1.2 Classification of Cells: Prokaryotic vs. Eukaryotic

Flashcards covering the characteristics of life, the differences between prokaryotic and eukaryotic cells, biological domains, and the nature of viruses based on the lecture notes.

Cell

A small membrane enclosed unit of life built with macromolecules that retains the characteristics of life.

Responsiveness

The ability of a cell to react to changing stimuli in its environment by altering its behavior.

Metabolism

The ability of a cell to take in or produce nutrients for survival and break them down through chemical reactions for restructuring.

Homeostasis

The ability to maintain a constant internal environment even though the external environment may fluctuate or change.

Central Dogma of Biology

The process where genetic information in DNA is transcribed into RNA, which is then translated into making proteins.

Genome

The complete set of genes in a cell that dictates the protein expression, structure, function, and behavior of that cell.

Prokaryotic Cells

Unicellular organisms that are very small ($2$ to $10\,\mu\text{m}$), simple, and lack a nucleus or membrane-bound organelles.

Eukaryotic Cells

Large, complex cells that can be unicellular or multicellular and contain a nucleus and membrane-bound organelles.

Nucleus

A membrane-bound structure in eukaryotic cells that encloses and protects the DNA.

Organelles

Membrane-bound structures within a eukaryotic cell that have specific shapes and performing different functions.

Cytosol

The fluid portion of the cell's cytoplasm where organelles and molecules are suspended.

Ribosomes

Structures found in all cell types that translate RNA into proteins.

Peptidoglycan

A semirigid layer that makes up the cell wall of prokaryotic cells, providing shape and preventing rupture.

Glycocalyx

A sugar-protein coating around a cell that provides virulence by protecting against a host's immune system.

Plasmids

Circular DNA found in some prokaryotic cells, as opposed to linear DNA.

Flagella

Long, whiplike extensions originating inside the cell that provide motility and locomotion.

Fimbrae

Short, hair-like extensions arising from the cell wall of bacteria that function in attachment rather than locomotion.

Cocci

Prokaryotic cells that are spherical or ball shaped.

Bacilli

Prokaryotic cells that are rod shaped; can occur as single cells or in chains.

Spirilla

Prokaryotic cells characterized by a helical or corkscrew shaped structure.

Vibrio

Prokaryotic cells shaped like a comma or a curved rod.

Archaea

A domain of prokaryotic cells known as extremophiles because they live in harsh environments like volcanic springs or freezing pools.

Heterotrophic

Organisms, such as those in kingdom Animalia, that must consume nutrients from the environment for energy.

Autotrophic

Organisms, such as plants, that can generate their own energy from inorganic materials and sunlight.

Cellulose

The carbohydrate that makes up the cell wall of plants to maintain shape and prevent water rupture.

Central Vacuole

A large organelle in plant cells filled with an aqueous solution that helps maintain turgor or shape.

Chloroplasts

Organelles containing the pigment chlorophyll, necessary for carrying out photosynthesis in plants.

Chitin

A glucose derivative that forms the cell wall in fungi.

Saprotrophic

Organisms that secrete enzymes to externally digest nutrients from decaying matter before absorbing them.

Protista

A diversified kingdom of mostly unicellular eukaryotic organisms that may be plant-like or animal-like.

Viruses

Nonliving infectious microbes that lack metabolism and can only replicate within a host cell.

Capsid

A protein coat that encloses the genetic material (DNA or RNA) of a virus.

Viral Envelope

A membrane surrounding a viral capsid that contains bits of the host cell's membrane to help infect the host.