Meet The Microbes Flashcards
What are the basic units of life?
Cells
Cells are the basic unit of life and biological structure and function.
What are unicellular organisms?
Single-celled organisms such as bacteria, algae, and protozoa
Examples include bacteria, algae, and protozoa.
What are multicellular organisms?
Organisms composed of more than one cell, organized into tissues and organs
Examples include plants and animals.
What does Cell Theory state?
- Cells are basic units of life. 2. All organisms are constructed of cells. 3. Cells arise from pre-existing cells.
No organism has been found that shows attributes of life that is not composed of cells.
What are the two types of cells based on internal organization?
Prokaryotes and Eukaryotes
Prokaryotes include bacteria and archaea; Eukaryotes include algae, yeast, fungi, protozoa, plants, and animals.
What characterizes eukaryotic cells?
Membrane-bound nucleus containing DNA organized into chromosomes and various organelles
Eukaryotes can be unicellular or multicellular.
What characterizes prokaryotic cells?
No nucleus, DNA localized in a region, and no membrane-bound organelles
All prokaryotes are independent, single-celled organisms.
What components make up a virus?
Genetic material (DNA or RNA), protein coat (capsid), and sometimes a lipid envelope
Viruses can only replicate inside a host.
What is the size range of bacteria?
Typically 1 – 10 μm
Eukaryotic cells are generally about 10 times larger than medium-sized bacteria.
What are the common shapes of bacteria?
Cocci (spherical), Bacilli (rod-shaped), Spirilla (spiral)
Shapes are important for identifying bacteria.
What is the primary function of the bacterial cell wall?
Provides shape, support, and protection to the plasma membrane
Composed of peptidoglycan polymers.
What are Gram-positive and Gram-negative bacteria?
Types of bacterial cell walls distinguished by their structure and staining properties
Gram-positive bacteria have a thick peptidoglycan layer; Gram-negative bacteria have a thinner layer and an outer membrane.
What is a plasmid?
Small circular rings of DNA that replicate independently of the chromosomal DNA
Plasmids can carry genes for antibiotic resistance.
How do bacteria move?
By taxis, often using a flagellum
Some bacteria cannot move independently and rely on external factors.
What is the prokaryotic genome like?
Consists of a single, circular chromosome and may include plasmids
Prokaryotes have about 1/1000 the DNA of eukaryotes.
