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73 terms

AP Biology Chapter 7 (A tour of the Cell- written by Campbell)

Cell organelles and functions
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Magnification
the ratio of an object's image to its real size
Resolving power
A measure of the clarity of the image; it is the minimum distance two points can be separated and still be distinguished as two separate points
Light microscopes (LMs)
Microscopes that use visible light to pass through the specimen and through glass lenses
Electron microscope
A microscope that instead of using light, focuses a beam of electrons through the specimen or on its surface
Scanning electron microscope (SEM)
an electron microscope commonly used for detailed study of the surface of the specimen
Transmission electron microscope (TEM)
an electron microscope commonly used to study the internal ultrastructure of cells
Cell fractionation
Goal to take cells apart; Uses a centrifuge that spins like a merry-go-round at various speeds
Cytoplasm
The entire region between the nucleus and the plasma membrane
Cytosol
A semifluid substance within the membrane of cells; where organelles are found
Nucleoid
Where the DNA is concentrated in the prokaryotic cell; no membrane separates this region from the rest of the cell
Plasma membrane
at the boundary of every cell, functions as a selective barrier; made of phospholipids and proteins
Nucleus
contains the chromatin, nucleolus, and nuclear envelope; contains most of the genes in the eukaryotic cell
Nuclear envelope
a double membrane enclosing the nucleus; perforated by pores
Chromatin
Within the nucleus; a fibrous material made of DNA and proteins
Chromosome
Chromatin fibers that coiled up, becoming thick enough to be discerned as separate structures; occurs when cell prepares to divide
nucleolus
a prominent structure within the nucleus; Ribosomal RNA is snthesized
Ribosome
particles made of ribosomal RNA and protein; the organelles that carry out protein synthesis (free/bound)
Endomembrane system
all the different membranes of the eukaryotic cell
vesicles
sacs made of membrane; transfer of membrane segments
Endoplasmic Reticulum (ER)
consists of a network of membranous tubules and sac; continuous with the nuclear envelope (smooth/rough)
Smooth ER
part of the ER where the cytoplasmic surface lacks ribosomes
Rough ER
part of the ER where cytoplasmic surface appears rough due to ribosomes attached
centrioles
structure in animal cells composed of cylinders of microtubule triplets; a pair involved in animal celll division
Golgi Apparatus
A center of manufacturing, warehousing, sorting, and shipping; modifies the products of the ER
Cis face
the "receiving" side of the golgi apparatus; closer to the ER
Trans face
the "shipping" side of the golgi apparatus; further away from the ER
Lysosome
a membrane-bound sac of hydrolytic enzymes that the cell uses to digest macromolecules
Phagocytosis
A process that describes Amoebas/Protists eating by engulfing smaller organisms or other food particles
Vacuoles/Vesicles
membrane-bound sacs within the cell (vacuoles larger than vesicles)
Food Vacuoles
formed by phacogytosis; pinches off of the plasma membrane and encloses a food particle
Contractile vacuoles
pumps excess water out of the cell (in many freshwater protists)
Central vacuole
The largest compartment in the plant cell; functions include storage, waste disposal, protection, and growth
Tonoplast
encloses the central vacuole; part of the endomembrane system
Peroxisome
a microbody containing enzymes that transfer hydrogen from various substrates to oxygen; produces hydrogen peroxide
Mitochondria
sites of cellular respiration (catabolic process that generates ATP); uses oxygen
intermembrane space
The narrow region between the inner and outer membranes of mitochondria
plastids
a family of closely related plant organelles (includes chloroplasts)
chloroplasts
sites of photosynthesis; found only in plants and algae
thylakoids
a membranous system in the form of flattened sacs inside of the chloroplasts
thylakoid space
the compartment within the stroma; contains the grana
granum
a stack of thylakoids (piled like poker chips)
stroma
the fluid outside of the thylakoids; cotains the chloroplast DNA, ribosomes, and enzymes
cytoskeleton
a network of fibers extending throughout the cytoplasm; gives the cell mechanical support, maintains shape, provides anchorage for organelles, motility
microtubules
the thickest of the three types of fibers that make up cytoskeleton; eukaryotic cells; hollow tube made from tubulin
microfilaments
the thinnest of the three types of fibers in cytoskeleton; two intertwined stands of actin
intermediate filaments
fibers with diameters in a middle range that make up cytoskeleton; fibrous proteins suercoiled into thicker cables
centrosome
a region near the nucleus where microtubules grow out from
cilia
locomotor appendages; usually occur in large numbers, have a back-and-forth motion
flagella
locomotor appendages; has an undulating motion
tubulin
a globular protein; constructs microtubules
dynein
a large contractile protein forming the side-arms of microtubule doublets in cilia and flagella
actin
a globular protein that links into chains, two of which twist helically about each other, forming microfilaments in muscle and other contractile elements in cells
myosin
a type of protein filament that interacts with actin filaments to cause cell contraction
plasmodesmata
porous holes between the plant cells; lets the cytoplasm become continous between the cells
cell wall
prevents the cell from bursting (not in animal cells)
primary cell wall
a relatively thin and flexible cell well secreted by young plant cells
secondary cell wall
a strong durable matrix often deposited in several laminated layers for plant cell protection and support
Extracellular Matrix
The substance in which animal tissue cells are embedded, consisting of protein and polysaccharides.
collagen
A glycoprotein in the extracellular matrix of animal cells that forms strong fibers, found extensively in connective tissue and bone; the most abundant protein in the animal kingdom.
Proteoglycan
A glycoprotein consisting of a small core protein with many carbohydrate chains attached, found in the extracellular matrix of animal cells. A proteoglycan may consist of up to 95% carbohydrate.
fibronectin
a glycoprotein that helps animal cells attach to the extracellular matrix.
integrin
A receptor protein built into the plasma membrane that interconnects the extracellular matrix and the cytoskeleton.
plasmodesmata
Open channels in the cell wall of a plant through which strands of cytosol connect from an adjacent cell.
desmosomes
specialized junctions that hold adjacent cell together, consist of dense plate at point of adhesion plus extracellular cementing material
tight junctions
Membranes of neighboring cells are pressed together, preventing leakage of extracellular fluid
gap junctions
Points that provide cytoplasmic channels from one cell to another with special membrane proteins. Also called communicating junctions.
basal body
a structure resembling a centriole that produces a cilium or flagellum and anchors this structure within the plasma membrane
motor molecule
protein that moves along either actin filaments or microtubules and translocates organelles
amyoplast
colorless plastids that store starch
macrophages
A type of white blood cell that engulfs microbes and destroys them by phagocytosis; also presents microbial antigens to T cells, helping stimulate the immune response
nucleolar organizer
a unique region (usually on one specific chromosome) that contains multiple repeats of genes encoding ribosomal RNA
cytoplasmic streaming
A circular flow of cytoplasm, involving myosin and actin filaments, that speeds the distribution of materials within cells.
chromoplast
plastids responsible for pigment synthesis and storage such as orange carotene, yellow xanthophylls and various other red pigments