Biologie cellulaire: Acides nucléiques

Biologie cellulaire et moléculaire - Acides nucléiques

• Acides nucléiques: Polymers of nucleotides
• Nucleotide composition:
  • Nitrogenous base
  • Pentose sugar
  • Phosphate group
• Purine bases: Adenine (A) and Guanine (G)
• Pyrimidine bases: Cytosine (C), Thymine (T), and Uracil (U)
• DNA base pairings: A-T, G-C
• RNA base pairings: A-U, G-C

Pentose

• Ribose: Sugar found in RNA
• Deoxyribose: Sugar found in DNA

Phosphate group

• Phosphoric acid: Component of nucleotides
• Linkage with pentose and bases: Forms the backbone for DNA and RNA

Nucleotide

• Definition: Nucleotide = nitrogenous base + pentose sugar + phosphate group
• Importance: Building blocks of DNA and RNA

ARN (RNA)

• Definition: Ribonucleic acid
• Structure: Single-stranded chain
• Sugar: Ribose
• Bases: A, U, G, C
• Sequence orientation: 5' to 3'

ADN (DNA)

• Definition: Deoxyribonucleic acid
• Structure: Double-stranded helix
• Sugar: Deoxyribose
• Bases: A, T, G, C
• Base pairings: A-T, G-C
• Sequence orientation: Antiparallel strands (5' to 3' and 3' to 5')
• Structure Function: Provides blueprint for all proteins and cellular processes

Génome

• Definition: Complete set of genetic material in an organism
• Units: Made-up out of base pairs
• Size: Varies significantly between organisms (viruses, bacteria mammals).
• Location (humans): Nucleus

La chromatine

• Definition: Complex of DNA and proteins(histones)
• Function: Compacts DNA for storage in the cell's nucleus
• Components: DNA coiled around histone proteins

Chromosome

• Definition: Highly organized structure of DNA
• Components: DNA, proteins (histones)
• Structure:
  • Condensed form of chromatin
  • Characteristic structure during cell division
  • Human Chromosome count: 23 pairs
• Size/length: Varies

Gène

• Definition: Specific sequences of DNA that code for particular proteins or RNA molecules
• Components: Introns and exons (coding DNA sequences).
• Regions: Promoters and other regulatory sequences

Epissage alternatif

• Definition: Mechanism involving different ways RNA sequences are cut to create new different protein combinations.

Régulation de l'expression des gènes

• Definition: Mechanisms controlling when and how genes are expressed.
• Control Elements: Regulatory elements near or distant to the gene.
• Factors controlling expression: Activators and Repressors proteins.

Testez vos connaissances sur les acides nucléiques, y compris leur structure, leur composition et leurs fonctions. Ce quiz explore les bases azotées, les sucres pentose et les groupes phosphates, ainsi que les différences entre l'ADN et l'ARN. Préparez-vous à approfondir votre compréhension des molécules fondamentales de la vie!