Cell Organelles and Kingdoms of Life Vocabulary

Vocabulary flashcards based on lecture notes covering cell structures, organelles, and prokaryotic kingdom classifications.

Prokaryotic Cell

A cell that does not contain a nucleus or other membrane-bound organelles (e.g., archaebacteria).

Eukaryotic Cell

A cell that contains a nucleus and other organelles, each surrounded by a thin membrane (e.g., multicellular organisms such as fungi, animals, and plants).

Organelles

Specialized cell structures within eukaryotic cells that perform specific functions to keep the cell alive, use energy, and reproduce (e.g., nucleus, vacuoles, golgi bodies).

Cytoplasm

Also known as cytosol, a jelly-like fluid in plant and animal cells where organelles float; it allows organelles to move around, store materials, and serves as the site for chemical reactions.

Cell Membrane

Also known as the plasma membrane, a dynamic barrier consisting of a flexible double layer of phospholipids that surrounds the cytosol, controls the movement of substances in and out of the cell, and maintains the internal environment.

Nucleus

The control center (brain) of eukaryotic cells that contains DNA, protects DNA from cytosol reactions, and controls cell division, cell activity, and the formation of cell structures.

Nuclear Envelope

The two-lipid layer membrane enclosing the nucleus of a eukaryotic cell that allows substances to enter and exit, with an outer layer extending into the endoplasmic reticulum.

Nucleolus

A rounded mass of proteins inside the nucleus where the construction of ribosomal subunits occurs for RNA, surrounded by DNA outside this area.

Endoplasmic Reticulum (ER)

A network of fluid-filled branching tubes and proteins extending from the nuclear envelope around the nucleus, functioning primarily to make lipids, enzymes, and other proteins.

Rough ER

A sub-kind of endoplasmic reticulum used to make protein chains and transport them.

Smooth ER

A sub-kind of endoplasmic reticulum that produces lipids and breaks down large molecules such as carbohydrates and some drugs.

Ribosomes

Spherical structures found in clusters or attached to the endoplasmic reticulum that receive signals from the nucleus to make proteins.

Golgi Bodies

Stacked pancake-like or layered pieces that collect and pack materials to be removed from the cell, prepare proteins and lipid (fat) molecules for use inside or outside the cell, and put finishing touches on protein chains delivered from the ER.

Mitochondria

Organelles (singular: mitochondrion) sometimes called "power plants" that provide the cell with a form of stored chemical energy ($\text{ATP}$).

Chloroplast

Plant-only organelles containing chlorophyll that give plants their green color and absorb light energy to turn it into glucose and oxygen.

Vesicles

Fluid-filled sacs found in animal cells (many per cell) that store waste and essential molecules needed for metabolism and transport material around the cell.

Vacuoles

Fluid-filled sacs in plant cells (typically only one per plant cell) that store waste and essential molecules for metabolism, keeping the cell rigid so plant stems and leaves remain firm.

Lysosome

Spherical organelles found only in animal cells that contain digestive enzymes to digest waste, cellular debris, break down excess or worn-out cell parts, and destroy invading viruses or bacteria.

Cell Wall

A supportive layer located just outside the cell membrane found only in plants that provides support for the cell and protection from physical injury.

Cytoskeleton

A network of protein filaments running through the cytoplasm that supports cell shape, anchors organelles, acts as a "railway" for transport, and helps with cytokinesis and overall cell movement.

Centrioles

Small cylindrical organelles usually found in pairs only in animal cells that create spindle fibers for cell division (mitosis/meiosis) and separate chromosomes by anchoring and organizing microtubules.

Hemifusome

A new organelle (2026) that acts as a specialized loading dock or sorting station where vesicles connect and transfer cargo, playing a key role in cellular recycling and waste disposal.

6 Kingdoms

The six overarching categories of life: Eubacteria, Archaebacteria, Protista, Fungi, Plants, and Animals.

Eubacteria

A kingdom and domain of unicellular prokaryotes commonly called bacteria (e.g., Staphylococcus) with cell walls made of peptidoglycan, reproducing asexually via binary fission.

Archaea

A domain and kingdom (archaebacteria) of unicellular prokaryotes (e.g., Sulfolobus archaea) with cell walls not made of peptidoglycan (or occasionally no cell wall) that reproduce asexually.

Pathogens

Infectious bacteria that are harmful from the point of view of the infected organism.

Binary Fission

The primary method of asexual reproduction used by prokaryotes (Eubacteria and Archaea) instead of mitosis.

Antibiotics

Substances produced by bacteria that can kill or weaken microorganisms.