Test 3 Semester 2 Flashcards
What is a virus?
A particle made of nucleic acid protein and in some cases lipids
How do viruses reproduce?
Viruses invade host cell and use cells to make proteins
What are viruses not considered living?
They don’t die, they crystallize, and they are not made of cells
Marine Bacteriophage?
Viruses that infect bacteria
What happens when viruses enter a cell?
Lytic infection or lysogenic infection will occur
Lyctic infection?
When a virus enters a cell it makes copies of it’s self and causes the cell to burst, releasing new virus particles that attack other cells.
Lysogenic infection?
A virus integrates part of it’s DNA called a prophage into the DNA host cell. The viral genetic information replicates along with the host cell’s DNA. Eventually the prophage will remove it’s self from the host cell DNA and make new virus particles. (Can become a lytic infection)
What are RNA viruses?
Contains RNA
uses host cell to copy/translate
What is a retrovirus?
A virus where the genetic information is copied backward from RNA to DNA instead of from DNA to RNA, then the DNA is inserted into the genome of the cell
What are prokaryotes?
unicellular organisms that lack a nucleus
How are prokaryotes classified?
They are classified either in domain bacteria or domain archaea
Bacteria vs. Archaea
Bacteria: is surrounded by a cell wall which contains peptidoglycan. Inside the cell wall is a membrane surrounding the cytoplasm.
Archaea: look similar to bacteria but are genetically closer to eukaryotes. Archaea lack peptidoglycan and have different membrane lipids than Bacteria.
What kind of environments are Archaea found in?
extreme conditions hot or cold volcano vent geysers & hot springs dead sea "black smokers" deep sea vents
How do prokaryotes differ in their form and function?
Bacili: are rod shaped
Cocci: are spherical
Spirilla: are spiral or corkscrew
Ecological role of prokaryotes?
- decomposers (break down dead matter)
- producers (carry out photosynthesis)
- some soil bacteria convert natural nitrogen gas into a form plants can use through a process called nitrogen fixation
- humans use bacteria in industry, food production, and other ways
