Molecular Biology Module 2 Quiz

Molecular Biology

• Molecular Biology is a course taught by Dr. Sherin.
• This course covers essential topics regarding the building blocks of proteins, their structure/properties, protein classification, and functions.
• Also covers various protein structures.
• Includes the study of collagen, elastin, keratin, coagulation factors, immunoglobulins, hormones, and protein structure/function.

Module 2

• Amino acids are the building blocks of proteins.
• Standard amino acid structure is covered.
• Amino acid classification, including essential amino acids, is discussed.
• Zwitterions are mentioned.
• Physical/chemical properties are elaborated.
• Protein diversity, including composition, solubility, nutritive value, conformation, and function are covered.
• Structural organization of proteins (primary, secondary, tertiary, and quaternary structures) is discussed.
• Forces that stabilize protein structures and shape are presented.
• Peptide bond structure and protein denaturation.
• Ramachandran plot is explained.

Proteins

• Proteins are the most abundant organic molecules in living systems.
• Proteins form the foundation of life's structure and function.
• Proteomics is the study of a large collection of proteins.
• Protein functions, both static (structural) and dynamic (enzymatic, hormonal, etc), are covered.
• Examples of structural proteins include collagen, elastin, and keratin.
• Dynamic proteins such as enzymes, hormones, and immunoglobulins.
• Blood clotting factors are also protein-based.

Collagen

• Collagen is the most abundant protein in the human body.
• Found in muscles, skin, tendons, blood vessels, cartilage, and connective tissue.
• Collagen production is influenced by age.
• Glycine, lysine, and proline are important amino acids in collagen's composition.
• Plant-based foods are high in these amino acids.

Elastin

• Elastin is a widely abundant protein in the body.
• Its role is related to flexibility and elasticity.
• Tissues requiring elasticity, like lungs, bladder, and blood vessels contain elastin.
• Proline, glycine, desmosine, and isodesmosine are crucial amino acids in elastin.

Keratin

• Keratin is a protein that forms hair, nails, and skin's outer layer (epidermis).
• It also maintains skin health.
• Various types of keratin function in different parts of the body.
• Examples include hair, skin, nails, claws, and feathers.
• Keratin types I and II are distinct.

Coagulation Factors

• Coagulation factors are proteins in blood, essential for clotting.
• They are crucial for preventing injuries and bleeding.
• Specific factors are listed, such as Fibrinogen, Prothrombin, etc to denote important coagulation factors.

Immunoglobulins/Antibodies

• Immunoglobulins (antibodies) are glycoprotein molecules produced by plasma cells (a type of white blood cell).
• Key role in the immune response and fight against bacteria and viruses.
• Antibodies and Antigens are described, and various Immunoglobulins (e.g., IgG, IgA, IgM, etc) are mentioned.

Hormones

• Hormones are chemical messengers that coordinate various bodily functions.
• Hormones are crucial for maintaining specific body processes like Metabolism, Homeostasis, Growth/Development, Sexual Function, Reproduction, Sleep-wake cycle & Mood.
• Endocrine system's part is explained, with various glands/organs that synthesize hormones.
• Various hormones are listed (e.g., TRH, CRH, etc.).

Elemental Composition of Proteins

• Proteins are composed primarily of carbon, hydrogen, oxygen, nitrogen, and sulfur.
• Specific percentages are given for each element.
• Kjeldahl's method is used to quantify proteins.

Structure of Amino Acids

• The diagram shows the general structure of amino acids and the different aspects of each amino acid's composition.
• Twenty common amino acids are discussed.
• The importance/role/optical activity of each amino acid is detailed.

Zwitterionic Property

• Zwitterion describes the neutral charge on amino acids.
• The pH at which a molecule exists as a zwitterion is called isoelectric point.

Physical properties of Amino Acids

• Amino acids are typically colorless, crystalline solids.
• They can taste sweet, tasteless or bitter.
• They have high melting points and varying solubility (in water and alcohol).
• The R-group, along with solvent pH, plays a role in solubility.

Chemical Properties of Amino Acids

• Reaction due to the carboxyl group (-COOH): Esters formation with alcohols, salt formation with bases
• Amino acids react to form amines through decarboxylation.
• Important biochemically active amines (histamine, tyramine, GABA) are referenced.

Reaction due to -NH2 group

• The amino group acts as a base, reacting with acids to form salts.
• Reaction with ninhydrin produces specific colors (e.g., blue, pink, purple) that help identify amino acids.
• Important reactions like transamination and oxidative deamination are covered.

Colour Reactions of Amino Acids

• Distinct color reactions are used to identify amino acids.
• Specific amino acid components that lead to specific colours. Examples like Biuret, Ninhydrin, Xanthoproteic are highlighted. Note: other colour reactions are elaborated as well.

Functions of Amino Acids

• Amino acids are the building blocks for all living things.
• The chain composition and characteristics determine protein function.
• Crucial roles in hormone production, muscle structure/function, nervous system, vital organ function, and overall cell structure are mentioned.

Amino Acids as Drugs

• Certain amino acids are used or are precursors to medications.
• Examples include D-penicillamine and N-acetylcysteine.

Protein Structure

• The hierarchical levels of protein organization are presented (primary, secondary, tertiary, and quaternary) -The figure demonstrates that amino acid sequence determines protein shape and function.
• Polypeptide chains and protein complexes are explained.
• Details about the primary structure (amino acid sequence) and the importance of the peptide bond in linking them.

Classification of Proteins

• Proteins can be categorized by composition, by nutrients, by function and by shape.
• Different types of proteins are illustrated, such as simple proteins, globular, fibrous, conjugated proteins (glycoproteins, nucleoproteins, lipoproteins, etc.), and derived proteins (proteoses, peptones, etc.).

Conditionally/ Essential Amino Acids

• Six amino acids are considered conditionally essential.
• They are required during certain phases of life. Examples include growing children and pregnant women.

Classification based on metabolic fate

• Describes how amino acids are used in the body for energy or to build other molecules.
• Grouping proteins relevant to glucogenic and ketogenic.
• Provides details about the categories of amino acids (e.g., glucogenic and ketogenic) and relates them to metabolic functions.

More Amino Acids

-Recent discoveries have led to the identification of more amino acids, such as selenocysteine and pyrrolysine.

• These, in addition to the 20 primary amino acids, are important in biological processes.

Genetic Code (page 22)

• A table illustrates how codons (triplet nucleotide sequences) specify amino acids in gene expression.
• This includes how various codons code for the same amino acid.

Denaturation of Proteins

• Denaturation affects protein structure/function.
• Factors like heat, pH changes and chemical/physical factors cause denaturation.
• Denatured proteins are insoluble.

Characteristics of Denaturation

• Describes the consequences of protein denaturation.
• The denatured protein loses its function.
• The reaction is mostly irreversible.

Additional Points

• Diagrams/visual aids are used to clarify protein structure/function in the lessons/course.