ABI Bioinformatics Guide 2024
  • INTRODUCTION
    • How to use the guide
  • MOLECULAR BIOLOGY
    • The Cell
      • Cells and Their Organelles
      • Cell Specialisation
      • Quiz 1
    • Biological Molecules
      • Carbohydrates
      • Lipids
      • Nucleic Acids (DNA and RNA)
      • Quiz 2
      • Proteins
      • Catalysis of Biological Reactions
      • Quiz 3
    • Information Flow in the Cell
      • DNA Replication
      • Gene Expression: Transcription
      • Gene Expression: RNA Processing
      • Quiz 4
      • Chromatin and Chromosomes
      • Regulation of Gene Expression
      • Quiz 5
      • The Genetic Code
      • Gene Expression: Translation
    • Cell Cycle and Cell Division
      • Quiz 6
    • Mutations and Variations
      • Point mutations
      • Genotype-Phenotype Interactions
      • Quiz 7
  • PROGRAMMING
    • Python for Genomics
    • R programming (optional)
  • STATISTICS: THEORY
    • Introduction to Probability
      • Conditional Probability
      • Independent Events
    • Random Variables
      • Independent, Dependent and Controlled Variables
    • Data distribution PMF, PDF, CDF
    • Mean, Variance of a Random Variable
    • Some Common Distributions
    • Exploratory Statistics: Mean, Median, Quantiles, Variance/SD
    • Data Visualization
    • Confidence Intervals
    • Comparison tests, p-value, z-score
    • Multiple test correction: Bonferroni, FDR
    • Regression & Correlation
    • Dimentionality Reduction
      • PCA (Principal Component Analysis)
      • t-SNE (t-Distributed Stochastic Neighbor Embedding)
      • UMAP (Uniform Manifold Approximation and Projection)
    • QUIZ
  • STATISTICS & PROGRAMMING
  • BIOINFORMATICS ALGORITHMS
    • Introduction
    • DNA strings and sequencing file formats
    • Read alignment: exact matching
    • Indexing before alignment
    • Read alignment: approximate matching
    • Global and local alignment
  • NGS DATA ANALYSIS & FUNCTIONAL GENOMICS
    • Experimental Techniques
      • Polymerase Chain Reaction
      • Sanger (first generation) Sequencing Technologies
      • Next (second) Generation Sequencing technologies
      • The third generation of sequencing technologies
    • The Linux Command-line
      • Connecting to the Server
      • The Linux Command-Line For Beginners
      • The Bash Terminal
    • File formats, alignment, and genomic features
      • FASTA & FASTQ file formats
      • Basic Unix Commands for Genomics
      • Sequences and Genomic Features Part 1
      • Sequences and Genomic Features Part 2: SAMtools
      • Sequences and Genomic Features Part 3: BEDtools
    • Genetic variations & variant calling
      • Genomic Variations
      • Alignment and variant detection: Practical
      • Integrative Genomics Viewer
      • Variant Calling with GATK
    • RNA Sequencing & Gene expression
      • Gene expression and how we measure it
      • Gene expression quantification and normalization
      • Explorative analysis of gene expression
      • Differential expression analysis with DESeq2
      • Functional enrichment analysis
    • Single-cell Sequencing and Data Analysis
      • scRNA-seq Data Analysis Workflow
      • scRNA-seq Data Visualization Methods
  • FINAL REMARKS
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  • What Are Polymers?
  • Major Classes of Biological Molecules

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  1. MOLECULAR BIOLOGY

Biological Molecules

PreviousQuiz 1NextCarbohydrates

Last updated 10 months ago

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The majority of biological molecules are carbon-based. Each carbon atom has the ability to form four bonds, typically with other carbon, hydrogen, oxygen, nitrogen, sulfur or phosphorus atoms.

When carbon atoms bond together, they create the carbon skeleton. The shape of this carbon skeleton, along with the positioning of other chemical groups defines the unique properties of a molecule.

The picture below provides an example of a biological molecule – serotonin. Serotonin is a signalling molecule used by neurons to communicate with each other.

What Are Polymers?

Proteins, nucleic acids and many of the carbohydrates are polymers – long molecules made of multiple repeating units called monomers. Monomers can be either identical (e.g. in cellulose) or similar (e.g. in DNA).

Major Classes of Biological Molecules

If you already have a biological background or do not want to indulge in the details of biological molecules' structure and functions, then consider the below information just enough to move on to the next chapter.

The four major classes of biological molecules are carbohydrates, proteins, nucleic acids (DNA and RNA) and lipids.

Class
Function

Carbohydrates

Serve as an energy source and as structural components

Proteins

Catalyse biochemical reactions, transport molecules, have structural, signalling and other structures

Nucleic acids (DNA and RNA)

Store and carry genetic information

Lipids

Store energy, make up cell membranes and serve as hormones

Serotonin is a biological molecule. Note that in this molecule carbon atoms form single or double bonds with other atoms. Image source: Molview.org
Formation and degradation of polymers Image source: Christinelmiller - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=98001922