Cell Biology: Nuclear Pores and Microtubules

Contains chromosomes, DNA replication machinery, and RNA transcription machinery.

Appears basophilic with H&E staining, and its activity level can be seen by its shape.

Largest organelle found in the cell.

Red blood cells have no nuclei.

A double membrane surrounding the nucleus, composed of an outer and inner membrane.

Part of the nuclear envelope continuous with the rough endoplasmic reticulum (RER) and studded with ribosomes.

Part of the nuclear envelope attached to the chromatin.

Small openings in the nuclear envelope that allow molecules to pass between the nucleus and cytoplasm.

The space between the inner and outer nuclear membranes.

The complex of DNA and proteins that forms chromosomes.

A dense region within the nucleus, where ribosomes are assembled.

The liquid material inside the nucleus.

A non-membranous, deeply stained structure in the nucleus, composed of light and dark areas. The light areas (pars amorpha) have a lot of nuclear sap; the dark areas (nucleolonema) house RNA granules (pars granulosa) and DNA/RNA filaments (pars fibrosa).

The nucleolus is the site where ribosomal RNA (rRNA) is made.

A protein solution that suspends chromatin and allows movement of nucleic acids through nuclear pores.

Provides a pathway for nucleic acids (like tRNA, rRNA, and mRNA) to travel through the nucleus.

tRNA, rRNA, and mRNA are examples of nucleic acids that move through the nuclear sap.

A perforation in the nuclear membrane, allowing passage of RNA and proteins, controlled by a complex structure.

The complex structure that controls movement through the nuclear pore, composed of various elements like cytoplasmic filaments, rings, and a central plug.

Part of the nuclear pore complex extending into the cytoplasm.

A crucial component in the nuclear pore complex, which plays a role in regulating transport.

Part of the nuclear pore complex located in the cytoplasm.

A structural element within the nuclear pore complex that forms part of the pore's intricate structure.

Part of the nuclear pore complex found within the nucleus.

Part of the nuclear pore complex inside the nucleus.

Part of the nuclear pore complex at the periphery or end.

The space between the components of the nuclear pore complex.

Hollow tubes with a dense wall and a clear central space, composed of tubulin dimers arranged in protofilaments.

Made of tubulin dimers (α-tubulin and β-tubulin). Thirteen protofilaments form one microtubule.

Measured in micrometers (µm) and nanometers (nm).

Not directly visible under light microscopy, but can be stained.

Clearly visible under electron microscopy as a tubular structure with a clear central space.

Controls all cell functions and houses genetic material.

Includes organelles (membranous and non-membranous), inclusions (paraplasma), and cytoskeleton (metaplasma).

Specialized structures within the cytoplasm with specific functions.

Organelles bounded by membranes, like the ER.

Organelles not enclosed by membranes, like ribosomes.

Substances in the cytoplasm used for storage or other tasks.

System of fibers that maintains cell shape and movement.

Complex of DNA, proteins (histones), and RNA that forms chromosomes within the nucleus.

Fundamental structural unit of chromatin, consisting of DNA wrapped around histone octamer.

Condensed form of chromatin, generally inactive in transcription.

Less condensed form of chromatin, actively involved in transcription.

A thread-like structure formed by nucleosomes in chromatin.

Protein that packages and orders DNA into nucleosomes.

Different degrees of packaging of DNA into chromosomes, from a short section of the double helix to an entire condensed mitotic chromosome.

Likely depicts a tissue sample with Heterochromatin.

Likely depicts a tissue sample with Euchromatin.

Microtubules exist as single, doublet, or triplet structures in the cytoplasm, with different arrangements in structures like cilia and centrioles.

Microtubules provide internal support, like scaffolding, for the cell.

Microtubules create pathways for molecules and organelles to move inside the cell.

Microtubules help separate chromosomes during cell division.

Microtubules enable movement through cilia and flagella.

Doublet microtubules are a specific arrangement found in structures like cilia and flagella.

Triplet microtubules are a special arrangement found in centrioles.

The cytoskeleton is made of different filaments with varying thicknesses and compositions.

Thin filaments, also known as Actin filaments, are responsible for muscle contraction and cell movement.

A type of cytoskeletal filament crucial for maintaining cell shape.

Myosin filaments, involved in muscle contraction and cellular processes. Largest type of filament in the cytoskeleton.

Thin filaments are primarily composed of actin proteins. They also stain with immunohistochemical stains.

These filaments include a range of proteins like keratin, desmin, and neurofilaments.

These filaments are made of myosin proteins.

Microfilaments, composed of actin, play a key role in muscle contraction. Microfilaments are crucial for muscle movements.

Microfilaments, composed of actin, are essential in cell division for creating the cleavage furrow during cytokinesis.

Microfilaments are essential for cell migration and formation of pseudopodia.

Intermediate filaments help maintain cell shape by providing structural stability. They link cells to other components and form a network.

7 nanometers

Only visible with immunohistochemistry

G-actin monomers polymerize into F-actin.

Muscle contraction, cell division, cell movement, and cell structure (microvilli & streaming).

25 nanometers

Only visible with immunohistochemistry

Tubulin dimers form protofilaments, which assemble into microtubules.

Transport, cell structure (cilia, flagella, centrioles), and cell division.

10 nanometers

Only visible with immunohistochemistry

Woven protein ropes.

Structural support for cells.

Glycogen, fat, and protein.

Substances giving cells color.