Exam II Flashcards
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
Endosymbiosis
a relationship between two species in which one organism lives inside the cell or cells of another organism
Secondary endosymbiosis
a process in eukaryotic evolution in which a heterotrophic eukaryotic cell engulfed a photosynthetic eukaryotic cell, which survived in a symbiotic relationship inside the heterotrophic cell
Excavata
one of four supergroups of eukaryotes proposed in a current hypothesis of the evolutionary history of eukaryotes; excavates have unique cytoskeletal features, and some species have an “excavated” feeding groove on one side of the cell body
Trypanosoma
Trypanosoma is a genus of kinetoplastids, a monophyletic group of unicellular parasitic flagellate protozoa. The name is derived from the Greek trypano- and soma because of their corkscrew-like motion. Most trypanosomes are heteroxenous and most are transmitted via a vector.
Trichomonas
Trichomonas is a genus of anaerobic excavate parasites of vertebrates. It was first discovered by Alfred François Donné in 1836 when he found these parasites in the pus of a patient suffering from vaginitis, an inflammation of the vagina. Donné named the genus from its morphological characteristics. The prefix tricho- originates from the Ancient Greek word thrix meaning hair, describing Trichomonas’s flagella. The suffix -monas (single unit), describes its similarity to unicellular organisms from the genus Monas.
Euglena
Euglena is a genus of single cell flagellate eukaryotics. It is the best known and most widely studied member of the class Euglenoidea, a diverse group containing some 54 genera and at least 800 species. Species of Euglena are found in freshwater and salt water.
SAR
one of four supergroups of eukaryotes proposed in a current hypothesis of the evolutionary history of eukaryotes; this supergroup contains a large, extremely diverse collection of protists from three major subgroups: stramenopiles, alveolates, and rhizarians
Plasmodium
Plasmodium is a genus of unicellular eukaryotes that are obligate parasites of vertebrates and insects. The life cycles of Plasmodium species involve development in a blood-feeding insect host which then injects parasites into a vertebrate host during a blood meal.
Stramenopiles
The heterokonts or stramenopiles are a major line of eukaryotes currently containing more than 25,000 known species. Most are algae, ranging from the giant multicellular kelp to the unicellular diatoms, which are a primary component of plankton.
Alveolates
The alveolates are a group of protists, considered a major clade and superphylum within Eukarya, and are also called Alveolata.
Archaeplastida
one of four supergroups of eukaryotes proposed in a current hypothesis of the evolutionary history of eukaryotes; this monophyletic group, which includes red algae, green algae, and plants, descended from an ancient protistan ancestor that engulfed a cyanobacterium
Unikonta
one of four supergroups of eukaryotes proposed in a current hypothesis of the evolutionary history of eukaryotes; this clade, which is supported by studies of myosin proteins and DNA, consists of amoebozoans and opisthokonts
Chlorophytes
7000+ algae species; most live in freshwater
Charophytes
the algae most closely related to plants
Bryophytes
an informal name for a moss, liverwort, or hornwort; a nonvascular plant that lives on land but lacks some of the terrestrial adaptations of vascular plants
Monilophytes
an informal name for a member of the phylum Monilophyta, which includes ferns, horsetails, and whisk ferns and their relatives (seedless vascular plants)
