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Anatomy & Physiology: The Unity Of Form & Function, 8th Edition (Ch. 3:
Cellular Form and Function) Questions & Answers 202 3 /
cytology - ANSWER-scientific study of cells
cell theory - ANSWER-the theory that cells form the fundamental structural and functional units of all living organisms
cells - ANSWER--functions: fight disease, store nutrients, connect things, line things, gather information and control body functions, involved in reproduction
-structure:
*nuclear envelope -> nucleus -> nucleolus
*plasma membrane
*cytoplasm -> cytoskeleton, organelles, inclusions, cytosol
intracellular fluid - ANSWER-fluid within cells; cytosol
extracellular fluid - ANSWER-fluid outside the cell; tissue fluid (ex. blood plasma, lymph, and cerebrospinal fluid
cytoplasm - ANSWER-fluid between the nucleus and surface membrane; contains the cytoskeleton, organelles, and inclusions
plasma (cell) membrane - ANSWER--stick cells together to form tissues; regulates exchange of materials that go in and out of a cell; involved in intracellular communication; gives cell its shape
-made of proteins, lipids, & carbohydrates; phospholipids are major components; semi-permeable membrane
cytoskeleton - ANSWER--supportive framework of protein filaments and tubules
-network of protein filaments and cylinders that structurally support a cell, determine its shape, organize its contents, direct the movement of materials within the cell, and contribute to movements of the cell as a whole
-composed of microfilaments, intermediate filaments, and microtubules
organelles - ANSWER-diverse structures that perform various metabolic tasks for the cell
inclusions - ANSWER--highly variable - fat droplets, glycogen granules, protein crystals, dust, bacteria, viruses; never enclosed in membranes
-foreign matter retained in cytoplasm
-(function) storage products or other products of cellular metabolism
phospholipids - ANSWER-75% of membrane molecules of the plasma membrane; drift laterally from place to place, spin on their axes, and flex their tails
glycolipids - ANSWER-5% of membrane lipids molecules of the plasma membrane; phospholipids with short carbohydrate chains on the extracellular face of the membrane; help form the glycocalyx
cholesterol - ANSWER-20% of membrane lipids molecules of the plasma membrane; molecules found near the membrane surfaces amid the phospholipids; interact with phospholipids and hold them still and stiffen the membrane; high concentrations can increase membrane fluidity by preventing phospholipids from becoming packed closely together
integral proteins - ANSWER-membrane protein; penetrate into the phospholipid bilayer or all the way through it
transmembrane proteins - ANSWER-membrane proteins that pass completely through
cyclic adenosine mono phosphate - ANSWER-the second messenger; activates kinases
kinases - ANSWER-cytoplasmic enzymes that add phosphate groups to other cellular enzymes
glycocalyx - ANSWER-a bacterial capsule that is made of a fuzzy coat of sticky sugars
functions:
-protects the plasma membrane from physical/chemical injury
-enables the immune system to recognize and selectively attack foreign organisms
-defense against cancer
-forms the basis of compatibility of blood transfusions, tissue grafts, and organ transplants
-cell adhesion (binds cells together so tissues do not fall apart)
-enables fertilization
-guides embryonic development
microvilli - ANSWER--extensions of the plasma membrane that serve primarily to increase the cell's surface area, developed in cells specialized for absorption
-(function) increase absorptive surface area; widespread sensory roles
-some appear as a fringe called the brush border at the atypical cell surface
-show little internal structure, but some have a bundle of stiff filaments of a protein called actin, which attach to the inside of the plasma membrane at the tip of the microvillus, and at its base they extend a little way into the cell and anchor the microvillus to a protein mesh called the terminal web
cilia - ANSWER--long hairlike projections of apical cell surface; axoneme with a usually 9+2 array of microtubules
-(function) move substances along cell surface; widespread sensory roles; secrete mucus
-each bends stiffly and produces a power stroke that pushes along the mucus or other matter
-recovery stroke restores it to the upright position
-responsible for several hereditary diseases called ciliopathies
-beat within a saline layer at the cell surface
-chloride pumps in the apical plasma membrane produce the saline layer by pumping Cl- into the extracellular fluid; sodium ions follow by electrical attraction and water follows by osmosis
-structural basis for movement is a core called the axoneme, which consists of an array of thin projection cylinders called microtubles
flagellum - ANSWER-whiplike tail of a sperm is the only function in humans; much longer than the cilium and has an identical axoneme, but between the axoneme and plasma membrane; long hair like extensions
pseudopods - ANSWER-cytoplasm-filled extensions of the cell varying in shape from fine, filamentous processes to blunt fingerlike ones; change continually (ex. amoeba, neutrophils, macrophage)
selective permeability - ANSWER-allows some substances to cross it (like nutrients and wastes) more easily than others (like proteins and phosphates)
passive mechanisms - ANSWER-requires no ATP; filtration, diffusion (simple and facilitated), osmosis
active mechanisms - ANSWER-require ATP; active (primary and secondary) and vesicular transport
carrier-mediated transport - ANSWER--movement of material through a cell membrane by carrier proteins
-carrier exhibits specificity for its ligand
-carrier exhibits saturation; as solute concentration rises, its rate of transport increases
-carriers don't chemically change their ligands, they simply pick them up on one side of the membrane and release them, unchanged, on the other
reverse osmosis - ANSWER-process of applying mechanical pressure to override osmotic pressure and drive water through a membrane against its concentration gradient; capillary filtration
hydrostatic pressure - ANSWER-force exerted by a fluid against the container wall
osmotic pressure - ANSWER-pressure that must be applied to prevent osmotic movement across a selectively permeable membrane
osmolarity - ANSWER-solute concentration expressed as molarity
tonicity - ANSWER-ability of a solution to affect fluid volume and pressure in a cell
hypotonic solution - ANSWER-solution has a lower solute concentration than the intracellular fluid; cells absorb water, swell, and may burst
hypertonic solution - ANSWER-solution has higher solute concentration of non permeating solutes than the ICF; causes cell to lose water and shrivel; may die of torn membranes and cytoplasmic loss
isotonic solution - ANSWER-total concentration of nonpermeating solutes is the same as the ICF; cause no change in cell volume or shape
uniport - ANSWER-carries only one type of solute
cotransport - ANSWER-simultaneous transport of two or more solutes in the same direction through a membrane by a carrier protein called symport, using either facilitated diffusion or active transport
countertransport - ANSWER-transport of two or more solutes in opposite directions through a membrane by a carrier protein called antiport, using either facilitated diffusion or active transport
facilitated diffusion - ANSWER--transport of particles through a selectively permeable membrane, down their concentration gradient, by a carrier that does not directly consume ATP
-transports solutes that cannot pass through the membrane unaided
- solute particle enters channel of a membrane protein
- solute binds to a receptor site on carrier, which changes conformation
- carrier releases the solute on the other side of the membrane
primary active transport - ANSWER--transport of solute particles through a selectively permeable membrane, up their concentration gradient, by a carrier that consumes ATP, which transfers a phosphate group to the transport protein
-calcium pump uses this mechanism
secondary active transport - ANSWER--transport of solute particles through a selectively permeable membrane, up their concentration gradient, by a carrier that does not itself use ATP but depends on concentration gradients produced by primary active transport elsewhere in the membrane
sodium potassium pump - ANSWER-good example of primary active transport; transmembrane protein; binds three NA+ simultaneously on the cytoplasmic side of the membrane, releases these to the ECF, binds two K+ simultaneously from the ECF, and releases these into the cell; each cycle consumes one ATP and exchanges three Na+ for two K+; keeps K+ concentration higher and Na+ concentration lower
functions:
-secondary active transport
-regulation of cell volume
-maintenance of membrane potential
microfilaments - ANSWER--thin protein filaments often in parallel bundles or dense networks in cytoplasm
-(function) support microvilli and plasma membrane; involved in muscle contraction and other cell motility, endocytosis, and cell division
-made of a protein called actin
-widespread throughout the cell but especially concentrated in a fibrous mat called the terminal web on the cytoplasmic side of the plasma membrane
-web provides physical support, lipids provide a permeability barrier
intermediate filaments - ANSWER--thicker protein filaments (8 to 10 nm thick) extending throughout the cytoplasm or concentrated at cell to cell junctions
-(function) give the cell its shape, resist stress, and participate in junctions that attach cells to their neighbors
-made of keratin in epidermal cells and fibrous things
nucleus - ANSWER--largest organelle in most cells, surrounded by a double membrane of nuclear pores
-(function) genetic control center of cell; directs protein synthesis; shelters the DNA
-enclosed in a double membrane called the nuclear envelope, which is perforated with nuclear pores formed by a ring of proteins known as the nuclear pore complex
-inside the nuclear envelope is a narrow but fibrous zone called the nuclear lamina, composed of a web of intermediate filaments; it supports the nuclear envelope and pores, provides points of attachment and organization for the chromosomes inside the nucleus, and plays a role in regulating the cell life cycle
-material in the nucleus is called the nucleoplasm, which includes chromatin (fine, threadlike matter composed of DNA and protein) and one or more dark-staining masses called nucleoli, where ribosomes are produced
endoplasmic reticulum (ER) - ANSWER-system of interconnected channels called cisterns enclosed by a unit membrane; cisterns are parallel, flattened sacks covered with ribosomes in rough ER; in smooth ER, cisterns are more tubular, branch more extensively, and lack ribosomes
rough ER - ANSWER--extensive sheets of parallel membranes with ribosomes on the outer surface
-(function) protein synthesis and manufacture of cellular membranes
smooth ER - ANSWER--branching network of tubules with smooth surface (no ribosomes); usually broken into numerous small segments in TEM photos
-(function) lipid synthesis, detoxification, calcium storage
ribosomes - ANSWER--small dark granules free in cytosol or on surface of rough ER and nuclear envelope
-(function) interpret the genetic code and synthesize polypeptides
golgi complex - ANSWER--several closely spaced, parallel cisternae with thick edges, usually near nucleus, often with many golgi vesicles nearby
-(function) receives and modifies newly synthesized polypeptides, synthesizes carbohydrates, adds carbohydrates to glycoproteins; packages cell products into golgi vesicles
golgi vesicles - ANSWER--round to irregular sacs near golgi complex, usually with light, featureless contents
-(function) become secretory vesicles and carry cell products to apical surface for exocytosis, or become lysosomes
lysosomes - ANSWER--round to oval sacs with single enclosing membrane, often a dark featureless interior but sometimes with protein layers or crystals
-formed by golgi
-(function) contain enzymes for intracellular digestion, autophagy, programmed cell death, and glucose mobilization
autophagy - ANSWER-lysosomal breakdown of a cell's own components
unicellular - ANSWER-made of one cell
multicellular - ANSWER-made of many cells
cell junctions - ANSWER-connections between one cell and another
tight junctions - ANSWER-completely encircles each cell and provides seal that prevents passage of materials between cells
desmosomes - ANSWER-holds cells together
gap junctions - ANSWER-provide cytoplasmic channels between adjacent animal cells; formed by a connexon
enzymes - ANSWER-carry out the final stages of starch and protein digestion in the small intestine, help produce second messengers, and break down hormones and other signaling molecules
receptors - ANSWER-binds to chemical messengers sent by other cells
channel proteins - ANSWER-passages that allow water and hydrophilic solutes to move through an individual membrane or protein tunnel
cell identity markers - ANSWER-bodies are enabled to tell which cells do and don't belong in our bodies
cell adhesion molecules - ANSWER-membrane proteins that cells adhere to one another and to extracellular material
second messengers system - ANSWER-when a messenger binds to a surface receptor, it may trigger changes within the cell that produce a second messenger in the cytoplasm
carrier proteins - ANSWER-transmembrane proteins that bind to glucose, electrolytes, and other solutes and transfer them to the other side of the membrane; come carriers, called pumps, consume ATP in the process
nucleolus - ANSWER-makes ribosomes and forms mRNA
