Nucleic Acids

Nucleic Acids Visually

Learn about nucleic acids with interactive visualizations. Explore DNA and RNA structure, function, replication, transcription, and translation with step-by-step animations and examples.

Nucleic Acids Nucleotide Structure DNA & RNA Structure Genetic Information Molecular Interactions Replication & Transcription Visual Simulation
Intro
Structure
Function
Replication
Transcription
Simulations

Introduction to Nucleic Acids

Nucleic acids are macromolecules that store and transmit genetic information in all living organisms. The two main types are DNA (deoxyribonucleic acid) and RNA (ribonucleic acid). These molecules are composed of nucleotides linked together by phosphodiester bonds.

Key Concepts:

  • Information Storage: Store genetic information in sequences of nucleotides
  • Universal Language: Use universal genetic code across all life forms
  • Double Helix: DNA forms iconic double helix structure
  • Base Pairing: Specific pairing rules (A-T/U, G-C) ensure accurate replication

Major Types:

  • DNA: Double-stranded, deoxyribose sugar, bases A, T, G, C
  • RNA: Single-stranded, ribose sugar, bases A, U, G, C
  • mRNA: Messenger RNA carries genetic code
  • tRNA/rRNA: Transfer and ribosomal RNA in protein synthesis

Nucleic Acid Structure

Nucleotide Components

Each nucleotide consists of three parts:

  1. Nitrogenous Base: Purine (A, G) or Pyrimidine (C, T/U)
  2. Pentose Sugar: Deoxyribose (DNA) or Ribose (RNA)
  3. Phosphate Group: Provides negative charge

DNA vs RNA Structure

  • DNA: Double-stranded, deoxyribose sugar, bases A, T, G, C
  • RNA: Single-stranded, ribose sugar, bases A, U, G, C

Base Pairing Rules

  • DNA: Adenine pairs with Thymine (A-T), Guanine pairs with Cytosine (G-C)
  • RNA: Adenine pairs with Uracil (A-U), Guanine pairs with Cytosine (G-C)

Interactive Nucleic Acid Structure

Nucleic Acid Functions

DNA Storage

Long-term storage of genetic information

  • Contains instructions for protein synthesis
  • Passed from parents to offspring
  • Stable double-stranded structure

mRNA

Messenger RNA carries genetic code from DNA

  • Transcribed from DNA template
  • Carries code to ribosomes
  • Temporary copy of genetic information

tRNA

Transfer RNA brings amino acids to ribosomes

  • Recognizes codons on mRNA
  • Carries specific amino acids
  • Ensures correct protein sequence

rRNA

Ribosomal RNA forms part of ribosomes

  • Catalyzes protein synthesis
  • Structural component of ribosomes
  • Most abundant RNA type

Regulatory RNAs

Control gene expression and other processes

  • microRNAs (miRNAs)
  • Small interfering RNAs (siRNAs)
  • Long non-coding RNAs (lncRNAs)

DNA Repair

Correct mutations and damage to genetic material

  • Excision repair mechanisms
  • Proofreading during replication
  • Maintenance of genetic integrity

DNA Replication

The Replication Process

  1. Initiation: Unwinding of double helix at origins of replication
  2. Elongation: Synthesis of new strands by DNA polymerase
  3. Leading strand: Continuous synthesis in 5' to 3' direction
  4. Lagging strand: Discontinuous synthesis forming Okazaki fragments
  5. Termination: Completion and proofreading of new DNA molecules

Key Enzymes

  • DNA Helicase: Unwinds the double helix
  • DNA Polymerase: Adds nucleotides to growing strand
  • DNA Ligase: Joins Okazaki fragments
  • Primase: Synthesizes RNA primers
  • Topoisomerase: Prevents tangling during unwinding

Interactive Replication Simulation

Medium

Transcription

The Transcription Process

  1. Initiation: RNA polymerase binds to promoter region
  2. Elongation: Synthesis of RNA strand complementary to DNA template
  3. Termination: Release of RNA transcript and polymerase
  4. Processing: Addition of cap and tail, splicing of introns

Differences from Replication

  • Only one DNA strand serves as template
  • RNA is single-stranded
  • Uses RNA nucleotides (A, U, G, C)
  • No primer required

Interactive Transcription Simulation

Differences from Other Biomolecules

Nucleic Acids vs Proteins

Nucleic Acids: Store and transfer genetic information using nucleotides (A, T/U, G, C)

Proteins: Perform functions using amino acids (20 types) with diverse structures and activities

Nucleic Acids vs Carbohydrates

Nucleic Acids: Information storage using C, H, O, N, P elements

Carbohydrates: Energy storage and structure using C, H, O in 2:1 ratio

Nucleic Acids vs Lipids

Nucleic Acids: Information molecules with hydrophilic backbone

Lipids: Hydrophobic molecules for energy storage and membrane structure

Interactive Nucleic Acid Simulations

DNA Double Helix Formation

Watch how complementary strands form the iconic double helix

Base Pairing Simulation

Observe how nucleotides form complementary pairs

37°C

Genetic Code Translator

Convert DNA/RNA sequences to amino acid sequences

Mutation Effects

See how mutations affect protein sequences

Nucleic Acid Calculators

Molecular Weight Calculator

Calculate the molecular weight of nucleic acids based on sequence

Base Composition Calculator

Analyze the base composition of nucleic acids

Tm Calculator

Calculate the melting temperature of DNA oligonucleotides

Example Exercises

Problem: Given the DNA template strand 5'-ATCGTACGTA-3', what would be the complementary strand sequence?

Solution: The complementary strand would be 3'-TAGCATGCAT-5'. Remember that A pairs with T and G pairs with C. Also note that the complementary strand runs in the opposite direction (antiparallel) to the template strand.

Explanation: Base pairing rules: A=T, G≡C; Antiparallel orientation: 5' to 3' directionality; Hydrogen bonds: 2 between A-T, 3 between G-C

Problem: If the DNA template strand is 3'-TACGTACGTA-5', what would be the resulting mRNA sequence?

Solution: The mRNA sequence would be 5'-AUGC AUGCAU-3'. During transcription, RNA polymerase synthesizes mRNA complementary to the template DNA strand, replacing thymine (T) with uracil (U).

Explanation: Template strand: 3' to 5' direction; mRNA synthesis: 5' to 3' direction; Base pairing: A (DNA) = U (RNA), T (DNA) = A (RNA), G (DNA) ≡ C (RNA), C (DNA) ≡ G (RNA)

Problem: Translate the mRNA sequence 5'-AUGGCCGUAUAU-3' into an amino acid sequence.

Solution: Breaking the sequence into codons: AUG-GCC-GUA-UAU. Amino acid sequence: Met-Ala-Val-Tyr (M-A-V-Y)

Explanation: AUG = Methionine (start codon), GCC = Alanine, GUA = Valine, UAU = Tyrosine

Multiple Choice Questions

1. Which nitrogenous base is found in RNA but not in DNA?
2. How many hydrogen bonds form between guanine and cytosine?
3. What is the direction of DNA synthesis during replication?
4. Which RNA molecule carries amino acids to the ribosome during translation?
5. What type of bond connects nucleotides in a nucleic acid strand?
6. Which enzyme is responsible for unwinding the DNA double helix during replication?

Export/Import Data

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DNA Structure

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RNA Structure

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Gene Expression

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DNA Replication

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