Cells and Cell Environments

Flashcards covering key vocabulary from lecture notes on cell types, structures, and their interactions with the environment, including osmosis and tonicity.

Cells

The smallest units of life; everything alive is made of cells.

Prokaryotic Cells

One of two main types of cells, lacking a membrane-bound nucleus and organelles.

Eukaryotic Cells

One of two main types of cells, possessing a true nucleus with a membrane and membrane-bound organelles.

Prokaryotes

Organisms made of prokaryotic cells, classified in the domains Bacteria or Archaea.

Eukaryotes

Organisms made of eukaryotic cells, placed in the domain Eukarya, can be unicellular or multicellular.

Domain Bacteria

Classification for true bacteria, prokaryotic organisms.

Domain Archaea

Classification for ancient prokaryotic organisms, often extremophiles, which may be newer than regular bacteria.

Extremophiles

Organisms that thrive in environments that are hard to live in, loving extreme conditions.

Unicellular Organisms

Organisms composed of a single cell.

Colonies (Prokaryotic)

Groups in which unicellular prokaryotes can live together, with individual cells remaining independent.

Nucleoid Region

The area in a prokaryotic cell where the single circular chromosome (DNA) is located, not surrounded by a membrane.

Chromosome (Prokaryotic)

A single, circular DNA molecule found in the nucleoid region of prokaryotic cells.

Cell Wall (Bacteria)

A rigid outer layer in bacterial cells, primarily made of peptidoglycan, providing strength and protection.

Peptidoglycan

The unique material making up the cell wall of bacteria.

Pseudo Peptidoglycan

A cell wall material found in some Archaea, different from bacterial peptidoglycan.

Haploid

A cell or organism having a single set of chromosomes; prokaryotes are haploid.

Linear Chromosomes

Rod-shaped chromosomes found in the nucleus of eukaryotic cells.

Chromatin

Decondensed or unwound DNA and associated proteins in eukaryotic cells when not undergoing mitosis or meiosis.

Membrane-Bound Organelles

Specialized structures within eukaryotic cells, such as chloroplasts, mitochondria, and Golgi apparatus, enclosed by membranes.

Extracellular Matrix (ECM)

A network of macromolecules found outside animal cells, providing structural support and other functions (e.g., in bone or cartilage).

Cellulose

A polysaccharide made of sheets of glucose, forming the cell walls of plant cells and some algae.

Chitin

A polysaccharide made of sugars and nitrogen, forming the cell walls of fungi.

Plasma Membrane

A phospholipid bilayer that surrounds the cytoplasm of all cells, regulating the passage of substances.

Capsule (Bacteria)

A jelly-like mass surrounding the cell wall of some bacteria, providing protection.

Ribosomes

Cellular structures in the cytoplasm where proteins are synthesized.

Inclusions

Particles of stored substances (like starch or lipids) in the cytoplasm that the cell needs to use.

Plasmids

Small, circular DNA molecules separate from the main chromosome, containing a few genes, found in prokaryotic cells and some eukaryotes like yeast.

Fimbriae

Hair-like structures on the outside of some bacterial cells that help them stick to surfaces.

Flagella

Tail-like structures that enable some cells (both prokaryotic and eukaryotic) to move.

Pili (Pellis)

A tube-like structure that allows some bacteria to connect to other cells and transmit plasmids.

Cytoskeleton

An internal structure made of protein fibers that supports the cell, allows communication, and serves as a track for cell structures (simpler in prokaryotes).

Cytosol

The gel-like liquid portion of the cytoplasm, the cell's solution.

Cytoplasm

All the material within a cell, enclosed by the plasma membrane, excluding the nucleus in eukaryotes (includes cytosol and embedded structures).

Solvent

The substance present in the greatest amount in a solution, typically water in living systems.

Aqueous Solution

A solution where water is the solvent.

Solutes

Substances that dissolve in a solvent (and thus in a solution), such as ions, organic compounds, or respiratory gases.

Extracellular Fluid (ECF)

The fluid found outside the cell, which is also a solution with its own level of solutes.

Osmotic Pressure

The pressure caused by water moving in and out of the cell across a semipermeable membrane; greatest where there is the most solute.

Osmosis

The movement of water across a semipermeable membrane from an area of high water concentration to an area of low water concentration, or where water follows solute.

Isotonic Solution

An extracellular fluid with the same solute concentration as inside the cell, resulting in no net water movement and a happy cell.

Hypertonic Solution

An extracellular fluid with a higher solute concentration than inside the cell, causing water to leave the cell.

Hypotonic Solution

An extracellular fluid with a lower solute concentration than inside the cell, causing water to enter the cell.

Plasmolysis

The process where the cell membrane pulls away from the cell wall in a hypertonic solution, particularly in bacterial cells, often leading to cell death.

Crenation

The shriveling of an animal cell (without a cell wall) in a hypertonic solution, eventually leading to cell death.

Nucleoid Associated Proteins (NAPs)

Proteins that package or hold DNA together in the circular chromosome of bacteria.

Histone Proteins

Proteins associated with DNA packaging in eukaryotic cells and often in Archaea, making Archaea more similar to eukaryotes than bacteria.

Extrachromosomal DNA

DNA found outside the main chromosome, such as plasmids.