Cell Biology: Cell Theory, Prokaryotes, and Eukaryotic Organelles

Vocabulary practice covering the fundamentals of cell theory, classifications of prokaryotic and eukaryotic cells, bacterial shapes, and the structure/function of organelles like the ER and Golgi apparatus.

Cell

The smallest unit of a living thing and the basic structural and functional unit of every organism.

Cell Theory

A biological principle stating: I. Cells are the basic living units of organization and function in all organisms. II. All cells come from existing cells.

Prokaryotes

Unicellular microorganisms from the domains Bacteria and Archaea that lack a nucleus and membrane-bound organelles.

Eukaryotes

Organisms that can be unicellular (like yeast or Chlamydomonas) or multicellular (plants and animals), characterized by having a nucleus and membrane-bound organelles.

Nucleoid

The region in a prokaryotic cell where the DNA is located.

Binary fission

A type of asexual reproduction used for cell division in prokaryotes due to their lack of a nucleus.

Peptidoglycan

The substance that makes up the cell walls of prokaryotes.

Cellulose

The material that composes the cell walls of plants and algae.

Chitin

The substance found in the cell walls of fungi.

Plasma membrane

A selective barrier and basic feature of all cells that acts as the cell surface membrane.

Cytosol

The semifluid or jellylike substance inside a cell where organelles are suspended.

Ribosomes

The protein factories of the cell and the site of protein synthesis; they are smaller and free in prokaryotes, but larger and either free or ER-bound in eukaryotes.

Chromosomes

Structures within the cell that carry genes in the form of DNA.

Mesosomes

Structures in bacteria that serve as the site for cellular respiration and ATP production.

Chloroplast

An organelle present in plant cells and algae that is the site of photosynthesis; cyanobacteria have photosynthetic lamellae instead.

Tonoplast

The membrane surrounding the large permanent central vacuole in plant cells.

Plasmodesmata

Channels and pits present in the cell walls of plants that allow for communication and transport between adjacent cells.

Glycogen granules

The form in which animal cells store carbohydrates.

Starch granules

The form in which plant cells store carbohydrates.

Cisternae

A network of membranous tubules and flattened sacs that make up the structure of the Endoplasmic Reticulum and Golgi apparatus.

ER lumen

The internal cisternal space of the Endoplasmic Reticulum that is separated from the cytosol by the ER membrane.

Smooth Endoplasmic Reticulum (SER)

A system of interconnected tubules lacking ribosomes involved in metabolizing lipids, synthesizing steroids like testosterone, and detoxifying drugs and poisons.

Rough Endoplasmic Reticulum (RER)

A region of the ER studded with ribosomes that acts as a membrane factory and produces secretory proteins such as glycoproteins.

Glycoprotein

A type of secretory protein produced in the RER that has carbohydrates attached to it.

Transport vesicle

A membranous vesicle that buds off from the RER to transit proteins from one part of the cell to another.

Golgi apparatus

A receiving and shipping center of the cell that modifies products of the ER; it consists of cis (receiving), medial (middle), and trans (shipping) regions.

Cocci

Spherical-shaped bacteria, such as Streptococcus pneumoniae, Streptococcus pyogenes (Streptococci), and Staphylococcus aureus (Staphylococci).

Bacilli

Rod-shaped bacteria, such as Bacillus anthracis, Salmonella typhi (flagellate rods), and Clostridium botulinum (spore-former).

Spirals

Bacterial shapes including Vibrios (Vibrio cholerae), Spirilla (Helicobacter pylori), and Spirochaetes (Treponema pallidum).

Prokaryotic Cell Size

Typically ranges between $0.1-0.5\,\mu\text{m}$, making them smaller than eukaryotic cells.