The document discusses the structure and functions of the cell membrane. It describes how the phospholipid bilayer is semipermeable and contains integral and peripheral proteins that facilitate transport. There are three main types of membrane transport: passive diffusion, active transport using ATP, and vesicular transport using exocytosis and endocytosis. Passive diffusion includes simple diffusion, facilitated diffusion through channels and carriers, and osmosis. Active transport includes the sodium-potassium pump and secondary active transport via symporters and antiporters.

1. 1
The
Cellular
Level
of
Organiza3on
Part
1:
Membrane
Structure
&
Transport
BIOL
121:
A&P
I
Chapter
3
Rob
Swatski
Associate
Professor
of
Biology
HACC
–
York
Campus
Textbookimages-Copyright©2014JohnWiley&Sons,Inc.Allrightsreserved.

2. Flagellum
Chroma.n
Nuclear
pore
Nuclear
envelope
Nucleolus
Glycogen
granules
CYTOPLASM
(cytosol
plus
organelles
except
the
nucleus)
Rough
endoplasmic
re.culum
(ER)
Membrane-­‐bound
ribosome
Golgi
complex
Microfilament
Sec.onal
view
Cytoskeleton:
Microtubule
Microfilament
Intermediate
filament
Microvilli
Centrosome:
Pericentriolar
material
Centrioles
PLASMA
MEMBRANE
Secretory
vesicle
Lysosome
Smooth
endoplasmic
re.culum
(ER)
Peroxisome
Mitochondrion
Microtubule
Cilium
Proteasome
Free
ribosomes
NUCLEUS:

3. 3
Main
Parts
of
a
Cell
Plasma
membrane
Cytoplasm
Nucleus

4. 4

5. 5

6. Plasma
Membrane
6

7. Phospholipids
Cell
structure
&
func.on
Plasma
membrane
Amphipathic
7

8. 8
Head
Polar
Hydrophilic
Glycerol
&
phosphate
Tails
Nonpolar
Hydrophobic
2
FaZy
acids
Phospholipid
Structure

9. 9

10. 10

11. 11
Permeable

12. 12
Impermeable

13. 13
Semipermeable

14. 14
Ion
Channel
Carrier
Receptor
Membrane
Proteins

15. More
Membrane
Proteins!
15
Enzyme
Linker
Cell-­‐iden.ty
marker
(Glycoprotein)

16. Extracellular
fluid
Plasma
membrane
Cytosol
Ion
channel
(integral)
Forms
a
pore
through
which
a
specific
ion
can
flow
to
get
across
membrane.
Most
plasma
membranes
include
specific
channels
for
several
common
ions.
Pore
Carrier
(integral)
Transports
a
specific
substance
across
membrane
by
undergoing
a
change
in
shape.
For
example,
amino
acids,
needed
to
synthesize
new
proteins,
enter
body
cells
via
carriers.
Carrier
proteins
are
also
known
as
transporters.
Receptor
(integral)
Recognizes
specific
ligand
and
alters
cell's
func.on
in
some
way.
For
example,
an.diure.c
hormone
binds
to
receptors
in
the
kidneys
and
changes
the
water
permeability
of
certain
plasma
membranes.
Enzyme
(integral
and
peripheral)
Catalyzes
reac.on
inside
or
outside
cell
(depending
on
which
direc.on
the
ac.ve
site
faces).
For
example,
lactase
protruding
from
epithelial
cells
lining
your
small
intes.ne
splits
the
disaccharide
lactose
in
the
milk
you
drink.
Linker
(integral
and
peripheral)
Anchors
filaments
inside
and
outside
the
plasma
membrane,
providing
structural
stability
and
shape
for
the
cell.
May
also
par.cipate
in
movement
of
the
cell
or
link
two
cells
together.
Cell
iden3ty
marker
(glycoprotein)
Dis.nguishes
your
cells
from
anyone
else's
(unless
you
are
an
iden.cal
twin).
An
important
class
of
such
markers
are
the
major
histocompa3bility
(MHC)
proteins.
MHC
protein
Products
Substrate
Ligand
Substance
to
be
transported
Ion

17. 17
Concentra3on
gradient

18. Electrochemical
Gradient
18

19. Membrane
Transport
Passive
Ac.ve
Vesicular
19

20. 20
Passive
Transport

21. Beginning
(a)
Intermediate
(b)
Equilibrium
(c)
Diffusion

22. 22
Diffusion

23. 23
Factors
Influencing
Diffusion
Rate

24. 24
Simple
Diffusion

25. Channel-­‐Mediated
Facilitated
Diffusion
25

26. 26

27. Carrier-­‐Mediated
Facilitated
Diffusion
27

28. 28

29. Osmosis
29

30. 30

31. Tonicity
Isotonic
Hypotonic
Hypertonic
31

32. 32
Isotonic

33. 33
Hypotonic

34. 34
Hypertonic

35. 35
Ac3ve
Transport
Needs
ATP
Transports
against
gradient
Ions,
AA,
glu
Primary
and
Secondary
Ac.ve
Transport
ATP

36. Primary
Ac3ve
Transport:
Na+-­‐
K+
pump
36

37. 37

38. Na+
gradient
Extracellular
fluid
Na+/K+
ATPase
3
Na+
expelled
2K+
2
K+
imported
ADP
ATP
3
Na+
K+
gradient
Cytosol
P
P
1
2
3
4
1
2
3
4
3
sodium
ions
(Na+)
from
the
cytosol
bind
to
the
inside
surface
of
the
sodium–
potassium
pump.
Na+
binding
triggers
ATP
to
bind
to
the
pump
and
be
split
into
ADP
and
P
(phosphate).
The
energy
from
ATP
splijng
causes
the
protein
to
change
shape,
which
moves
the
Na+
to
the
outside.
2
potassium
ions
(K+)
land
to
the
outside
surface
of
the
pump
and
cause
the
P
to
be
released.
The
release
of
the
P
causes
the
pump
to
return
to
its
original
shape,
which
moves
the
K+
into
the
cell.
Primary
Ac3ve
Transport:
Na+-­‐
K+
pump
-­‐
REVIEW

39. Secondary
Ac3ve
Transport:
Symporters
39

40. Secondary
Ac3ve
Transport:
An3porters
40

41. Vesicular
Transport:
Endocytosis
Phagocytosis
Receptor-­‐
Mediated
Endocytosis
Bulk-­‐Phase
Endocytosis
(Pinocytosis)
41

42. Phagocytosis
42

43. 43
Phagocytosis

44. 44
Receptor-­‐Mediated
Endocytosis

45. Bulk-­‐Phase
Endocytosis
(Pinocytosis)
45

46. 46
Transcytosis
Vesicular
transport
Endocytosis,
intracellular
transport,
exocytosis
Exocytosis
Secretory
vesicles
Enzymes,
hormones,
NT’s,
wastes

47. 47