Organelles & Compartmentalization

Flashcards about cell organelles and compartmentalization, covering definitions, advantages, and examples.

Organelles

Discrete subunits of cells adapted to perform specific functions.

Structures not considered organelles

Cell wall, cytoskeleton, and cytoplasm.

Structures considered organelles

Nuclei, vesicles, ribosomes, and the plasma membrane.

Advantage of separating nucleus and cytoplasm

Limits separation of the activities of gene transcription and translation, allows post-transcriptional modification of mRNA before meeting ribosomes.

Advantages of compartmentalization in the cytoplasm of cells

Concentration of metabolites and enzymes, and the separation of incompatible biochemical processes.

Which type of cells are compartmentalized

Eukaryotic cells.

Compartmentalization

Specialized areas or structures within the cell body that carry out certain functions.

Nucleus

Site of most cellular DNA, which, with associated proteins, comprises chromatin.

Mitochondria

Cell's power plants.

Cytoskeleton

Composed of microtubules and microfilaments, supports the cell and is involved in cell and organelle movement.

Rough endoplasmic reticulum

Site of much protein synthesis.

Centrioles

Associated with nuclear division.

Plasma membrane

Separates the cell from its environment and regulates traffic of materials into and out of the cell.

Separation of nucleus and cytoplasm in eukaryotes

Chromosomes are kept inside the membrane-bound nucleus, separating them from the cytoplasm.

Process in prokaryotes due to lack of nuclear membrane

Proteins are synthesized directly along mRNA while it is transcribed from the DNA.

Post-transcriptional modification in eukaryotes

Transcript is modified in several ways before leaving the nucleus.

Example of compartmentalization in Paramecium

Ingested food is digested inside the vacuoles where the pH drops down to pH2, and later rises above pH7.

Localized conditions

Concentration of enzymes and/or substrates.

Protective advantage of compartmentalization

Isolation of harmful substances to prevent damage to the cell.