Exam 1 Flashcards
Biology
The science of life
Cell Theory
The scientific theory that the cell is the basic unit of life, of which all living things are composed, and that all cells are derived from pre-existing cells.
Systematics
The scientific study of the diversity of organisms and their evolutionary relationships. Taxonomy is an aspect of systematics. See taxonomy.
Pathogens
An organism, usually a microorganism, capable of producing disease.
Protists
One of a vast informal group of eukaryotic organisms, primarily unicellular or simple multicellular; mostly aquatic.
Evolution.
Any cumulative genetic changes in a population from generation to generation. Leads to differences in populations and explains the origin of all the organisms that exist today or have ever existed.
Homeostasis
The balanced internal environment of the body; the automatic tendency of an organism to maintain such a steady state.
Biological diversity or biodiversity
The variety of living organisms considered at three levels: genetic diversity, species diversity, and ecosystem diversity.
Prokaryotes
A cell that lacks a nucleus and other membrane-enclosed organelles; includes the bacteria and archaea (kingdoms Bacteria and Archaea). Compare with eukaryote.
Colonies
An association of loosely connected cells or individuals of the same species.
Cells
Vary greatly in size and appearance, basic unit that all organisms consist of.
Plasma Membrane
The selectively permeable surface membrane that encloses the cell contents and through which all materials entering or leaving the cell must pass.
Evolution
Any cumulative genetic changes in a population from generation to generation. Evolution leads to diff erences in populations and explains the origin of all the organisms that exist today or have ever existed.
coccus (pl., cocci)
A bacterium with a spherical shape. Compare with bacillus, spirillum, vibrio, and spirochete.
Coenocytic
An organism consisting of a multinucleate cell, i.e., the nuclei are not separated from one another by septa.
Unicellular organisms
Some of the simplest life-forms, each consists of a single cell.
Multicellular organisms
May consist of billions of cells specialized to perform specific functions.
Plasma membrane
Every cell is enveloped by a protective plasma membrane that separates it from the surroundings external environment.Regulates passage of material between the cell and its environment.
Organelles
One of the specialized structures within the cell, such as the mitochondria, Golgi complex, ribosomes, or contractile vacuole; many organelles are membrane-enclosed.
Microvilli
(sing., microvillus) Minute projections of the plasma membrane that increase the surface area of the cell; found mainly in cells concerned with absorption or secretion, such as those lining the intestine or the kidney tubules.
Light microscope (LM)
consists of a tube with glass lenses at each end. Because it contains several lenses, the modern light microscope is referred to as a compound microscope. Visible light passes through the specimen being observed and through the lenses. Light is refracted (bent) by the lenses, magnifying the image. Images obtained with light microscopes are referred to as light micrographs, or LMs.
Taxonomy
The science of naming, describing, and classifying organisms; see systematics.
Classification
arranging organisms into groups based on similarities that reflect evolutionary relationships among lineages.
Binomial system of nomenclature
System of naming a species by the combination of the genus name and a specific epithet.
bacillus (pl., bacilli)
A rod-shaped bacterium. Compare with coccus, spirillum, vibrio, and spirochete.
spirochete
A long, flexible, helical bacterium. Compare with spirillum, vibrio, bacillus, and coccus.
spirillum (pl., spirilla)
A long, rigid, helical bacterium. Compare with spirochete, vibrio, bacillus, and coccus.
Mutualism
In ecology, a symbiotic relationship in which both partners benefi t from the association. Compare with parasitism and commensalism.
Commensalism
A type of symbiosis in which one organism benefi ts and the other one is neither harmed nor helped. Compare with mutualism and parasitism.
Deoxyribonucleic acid, DNA
Double-stranded nucleic acid; contains genetic information coded in specific sequences of its constituent nucleotides.
Magnification
the ratio of the size of the image seen with the microscope to the actual size of the object.
genus (pl., genera)
A taxonomic category made up of related species.
vibrio.
A spirillum (spiral-shaped bacterium) that is shaped like a comma. Compare with spirillum, spirochete, bacillus, and coccus.
Parasitism
A symbiotic relationship in which one member (the parasite) benefi ts and the other (the host) is adversely affected. Compare with commensalism and mutualism.
Organelles
Internal structure of cells that are specialized to perform specific functions.
Resolution aka resolving power
The ability of a microscope to show fine detail, defined as the minimum distance between two points at which they are seen as separate images.
specific epithet
The second part of the name of a species designates a specific species belonging to that genus.
nuclear area, also referred to as the nucleoid,
Region of a prokaryotic cell that contains DNA; not enclosed by a membrane. Also called nucleoid.
Plankton
Free-floating, mainly microscopic aquatic organisms found in the upper layers of the water; consisting of phytoplankton and zooplankton. Compare with nekton.
Prokaryotic cells
Exclusive to bacteria and to microscopic organisms called archaea.Do not have a nucleus or other membrane-enclosed organelles.
Electron microscope (EM)
A microscope capable of producing highresolution, highly magnified images through the use of an electron beam (rather than light). Transmission electron microscopes (TEMs) produce images of thin sections; scanning electron microscopes (SEMs) produce images of surfaces.
Family
A taxonomic category made up of related genera.
Cell wall
The structure outside the plasma membrane of certain cells; may contain cellulose (plant cells), chitin (most fungal cells), peptidoglycan and/or lipopolysaccharide (most bacterial cells), or other material.
serial endosymbiosis
The hypothesis that certain organelles such as mitochondria and chloroplasts originated as symbiotic prokaryotes that lived inside other, free-living prokaryotic cells.
Eukaryotic cells
Typically contains a variety of organelles enclosed by membranes, including a nucleus, which houses DNA
Nucleus
Houses DNA (1) The central reason of an atom that contains the protons and neutrons. (2) A cell organelle in Eukaryotes that contain the DNA and serves as the control center of the cell. (3) A mass of nerve cell bodies in the central nervous system.
Biological growth
Involves an increase in the size of individual cells of an organism, in the number of cells, or in both.
Development
All the progressive changes that take place throughout the life of an organism.
Ultrastructure
Fine details of cells obtained by the electron microscope
Cell fractionation
The technique used to separate the components of cells by subjecting them to centrifugal force. See differential centrifugation and density gradient centrifugation
orders
A taxonomic category made up of related families.
classes
A taxonomic category made up of related orders.
phylum (pl., phyla)
A taxonomic grouping of related, similar classes; a category beneath the kingdom and above the class.
kingdoms
A broad taxonomic category made up of related phyla; many biologists currently assign living organisms to five kingdoms and several “supergroups”.
peptidoglycan
A modified protein or peptide having an attached carbohydrate; component of the bacterial cell wall.
Gram-positive
A thick layer of peptidoglycan molecules is held together by amino acids. Contain peptidoglycan.
Gram-negative
A thin layer of peptidoglycan is covered by an outer membrane.
Capsule or slime layer
(1) The portion of the moss sporophyte that contains spores. (2) A simple, dry, dehiscent fruit that develops from two or more fused carpels and opens along many sutures or pores to release seeds. (3) A gelatinous coat that surrounds some bacteria.
Monophylectic
A group of organisms that includes a recent common ancestor and all its descendants; a clade. Compare with polyphyletic group and paraphyletic group.
Paraphyletic group
A group of organisms made up of a common ancestor and some, but not all, of its descendants. Compare with monophyletic group and polyphyletic group.
Excavates
A diverse group of unicellular protists with flagella. These protists are so named because many have a deep, or excavated, oral groove. Unlike other protists, excavates have atypical, greatly modified mitochondria. Many excavates are endosymbionts and live in anoxic (without oxygen) environments. These excavates do not carry out aerobic respiration; they obtain energy by the anaerobic pathway of glycolysis (presumably by fermentation.
Metabolism
The sum of all the chemical activities of the organisms
Homeostasis
an appropriate, balanced internal environment.
Stimuli
Physical or chemical changes in their internal or external environment.
Cilia (pl.) (cilium, sing.)
One of many short, hairlike structures that project from the surface of some eukaryotic cells and are used for locomotion or movement of materials across the cell surface.
Centrifuge
A device used to separate cells or their components by subjecting them to centrifugal force.
differential centrifugation
Separation of cell particles according to their mass, size, or density. In differential centrifugation, the supernatant is spun at successively higher revolutions per minute.
density gradient centrifugation
Procedure in which cell components are placed in a layer on top of a density gradient, usually a sucrose solution and water. Cell structures migrate during centrifugation, forming a band at the position in the gradient where their own density equals that of the sucrose solution.
Prokaryotic cell
One of the two basic type of cells, bacteria and archaea are prokaryotic cells.
domains
(1) A structural and functional region of a protein. (2) The broadest taxonomic category; each domain includes one or more kingdoms.
taxon (pl., taxa)
A formal taxonomic group at any level, e.g., phylum or genus.
Plantae
One of two kingdoms for organisms.
Animalia
One of two kingdoms for organisms.
Pili (sing., pilus)
Hairlike structures on the surface of many bacteria; function in conjugation or attachment.
fimbriae (sing., fi mbria).
Hairlike structures that project from the cell surface of some prokaryotes; help bacteria to adhere to one another and to attach to the surfaces of cells they infect.
Endospores
A resting cell formed by certain bacteria; highly resistant to heat, radiation, and disinfectants.
Flagella
A long, whiplike structure extending from certain cells and used in locomotion. (1) Eukaryote flagella consist of two central, single microtubules surrounded by nine double microtubules (9 + 2 structure), all covered by a plasma membrane. (2) Prokaryote flagella are filaments rotated by special structures located in the plasma membrane and cell wall.
Diplomonads
Small, mostly parasitic zooflagellates with one or two nuclei, no functional mitochondria, and 2 or more flagella
Parabasalids
Anaerobic, flagellated excavates that often live in animals; examples include trichonymphs and trichomonads.
Trichonymphs
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trichomonad
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Cell theory
The scientific theory that the cell is the basic unit of life, of which all living things are composed, and that all cells are derived from pre-existing cells.
Nuclear area or nucleoid
Region of a prokaryotic cell that contains DNA; not enclosed by a membrane. Also called nucleoid.
Protista
Ernst Haeckel, proposed that a third kingdom, Protista, be established to accommodate bacteria and other microorganisms. However, biologists largely ignore this suggestion.
Chemotaxis
movement in response to chemicals in the environment.
euglenoids
A group of mostly freshwater, flagellate, unicellular algae that move by means of an anterior flagellum and are usually photosynthetic.
Flagella (pl.) flagellum (sing.)
A long, whiplike structure extending from certain cells and used in locomotion. (1) Eukaryote flagella consists of two central, single micro tubules surrounded by nine double microtubules (9+2 structure), all covered by a plasma membrane. (2) Prokaryote flagella are filaments rotated by special structures located in the plasma membrane and cell wall.
Sessile
Permanently attached to one location, e.g., coral animals.
Flagella (sing. Flagellum)
A long, whiplike structure extending from certain cells and used in locomotion. (1) Eukaryote flagella consist of two central, single microtubules surrounded by nine double microtubules (9 + 2 structure), all covered by a plasma membrane. (2) Prokaryote flagella are filaments rotated by special structures located in the plasma membrane and cell wall.
Fungi (sing. fungus)
A heterotrophic eukaryote with chitinous cell walls and a body usually in the form of a mycelium of branched, threadlike hyphae. Most fungi are decomposers; some are parasitic.
Bacteria
Prokaryotic organisms that have peptidoglycan in their cell walls; most are decomposers, but some are parasites and others are autotrophs. Bacteria is the name of one of the two prokaryotic domains. Compare with archaea.
Plasmids
Small, circular, double-stranded DNA molecule that carries genes separate from those in the main DNA of a cell.
Binary fission
Equal division of a prokaryotic cell into two; a type of asexual reproduction.
phagocytosis
Literally, “cell eating”; a type of endocytosis by which certain cells engulf food particles, microorganisms, foreign matter, or other cells.
Pellicle
A flexible outer covering consisting of protein; characteristic of certain protists, e.g., ciliates and euglenoids.
Asexual reproduction
Reproduction in which there is no fusion of gametes and in which the genetic makeup of parent and of offspring is usually identical.
Sexual reproduction
A type of reproduction in which two gametes (usually but not necessarily, contributed by two different parents) fuse to form a zygote.
Adaptations
Inherited characteristics that enhance an organism’s ability to survive in a particular environment.
Ribosomes
Organelles that are part of the protein synthesis machinery of both prokaryotic and eukaryotic cells; consist of a larger and smaller subunit, each composed of ribosomal RNA (rRNA) and ribosomal proteins.
Cytoplasm
The plasma membrane and cell contents with the exception of the nucleus.
Nucleoplasm
The contents of the cell nucleus.the part of the cell within the nucleus is nucleoplasm.
Archaea
Prokaryotic organisms with a number of features, such as the absence of peptidoglycan in their cell walls, that set them apart from the bacteria. Archaea is the name of one of the two prokaryotic domains. Compare with bacteria.
Eukarya
*One of the three domains.
Clade
A group of organisms containing a common ancestor and all its descendants; a monophyletic group.
Gene transfer
Exchange of genes
Horizontal gene transfer
G
Trypanosomes
excavates with a single mitochondrion that has an organized deposit of DNA called a kinetoplastid.
kinetoplastid
A single mitochondrion with an organized deposit of DNA; characteristic of trypanosomes.
chromalveolates
A supergroup composed of diverse protists with few shared characters; most are photosynthetic, and heterotrophic chromalveolates, such as the water molds and ciliates, probably descended from autotrophic ancestors. Divided into two main groups, alveolates and stramenopiles.
Reductionism
Learning about a structure by studying its parts.
Emergent properties
Characteristics of an object, process, or behavior that could not be predicted from its component parts; can be identified at each level as we move up the hierarchy of biological organization.
Cytosol
The fluid component of the cytoplasm in which the organelles are suspended.
Endomembrane system
A protein that is tightly associated with the lipid bilayer of a biological membrane; a transmembrane integral protein spans the bilayer. Compare with peripheral membrane protein.
PhyloCode
An approach to classification known as phyloCode in which organisms are grouped into Clades based on evolutionary relationships.
Phylogenetic tree
A branching diagram that shows lines of descent among a group of related species.
Conjugation
(1) A sexual process in ciliate protists that involves exchange of haploid nuclei with another cell. (2) A mechanism for DNA exchange in bacteria that involves cellto-cell contact.
Sex pili
long, hairlike extensions that project from the cell surface.
alveolates
Protists that have alveoli, flattened vesicles located just inside the plasma membrane; include the dinoflagellates, apicomplexans, and ciliates. See chromalveolates.
alveolus (pl., alveoli)
(1) An air sac of the lung through which gas exchange with the blood takes place. (2) Saclike unit of some glands, e.g., mammary glands. (3) One of several flattened vesicles located just inside the plasma membrane in certain protists.
Atom
The smallest unit of a chemical element that retains the characteristic properties of that element.
Vesicles
Any small sac, especially a small, spherical, membrane-enclosed compartment, within the cytoplasm.
Cladogram
A branching diagram that illustrates taxonomic relationships based on the principles of cladistics.
Autotrophs
An organism that synthesizes complex organic compounds from simple inorganic raw materials; also called producer or primary producer. Compare with heterotroph. See chemoautotroph and photoautotroph.
stramenopiles
Protists that have motile cells with two flagella, one of which has tiny hairlike projections off the shaft ; include water molds, diatoms, golden algae, and brown algae. See chromalveolates.
Molecule
The smallest particle of a covalently bonded elements or compound; two or more atoms joined by covalent bonds.
Nucleus (pl. nuclei)
1) The central region of an atom that contains the protons and neutrons. (2) A cell organelle in eukaryotes that contains the DNA and serves as the control center of the cell. (3) A mass of nerve cell bodies in the central nervous system. Compare with ganglion.
Branch
Each branch in a cladogram represents a clade, a group of organisms with a common ancestor. Each branching point, referred to as a node (depicted by a circle), represents the divergence, or splitting, of two or more new groups from a common ancestor.
Heterotrophs
An organism that cannot synthesize its own food from inorganic raw materials and therefore must obtain energy and body-building materials from other organisms. Also called consumer. Compare with autotroph. See chemoheterotroph and photoheterotroph.
Dinoflagellates
A unicellular, biflagellate, typically marine protist that is an important component of plankton; usually photosynthetic.
Tissues
A group of closely associated, similar cells that work together to carry out specific functions.
Organs
A specialized structure, such as the heart or liver, made up of tissues and adapted to perform a specific function or group of functions.
Organ system
An organized group of tissues and organs that work together to perform a specialized set of functions, e.g., the digestive system or circulatory system.
Nuclear envelope
The double membrane system that encloses the cell nucleus of eukaryotes.
Nuclear pores
Structures in the nuclear envelope that allow passage of certain materials between the cell nucleus and the cytoplasm.
Root
The root, or node at the base of the cladogram, represents the most recent common ancestor of all of the clades depicted in the tree.
Vertical gene transfer
which genes are transmitted from parent to off spring within the same species.
Chemotrophs
Organism that uses organic compounds or inorganic substances, such as iron, nitrate, ammonia, or sulfur, as sources of energy. Compare with phototroph. See chemoautotroph and chemoheterotroph.
Phototrophs
Organism that uses light as a source of energy. Compare with chemotroph. See photoautotroph and photoheterotroph.
Photoautotrophs
An organism that obtains energy from light and synthesizes organic compounds from inorganic raw materials; includes plants, algae, and some bacteria. Compare with photoheterotroph, chemoautotroph, and chemoheterotroph.
zooxanthellae (sing., zooxanthella)
Endosymbiotic, photosynthetic dinofl agellates found in certain marine invertebrates; their mutualistic relationship with corals enhances the corals’ reef-building ability.
Red tides
A red or brown coloration of ocean water caused by a population explosion, or bloom, of dinoflagellates.
Apicomplexans
A group of parasitic protists that lack structures for locomotion and that produce sporozoites as infective agents; malaria is caused by an apicomplexan.
Organism
Any living system consisting of one or more cells.
Population
A group of organisms of the same species that live in a defined geographic area at the same time.
Nuclear lamina
A fibrous network of protein filaments, called the nuclear lamina, forms an inner lining for the nuclear envelope.
(DNA) Replication
The process by which DNA is duplicated; ordinarily a semiconservative process in which a double helix gives rise to two double helices, each with an “old” strand and a newly synthesized strand.
Horizontal gene transfer or lateral gene transfer.
In this process, genes move from one species to another species in the same generation.
Phylogeny
The complete evolutionary history of a group of organisms.
Chemoautotrophs
Organism that obtains energy from inorganic compounds and synthesizes organic compounds from inorganic raw materials; includes some bacteria and many archaea. Compare with photoautotroph, photoheterotroph, and chemoheterotroph.
Photoheterotrophs
An organism that can carry out photosynthesis to obtain energy but cannot fix carbon dioxide and therefore requires organic compounds as a carbon source; includes some bacteria and archaea. Compare with photoautotroph, chemoautotroph, and chemoheterotroph.
sporozoites
The infective sporelike state in apicomplexans.
Ciliates
A unicellular protist covered by many short cilia.
Community
An association of populations of different species living together in a defined habitat with some degree of interdependence.
Genes
A segment of DNA that serves as a unit of hereditary information; includes a transcribable DNA sequence (plus associated sequences regulating its transcription) that yields a protein or RNA product with a specific function.
Population
A group of organisms of the same species that live in a defined geographic area at the same time.
Chemoheterotrophs
Organism that uses organic compounds as a source of energy and carbon; includes animals, fungi, many bacteria, and a few archaea. Compare with photoautotroph, photoheterotroph, and chemoautotroph.
Cilia
Fine short hairlike, extend through the pores in the pellicle to facilitate movement.
Ecosystem
The interacting system that encompasses a community and it’s nonliving, physical environment.
Biosphere
All of Earth’s living organisms, collectively.
Messenger RNA (mRNA)
RNA that specifies the amino acid sequence of a protein; transcribed from DNA.