Any organism whose cells do not contain a nucleus.
If something is referred to as bacillus, what is it?
A rod-shaped bacterium.
If something is referred to as spirillum, what is it?
A spiral-shaped bacterium.
If something is referred to as coccus, what is it?
A sphere-shaped bacterium.
What is a chemoheterotroph?
An organism that must take in organic molecules for both energy and carbon.
What is a photoheterotroph?
An organism that is photosynthetic but needs needs organic compounds as a carbon source.
What is a photoautotroph?
An organism that uses energy from sunlight to convert carbon dioxide and water inti carbon compounds.
What is a chemoautotroph?
An organism that makes organic carbon molecules from carbon dioxide using energy from chemical reactions.
What is an obligate anaerobe?
An organism that must live in the absence of oxygen.
What is an obligate aerobe?
An organism that must have a constant supply of oxygen to survive.
What is a facultative anaerobe?
An organism that can survive with or without oxygen.
What is binary fission?
A type of asexual reproduction in which an organism an organism replicates its DNA and divides in half, producing two genetically identical daughter cells.
What is conjugation?
Form of sexual reproduction in which paramecia and some prokaryotes exchange genetic information.
What is an endospore?
Type of spore formed when a bacterium produces a thick internal wall that encloses its DNA and a portion of its cytoplasm.
What is nitrogen fixation?
The process by which nitrogen gas is converted into ammonia.
What is a virus?
A nonliving particle, made up of nucleic acid, protein, and sometimes lipids, that can only reproduce by infecting living cells.
What is a capsid?
The outer protein coat of a virus.
What is a bacteriophage?
A virus that infects and kills bacteria.
What is a lytic infection?
A type of infection in which a virus enters a cell, makes copies of itself, and causes the cell to burst, or lyse, hence the name lytic infection.
What is a lysogenic infection?
A type of infection in which a virus embeds its DNA into the host cell's DNA and then is replicated along with the rest of the cell's DNA. After some time, the viral DNA separates from the DNA of all of the cells it has infected and takes the steps a lytic infection would take.
What is a prophage?
The viral DNA embedded into a host cell's DNA during lysogenic infections.
What is a retrovirus?
A virus that contains RNA as its genetic information.
What is a pathogen?
A disease-causing agent.
What is a vaccine?
A preparation of weakened or killed pathogens. Administered to a person in order for them to build up immunity to the pathogen.
What is an antibiotic?
A compound that blocks the growth and reproduction of bacteria.
What is a viroid?
A single-stranded RNA molecule that has no surrounding capsid.
What is a prion?
An infectious particle made up of protein rather than a nucleic acid.
What are three ways eubacteria differ from archaebacteria?
Eubacteria have cell walls containing peptidoglycans. Archaebacteria have cell walls without peptidoglycan.
The DNA sequences of key archaebacterial genes are more like those of eukaryotes than those of eubacteria.
Eubacteria can be found almost everywhere. Archaebacteria live in extremely harsh environments.
What are four ways scientists identify prokaryotes?
By their shapes, by the chemical nature of their cell walls, by the way they move, and by the way they obtain energy.
What are two distinguishing characteristics of prokaryotes?
They do not contain a nucleus, and they are generally smaller than eukaryotic cells.
How do scientists distinguish between Gram-positive and Gram-negative bacteria?
Gram-positive bacteria are appear purple. Gram-negative bacteria appear pink or light red.
Gram-positive bacteria have cell walls with peptidoglycans. Gram-negative bacteria don't.
What does a typical virus consist of?
A DNA or RNA core and a protein coat (capsid).
What are the two ways in which bacteria produce disease?
Some bacteria damage the cells and tissues of the infected organism and break down the cells for food.
Others release toxins (poisons) that travel throughout the body and interfere with the normal activity of the host.
What are three ways to control bacterial growth?
Sterilization, disinfection, and food processing.
What is the general way in which viruses produce disease?
They disrupt the body's equilibrium.
How is a capsid protein important to the functioning of a virus?
They bind to repressors on the outside of a cell and trick the cell into allowing the virus inside.
Why are viruses highly specific to the cells they infect?
The capsid must bind precisely to the proteins on the cell's surface and the virus must use the host's genetic system.
If a bacterium contains chlorophyll a, then to what group of bacteria does it belong?
Cyanobacteria, a group of photoautotrophic bacteria.