Cell Ultrastructure: Centrioles, Cilia, and Cell Junctions

These flashcards cover the key concepts of the cytoskeleton, centrioles, and cell junctions as discussed in the lecture notes.

What is the role of the cytoskeleton in the cell?

The cytoskeleton provides structural support and maintains the cell's shape.

What are the three main components of the cytoskeleton?

Microtubules, microfilaments, and intermediate filaments.

What is the microtubular structure of centrioles composed of?

Centrioles are composed of 9 sets of triplets arranged in a cylinder (9x0 structure) made up of tubulin.

What is the origin of microtubular spindle fibers?

They originate from gamma-tubulin rings in the centrosome.

What are the three main types of intercellular junctions?

Adhering (anchoring) junctions, tight junctions, and gap junctions.

What is the composition and function of microtubules?

Microtubules are hollow cylinders composed of tubulin and play roles in structure, movement, and cell division.

What is the primary function of microfilaments?

Microfilaments, or actin filaments, are involved in maintaining cell shape and motility.

What are intermediate filaments primarily composed of?

Intermediate filaments are heterogeneous and consist of various proteins including keratins.

How do centrioles replicate prior to cell division?

Centrioles replicate and grow new daughter centrioles at right angles to the existing centrioles.

What structure guides microtubule organization in the cell?

The centrosome serves as the main microtubule organizing center in the cell.

What do gap junctions facilitate in adjacent cells?

Gap junctions allow for the interchange of small ions and molecules between adjacent cells.

What are the two main types of desmosomes?

Spot desmosomes (macula adherens) and hemidesmosomes.

What autoimmune disease affects desmosomes leading to skin blistering?

Pemphigus vulgaris.

What is the typical structure of tight junctions?

Tight junctions form a belt-like structure that acts as a barrier between cells.

How do cadherins function in adhering junctions?

Cadherins link adjacent cells by connecting their cytoskeletons through transmembrane proteins.