Cell Structure and Eukaryotic Components

Vocabulary-style flashcards covering the structural characteristics of prokaryotic and eukaryotic cells, common cellular features, and the components of the endomembrane system.

Prokaryotic Cells

Cells typically of size $1-10\,\mu m$ that lack a nucleus, containing DNA in an unbound nucleoid and dividing by binary fission.

Eukaryotic Cells

Cells typically $10-100\,\mu m$ in size with DNA organized in linear chromosomes inside a nucleus and containing membrane-bound organelles.

Nucleoid

The region in a prokaryotic cell where DNA is located in one circular strand, which is not bound by a membrane.

Plasma Membrane

A phospholipid bilayer found in all cells that acts as a selective barrier for $O_2$, nutrients, and waste.

Cell Theory

States that all life is made of cells, all cells have 4 common features, and all cells have a common evolutionary ancestor.

Cytosol

The semi-fluid substance found within the cytoplasm of all cells.

Ribosomes

Non-membrane-bound structures made of ribosomal RNA ($rRNA$) and proteins that synthesize primary polypeptides.

Nuclear Envelope

A double membrane made of lipid bilayers that encloses the nucleus and is perforated by nuclear pores.

Chromatin

The materials that make up chromosomes, consisting of a combination of DNA and proteins.

Nucleolus

A region inside the nucleus without a membrane that is responsible for making ribosomal RNA ($rRNA$) and proteins.

Nuclear Lamina

A network of proteins lining the inside of the nuclear envelope that maintains the shape of the nucleus.

Theory of Endosymbiosis

A theory explaining the origin of mitochondria and chloroplasts, noting they have their own DNA and ribosomes and divide by binary fission, similar to prokaryotic cells.

Endomembrane System

A system of phospholipid bilayers inside the cell, including the nuclear envelope, ER, Golgi, lysosomes, and vacuoles, that are either continuous or connected via vesicles.

Lumen

The internal space or compartment found inside the phospholipid bilayers of the endomembrane system.

Smooth Endoplasmic Reticulum (SER)

A region of the ER lacking ribosomes that synthesizes lipids, metabolizes polysaccharides, detoxifies drugs, and stores calcium ions ($Ca^{2+}$).

Rough Endoplasmic Reticulum (RER)

A region of the ER with ribosomes on its surface where proteins are folded and modified, and glycoproteins are secreted.

Golgi Apparatus

A stack of membranous sacs called cisternae that modifies, sorts, and packages products from the ER for shipping via transport vesicles.

Lysosomes

Sacs of hydrolytic enzymes that act as the cell stomach by breaking down complex molecules.

Vacuoles

Membrane-bound containers from the ER and Golgi used for maintenance, including food storage, pumping water (contractile), or holding water (central).

Binary Fission

The method of division used by prokaryotic cells, mitochondria, and chloroplasts.