Biologia: Ribonucleic Acid (RNA)

Ribonucleic Acid (RNA)

• RNA is a single-stranded nucleic acid, differing from DNA in its sugar component (ribose instead of deoxyribose) and one of its nitrogenous bases (uracil instead of thymine).
• Different types of RNA exist, each with a specific function:
  • Messenger RNA (mRNA): Carries genetic information from DNA to ribosomes.
  • Transfer RNA (tRNA): Carries amino acids to ribosomes during protein synthesis.
  • Ribosomal RNA (rRNA): A component of ribosomes, essential for protein synthesis.
  • MicroRNA (miRNA): Regulates gene expression by binding to mRNA.
  • Small interfering RNA (siRNA): Involved in gene silencing.
  • Long non-coding RNA (lncRNA): Involved in various cellular processes, often influencing gene expression and alternative splicing.

Deoxyribonucleic Acid (DNA)

• DNA is a double-stranded helix formed by a specific pairing of nitrogenous bases (adenine with thymine, cytosine with guanine).
• It contains the genetic instructions for the development, functioning, and reproduction of all known organisms and many viruses.

Lipid Composition in Plasma Membrane

• Plasma membranes are primarily composed of phospholipids, a type of lipid with a hydrophilic head and two hydrophobic tails.
• These phospholipids form a bilayer, with the hydrophilic heads facing outward and the hydrophobic tails facing inward.
• Cholesterol is another important lipid component of the plasma membrane, contributing to its fluidity and structural integrity.
• Glycolipids are also present, contributing to cell recognition and signaling.

Protein in Plasma Membrane and Classification

• Proteins are crucial membrane components, performing various functions including transport, enzymatic activity, cell signaling, and structural support.
• Membrane proteins can be classified based on their location within the membrane:
  • Integral proteins: Embedded in the lipid bilayer, often spanning across the membrane (transmembrane proteins).
  • Peripheral proteins: Located on the surface of the membrane, often attached to integral proteins or the phospholipid heads.
• Other protein classifications are based on their function, including:
  • Receptors: Bind to specific molecules outside the cell, initiating cellular responses.
  • Channels: Allow specific molecules to pass through the membrane.
  • Carriers: Bind to specific molecules and transport them across the membrane.
  • Enzymes: Facilitate chemical reactions within or adjacent to the membrane.

Carbohydrate Composition and Classification

• Carbohydrates are also part of the plasma membrane, attached to lipids (glycolipids) or proteins (glycoproteins).
• These carbohydrate chains play a crucial role in cell-cell recognition, adhesion, and signaling.
• Carbohydrate classifications are based on their structural complexity, including monosaccharides (simple sugars like glucose, fructose, galactose), disaccharides (two monosaccharides linked together), and polysaccharides (long chains of monosaccharides).
• Further carbohydrate classification can be based on the linkages between the monosaccharides in the polymer chain. Different types of linkages affect the chemistry and function of the larger molecule.

Este quiz aborda le structura e functiones de RNA, un acido nucleico a filamento singular. Explora le differentias inter RNA e DNA, e le varios typos de RNA como mRNA, tRNA, e rRNA.