Biochemistry Module 1: Introduction to BCH2IBM

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Biochemistry Module 1 - Introduction

• The module is titled "Re-cap BCH2IBM"
• The module's introduction is presented in a module called "BCH2IBM"
• The presenter is Katrina Binger
• The module is from a department of Biochemistry and Genetics
• Key molecules discussed include DNA, RNA, and Protein.
• Metabolism is also mentioned

Intended Learning Outcomes (ILOs)

• The lecture is a revision of BCH2IBM and is not assessable

Cellular Life

• Cellular life is presented in a hierarchical structure, encompassing levels 4, 3, 2 and 1
• Hierarchical structure includes Supramolecular Complexes, Macromolecules, Monomeric Units respectively,
• Cells and organelles are included in the top level - level 4.
• Key components such as Chromatin, DNA, Protein, Plasma Membrane and Cell Wall are within level 3 and 2
• Basic monomeric components such as Nucleotides, Amino Acids and Sugars are at the lowest level 1.

The Central Dogma

• DNA is transcribed to RNA
• RNA is translated to Protein.
• Introns are removed from pre-mRNA through splicing, leaving exons joined together.
• The processes include post-translational modification.

DNA

• Organized into nucleosomes
• Long-lived, chemically stable
• High-fidelity replication; detailed mechanism
• Chromatin is composed of "nucleosomes," where DNA wraps around histones

RNA

• Flexible
• Chemically unstable
• Various types: Ribosomal (rRNA), messenger (mRNA), transfer (tRNA)
• Secondary structure includes hairpins, double-helical stem regions, and stem-loops.

mRNA, rRNA, and tRNA

• mRNA's role in transcription: mRNA is created in the nucleus using DNA as a template
• mRNA serves as a "blueprint" for building proteins
• rRNA's role in translation: rRNA is a part of ribosomes which help in linking amino acids together.
• tRNA's role in translation: tRNA has an anticodon that matches a codon on the mRNA

Protein Synthesis

• RNA holds instructions for protein synthesis.
• Codons (3 nucleotides on RNA) match anticodons on tRNA.
• Different tRNAs are linked to specific amino acids.
• Amino acids form polypeptide chains via peptide bonds.

Hierarchical Structure of Proteins

• A hierarchical system demonstrating how proteins are constructed
• Shows how proteins go from amino acids, building up through secondary protein structure, tertiary protein structure and quaternary protein structure

Amino Acids

• 20 amino acids, differing by their R-groups with varying properties like hydrophobic/hydrophilic, bulky/small, flexible/rigid, and charged/disulfide
• Amino acids are identified by full names, 3-letter abbreviations and single letter codes.
• Key groups include charged amino acid types

Charged Amino Acids

• Five charged amino acids: Arg, Lys, Asp, Glu, and His
• Their behavior as acids/bases depends on pH
• pH significantly influences amino acid charge, impacting protein folding and function
• Example given of Histidine, highlighting how its charge changes with pH

Protein Folding

• The folding and 3D shape of a protein results from chemical interactions between amino acid R-groups.
• Interactions can be categorized into hydrophobic interactions, van der Waals interactions, disulfide bonds, ionic bonds, and hydrogen bonds.

Protein Structure: Secondary

• Two key structures presented here include α-helices and β-sheets
• Describes antiparallel and parallel β-sheet arrangement.
• Key structural components are provided (Carbon, Hydrogen, Oxygen, Nitrogen, R group).

Protein Structure: Tertiary and Quaternary

• Tertiary structure involves interactions within a single polypeptide chain
• Quaternary structure involves interactions between multiple polypeptide chains.
• Examples like the interactions in haemoglobin are included.

Cellular Compartmentalisation

• Lipids are crucial for defining cell structure and internal compartments.
• Lipid families such as fatty acids, phospholipids, and others are essential components of cell membranes.
• Membranes regulate diverse functions including protein transport, endocytosis, and exocytosis.

Signalling

• Six critical characteristics of signal transduction: specificity, amplification, modularity, desensitization, integration of pathways, and regulation by localization.
• Key components of cell signalling such as Receptor protein and Intracellular signaling protein are shown

Summary

• BCH2IBM focused on the molecular mechanisms underlying the DNA>RNA>Protein part of the central dogma.
• BCH2MBC will continue understanding cellular mechanisms underlying Protein>Metabolism.

Resources

• All BCH2IBM lecture slides are accessible on the LMS
• Several chapters are available from Lehninger Principles of Biochemistry (7th Edition)