AP Bio Organelles

Ribosomes

Made of ribosomal RNA (rRNA) and protein. Synthesize protein according to an mRNA sequence. Found in ALL cells (evidence of common ancestry).

Cytoplasm/cytosol

Gelatinous liquid that fills the inside of the cell.

Nucleus

Double membrane (also called nuclear envelope) surrounds the cell’s DNA.

Nucleolus

Small, dense, spherical structure located inside the nucleus. This is the site where ribosomes are made.

Endoplasmic reticulum

Roles in molecule synthesis, mechanical support, and intracellular transport. Two types - smooth and rough. Rough ER is associated with membrane-bound ribosomes. It is associated with protein synthesis and folding. Smoother ER functions include detoxification and lipid synthesis.

Golgi complex

Consists of a series of flattened membrane sacs. Functions include correct folding and chemical modification of newly synthesized proteins, and packaging for protein trafficking.

Mitochondria

Organelle with a double membrane structure. Outer membrane is smooth, but inner membrane is highly convoluted/folded. Uses glucose and oxygen to make ATP energy for the cell.

Lysosomes

Membrane-enclosed sacs that contain hydrolytic enzymes important for intracellular digestion, recycling of cell’s organic materials, and programmed cell death (apoptosis).

Vacuoles

Membrane-bound sacs that play many different roles/functions. Roles often have to do with storage and release of macromolecules and cellular waste products. In plants, vacuoles aid in retention of water for turgor pressure.

Chloroplasts

Have a double outer membrane plus an inner thylakoid membrane. Found in photosynthetic algae and plants, use energy from the sun to produce sugar.

Plasma membrane

Selectively permeable barrier (select molecules can cross based on their properties, while others cannot) that defines the outer boundary of the cell.

Cytoskeleton

The cytoskeleton consists of 3 main types of fibrous proteins with different functions in cell structure, strength, and transport.

Intermediate filaments

Intermediate filaments are the “steel cables” of the cell, providing structural support to cells and tissues.

Microtubules

Microtubules function in trafficking, as cellular contents are transported throughout the interior of the cell by motor proteins that “walk” along microtubule highways.

Actin

Actin has a role in large scale cell movement (movement of the cell as a whole).