Prokaryotic Cells Flashcards
What do all cells possess at the simplest level of construction?
Cytoplasm, chromosomes, and ribosomes.
What is cytoplasm?
A gel-like substance made of water and dissolved chemicals needed for growth, contained in the plasma membrane.
What are ribosomes used for?
Production of proteins.
What distinguishes prokaryotic cells?
They lack a nucleus and membrane-bound organelles, and have a single circular chromosome located in a nucleoid.
Which types of cells are prokaryotic?
Archaea and Bacteria.
What are the different cell morphologies?
Coccus (round), bacillus (rod), vibrio (curved rod), coccobacillus (short rod), spirillum (spiral), spirochete (long, loose helical spiral).
What are the arrangements of cocci?
Single coccus, diplococcus (two cocci), tetrad (group of 4 cells), streptococcus (chain of cocci), staphylococcus (cluster of cocci).
What are the arrangements of bacilli?
A single rod (bacillus), diplobacillus (two rods), streptobacillus (chain of rods), palisade (V or L shaped formation of rods).
How is morphology maintained in prokaryotic cells?
By the cell wall.
What is the function of the cell wall?
It protects the cells from changes in osmotic pressure.
What is osmosis?
The process where water diffuses across a semi-permeable membrane until concentrations become equal.
What are the types of external environments of a cell?
Isotonic (equal solute concentrations), hypertonic (solute concentration outside exceeds), hypotonic (solute concentration inside exceeds).
What are prokaryotic chromosomes like?
Typically circular, haploid/unpaired, and not bound by a complex membrane.
What are plasmids?
Small, circular double-stranded DNA molecules found in some cells, often carrying genes that provide advantages like antibiotic resistance.
What are ribosomes responsible for?
Protein synthesis.
What are inclusions in prokaryotic cells?
Cytoplasmic structures that store excess nutrients and reduce osmotic pressure.
What are types of nutrient inclusions?
Glycogen and starches, volutin granules, sulfur granules, and polyhydroxybutyrate (PHB).
What are gas vacuoles?
Accumulations of small, protein-lined vesicles of gas that allow cells to alter their buoyancy.
What are endospores?
Dormant structures that protect the bacterial genome under unfavorable conditions.
What is the process of sporulation?
The process in which vegetative cells turn into endospores when conditions become unfavorable.
What is the difference between vegetative and endospore cells?
Vegetative cells are sensitive to temperature and radiation, while endospores are resistant and dormant.
What is the plasma membrane?
The structure that encloses the cytoplasm and internal structures, exhibiting selective permeability.
What is the fluid mosaic model?
A description of the plasma membrane’s structure, where components move fluidly and consist of diverse lipids and proteins.
What is active transport?
The movement of molecules against the concentration gradient, requiring energy (ATP).
