AP Biology Quest Chapters 6 and 7

peripheral proteins

____ _____ are proteins that are not embedded in the lipid bilayer at all; they are appendages loosely bound to the surface of the membrane, often to exposed parts of integral proteins.`

endosymbiot cell

a cell living within another cell

pseudopodia

a cell such as an amoeba crawls along a surface by extending cellular extensions called this. _____ extend by assembly of actin subunits into microfilament network that convert cytoplasm from a sol to a gel inside these cell projections.

phagocytosis

a celll engulfs a particle by wrapping pseudopodia around it and packaging it within a membraneous sac called a food vacuole. the particle will be digested after the food vacuole fuses with a lysosome containing hydrolytic enzymes.

amyloplast

a colorless organelle that stores starch (amylose), particularly in roots and tubers.

nuclear matrix

a framework of protein fibers extending throughout the nuclear interior. this structure as well as the nuclear lamina may help organize the genetic material so it functions efficiently

tubulin

a globular protein that constructs the wall of the hollow tube of microtubules.

actin

a globular protein that makes microfilaments, also naming them _____ filaments.

lysosome

a membraneous sac of hydrolytic enzymes that an animal cell uses to digest (hydrolyze) macromolecule; this structure carries out intracellular digestion. this structure works best in acidic environments. excessive leakage of this structure can destroy a cell by self-digestion. this structure uses their hydrolytic enzymes to recycle the cell's own organic material.

proteoglycan

a molecule that consists of a small core protein with many carbohydrate chains covalently attached, so that it may be up to 95% carbohydrate.

nuclear lamina

a netlike array of protein filaments than maintains the shape of the nucleus by mechanically supporting the nuclear envelope. this structure as well as the nuclear matrix may help organize the genetic material so it functions efficiently

cytoskeleton

a network of fibers extending throughout the cytoplasm; plays a major role in organizing the structures and activities of the cell, is composed of three types of molecular structures: microtubules, microfilaments, and intermediate filaments

amphipathic

a phospholipid is an _____ molecule, meaning it has both a hydrophilic region and a hydrophobic region

centrosome

a region that is often located near the nucleus and is considered a "microtubule-organizing center"; microtubules grow out from this term. these microtubules function as compression-resisting gliders of the cytoskeleton.

cytosol

a semifluid, jellylike substance in cells. has a neutral pH, which is helpful if a structure of the cell, like the lysosome (one that contains an acidic fluid) would rupture or leak. this neutral pH does not cause harm to the productivity of the cell or jeopardize other structures activity.

contransport

a single ATP-powered pump that transports a specific solute can indirectly drive the active transport of several other solutes in a mechanism called this. a substance that has been pumped across a membrane can do work as it moves back across the membrane by diffusion, analogous to water that has been pumped uphill and performs work as it flows back down.

perioxisome

a specialized metabolic compartment bounded by a single membrane. this structure contains enzymes that remove hydrogen atoms from various substrates and transfer them to oxygen (O2), thus producing hydrogen peroxide (H2O2) A by-product (from which the organelle derives it's name). some of this term use oxygen to break fatty acids down into smaller molecules that are transported to mitochondria and used as fuel for cellular respiration. ____ in the liver detoxify alcohol and other harmful compounds by transferring hydrogen from the poisons to oxygen.

ligands

a term for any molecule that binds specifically to a receptor site on another molecule

electrogenic pump

a transport protein that generates voltage across a membrane is called this.

primary cell wall

a young plant cell first secretes a relatively thin and felxible wall called this. in growing cells, the cellulose fibrils are oriented at right angles to the direction o cell expansion. observations have supported researchers hypotheses that microtubules in the cell cortex guide cellulose synthase as it synthesizes and deposits cellulose fibrils. by orienting cellulose deposition, microtubules thus affect the growth pattern of the cells.

golgi apparatus

after leaving the ER, many transport vesicles travel to this structure, which can be thought of as the warehouse for receiving, storing, shipping, and even some manufacturing. here, products of the ER, such as proteins, are modified and stored and then sent to other destinations. this structure is especially extensive in cells specialized for secretion.

phagocytosis

amoebas and many other protists eat by engulfing smaller organisms or food particles, which is referred to as this process. the first syllable of the term means "to eat", while the second syllable means "vessel". there is a food vacuole formed this way and fuses with a lysosome, whose enzymes digest the food.

cell wall

an extracellular structure of plant cells that distinguishes them from animal cells. this term protects the plant cell, maintains its shape, and prevents excessive uptake of water. on the level of the whole plant, the strong walls of specialized cells hold the plant up against the force of gravity.

small cells

are big or small cells more successful in their ratio of surface area to volume?

mitochondria

are the sites of cellular respiration, the metabolic process that uses oxygen to generate ATP by extracting energy from sugars, fats, and other fuels.

plasmolysis

as the plant cell shrivels, its plasma membrane pulls away from the wall. this phenomenon, called _____, causes the plant to wilt and can lead to plant death. the walled cells of bacteria and fungi also ______ in hypertonic environments.

fibronectin

attached the the extracellular matrix (ECM) by ECM glycoproteins such as this term. ____ and other ECM proteins bind to cell-surface receptor proteins called integrins that are built into the plasma membrane.

middle lamella

between primary walls of adjacent cells is this term, a thin layer ruch in sticky polysaccharides called pectins. the ____ ____ glues adjacent cells together.

transport proteins

cell membranes are permeable to specific ions and a variety of polar molecules. these hydrophilic substances can avoid contact with the lipid bilayer by passing through this term, that spans the membrane. some of these proteins are also called channel proteins, and function by having a hydrophilic channel that certain molecules or atomic ions use as a tunnel through the membrane.

secondary cell wall

cells add this between the plasma membrane and the primary wall. the _____ _____, often deposited in several laminated layers, has a strong and durable matrix that affords the cell protection and support.

ion channels

channel proteins that transport ions are called this term

ribosomes

complexes made of ribosomal RNA and protein, are the cellular components that carry out protein synthesis

nucleus

contains most of the genes in the eukaryotic cell. it is usually the most conspicuous organelle in a eukaryotic cell, averaging about 5 um in diameter

motor proteins

cytoskeletal elements and motor proteins work together with plasma membrane molecules to allow whole cells to move along fibers outside the cell. ____ _____ bring about the bending of cilia and flagella by gripping microtubules within those organelles and sliding them against each other.

dyneins

each outer doublet also has pairs of protruding proteins spaced along its length and reaching toward the neighboring doublet; there are large motor proteins called _____, each composed of several polypeptides. this type of molecule performs a complex cycle of movements caused by changes in the shape of the protein, with ATP providing the energy for these changes.

receptor-mediated endocytosis

enables the cell to acquire bulk quantities of specific substances, even though those substances may not be very concentrated in the extracellular fluid. embedded in the membrane are proteins with specific receptor sites exposed to the extracellular fluid, to which specific substances (ligands) bind. the receptor proteins then cluster in regions of the membrane called coated pits, which are lined on their cytoplasmic side by a fuzzy layer of coat proteins. next, each coasted put forms a vesicle containing the ligand molecules. notice that there are relatively the vesicle, but other molecules (purple) inside the vesicle, but other molecule (green) are also present. after the ingested material is liberated form the vesicle, the emptied receptors are recycled to the plasma membrane by the same vesicle.

mitochondrial matrix

enclosed by the inner membrane; this term contains many different enzymes as well as the mitochondrial DNA and ribosomes. enzymes in the matrix catalyze some of the steps of cellular respiration. other proteins that function in respiration, including the enzyme that makes ATP, and built into the inner membrane.

nuclear envelope

encloses the nucleus, separating its contents from the cytoplasm

cell motility

encompasses both changes in cell location and more limited movements of parts of the cell. this term generally requires the interaction of the cytoskeleton with motor proteins

integrins

fibronectin and other ECM proteins bind to cell-surface receptor proteins called this term that are built in to plasma membrane. ____ span the membrane and bind on their cytoplasmic side to associated proteins attached to microfilaments of the cytoskeleton.

electron microscope (EM)

focuses a beam of electrons through the specimen or onto its surface. resolution is inversely related to the wavelength of the radiation a microscope uses for imaging, and electron beams have much shorter wavelengths than visible light.

food vacuoles

formed by phagocytosis

collagen

forms strong fibers outside the cells. in fact, this term accounts for about 40% of the total protein in the human body. the collagen givers are embedded in a network woven out of proteoglycans secreted by cells.

chloroplasts

found in plants and algae, are the sites of photosynthesis. these organelles convert solar energy chemical energy by absorbing sunlight and using it to drive the synthesis of organic compounds such as sugars from carbon dioxide and water.

plasma membrane

functions as a selective barrier that allows passage of enough oxygen, nutrients, and wastes to service the entire cell

microtubules

hollow rods measuring about 25 nm in diameter and from 200 nm in diameter and from 200 nm to 25 um in length. the wall of the hollow tube is constructed from a globular protein called tubulin.

isotonic

if a cell without a wall, such as an animal cell, is immersed in an environment that is ______ to the cell there will be no net movement of water across the plasma membrane. water diffuses across the membrane, but at the same rate in both directions. in an isotonic environment, the volume of an animal cell is stable.

concentration gradient

in absence of other forces, a substance will diffuse from where it is more concentrated to where it is less concentrated. in other words, any substance with diffuse down its _____ _____, the region along which the density of a chemical substance increases or decreases

flagella/cilia

in eukaryotes, a specialized arrangement of microtubules is responsible for the beating of this type of cell/part of a cell. this term is defined as microtubule-containing extensions that project from some cells. allows cells to propel through water by this by acting like a locomotor appendage. when this appendage extends from cells that are held in place as part of a tissue layer, they can move fluid over the surface of the tissue.

osmoregulation

in hypertonic or hypotonic environments, however organisms that lack rigid cell alls mist have other adaptations for _____, the control of solute concentrations and water balance.

cytoplasmic streaming

in plant cells, both actin-myosin interactions and sol-gel transformations brought about by actin may be involved in this term, defined as a circular flow of cytoplasm within cells. this movement, which is especially common in large plant cells, speeds the distribution of materials within the cell.

fluid mosaic model

in this model, the membrane is a fluid structure with a "mosaic" of various proteins embedded in or attached to a double layer (bilayer) of phospholipids.

nucleolus

in this structure ribosomal RNA (rRNA) is synthesized from instructions. proteins are imported from the cytoplasm and are assembled with rRNA into large and small subunits of ribosomes.

endomembrane system

includes the nuclear envelope, the endoplasmic reticulum, the Golgi apparatus, lysosomes, various kinds of vesicles and vacuoles, and the plasma membrane. this system carries out a variety of tasks in the cell, including synthesis of proteins, transport of proteins into membranes and organelles or out of the cell, metabolism and movement of lipids, and detoxification of poisons. the membranes of this system are related either through direct physical continuity or by the transfer of membrane segments as tiny vesicles.

thylakoids

inside the chloroplast is another membraneous system in the form of flattened, interconnected sacs called these. in some regions thylakoids are are stacked like poker chips; each stack is called a granum.

endoplasmic reticulum

is accounts for more than half the total membrane in many eukaryotic cells. the first word of this term means "within the cytoplasm" while the second word of this term means "little net". this structure consists of a network of membraneous tubules and sacs called cisternae (from the latin word cisterna, or reservoir for liquid). this structure separates the internal compartment, called the ____ ____ lumen (cavity) or citernal space, from the cytosol. and because this structure is continuous with the nuclear envelope , the space between the two membranes of the envelope is continuous with the lumen of the _____ _____.

rough ER

is studded with ribosomes on the outer surface of the membranes and thus appears rough through the electron microscope. this structure is integral to the cell because of it's ability to synthesize the protein insulin in the ER and secrete this hormone into the bloodstream. in addition to making secretory proteins, this structure is a membrane factory for the cell; it grows in place by adding membrane proteins and phospholipids to its own membrane.

scanning electron microscope (SEM)

is useful for detailed study of the topography of a specimen. this electron beam scans the surface of the sample, usually coated with a thin film of gold. the beam excites electrons on the surface, and these secondary electrons are detected electronic signal to a video screen. the result is an image of the specimen's surface that appears three-dimensional.

vacuoles

large vesicles derived from the endoplasmic reticulum and Golgi apparatus. thus, this structure are an integral part of a cell's endomembrane system. the membrane of this structure is selective in transporting solutes, and as a result, the solution inside this structure differs in composition from the cytosol.

autophagy

lysosomes use their hydrolytic enzymes to recycle the cell's own organic matter. during this process, a damaged organelle or small amount of cytosol becomes surrounded by a double membrane (of unknown origin), and a lysosome fuses with the outer membrane of this vesicle.

gated channels

many ion channels function as _____ _____, which open or close in response to a stimulus. for some ____ ____, the stimulus is electrical.

lysosomal membrane

membrane of the lysosome. made by rough ER.

endosymbiot theory

mitochondria and chloroplasts display similarities with bacteria that led to this theory, which states that an early ancestor of eukaryotic cells engulfed an oxygen-using nonphototsynthetic prokaryotic cell. Eventually, the engulfed cell formed a relationship with the host cell in which it was enclosed, becoming an _________. over the course of evolution, the host cell and its ______ merged into a single organism, a eukaryotic cell with a mitochondrion. at least one of these cells may have then taken up a photosynthetic prokaryote, becoming the ancestor of eukaryotic cells that contain chloroplasts.

facilitated diffusion

molecules and ions impeded by the lipid bilayer of the membrane diffuse passively with the help of transport proteins that span the membrane. this phenomenon is called this term.

eukaryotic cells

most of the DNA is in an organelle called the nucleus, which is bounded by a double membrane

integral proteins

one of the two major populations of membrane proteins. this term penetrates the hydrophobic interior of the lipid bilayer. the majority are transmembrane proteins, which span the membrane; other ____ _____ extend only partway into the hydrophobic interior.

diffusion

one result of constant motion (because of thermal heat) is this term, defined as the movement of molecules of any substance so that they spread out evenly into the available space. each molecule in this process moves randomly, yet ____ of a population of molecules may be directional.

flaccid

plants that are not too woody, such as most house plants, depend for mechanical support on cells kept turgid by a surrounding hypotonic solution. if a plant's cell sand their surroundings are isotonic, there is no not tendency for water to enter, and the cells become this term (limp).

glycoproteins

proteins that have carbohydrates covalently bonded to them. the carbohydrates are attached to the proteins in the ER by enzymes built into the ER membrane.

contractile vacuoles

pump excess water out of the cell, thereby maintaining a suitable concentration of ions and molecules inside the cell. these vacuoles in plants and fungi carry out enzymatic hydrolysis, a function shared by lysosomes in animal cells.

vesicles

sacs made of membrane

microfilaments

solid rods about 7 nm in diameter. they are also called actin filaments because they are built from molecules of actin, a globular protein. a ______ is a twisted double chain of actin subunits. this term can form structural networks when certain proteins bind along the side of an actin filament and allow a new filament to extend as a branch. present in all eukaryotes, similar to microtubules. function is to bear tension (pulling forces) and helps supports the cell's shape. this network gives the outer cytoplasmic layer of a cell, called the cortex, the semisolid consistency of a gel, in contrast with the more fluid (sol) state of the interior cytoplasm. this term also is fundamental to cell motility, particularly as part of the contractile apparatus of muscle cells.

glycoproteins

some membrane carbohydrates are covalently bonded to lipids, forming molecules called glycolipids. however, most membrane carbohydrates are covalently bonded to proteins. these membrane carbohydrates that are covalently bonded to proteins are called this.

glycolipids

some membrane carbohydrates are covalently bonded to lipids, forming molecules called this

glyxysomes

specialized peroxisomes; found in the fat-storing tissues of plant seeds. these organelles contain that initiate the conversion of fatty acids to sugar, which the emerging seedling uses as a source of energy and carbon until it can produce its own sugar by photosynthesis.

chromosomes

structures that carry the genetic information. each ____ contains one long DNA molecule associated with many proteins. these coil allowing them to fit in the nucleus.

prokaryotic cell

the DNA is concentrated in a region that is not membrane-enclosed

tonicity

the ability of a surrounding solution to cause a cell to gain or lose water. the _____ of a solution depends in part on its concentration of solutes that cannot cross the membrane (non penetrating solutes) relative to that inside the cell. if there is a higher concentration of non penetrating solutes in the surrounding solution, water will tend to leave the cell, and vice versa.

pinocytosis

the cell "gulps" droplets of extracellular fluid into tiny vesicles. it is not the fluid itself that is needed by the cell, but the molecules dissolved in the droplets. because any and all included solutes are taken into the cell, pinocytosis is nonspecific in the substances it transports.

exocytosis

the cell secretes certain biological molecules by the fusion of vesicles with the plasma membrane; this process is called this term. a transport vesicle that has budded from Golgi apparatus moves along microtubules of the cytoskeleton to the plasma membrane. when the vesicle membrane and plasma membrane come into contact, specific proteins rearrange the lipid molecules of the two bilayers so that the two membranes fuse. the contents of the vesicle then spill to the outside of the cell, and the vesicle membrane becomes part of the plasma membrane

endocytosis

the cell takes in biological molecules and particulate matter by forming new vesicles from the plasma membrane

plastids

the chloroplast is a specialized member of a family closely related plant organelles called this.

chromatin

the complex of DNA and proteins making up chromosomes

passive transport

the diffusion of a substance across a biological membrane is called this term because the cell foes not have to expend energy to make it happen. the concentration gradient itself represent potential energy and drives diffusion.

osmosis

the diffusion of free water across a selectively permeable membrane, whether artificial or cellular, is called ______. the movement of water across cell membranes and the balance of water between the cell and its environment are crucial to organisms.

stroma

the fluid outside the thylakoids; contains the chloroplast DNA and ribosomes many enzymes membranes of chloroplast divide

cytoplasm

the interior of prokaryotic and eukaryotic cells. this term refers only to the region between the nucleus and the plasma membrane.

extracellular matrix (ECM)

the main ingredients of this term are glycoproteins and other carbohydrate-containing molecules secreted by the cells. the most abundant of the glycoproteins includes collagen

organelles

the membrane-enclosed structures within eukaryotic cells. the electron microscope was needed to see these structures in detail.

basal body

the microtubule assembly of a cilium or flagellum is anchored in the cell by this term, which is structurally very similar to a centriole, with microtubule triplets a "9 + 0" pattern.

cortex

the network of microfilaments gives the outer cytoplasmic layer of a cell, called the ____, the semisolid consistency of a gel, in contrast with the more fluid (sol) state of the interior cytoplasm.

cristae

the outer membrane is smooth, but the inner membrane is convoluted, with infoldings called this term. the inner membrane divides the mitochondrion into two internal compartments. the first is the intermembrane space, the narrow region between the inner and outer membranes. the second compartment, the mitochondrial matrix, is enclosed by the inner membrane.

smooth ER

the outer surface of this structure lacks ribosomes, therefore acquiring it's name. this structure is integral because of it's synthesis of lipids, metabolism of carbohydrates, detoxification of drugs and poisons, and storage of calcium ions.

aquaporins

the passage of water molecules through the membrane in certain cells is greatly facilitated by channal proteins know as this.

nucleoid

the region in prokaryotic cells where the DNA is not membrane-enclosed

granum

the regions in the chloroplast where the thylakoids are stacked like poker chips; each stack is called this.

turgid

the relatively inelastic wall will expand only so much before it exerts a back pressure on the cell, called turgor pressure, that opposes further water uptake. at this point the cell is _____ (very firm), which is the healthy state for most plant cells.

proton pump

the sodium-potassium pump appears to be the major electrogenic pump of animal cells. the main electrogenic pump of plants, fungi, and bacteria, is a ____ ____, which actively transports protons (hydrogen ions, H+) out of the cell. the pumping of H+ transfers positive charge from the cytoplasm to the extracellular solution. by generating voltage across membranes, electrogenic pumps help store energy that can be tapped for cellular work. one important use of proton gradients in the cell is for ATP synthesis during cellular respiration.

the three parts of the chloroplast

the space of the chloroplast is divided into three compartments: the inner membrane space, the stroma, and the thylakoid space

membrane potential

the voltage across a membrane, called a _____ ____, ranges from about -50 to -200 millivolts (mV). the _____ ______ acts like a battery, an energy source that affects the traffic of all charged substances across the membrane. Because the outside of the cell is negative compared to the outside, the _______ _____ favors the passive transport of cations into the cell and anions out of the cell. thus, two forces drive the diffusion of ions across a membrane: a chemical force (the ion's concentration gradients) and an electrical force (the effect of the ______ ______ on the ion's movement).

intermediate filaments

these filaments are named for their diameter which, at 8-12 nm, is larger than the diameter of microfilaments but smaller than that of microtubules. specialized for bearing tension (like microfilaments), ______ ________ are a diverse class of cytoskeletal elements.

cilia

this appendage of cells specifically moves in a back and forth motion (flagella or cilia)

flagella

this appendage of cells specifically moves in a snakelike motion (flagella or cilia)

transmission electron microscope (TEM)

this microscope is used to study the internal structure of cells and aims an electron beam through a very thin section of the specimen, similar to the way a light microscope transmits light through a slide. the specimen has been stained with atoms of heavy metals, which attach to certain cellular structures, this enhancing the electron diversity of some parts of the cell more than others. the result displays an image with the pattern of transmitted electrons. this microscope uses magnets as lenses to bend the paths of the electrons.

hypertonic

this word means "more", in the case referring to non penetrating solutes. the cell will lsoe ater, shrivel, and probably die. this is one way an icrease in the salinity (saltiness) of a lake caln kill animals there; if the lake water becomes _______ to the animal's cells, the cells might shrivel and die.

myosin

thousands of actin filaments are arranged parallel to one another along the length of a muscle cell, interdigitated with thicker filaments made of a protein called this. like dynein when it interacts with microtubules, _____ acts as a motor protein by means of projections that "walk" along the actin filaments.

electrochemical gradient

thus, two forces drive the diffusion of ions across a membrane: a chemical force (the ion's concentration gradients) and an electrical force (the effect of the membrane potential on the ion's movement). the combination of forces acting on an ion is called the _____ ____.

active transport

to pump a solute across a membrane against its gradient requires work; the cell must expend energy. therefore, this type of membrane traffic is called ____ _____, the transport proteins that move solutes against their concentration gradients are all carrier proteins rather than channel proteins.

transport vesicles

vesicles in transit from one part of the cell to another are called this.

light microscope (LM)

visible light is passed through the specimen and then through glass lenses. the lenses refract (bend) the light in such a way that the image of the specimen is magnified as it is projected into the eye or into the camera.

sodium-potassium pump

when a protein changes it shape in a manner that translocates a solute bound to the protein across the membrane. one transport system that works this way is the _____-_______ _____, which exchanges Na+ for K+ across the plasma membrane of animal cells.

hypotonic

when cells take up too much water; hazardous. water will enter the cell faster than it leaves, and the cell will swell and lyse (burst) like an overfilled water balloon.

chromoplast

which has pigments that give fruits and flowers their orange and yellow hues

centrioles

within the centrosome is a pair of these, each composed of nine sets of triplet microtubules arranged in a ring. before an animal cell divides, the centrioles replicate.