Eukaryotic Cell Structure: Nucleus & Endomembrane System

Vocabulary flashcards covering the eukaryotic cell nucleus, the endomembrane system, organelle structures, and protein transport pathways based on Dr. Humphrey's Biol 110_112 lecture.

Organelles

Internal membrane-bound compartments in eukaryotic cells, translating to "little organs," that perform distinct specialized functions.

Nucleus

A eukaryotic structure that stores genetic information, serves as the site of ribosome assembly, and is where RNA is produced (transcription).

Nuclear envelope

A double lipid bilayer membrane that defines the nucleus, consisting of an inner and outer lipid bilayer membrane, with the outer bilayer connected to the smooth and rough ER.

Nuclear pores

Passages through the nuclear envelope that regulate nuclear transport via both passive and active transport.

Chromatin

Chromosomal DNA bound to DNA binding proteins located within the nucleus.

Nucleolus

A non-organelle area inside the nucleus where ribosomes are assembled.

Endomembrane System

A network of internal lipid bilayer membranes within a eukaryotic cell that includes the endoplasmic reticulum (SER and RER), Golgi apparatus, and vesicles.

Lumen

The internal space located inside the interconnected tubules of the endoplasmic reticulum.

Smooth Endoplasmic Reticulum (SER)

A region of interconnected endoplasmic reticulum tubules lacking ribosomes; functions as the site of lipid synthesis, fatty acid desaturation, cholesterol synthesis, and some carbohydrate synthesis.

Rough Endoplasmic Reticulum (RER)

A region of the endoplasmic reticulum studded with ribosomes on its surface; specializes in synthesizing proteins destined for export from the cell, association with the outer plasma membrane, or use within the endomembrane system.

Golgi Apparatus

An endomembrane organelle consisting of a series of flattened lipid bilayer sacs (tubes) not connected to other structures; functions to modify molecules, sort them by destination, and release them in vesicles.

cis face

The receiving region of the Golgi apparatus where transport vesicles arriving from the endoplasmic reticulum fuse.

trans face

The exit region of the Golgi apparatus where transport vesicles bud off and depart toward their final destinations.

Pro-insulin

The inactive precursor form of insulin synthesized in the rough endoplasmic reticulum prior to being transported to the Golgi apparatus for maturation.

Exocytosis

The cellular process where secretory vesicles fuse with the cell membrane to release contents, such as mature insulin, into the extracellular fluid.