Test 2 Flashcards
Visible light is passed through a specimen and then through glass lenses
Light microscope
Ratio of an object’s image size to its real size
Magnification
Clarity of the image, or the minimum distance of two distinguishable points
Resolution
Visible differences in brightness between parts of the sample
Contrast
The membrane enclosed structures in eukaryotic cells
Organelles
Focuses a beam of electrons onto the surface of a specimen, providing images that look 3D
Scanning electron microscope
Focuses a beam of electrons through a specimen
Transmission electron microscope
A selective barrier that allows sufficient passage of oxygen, nutrients, and waste to service the volume of every cell
Plasma membrane
Contains most of the DNA in a eukaryotic cell
Nucleus
Encloses the nucleus, separating it from the cytoplasm
Nuclear envelope
Lines the nuclear envelope, composed of intermediate filaments and other proteins
Nuclear Lamina
Process by which cell’s recycle own organelles and macromolecules
Autophagy
Found in many fresh water protists, pump excess water out of cells
Contractile vacuoles
Found in many mature plant cells, hold organic compounds and water
Central vacuoles
Sites of cellular respiration
Mitochondria
Sites of photosynthesis
Chloroplasts
Suggests that an early ancestor of eukaryotes engulfed an oxygen using non photosynthetic prokaryotic cell
Endosymbiote theory
A cellular structure consisting of one DNA molecule and associated protein molecules.
Chromosome
A specialized structure in the nucleus, consisting of chromosomal regions containing ribosomal RNA (rRNA) genes along with ribosomal proteins imported from the cytoplasm
Nucleolus
The collection of membranes inside and surrounding a eukaryotic cell, related either through direct physical contact or by the transfer of membranous vesicles
The endomembrane system
A membranous sac in the cytoplasm of a eukaryotic cell.
Vesicle
An extensive membranous network in eukaryotic cells, continuous with the outer nuclear membrane and composed of ribosome-studded (rough) and ribosome-free (smooth) regions.
Endoplasmic reticulum
That portion of the endoplasmic reticulum that is free of ribosomes.
Smooth ER
That portion of the endoplasmic reticulum with ribosomes attached.
Rough ER
A protein with one or more covalently attached carbohydrates.
Glycoproteins
A small membranous sac in a eukaryotic cell’s cytoplasm carrying molecules produced by the cell.
Transport vesicles
An organelle in eukaryotic cells consisting of stacks of flat membranous sacs that modify, store, and route products of the endoplasmic reticulum and synthesize some products, notably noncellulose carbohydrates.
Golgi apparatus
A membrane-enclosed sac of hydrolytic enzymes found in the cytoplasm of animal cells and some protists.
Lysosome
A type of endocytosis in which large particulate substances or small organisms are taken up by a cell.
Phagocytosis
A membrane-bounded vesicle whose specialized function varies in different kinds of cells.
Vacuole
A membranous sac formed by phagocytosis of microorganisms or particles to be used as food by the cell.
Food vacuole
An infolding of the inner membrane of a mitochondrion.
Crista
The compartment of the mitochondrion enclosed by the inner membrane and containing enzymes and substrates for the citric acid cycle, as well as ribosomes and DNA.
Mitochondrial matrix
A flattened, membranous sac inside a chloroplast
Thylakoid
A stack of membrane-bounded thylakoids in the chloroplast.
Granum
The dense fluid within the chloroplast surrounding the thylakoid membrane and containing ribosomes and DNA
Stroma
One of a family of closely related organelles that includes chloroplasts, chromoplasts, and amyloplasts
Plastid
An organelle containing enzymes that transfer hydrogen atoms from various substrates to oxygen ( O 2 ) , producing and then degrading hydrogen peroxide H 2 O 2 .
Peroxisome
A network of microtubules, microfilaments, and intermediate filaments that extend throughout the cytoplasm and serve a variety of mechanical, transport, and signaling functions.
Cytoskeleton
A protein that interacts with cytoskeletal elements and other cell components, producing movement of the whole cell or parts of the cell.
Motor protein
A hollow rod composed of tubulin proteins that makes up part of the cytoskeleton in all eukaryotic cells and is found in cilia and flagella
Microtubule
A structure present in the cytoplasm of animal cells that functions as a microtubule-organizing center and is important during cell division
Centrosome
A structure in the centrosome of an animal cell composed of a cylinder of microtubule triplets arranged in a “9+0” pattern
Centriole
A long cellular appendage specialized for locomotion.
Flagella
A short appendage containing microtubules in eukaryotic cells
Cilia
A cable composed of actin proteins in the cytoplasm of almost every eukaryotic cell, making up part of the cytoskeleton and acting alone or with myosin to cause cell contraction
Microfilament
A globular protein that links into chains, two of which twist helically about each other, forming microfilaments (actin filaments) in muscle and other kinds of cells.
Actin
A component of the cytoskeleton that includes filaments intermediate in size between microtubules and microfilaments.
Intermediate filaments
A protective layer external to the plasma membrane in the cells of plants, prokaryotes, fungi, and some protists
Cell wall
The meshwork surrounding animal cells, consisting of glycoproteins, polysaccharides, and proteoglycans synthesized and secreted by cells.
Extra cellular matrix
A glycoprotein in the extracellular matrix of animal cells that forms strong fibers, found extensively in connective tissue and bone
Collagen
A large molecule consisting of a small core protein with many carbohydrate chains attached, found in the extracellular matrix of animal cells.
Proteoglycan
An extracellular glycoprotein secreted by animal cells that helps them attach to the extracellular matrix.
Fibronectin
In animal cells, a transmembrane receptor protein with two subunits that interconnects the extracellular matrix and the cytoskeleton.
Integrin
An open channel through the cell wall that connects the cytoplasm of adjacent plant cells, allowing water, small solutes, and some larger molecules to pass between the cells.
Plasmodesmata
A type of intercellular junction between animal cells that prevents the leakage of material through the space between cells.
Tight junction
A type of intercellular junction in animal cells that functions as a rivet, fastening cells together.
Desmosome
A type of intercellular junction in animal cells, consisting of proteins surrounding a pore that allows the passage of materials between cells.
Gap junction
Having both a hydrophilic region and a hydrophobic region.
Amphipathic
The currently accepted model of cell membrane structure, which envisions the membrane as a mosaic of protein molecules drifting laterally in a fluid bilayer of phospholipids.
Fluid mosaic model
A transmembrane protein with hydrophobic regions that extend into and often completely span the hydrophobic interior of the membrane and with hydrophilic regions in contact with the aqueous solution on one or both sides of the membrane
Integral protein
A protein loosely bound to the surface of a membrane or to part of an integral protein and not embedded in the lipid bilayer.
Peripheral protein
A lipid with one or more covalently attached carbohydrates.
Glycolipid
A transmembrane protein that helps a certain substance or class of closely related substances to cross the membrane.
Transport protein
A channel protein in a cellular membrane that specifically facilitates osmosis, the diffusion of free water across the membrane.
Aquaporin
The random thermal motion of particles of liquids, gases, or solids
Diffusion
A region along which the density of a chemical substance increases or decreases.
Concentration gradient
The diffusion of a substance across a biological membrane with no expenditure of energy.
Passive transport
The diffusion of free water across a selectively permeable membrane.
Osmosis