Exam II Flashcards
(101 cards)
Protocell
an abiotic precursor of a living cell that had a membrane-like structure and that maintained an internal chemistry different from that of its surroundings
Cocci
any spherical or roughly spherical bacteria
Bacilli
a rod-shaped bacterium
Spirilla
any curved bacteria
Gram stain
Samples are first stained with crystal violet dye and iodine, then rinsed in alcohol, and finally stained with a red dye such as safranin that enters the cell and binds to its DNA.
Gram-positive
Bacteria have relatively simple walls composed of a thick layer of peptidoglycan.
Gram-negative
Bacteria have less peptidoglycan and are structurally more complex, with an outer membrane that contains lipopolysaccharides.
Photoautotroph
any organism that derives its energy for food synthesis from light and is capable of using carbon dioxide as its principal source of carbon
Chemoautotroph
an organism, typically a bacterium, that derives energy from the oxidation of inorganic compounds
Photoheterotroph
organisms that use light for energy but cannot use carbon dioxide as their sole carbon source
Chemoheterotroph
an organism which derives its energy from chemicals and needs to consume other organisms in order to live
Extremophile
an organism that lives in environmental conditions so extreme that few other species can survive there; extremophiles include extreme halophiles (“salt lovers”) and extreme thermophiles (“heat lovers”)
Endotoxins
a toxic component of the outer membrane of certain gram-negative bacteria that is released only when the bacteria die
Exotoxins
a toxic protein that is secreted by a prokaryote or other pathogen and that produces specific symptoms, even if the pathogen is no longer present
Botulism
a rare poisoning caused by toxins produced by Clostridium botulinum bacteria;
Botulism can be fatal and requires emergency medical care. It can occur in infants, be spread in food, or infect a wound.
Symptoms include difficulty swallowing or speaking, facial weakness, and paralysis.
Treatments are an antitoxin injection and breathing assistance.
Anthrax
a rare but serious bacterial illness;
Anthrax is caused by a spore-forming bacterium. It mainly affects animals. Humans can become infected through contact with an infected animal or by inhaling spores.
Symptoms depend on the route of infection. They can range from a skin ulcer with a dark scab to difficulty breathing.
Antibiotic treatment cures most infections. Inhaled anthrax is harder to treat and can be fatal.
Tetanus
a serious bacterial infection that causes painful muscle spasms and can lead to death;
Tetanus is a potentially fatal bacterial infection that affects the nerves. A vaccine can easily prevent the infection, which has no cure.
Tetanus causes painful muscle contractions, particularly in the jaw and neck. It can interfere with the ability to breathe, eventually causing death.
Treatment focuses on managing complications.
Cholera
a bacterial disease causing severe diarrhea and dehydration, usually spread in water;
Cholera is rare in industrialized countries. It’s fatal if not treated right away.
Key symptoms are diarrhea and dehydration. Rarely, shock and seizures may occur in severe cases.
Treatment includes rehydration, IV fluids, and antibiotics.
Salmonella
an infection with salmonella bacteria, commonly caused by contaminated food or water;
Salmonella is most common among children. People with compromised immune systems, such as older adults, babies, and people with AIDS, are more likely to have severe cases.
Symptoms include diarrhea, fever, chills, and abdominal pain.
Most people only need fluids to recover in less than a week. Severe infections may require medical care including IV fluids and sometimes antibiotics.
Lyme’s disease
a tick-borne illness caused by the bacterium Borrelia burgdorferi;
Deer ticks can carry the bacteria that causes Lyme disease.
Lyme disease causes a rash, often in a bull’s-eye pattern, and flu-like symptoms. Joint pain and weakness in the limbs also can occur.
Most people with Lyme disease recover completely with appropriate antibiotic treatment. For those who develop syndromes after their infection is treated, pain medications may provide symptomatic relief.
Chlamydia
a common sexually transmitted infection that may not cause symptoms;
Chlamydia affects people of all ages but is most common in young women.
Many who have chlamydia don’t develop symptoms, but they can still infect others through sexual contact. Symptoms may include genital pain and discharge from the vagina or penis.
Antibiotic therapy for the affected patient and the patient’s sexual partners is recommended. Screening for other common sexually transmitted infections should also be performed.
Stromatolite
layered rock that results from the activities of prokaryotes that bind thin films of sediment together
Oxygen revolution
the biologically induced appearance of dioxygen in Earth’s atmosphere 2300 million years ago
Mixotrophy
an organism that is capable of both photosynthesis and heterotrophy
