Biology Chapter 3

Front 1

Passive Transport

Back 1

any thermodynamically favorable
movement of solute across a
membrane

Front 2

Simple diffusion

Back 2

diffusion of a solute through a
membrane without help from a
protein

Front 3

Plasma membrane is a barrier to

Back 3

movement of all large and/or
hydrophilic solutes

Front 4

Facilitated Diffusion

Back 4

movement of a solute across
a membrane down a gradient
when the membrane is impermeable
to the solute

Front 5

Channel and Carrier proteins
give the membrane

Back 5

selective permeability

Front 6

Gated channels

Back 6

ion channels that open in
response to a specific
environmental stimuli

Front 7

Voltage-gated ion channel

Back 7

opens in response to a change in
the electrical potential across
a membrane

Front 8

Ligand-gated ion channel

Back 8

opens in response to binding of
a specific molecule like a
neurotransmitter

Front 9

Ion channels are only involved
in

Back 9

facilitated diffusion, movement
down an electrochemical
gradient

Front 10

Carrier proteins

Back 10

bind to molecule to be
transported on one side of
membrane and undergo a
conformational change to move
the molecule to the other side

Front 11

Pore

Back 11

tube through the membrane
which is so large that it is not
selective for any particular
molecule, eukaryotic plasma
membranes do NOT contain them

Front 12

Rate of Simple Diffusion limited
by

Back 12

surface area of the membrane and
the size of the gradient

Front 13

Rate of Facilitated Diffusion
limited by

Back 13

the finite number of integral
membrane proteins, exhibits
saturation kinetics

Front 14

Active Transport

Back 14

movement of molecules through
the plasma membrane against
a gradient, requires energy
input

Front 15

Primary Active Transport

Back 15

transport of a molecule is
coupled to ATP hydrolysis

Front 16

Secondary Active Transport

Back 16

transport not coupled directly
to ATP hydrolysis, but to the
flow of an ion down its
electrochemical gradient
(commonly Na ions), glucose
transport

Front 17

Na+/K+ ATPase

Back 17

transmembrane protein in the
plasma membrane of all cells
in the body
- pumps 3 Na+ out of cell and
2 K+ into cell and
hydrolyzes 1 ATP
- establishes resting membrane
potential

Front 18

Potassium Leak Channels

Back 18

potassium ions pumped into the
cell are able to leak out, down
its concentration gradient,
sodium ions cannot flow back
into cell

Front 19

Resting membrane potential

Back 19

potential created by
Na+/K+ ATPase, net negative
charge on the interior of cell,
-70mV

Front 20

Na+/K+ ATPase important in 3
ways:

Back 20

1) to maintain osmotic balance
between the cellular interior
and exterior
2) to establish resting
membrane potential
3) to provide sodium
concentration gradient used to
drive secondary active
transport

Front 21

Ions with higher EXTRACELLULAR
concentrations than
intracellular concentrations:

Back 21

Na+, Cl-, Ca2+

Front 22

Ions with higher intracellular
concentrations than
extracellular concentrations:

Back 22

K+

Front 23

Exocytosis

Back 23

process to transport material
outside of cell in which a
vesicle in cytoplasm fuses with
plasma membrane and contents of
vesicle expelled, ex. hormones
and digestive enzymes

Front 24

Endocytosis

Back 24

materials are taken into cell
by an invagination of a piece
of cell membrane to form a
vesicle (endosome)

Front 25

3 types of endocytosis:

Back 25

1)phagocytosis
2)pinocytosis
3)receptor-mediated endocytosis

Front 26

Phagocytosis

Back 26

nonspecific uptake of large
particulate matter into a
phagocytic vesicle which later
merges with a lysosome, ex.
macrophages

Front 27

Pinocytosis

Back 27

nonspecific uptake of small
molecules and extracellular
fluid

Front 28

Receptor-mediated endocytosis

Back 28

very specific, binding of a
specific molecule via receptors
, ex. cholesterol uptake from
the blodd

Front 29

3 main types of signal-
transducing cell surface
receptors

Back 29

1) ligand-gated ion channels
2) catalytic receptors
3) G-protein linked receptors

Front 30

Ligand-gated ion channels

Back 30

open an ion channel upon binding
of a particular neurotransmitter

Front 31

Catalytic receptors

Back 31

have an enzymatic active site
on cytoplasmic side of membrane
and initiated by ligand binding
at extracellular surface, ex.
protein kinases

Front 32

G-protein linked receptor

Back 32

does not directly transduce its
signal, but transmits it via
a second messenger, binds GTP

Front 33

Second messengers

Back 33

allows for a much greater signal
than receptor alone via cascade
amplification, ex. cAMP- second
messeger for hormone glucagon
and epinephrine (universal
hunger signal)

Front 34

Stimulatory G-protein linked
receptors

Back 34

activates adenylyl cyclase,
which forms more cAMP and
further cascade

Front 35

Inhibitory G-protein linked
receptors

Back 35

inactivates adenylyl cyclase,
less cAMP

Front 36

G-protein linked receptors and
phospholipase C

Back 36

different second messenger
cascade, activates phospholipase
C, causing an increase in
cytoplasmic Ca2+ levels

Front 37

Cytoskeleton composed of
3 proteins:

Back 37

1)microtubules
2)intermediate filaments
3)microfilaments
- quartenary protein structure

Front 38

Microtubules

Back 38

hollow rod composed of two
globular proteins, alpha and
beta tubulin, also assist in
transport of substances within
cell

Front 39

Microtubule organizing center
(MTOC)

Back 39

located near nucleus,
microtubules elongate from here,
contains centrioles
- MTOC essential for mitosis,
but not centrioles

Front 40

Cilia

Back 40

small hairs on the cell surface
which move fluids past the cell
surface

Front 41

Flagellum

Back 41

large tail which moves the cell
by wiggling

Front 42

Both cilia and flagella have:

Back 42

9+2 arrangement,
9 pairs of microtubules
surrounding 2 lone microtubules
in the middle, each connected
to each other by dynein

Front 43

Microfilaments

Back 43

rods formed in the cytoplasm
from actin polymerization,
dynamic, responsible for gross
movements of entire cell

Front 44

Intermediate filaments

Back 44

in between thickness,
heterogeneous composition of
polypeptides unlike microtubules
and microfilaments,
-permanent (microfilaments and
microtubules are often
assembled and disassembled)

Front 45

Tight junctions

Back 45

form a seal between the
membranes of adjacent cells that
blocks the flow of molecules
across the entire cell layer

Front 46

Apical surface

Back 46

surface of the plasma membrane
facing the intestinal lumen

Front 47

Basolateral surface

Back 47

plasma membrane on the other
side of the cell facing the
tissues beneath

Front 48

Desmosomes

Back 48

do not form a seal, but hold
cells together at spots

Front 49

Gap junctions

Back 49

form pore-like connections
between adjacent cells, allowing
the two cells cytoplasms to mix,
large enough to permit the
exchange of solutes such as
ions, amino acids, and
carbohydrates
-allows membrane
depolarization of an action
potential to pass between
cells in smooth muscle and
cardiac muscle

Front 50

Interphase

Back 50

G1, S, and G2 phases,
- cell spends most of time in
this phase
- blood cells, neurons, and
cells on surface of skin are
permanently in interphase
-not visible with light
microscope without special
stains
-(2n*2) chromosomes

Front 51

Mitosis stages:

Back 51

1)prophase
2)metaphase
3)anaphase
4)telophase

Front 52

Mitosis phases:

Back 52

1)prophase
2)metaphase
3)anaphase
4)telophase

Front 53

Prophase

Back 53

chromatin densely packed into
chromosomes
-visible under light microscope
-nucleolus disappears
-spindle appears
-centrioles migrate to
opposite ends of cell
-23 homologous pairs of
chromosomes

Front 54

Sister chromatids

Back 54

identical copies of a
chromosome attached to each
other at the centromere

Front 55

Homologous chromosomes

Back 55

equivalent but nonidentical
and do not come anywhere near
each other during mitosis

Front 56

Metaphase

Back 56

all the chromosomes line up
at the center of the cell
forming the metaphase plate

Front 57

Anaphase

Back 57

spindle fibers shorten and the
centromeres of each sister
chromatid pair are pulled apart,
cell elongates, cytokinesis
begins

Front 58

Telophase

Back 58

a nuclear membrane forms around
the bunch of chromosomes at
each end of the cell,
chromosomes decondense,
nucleolus becomes visible
-2n chromosomes
-cytokinesis complete
-cell split in two