Chapter 6: A Tour of the Cell

47055468	light microscope	a microscope in which visible light ia passed through the specimen and then through glass lenses; can magnify effectively to 1000 times; lenses refract light so that the image of the specimen is magnified as it is projected
47055469	magnification	the ratio of an object's image size to its real size
47055470	resolution	a measure of the clarity of the image; the minimum distance two points can be separated and be distinguished as two points
47055471	Robert Hooke	Who first saw cell walls?
47055472	Anton van Leeuwenhoek	Who was the first to see living cells?
47055473	contrast	a measure of the accentuation of differences in a sample's parts
47055474	organelles	membrane-enclosed compartments within a cell; too small to be seen with a light microscope
47055475	electron microscope	a microscope that focuses a beam of electrons through the specimen or onto its surface
47055476	cell ultrastructure	the cellular anatomy revealed by an electron microscope
47055477	scanning electron microscope	a microscope that is especially useful for the detailed study of the surface of a specimen; electron beams scan the surface of the sample, which is usually coated with a thin film of gold, allowing electrons on the surface to be deleted and translated into an image; result is a 3D topographic image
47055478	transmission electron microscope	a microscope that is used to study the internal ultrastructure of cells; aims an electron beam through a thin section of specimen that is coated with atoms of heavy metals, allowing open space to result in an image of transmitted electrons; lenses are electromagnets
47055479	cytology	the study of cell structure
47055480	cell fractionation	a technique for studying cell structure and function that takes cells apart and separates major organelles and other subcellular structures from one another; enables researchers to prepare specific cell components in bulk and identify
47055481	cytosol	a semifluid, jelly-like substance enclosed by the membrane; contains all organelles and other components
47055482	plasma membrane	a selective barrier that allows sufficient passage of oxygen, nutrients, and wastes to service the entire cell
47055483	nucleus	organelle that contains most of the DNA; is the largest organelle
47055484	nuclear envelope	organelle that encloses the nucleus, separating it from the cytoplasm; composed of two phospholipid bilayer membranes; perforated by pore structures, each of which has continuous membrane surrounding it
47055485	pore complex	lines the nuclear envelope to regulate the entry and exit of proteins, RNA, and some large complexes of macromolecules
47055486	nuclear lamina	a netlike array of protein filaments that maintains the shape of the nucleus by mechanically supporting the nuclear envelope
47055487	nuclear matrix	a network of fibers that extends throughout the nuclear interior; adds extra support
47055488	chromosomes	structures that carry genetic information; technically exists only when cells are dividing
47055489	chromatin	the functioning form of DNA (chromosomes), a complex structure including DNA and proteins;
47055490	nucleolus	a structure within the nondividing nucleus that synthesizes rRNA from instructions in DNA; also constructs ribosomal units from rRNA and protein; number depends on species and life stage of cell
47279697	ribosomes	complexes made of ribosomal RNA and proteins that carry out protein synthesis
47279698	free ribosomes	ribosomes that float in the cytosol to make the proteins that are used there
47279699	bound ribosomes	ribosomes that are attached to the endoplasmic reticulum to make proteins to be exported, to be embedded in membranes, and to be shipped elsewhere within the cell
47279700	endomembrane system	collection of different membranes within cell that carries out a variety of tasks within it; responsible for synthesis and transport of proteins, metabolism, movement of lipids, and detoxification of poisons
47279701	vesicles	sacs made of membrane that transfer membrane segments within the cell
47279702	endoplasmic reticulum	an extensive network of membranes that accounts for more than half of total membranes in cells
47279703	smooth endoplasmic reticulum	endoplasmic reticulum whose outer surface lacks ribosomes; functions in diverse metabolic processes (lipid synthesis, metabolism of carbs, detox of poisons, production of hormones, stores calcium ions)
47279704	rough endoplasmic reticulum	endoplasmic reticulum whose outer surface has ribosomes, which secrete proteins; as proteins grow, they are threaded into ER lumen through a pore formed by a protein complex in the ER membrane; as protein enters, it is folded into shape
47279705	glycoproteins	proteins that have carbohydrates covalently bonded to them
47279706	Golgi apparatus	organelle that modifies and stores products of the endoplasmic reticulum, such as proteins, before sending them to other parts of the cell; has a distinct structural polarity with two opposing poles (cis face and trans face) which act as receiving and shipping centers; sorts molecules according to final destination
47279707	cisternal maturation model	model that explains that Golgi's cisternae progress from the cis face to the trans face, carrying and modifying cargo as they move
47279708	lysosome	a membranous sac of hydrolytic enzymes that an animal cell uses to digest macromolecules; acidic environment is prime for these; responsible for intracellular digestion, such as phagocytosis
47279709	phagocytosis	the occurrence in which protists eat by engulfing smaller organisms or other food particles; the resulting food vacuole fuses with the lysosome, whose enzymes digest it--products then pass into cytosol as nutrients for the cell
47279710	food vacuoles	vacuoles that are formed by phagocytosis
47279711	contractile vacuoles	vacuoles that pump excess water out of the cell to maintain the proper concentration of ions and molecules
47279712	central vacuoles	vacuoles that develop from the culmination of smaller vacuoles originating from the ER and the Golgi apparatus; an integral part of plant cells because it selects transporting solutes (can take up to 90% of cell's volume); holds plants' proteins, inorganic ions, disposes dangerous metabolic by-products, contains color pigments, enables growth, protects from poison
47279713	mitochondria	the site of cellular respiration; made of two membranes: a smooth outer, and a rough inner
47279714	chloroplasts	the site of photosynthesis; made of two membranes, both smooth;
47279715	cristae	the folds of a mitochondrion's inner membrane; stores the enzyme that helps make ATP
47279716	grana	stacked membranous compartments within the chloroplast
47279717	thylakoid	singular membranous compartment within the chloroplast
47279718	stroma	fluid inside of chloroplast; contains DNA, ribosomes, and enzymes
47279719	peroxisome	an oxidative organelle that is not part of the endomembrane system; imports proteins primarily from cytosol; helps detoxify hydrogen peroxide; use asexual reproduction
47279720	mitochondrial matrix	a matrix enclosed by membrane mitochondria; contains enzymes, DNA, and ribosomes; catalyzes part of cellular respiration
47279721	glyoxysomes	specialized peroxisomes found in fat-storing tissues of plant seeds that have enzymes which convert fatty acids to sugars; used for energy until photosynthesis occurs to produce its own sugar
47413408	cytoskeleton	a network of fibers extending throughout the cytoplasm; organizes structures and activities within the cell; has three main components: microtubules, intermediate filaments, and microfilaments
47413409	microtubules	hollow rods constructed from globular protein, tubulin, which consists of two polypeptide chains: an alpha tubulin and a beta tubulin; function: shape and support the cell, serve as tracks for transport for motor proteins, separate chromosomes during cell division
47413410	centrosome	a region located near the nucleus that organizes microtubules that specialize in resisting compression from the cytoskeleton
47413411	centriole	part of the centrosome; composed of nine fused sets of triplet microtubules arranged in a ring; they replicate before an animal cell divides
47413412	cilia	microtubule-containing extensions of a cell that project it; lie perpendicular to the axis of motion; usually hundreds or thousands of these per cell
47413413	flagella	microtubule-containing extensions of a cell that project it; lie in the same axis of motion; usually 1-3 per cell (humans only have these on sperm cells)
47413414	basal body	the microtubule assembly of cilium or flagellum anchors to the cell based on structure that is identical to centriole
47413415	dyneins	a large motor protein on the outer doublets of cilia and flagella that provides bending movement for microtubules; performs movements by conformational changes, which ATP causes with energy
47413416	microfilaments	solid thread-like structures that are responsible for structure and support, amoeboid movement, and muscle contractions
47413417	actin	the globular protein that makes up microfilaments
47413418	pseudopodia	the part of a cell that is responsible for the conversion of cytoplasm from fluidy sol to a gel; this part functions due to localized contractions through actin and myosin movement
47413419	cytoplasmic streaming	a circular flow of cytoplasm within cells that results from actin-myosin interactions; speeds distribution of materials within cell; occurs a lot around the central vacuole of plant cells
47413420	intermediate filaments	an organelle specialized for bearing tension; associated with the keratin family of proteins; even after cell death, this part remains; responsible for fixing the positioning of organelles and stabilizing the cell's shape
47413421	cell wall	an extracellular structure of plant cells that serves as a means of protection, maintenance of shape, and balance of water intake; holds plants against gravity (some prokaryotes, fungi, and protists have this, but animals never do)
47413422	primary cell wall	the initial stage of a plant's extracellular structure; formed when microtubules in the cell cortex guide cellulose synthase as it deposits fibrils to aid in growth
47413423	cortex	the outer cytoplasmic layer of a cell; has a semisolid consistency of a gel
47413424	middle lamella	a structure that is situated between the primary cell walls of adjacent cells; has a layer with sticky polysaccharides, which glues adjacent cells together
47413425	secondary cell wall	a structure within plants that lies between the plasma membrane and the primary cell wall to add more strength to the overall structure
47413426	extracellular matrix	a structure outside of animal cells that contains glycoproteins, most of which are collagens, that create a web outside of the cell
47413427	collagen	a protein that accounts for about 40% of all protein in the human body; it is embedded in networks woven from proteoglycans, which consist of small core proteins with many carbohydrate chains covalently attached
47413428	fibronectin	a protein of the extracellular matrix that connects it to the cell by binding to integrin
47413429	integrin	a receptor protein built into the cell's membrane that aids fibronectin's connection to the cell from the extracellular matrix
47413430	tight junction	a cellular junction formed by plasma membranes of adjacent cells pressed tightly against each other and bound by proteins; they form continuous seals to prevent leakage of extracellular fluid
47413431	desmosomes	a cellular junction that fastens cells together into strong sheets
47413432	gap junction	a cellular junction that provides cytoplasmic channels from one cell to another (similar to plasmodesmata in plants); it allows for the passing of small molecules and is necessary for communication between cells in different tissues
47413433	compartmentalization	The following are benefits of what within the eukaryotic cell? 1) individualized microenvironments, 2) membranes in membrane-bound organelles provide more surface area, 3) can store waste that would otherwise be harmful, 4) allows for space for poisons
47413434	mimicry	taking on the appearance of another organism for self-defense
47413435	Batesian	the type of mimicry in which an organism appears to be more dangerous than it actually is; the mimic is harmless while the model is dangerous
47413436	Mullerian	the type of mimicry in which the mimic and the model are dangerous
47413437	replication	the process DNA goes through when it copies itself
47413438	transcription	the process that occurs when enzymes separate the two strands of DNA and replace one strand with messenger RNA, and then re-bind both strands
47413439	translation	the process that occurs when protein synthesis ensues; going from RNA to a protein
47413440	triplet	a sequence of DNA nucleotides that codes for an amino acid
47413441	codon	a sequence of RNA nucleotides that codes for an amino acid
47413442	leader sequence	a sequence of nucleotides on every messenger RNA region that merely regulates where to start the translation process
47413443	plasmodesmata	narrow threads of cytoplasm that pass through the cell walls of adjacent plant cells, allowing for communication between them
47413444	aminoacyl tRNA synthetases	the 64 different enzymes, each of which corresponds to a unique amino acid
47413445	anti-codon	the complementary nucleotide sequence on transfer RNA that is physically positioned across from each codon on mRNA
47413446	nucleolar organizers	structures within a cell that put ribosomal RNA and proteins together to form ribosomal subunits
47413869	endosymbiotic theory	a theory that proposed that both mitochondria and chloroplasts were once free-living bacteria; at one point, a eukaryotic cell engulfed bacteria, and lysosomes did not come to function--bacteria are now codependent on the cell
47413870	green	color that chloroplasts give
47413871	colored	color that chromoplasts give
47413872	colorless	color that amyloplasts give
47413873	protein pair	an element of the cytoskeleton plus a motor protein (track + engine--actin + myosin)
47413874	9+2 structure	the structure of cilia and flagella cross sections
47413875	radial spokes	the proteins that extend from the fused doublets to the unfused central tubule within cilia and flagella; these never move--they keep the cell in tact and attached, which causes bending when other proteins move
47413876	myofibril	the individual muscle strand within each muscular fiber that runs its entire length; contains microfilaments and the functioning space of muslce