2.5 Flashcards
What are prokaryotic cells characterized by?
No true nucleus, circular DNA, no membrane-bound organelles, smaller ribosomes (70S type)
Prokaryotic cells include bacteria and archaea, which lack a defined nucleus and organelles found in eukaryotic cells.
What is the function of the cell wall in a bacterial cell?
Physical barrier that protects against mechanical damage and excludes certain substances
The cell wall is primarily composed of peptidoglycan, which provides structural support.
What role does the capsule play in bacterial cells?
Protects bacterium from other cells and helps groups of bacteria to stick together for further protection
The capsule is a layer of mucilaginous slime that enhances bacterial survival.
What is the role of the cell-surface membrane in prokaryotic cells?
Acts as a differentially permeable layer that controls the entry and exit of chemicals
This membrane is crucial for maintaining homeostasis within the bacterial cell.
What is the function of flagella in some bacteria?
Aids movement of bacterium because its rigid corkscrew shape and rotating base help the cell spin through fluids
Not all bacteria possess flagella; they are present in specific types that require motility.
What is the genetic material in bacteria primarily composed of?
Circular DNA
This DNA is not organized into chromosomes like in eukaryotic cells.
What are plasmids and what is their significance in bacteria?
Small circular molecules of DNA that can reproduce independently and carry genes that aid survival
Plasmids often confer antibiotic resistance and are used as vectors in genetic engineering.
How do prokaryotic cells differ from eukaryotic cells regarding the presence of organelles?
Prokaryotic cells have no membrane-bound organelles, while eukaryotic cells do
Examples of membrane-bound organelles include mitochondria and the endoplasmic reticulum.
What is the size range of most bacteria?
0.1 to 10 micrometers in length
Their small size contributes to their adaptability and success in various environments.
True or False: Eukaryotic cells contain ribosomes that are smaller than those in prokaryotic cells.
False
Eukaryotic ribosomes (80S type) are larger than prokaryotic ribosomes (70S type).
What type of wall do most bacterial cells possess?
Cell wall made of peptidoglycan
This structure is essential for maintaining the shape and integrity of the bacterial cell.
Fill in the blank: Bacteria can produce enzymes that break down _______.
antibiotics
This ability is often linked to genes found on plasmids.
What is the role of ribosomes in bacteria?
Synthesize proteins
Despite being smaller, bacterial ribosomes are fully functional in protein synthesis.
What is the primary agent that causes cholera?
Vibrio cholerae
This bacterium is a curved, rod-shaped prokaryote responsible for the disease.
