Biology Class Cells Structure

Front 1

cell

Back 1

a membrane-bound structure that is the basic nit of life

Front 2

cell membrane

Back 2

the lipid bilayer that forms the outer boundary of the cell

Front 3

cell theory

Back 3

the theory that all living things are made up of cells, that cells are
the basic units of organisms, and that cells come only from existing cells

Front 4

cell wall

Back 4

a rigid structure that surrounds the cells of plants, fungi, many
protists, and most bacteria

Front 5

chloroplast

Back 5

a plastid containing chlorophyll; the site of photosynthesis

Front 6

chromatin

Back 6

the DNA and proteins in the nucleus of a nondividing cell

Front 7

chromosome

Back 7

DNA and protein in a coiled, rod-shaped form that occurs during
cell division (81)

Front 8

cilium

Back 8

a short, hairlike organelle that extends from a cell and functions in
locomotion or in the movement of substances across the cell surface (80)

Front 9

cytoplasm

Back 9

the region of a cell between the cell membrane and the nucleus (75)
)

Front 10

cytoskeleton

Back 10

a network of long protein strands in the cytosol that helps
maintain the shape and size of a eukaryotic cell (79

Front 11

endoplasmic reticulum

Back 11

a system of membranous tubules and sacs in
eukaryotic cells that functions as a path along which molecules move from one
part of the cell to another (77)

Front 12

eukaryote

Back 12

a cell that contains a nucleus and membrane-bound organelles (72)

Front 13

flagellum

Back 13

a hairlike structure made up of microtubules that function in
locomotion (80)

Front 14

Golgi apparatus

Back 14

a system of membranes in eukaryotic cells that modifies
proteins for export by the cell (78)

Front 15

integral protein

Back 15

a protein imbedded in the bilayer of the cell membrane (74)

Front 16

lysosome

Back 16

an organelle containing digestive enzymes, existing primarily in
animal cells (79)

Front 17

mitochondrion

Back 17

the organelle that is the site of aerobic respiration in eukaryotic
cells (76)

Front 18

microtubule

Back 18

a hollow tube of protein that constitutes the largest strand in the
cytoskeleton (79)

Front 19

nuclear envelope

Back 19

a double membrane that surrounds the nucleus of a
eukaryotic cell (80)

Front 20

nucleus

Back 20

the structure in which ribosomes are synthesized and partially
assembled; found in most nuclei (81)

Front 21

nucleolus

Back 21

in a eukaryotic cell, the organelle that contains most of the DNA and
directs the cell's activities (72)

Front 22

organelle

Back 22

one of several formed bodies with a specialized function that is
suspended in the cytoplasm and found in eukaryotic cells (71)

Front 23

peripheral protein

Back 23

a protein attached to the interior or exterior surface of the
cell membrane (74)
protozoan a single-celled, eukaryotic protist that is able to move
independently (84)

Front 24

plastid

Back 24

an organelle of plant cells that contains starch, fats, or pigments (83)

Front 25

prokaryote

Back 25

a unicellular organism that lacks a nucleus and membrane-bound
organelles (72)

Front 26

ribosome

Back 26

an organelle that functions in the synthesis of proteins (77)

Front 27

rough endoplasmic reticulum

Back 27

the portion of the endoplasmic reticulum that
contains attached ribosomes (76)

Front 28

selectively permeable membrane

Back 28

a membrane that keeps out some molecules
but allows others to pass through (73)

Front 29

smooth endoplasmic reticulum

Back 29

the portion of the endoplasmic reticulum that
lacks attached ribosomes (76)

Front 30

spindle fiber

Back 30

one of the microtubules that extend across a dividing eukaryotic
cell; assists in the movement of chromosomes (79)

Front 31

vacuole

Back 31

a fluid-filled organelle that stores enzymes or metabolic wastes in a
plant cell (82)

Front 32

thylakoid

Back 32

a flattened, membranous sac inside a chloroplast; contains most of
the components involved in the light reactions of photosynthesis (83)

Front 33

active transport

Back 33

the movement of a substance across a cell membrane against a
concentration gradient; requires the cell to expend energy

Front 34

carrier protein

Back 34

a protein that transports specific substances across a biological
membrane (99)

Front 35

concentration gradient

Back 35

the difference in concentration of a substance across
space (95)

Front 36

contractile vacuole

Back 36

an organelle in protists that expels water (97)

Front 37

cytolysis

Back 37

the bursting of a cell (99)

Front 38

the process by which molecules move from an area of greater
concentration to an area of lesser concentration (95)

Back 38

diffusion

Front 39

endocytosis

Back 39

the process by which a cell surrounds and engulfs
substances (103)

Front 40

equilibrium

Back 40

a state that exists when the concentration of a substance is the
same throughout a space (95)

Front 41

exocytosis

Back 41

a process in which a vesicle inside a cell fuses with the cell
membrane and releases its contents to the external environment (104)

Front 42

facilitated diffusion

Back 42

a process in which substances move down their
concentration gradient across the cell membrane with the assistance of carrier
proteins (99)

Front 43

hypotonic

Back 43

describing a solution whose solute concentration is lower than that
inside a cell (96

Front 44

hypertonic

Back 44

describing a solution whose solute concentration is higher than that
inside a cell (96)

Front 45

isotonic

Back 45

describing a solution whose solute concentration equals that inside a
cell (97)

Front 46

ion channel

Back 46

a membrane protein that provides a passageway across the cell
membrane through which an ion can diffuse (100)

Front 47

isotonic

Back 47

describing a solution whose solute concentration equals that inside a
cell

Front 48

plasmolysis

Back 48

passive transport the movement of substances across a cell membrane without
the use of cell energy (95)
the shrinking or wilting of a walled cell in a hypertonic
environment (98)

Front 49

phagocytosis

Back 49

phagocyte a cell that engages in phagocytosis (104)
a type of in which a cell engulfs large particles or
whole cells (103)

Front 50

pinocytosis

Back 50

a type of endocytosis in which a cell engulfs solutes or
fluids (103)

Front 51

sodium-potassium

Back 51

pump a carrier protein that actively transports K+ ions
into and Na+ ions out of cells (101)

Front 52

turgor

Back 52

pressure water pressure within a plant cell (98)