involved in uterine contraction.
- Vasopressin, produced by the posterior pituitary gland, stimulates water retention by the kidneys.
- Enkephalins, also known as encephalins, inhibit the sense of pain in the brain.
- Angiotensins, Angiotensin II has hypertensive effects and stimulates the release of aldosterone from the adrenal glands.

Proteins, Peptides & Amino Acids

Proteins are the most abundant organic molecules in living systems, making up 50% of cellular dry weight.
They are composed of 20 amino acids, organized into primary, secondary, tertiary, and quaternary structure.

Origin of the Word "Protein"

The word "protein" comes from the Greek word "proteios", meaning "holding first place".
It was first suggested by Swedish chemist Berzelius and later used by Dutch chemist Mulder.

Functions of Proteins

Proteins have both dynamic and static functions, including:
- Clotting factors
- Respiration
- Enzymes
- Hormones
- Genetic control
- Muscle contraction
- Storage

Classification of Proteins

Proteins can be classified based on their:
- Solubility and composition
- Function
- Shape and size
They are mainly classified into three major groups:
- Simple proteins (e.g. albumins, globulins)
- Conjugated proteins (e.g. glycoproteins, nucleoproteins)
- Derived proteins (e.g. fibrin, coagulated albumin)
Proteins can also be classified based on their function, including:
- Structural proteins
- Enzymes or catalytic proteins
- Transport proteins
- Hormonal proteins
- Contractile proteins
- Storage proteins
- Genetic proteins
- Defense proteins
- Receptor proteins
Additionally, proteins can be classified based on their nutritional value, including:
- Complete proteins (e.g. egg albumin, milk casein)
- Incomplete proteins

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Description

This quiz covers the colour reactions of proteins, including the Biuret reaction, to identify the nature of amino acids. It also touches on biologically important peptides like Glutathione.