Cellular Organelles: Functions and Structures

Organelles

An organelle is a small, specialized structure within a cell that performs a specific function. Examples include mitochondria and lysosomes.

Functions of the Cell or Plasma Membrane

1. This structure surrounds the cell, separating it from the external environment.
2. It forms a barrier that allows the cell to incorporate water and nutrients and remove metabolic waste.

Ribosomes

Ribosomes are organelles formed by the combination of different proteins and RNA (ribonucleic acid).

The Golgi apparatus is an organelle that receives immature proteins from the rough endoplasmic reticulum (RER) and releases vesicles containing mature proteins.

• RE: Endoplasmic reticulum
• PER: Ribosomes that have completed the synthesis of a protein

Location and Structure of Ribosomes

Ribosomes are located in the cytoplasm or associated with the endoplasmic reticulum, where they translate the genetic message contained in DNA.

Cytoskeleton: Function and Components

The cytoskeleton is the internal support structure of animal cells. It is formed as a framework of three types of proteins: microtubules, intermediate filaments, and microfilaments.

Cilia and Flagella

• Cilia are numerous, short projections that, in organisms such as the paramecium, allow for movement and capture of food.
• Flagella are unique, long structures that help cells move. Eukaryotic cells have structures to move and, sometimes, to provide mobility.

Organelles

Organelles are structures that play specific roles within the cell.

Cytoplasm

The cytoplasm is the contents inside the cell, rich in water and mineral salts.

Cell Nucleus

The cell nucleus stores most of the cell's genetic information (DNA), which controls and regulates cellular activities.

Protein Processing in the Golgi Apparatus

The Golgi apparatus works like an assembly line, receiving immature proteins from the endoplasmic reticulum.