Cellular Processes and Organelles: Transport and Functions

Posted on Feb 12, 2025 in Biology

Cellular Processes and Organelles

Regular Golgi transit occurs through vesicles. It’s involved in intracellular synthesis and secretion of complex molecules. Additionally, it is responsible for the repair of the cell membrane. Degradative lysosomes have a digestive function, and mitochondrial respiration (aerobic) supplies most of the energy to the cell. The centrosome directs cell division. Glyoxysomes convert fat to carbohydrates. The glycocalyx includes sugars attached to proteins or lipids of the mitochondrial membrane. Its function is cellular respiration, and ATP has two membranes. Microtubules possess their own genetic material and are responsible for intracellular transport of waste products. Plant cells secrete vacuoles and remove salts and solutes. Flagella give mobility to the cell. Centrioles function in cell division.

Ribosomal protein synthesis is formed by ARN.

  • Two membranes: Nucleus, chloroplasts, mitochondria.
  • One membrane: Golgi apparatus, peroxisomes, vacuoles, lysosomes.
  • Without membrane: Nucleolus, ribosomes, centrioles.

Cellular Transport Mechanisms

Dissemination through channels in membrane proteins. This process does not require cellular energy, as the materials move through a gradient of glucose concentration. Materials include potassium and sodium. This occurs more rapidly when the temperature is higher and when there are more special proteins in the membrane. Two proteins are required: a protein channel and a receiver. This allows the passage of materials that cannot penetrate the phospholipid layer.

Active transport: The movement of materials is achieved through a set of regions of low membrane concentration to regions of high concentration, so the cells accumulate materials such as potassium ions or amino acids. This necessitates a configuring protein and requires ATP energy expenditure by the cell. Transport through protein is generated when one end of this protein generates a link. The link with the material changes the structure of the protein and opens the channel through which the material enters.

Transport of materials in suspension: This movement is made by relatively large materials through the formation of vesicles that do not allow mixing with the cytosol. There are two ways:

  • Endocytosis: When the materials are moving within the cell. Endocytosis of a fluid is called pinocytosis, and of a solid, phagocytosis.
  • Exocytosis: Materials are carried from the inside out. The membrane vesicles travel to fuse with the cell membrane, releasing their cargo from the cell (secretion).

Organelles and Their Functions

  • Ribosomes: Protein synthesis.
  • Endoplasmic reticulum:
    • Smooth endoplasmic reticulum: Formed by smooth membranous sacs in the absence of ribosomes. Responsible for cellular detoxification and lipid metabolism.
    • Rough endoplasmic reticulum: Synthesizes glycoproteins and enzymes. Carries substances and organelles, originating as dictyosomes and lysosomes.
  • Golgi Apparatus: Regulates intracellular traffic by vesicles. Synthesis of complex molecules such as secreted mucopolysaccharides. Responsible for the repair of the cellular membrane.
  • Lysosomes: Digestive and degradative function.
  • Mitochondria: Respiration and provides energy for aerobic cellular activity.
  • Centrosomes: Cell division.
  • Glyoxysomes: Convert fat to carbohydrates.