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)
Gymnosperms
a vascular plant that bears naked seeds–seeds not enclosed in protective chambers
Angiosperms
a flowering plant, which forms seeds inside a protective chamber called an ovary
Alternation of generations
a life cycle in which there is both a multicellular diploid form, the sporophyte, and a multicellular haploid form, the gametophyte; characteristic of plants and some algae
Gametophyte
in organisms (plants and some algae) that have alternation of generations, the multicellular haploid form that produces haploid gametes by mitosis; the haploid gametes unite and develop into sporophytes
Sporophyte
in organisms (plants and some algae) that have alternation of generations, the multicellular diploid form that results from the union of gametes; meiosis in the sporophyte produces haploid spores that develop into gametophytes
Cuticle
a waxy covering on the surface of stems and leaves that prevents desiccation in terrestrial plants
Stomata
a microscopic pore surrounded by guard cells in the epidermis of leaves and stems that allows gas exchange between the environment and the interior of the plant
Antheridia
in plants, the male gametangium, a moist chamber in which gametes develop
Archegonia
in plants, the female gametangium, a moist chamber in which gametes develop
Xylem
vascular plant tissue consisting mainly of tubular dead cells that conduct most of the water and minerals upward from the roots to the rest of the plant
Phloem
vascular plant tissue consisting of living cells arranged into elongated tubes that transport sugar and other organic nutrients throughout the plant
Mycelium
the densely branched network of hyphae in a fungus
Hyphae
one of many connected filaments that collectively make up the mycelium of a fungus
Yeast
single-celled fungus; yeasts reproduce asexually by binary fission or by the pinching of small buds off a parent cell; many fungal species can grow both as yeasts and as a network of filaments; relatively few species grow only as yeasts
Septa
one of the cross-walls that divide a fungal hypha into cells; septa generally have pores large enough to allow ribosomes, mitochondria, and even nuclei to flow from cell to cell
Plasmogamy
in fungi, the fusion of the cytoplasm of cells from two individuals; occurs as one stage of sexual reproduction, followed later by karyogamy
Heterokaryotic
a fungal mycelium that contains two or more haploid nuclei per cell
Karyogamy
in fungi, the fusion of haploid nuclei contributed by the two parents; occurs as one stage of sexual reproduction, preceded by plasmogamy
Saprophytic
Saprotrophic nutrition or lysotrophic nutrition is a process of chemoheterotrophic extracellular digestion involved in the processing of decayed organic matter. It occurs in saprotrophs and heterotrophs, and is most often associated with fungi and soil bacteria.
Chytrids
a member of the fungal phylum Chytridiomycota, mostly aquatic fungi with flagellated zoospores that represent an early-diverging fungal lineage
Zygomycetes
a member of the fungal phylum Zygomycota, characterized by the formation of a sturdy structure called a zygosporangium during sexual reproduction
Yoke
referring to the fusion of two hyphal strands which produces zygospores
Glomeromycetes
a member of the fungal phylum Glomeromycota, characterized by a distinct branching form of mycorrhizae called arbuscular mycorrhizae
Arbuscular mycorrhizae (endomycorrhizal)
association of a fungus with a plant root system in which the fungus causes the invagination of the host (plant) cells’ plasma membranes
Ectomycorrhizal
association of a fungus with a plant root system in which the fungus surrounds the roots but does not cause invagination of the host (plant) cell’s plasma membrane
Ascomycetes
a member of the fungal phylum Ascomycota, commonly called sac fungus; the name comes from the saclike structure in which the spores develop
Basidiomycetes
a member of the fungal phylum Basidiomycota, commonly called club fungus; the name comes from the club-like shape of the basidium
Lichens
the mutualistic association between a fungus and a photosynthetic alga or cyanobacterium
Choanoflagellates
The choanoflagellates are a group of free-living unicellular and colonial flagellate eukaryotes considered to be the closest living relatives of the animals. Choanoflagellates are collared flagellates having a funnel shaped collar of interconnected microvilli at the base of a flagellum.
Traits shared by most animals
- Heterotrophic
- Multicellular
- Muscles and nerve cells
- Reproduce sexually (most)
Asymmetry
the lack or absence of symmetry
Radial symmetry
symmetry in which the body is shaped like a pie or barrel (lacking a left side and a right side) and can be divided into mirror-imaged halves by any plane through its central axis
Bilateral symmetry
body symmetry in which a central longitudinal plane divides the body into two equal but opposite halves
Coelomate
an animal that possesses a true coelem (a body cavity lined by tissue completely derived from mesoderm)
Acoelomate
a solid-bodied animal lacking a cavity between the gut and outer body wall
Pseudocoelomate
an animal whose body cavity is lined by tissue derived from mesoderm and endoderm
Endoderm
the innermost of the three primary germ layers in animal embryos; lines the archenteron and gives rise to the liver, pancreas, lungs, and the lining of the digestive tract in species that have these structures
Ectoderms
the outermost of the three primary germ layers in animal embryos; gives rise to the outer covering and, in some phyla, the nervous system, inner ear, and lens of the eye
Mesoderm
the middle primary germ layer in a triploblastic animal embryo; develops into the notochord, the lining of the coelem, muscles, skeleton, gonads, kidneys, and most of the circulatory system in species that have these structures
Deuterostome
in animals, a developmental mode distinguished by the development of the anus from the blastopore; often also characterized by radial cleavage and by the body cavity forming as outpockets of mesodermal tissue
Protostome
in animals, a developmental mode distinguished by the development of the mouth from the blastopore; often also characterized by spiral cleavage and by the body cavity forming when solid masses of mesoderm split
Hox genes
the master regulatory genes that control placement and spatial organization of body parts in animals, plants, and fungi by controlling the developmental fate of groups of cells
Adaptive radiations
period of evolutionary change in which groups of organisms form many new species whose adaptations allow them to fill different ecological roles in their communities
Plate tectonics
the theory that the continents are part of great plates of Earth’s crust that float on the hot, underlying portion of the mantle; movements in the mantle cause the continents to move slowly over time
Totipotent
describing a cell that can give rise to all parts of the embryo and adult, as well as extraembryonic membranes in species that have them
Innate immunity
a form of defense common to all animals that is active immediately upon exposure to a pathogen and that is the same whether or not the pathogen has been encountered previously
Adaptive immunity
a vertebrate-specific defense that is mediated by B lymphocytes (B cells) and T lymphocytes (T cells) and that exhibits specificity, memory, and self-nonself recognition; also called acquired immunity
Toll-like receptors
a membrane receptor on a phagocytic white blood cell that recognizes fragments of molecules common to a set of pathogens
TLR4
located on immune cell plasma membranes, recognizes lipopolysaccharide, a type of molecule found on the surface of many bacteria
TLR5
recognizes flagellin, the main protein of bacterial flagella
Lymphocyte
a type of white blood cell that mediates immune responses; the two main classes are B cells and T cells
B cells
the lymphocytes that complete their development in the bone marrow and become effector cells for the humoral immune response
T cells
the class of lymphocytes that mature in the thymus; they include both effector cells for the cell-mediated immune response and helper cells required for both branches of adaptive immunity
Clonal selection
the process by which an antigen selectively binds to and activates only those lymphocytes bearing receptors specific for the antigen; the selected lymphocytes proliferate and differentiate into a clone of effector cells and a clone of memory cells specific for the stimulating antigen
Hadean eon
(4600-4000 MYA)
Origin of Earth
Archean eon
(4000-2500 MYA)
Oldest known rocks on Earth’s surface
Oldest fossils of cells (prokaryotes) appear
Concentration of atmospheric oxygen begins to increase
Proterozoic eon
(2500-541 MYA)
Oldest fossils of eukaryotic cells appear
Diverse algae and soft-bodied invertebrate animals appear
Phanerozoic eon
(541 MYA-Present)
Marine algae abundant; colonization of land by diverse fungi, plants, and animals
Origin of genus Homo
Paleozoic era
Sudden increase in diversity of many animal phyla (Cambrian explosion)
Colonization of land by diverse fungi, plants, and animals
Mesozoic era
First mammals, first dinosaurs, first flowering plants, extinction of dinosaurs
Cenozoic era
Mammals diversify, human evolution
