Biology Chapters 4 And 5

Front 1

cell theory

Back 1

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 2

organelles

Back 2

a cell component that performs specific functions for the cell

Front 3

cell membrane

Back 3

the lipid bilayer that forms the outer boundary of a cell

Front 4

nucleus

Back 4

the organelle that contains most of the DNA and directs most of the cells activities

Front 5

eukaryotes

Back 5

a cell that contains a nucleus and membrane bound organelles

Front 6

Prokaryotes

Back 6

a unicellular organism that lacks a nucleus and membrane bound organelles

Front 7

selectively permeable

Back 7

a membrane that keeps out some molecules but allows others to pass through.

Front 8

periphereal protien

Back 8

protien attached to the interior or exterior surface of the cell membrane

Front 9

integreal protiens

Back 9

a protien embedded in the bilayer of the cel membrane

Front 10

fluid mosaic model

Back 10

a modle of a cell membrane structure representing the dynamic nature of membrane lipids and protiens

Front 11

cytoplasm

Back 11

the region of a cell between the cell membrane and the nucleus

Front 12

cytosol

Back 12

teh gelatin aqueous fluid that bathes the organelles on the inside of the cell membrane

Front 13

mitochondria

Back 13

the organelle that is the site of aerobic respiration in eukaryotic cells

Front 14

cristae

Back 14

a fold in the inner membrane of the mitochondria

Front 15

ribosomes

Back 15

an organelle that functions in the synthesis of protiens

Front 16

endoplastic reticulum

Back 16

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

Front 17

rough endoplasmic reticulum

Back 17

the portion of the endoplasmic reticulum that contains attached ribosomes

Front 18

smooth endoplasmic reticulum

Back 18

the portion of the endoplasmic reticulum that lacks attached ribosomes

Front 19

golgi apparatus

Back 19

a system of membranes in eukaryotic cells that modifies protiens for export by the cell

Front 20

Lyosomes

Back 20

an organelle containing digestive enzymes, existing primarily in animal cells

Front 21

cytoskeleton

Back 21

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

Front 22

micofiliments

Back 22

a polymer chain of the protien actin; the smallest strand in the cytoskeleton

Front 23

microtubule

Back 23

a hollow tube of protien that constitutes the largest strand of the cytoskeleton

Front 24

actin

Back 24

one of two protien filaments in a muscle cell that function in contraction

Front 25

spindle fibers

Back 25

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

Front 26

cilia

Back 26

short hairlike organelles that extend from a cell and functions in locomotion or in the movement of substances across the cell surface

Front 27

flagella

Back 27

a hairlike structure made up of microtubules that function in locomotion

Front 28

nuclear matrix

Back 28

the nuclear skeleton; a shap maintaining protien

Front 29

nuclear envelope

Back 29

a double membrane that surrounds the nucleus of a eukaryotic cell

Front 30

chromatin

Back 30

the DNA and protien in the nucleus of a non dividing cell

Front 31

chromosomes

Back 31

DNA and protien in a coiled, rod shaped form that occurs during cell division

Front 32

nuclear pores

Back 32

a small hole in the nuclear envelope through which substances pass between the nucleaus and the cytoplasm

Front 33

nucleolus

Back 33

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

Front 34

cell wall

Back 34

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

Front 35

vacuoles

Back 35

a fluid filled organelle that stores enzymes or metabolic wastes in a plant cell.

Front 36

plastids

Back 36

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

Front 37

chloroplast

Back 37

a plastid containing chlorophyll; the site of photosynthesis

Front 38

thylakoids

Back 38

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

Front 39

tissues

Back 39

in most multicellular organisms, a group of similar cells that carry out a common functions

Front 40

organ

Back 40

several types of body tissues that together perform a function

Front 41

organ system

Back 41

a group of organs that interact to perform a set of related tasks

Front 42

colonial organisms

Back 42

a collection of genetically identical cells that live together in a closely connected group.

Front 43

diffusion

Back 43

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

Front 44

concentration gradient

Back 44

the difference in concentration of a substance across a space

Front 45

equilibrium

Back 45

a state that exists when the concentration of a substance is the same through out a space

Front 46

osmosis

Back 46

the diffusion of water across a selectively permeable membrane

Front 47

hypotonic

Back 47

describing a solution whose solute concentration is lower then that inside a cell.

Front 48

hypertonic

Back 48

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

Front 49

isotonic

Back 49

describing a solution whose solute concentration equals that inside a cell

Front 50

contractile vacuoles

Back 50

an organelle in protists that expels water

Front 51

turgor pressure

Back 51

water pressure within a plant cell

Front 52

plasmolysis

Back 52

the shrinking or wilting of a walled cell in a hypertonic environment

Front 53

cytolysis

Back 53

the bursting of a cell

Front 54

facilitated diffusion

Back 54

a process in which substances move down thier concentration gradient across the cell membrane with the assistance of carrier protiens

Front 55

carrier protiens

Back 55

a protien that transports specific substances across a biological membrane

Front 56

ion channels

Back 56

a membrane protien that provides a passageway across the cell membrane through which an ion can diffuse

Front 57

active transport

Back 57

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

Front 58

sodium-potassium pump

Back 58

a carrier protien that actively transports K+ ions into and Na+ ions out of the cell

Front 59

vesicle

Back 59

a membrane bound sac in a eukaryotic cell that contains materials involved in endocytosis, exocytosis, or transport within a cell

Front 60

pinocytosis

Back 60

a type of endocytosis in which a cell engulfs solutes or fluids

Front 61

phagocytosis

Back 61

a type of endocytosis in which a cell engulfs large particles or large cells

Front 62

phagocytes

Back 62

a cell that engages in phagocytosis.

Front 63

exocytosis

Back 63

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