Prokaryotes Flashcards
What 2 of life’s 3 domains entirely consists of prokaryotes?
Bacteria and Archaea.
What are prokaryotes?
Single-celled organisms that lack organelles such as the nucleus, chloroplasts, and mitochondria.
Are prokaryotes all one size and shape?
No they differ in size and shape, but usually they are very small.
How do prokaryotes survive?
Some are motile meaning they can move about, others adhere to a surface or drift passively in liquid surroundings. Many bacteria form films on surfaces. Protective endospores allow bacteria to withstand adverse conditions. They are specialized for specific habitats and have diverse metabolisms.
How do prokaryotes reproduce?
They reproduce asexually by binary fission.
How do prokaryotes affect humans and other organisms?
They play important roles in animal and human nutrition. They capture nitrogen for plants and feed nitrogen to the plants so that the plants can grow. Prokaryotes breakdown complex organic molecules. They also clean up pollution. Some bacteria harm humans though by causing them to get diseases.
What are nitrogen-fixing bacteria? And what do they do to help plants?
Bacteria that live in soil and in specialized nodules. They capture nitrogen from air trapped in soil and combine it with hydrogen to produce ammonium a nitrogen containing nutrient that plants can use directly.
Are viruses composed of cells?
No they are not composed of cells.
Can viruses on their own accomplish the tasks of living cells perform?
No
What are viruses composed of?
A molecule of DNA or RNA surrounded by a protein coat.
What are viroids?
Infectious particles that lack a protein coat and consists of nothing more than short circular strands of RNA.
What are Prions?
An infectious agent that consists of only protein.
