What are essential and non-essential amino acids? Give two examples of each type.

\\(\text {Essential Amino Acids}:\\) Amino acids which can't be created in our body but can only be received from proper food or diet are called \\(\text {Essential Amino Acids}\\). Examples- Histidine, Isoleucine, Lysine.\\(\text {Non- essential amino acids}:\\) Amino acids which can be created in our body itself are \\(\text {Non- essential amino acids}\\). Examples-alanine, arginine, asparagine, aspartic acid. Examples- Histidine, Isoleucine, Lysine.

Which of the following amino acid is neutral ?

Neutral Amino acids: Glycine, Alanine, leucine, Isoleucine, valine, phenylalanine, Proline, methionine, serine, threonine, tyrosine, cysteine, glutamine, asparagine, tryptophan.Acidic amino acids: Aspartic acid, glutamic acidBasic amino acids: Lysine, histidine, ArginineTherefore, option B is correct

Define the following as related to proteins :(i) Peptide linkage (ii) Primary structure(iii) Denaturation

I) Peptide linkage is the peptide bond formed between the amino acids. It is a covalent bond formed between amino group of one molecule and carboxylic acid group of another molecule.II)The primary structure of a peptide or protein is the linear sequence of its amino acid structural units. The primary structure of a protein is reported starting from the amino-terminal (N) end to the carboxyl-terminal (C) end.(III) The process in which proteins or nucleic acids lose the quaternary structure, tertiary structure and secondary structure which is present in their native state known as denaturation. by application of some external stress or compound such as a strong acid or base, a concentrated inorganic salt, an organic sol.

Recognise the figure and find out the correct matching.

A) Correct option C B) Explanation for the correct option: Figure A shows the secondary structure and B represented the tertiary structure.The secondary structure of the protein, which has hydrogen bonds in addition to the peptide bonds that provide stability to the protein.The tertiary structure is formed when secondary proteins fold more than once.

The melting points and solubility in water of amino acids are generally higher than of corresponding halo acids.

Like ionic compounds, amino acids have a strong electrostatic attraction when present in zwitterion. Because of this, they have a melting point and solubility in higher than the corresponding haloacids.

What is a peptide bond?

A peptide bond is a chemical bond formed between two molecules when the carboxyl group of one molecule reacts with the amino acid group of the other molecule, resulting into the formation of an amide group along with a molecule of water. The reaction is known as dehydration synthesis/ condensation reaction and the resulting \\( CO-NH \\) bond is known as a peptide bond.

Write short notes on: Zwitter ion.

A zwitterion is a molecule that has at least two functional groups: one having a positive charge and the other having a negative charge, with an overall charge of zero. Zwitterions can form from other molecules called ampholytes, or amphoteric compounds and can act as both an acid and a base.Zwitterions are polyelectrolytes that contain both positively and negatively charged groups, and the overall charges are neutral.

Amino acids generally exist in the form of Zwitterions. This means they contain :

Basic \\({-COO}^{-}\\) group and acidic \\(-\overset {+}{N}{H}_{3}\\) groupA zwitterion is a compound with no overall electrical charge, but which contains separate parts which are positively and negatively charged. In aqueous solution, the carboxyl group can lose a proton (becomes basic group) and amino group can accept a proton (becomes acidic) giving rise to the dipolar ion known as Zwitterions.\\(\underset{\text{amino acid}}{{H}_{2}N-CH(R)-COOH} \rightleftharpoons \underset{Zwitterion}{{H}_{3}\overset{+}{N}-CH(R)-{COO}^{-}}\\)

Define peptide linkage.

Peptide linkage is a peptide bond which is formed between two amino acid[- CO- NH-]\\(H_ 2N-CH\boxed { -CO-NH- } -CH_3\\)

Structure of Proteins | Definition, Examples, Diagrams

definition

Proteins

Proteins are highly complex nitrogenous organic compound of very high molecular masses. All proteins are polymers of alpha amino acids.
Example: Glycine, Alanine, Valine etc.

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Classify Proteins on the basis of Molecular structure

1) Fibrous proteins.
2) Globular proteins.

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Definition and example of fibrous proteins

The proteins which consists of linear, thread like polypeptide chains arranged or twisted to form fibers are called fibrous proteins.
Example: Collagen in tendons, myosin in muscles etc.

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Characteristics of fibrous proteins

1) Linear thread like structure.
2) Long chain is held together by hydrogen bond and some disulphide bonds.

definition

Globular proteins

The proteins which consists of polypeptide chains folded in such a way so as to give a spherical shape to the protein molecule are called globular proteins.
All enzymes, several hormones such as insulin etc are example of globular proteins.

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Characteristics of globular proteins

Globular proteins have some following characteristic:
1) Spheroidal shape
2) Interaction forces between different sites in the same polypeptides:
  a) Disulphides bridging
  b) Hydrogen bonding
  c) Van der waals
3) These are soluble in water
4) They are very sensitive to change in temperature and pH

diagram

Denaturation of protein

Proteins when subject to external factors such as heat, alkalies, and several electrolytes, they undergo coagulation to form fibrous proteins which are insoluble in water. This leads to change in physical and biological properties of proteins. This type of proteins are called as denatured and process is called as denaturation.

Structure of Proteins

definition

Proteins

definition

Classify Proteins on the basis of Molecular structure

definition

Definition and example of fibrous proteins

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Characteristics of fibrous proteins

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Globular proteins

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Characteristics of globular proteins

diagram

Denaturation of protein

REVISE WITH CONCEPTS

Amino acids

Quick Summary With Stories

Structure of Proteins-I

Structure of Proteins-II

Native and Denatured Proteins

What are essential and non-essential amino acids? Give two examples of each type.

Which of the following amino acid is neutral ?

Define the following as related to proteins :
(i) Peptide linkage
(ii) Primary structure
(iii) Denaturation

Recognise the figure and find out the correct matching.

The melting points and solubility in water of amino acids are generally higher than of corresponding halo acids.

What is a peptide bond?

Which of the following compounds can form a zwitter ion?

Write short notes on: Zwitter ion.

Amino acids generally exist in the form of Zwitterions. This means they contain :

Define peptide linkage.