Chapter 4.5: Compartmentalization Occurs in Prokaryotic Cells and Is Extensive in Eukaryotic Cells

Flashcards from Chapter 4.5 of Principles of Life, 3rd Edition.

Catabolism

The breaking down of complex molecules into simpler ones, releasing energy

Anabolism

The building up of complex molecules from simpler ones, requiring energy

Organelles

Membrane-enclosed compartments in the cytoplasm that separate cellular chemical reactions

Prokaryotes

Organisms in the domains Archaea and Bacteria, which are generally small, single-celled, and lack a nucleus or membrane-enclosed components, separating reactions via protein structures

Eukaryotes

Organisms including plants, fungi, protists, and animals, which are much larger and have membrane-enclosed organelles

Carboxysomes

Microcompartments in prokaryotes that convert CO₂ into carbohydrates

Metabolosomes

Compartments in prokaryotes that collect and break down toxic molecules

Encapsulin

A protein comprising prokaryotic structures that contain compartmentalized proteins, like peroxidase, which breaks down toxic molecules

Gas vesicle

Another prokaryotic compartment which adjusts buoyancy for optimal nutrient aquisition

Nucleoid

A region of the prokaryotic cell that contains the circular bacterial chromosome

Ribosomes

Large structures that comprise numerous proteins and RNAs for protein synthesis

Cyanobacteria

A unique group of prokaryotes that possesses membrane-enclosed structures for photosynthesis

Nucleus

The largest organelle, holding the cell’s DNA for replication and transcription; this is enclosed in the nuclear envelope with nuclear pores

Nucleolus

A region in the nucleus where ribosomes are formed

Chromosomes

These are made up of threads of DNA and protein, called chromatin

Endomembrane system

A system of membrane-enclosed compartments that modify and exchange material, including:

• The nuclear envelope

• Endoplasmic reticulum

• Golgi apparatus

• Lysosomes

Endoplasmic reticulum (ER)

A part of the endomembrane system with a distinct interior and high surface area, divided into rough and smooth variants depending on a cell’s function

Rough endoplasmic reticulum (RER)

A section of the endoplasmic reticulum with ribosomes for modification and transport

• This process can produce glycoproteins, for cell signaling

Smooth endoplasmic reticulum (SER)

A section of the endoplasmic reticulum that lacks ribosomes and has a more tubular shape, functioning for lipid synthesis, chemical detoxification, and calcium ion storage

Golgi apparatus

A stack of flattened membranous sacs called cisternae that further modifies proteins, which enter and exit on designated sides for sequential modification before being released elsewhere

Primary lysosomes

Organelles that originate from the Golgi apparatus and contain hydrolases for macromolecule digestion

Secondary lysosome

The product of a primary lysosome and a vesicle with nutrients after phagocytosis, allowing for digestion and waste production

Autophagy

The programmed destruction of cell components, carried out by lysosomes, in order to maintain homeostasis

Mitochondria

These break down energy-rich molecules in eukaryotic cells to produce ATP, and have their own autonomously dividing DNA to adjust to the needs of the cell

Cristae

The folds on the inner side of a mitochondria for greater surface area to perform energy metabolism

Chloroplast

A plastid in plants that has circular, autonomously dividing DNA like mitochondria, serving as the site of photosynthesis

Thylakoids

Flat, hollow discs inside chloroplasts that convert light energy to chemical bond energy

Stroma

The aqueous fluid inside a chloroplast surrounding the thylakoids that synthesize carbohydrates

Peroxisomes

Small organelles in eukaryotes that accumulate and break down toxic peroxides

Glyoxysomes

Organelles that convert lipids to carbohydrates in plants

Vacuole

A space in eukaryotic (particularly plant and fungi) cells that serves as waste product and pigment storage, structural support, and hydrolyzing centers

• May be contractile, forcefully expelling excess water through a pore structure