1

Biology
112Unit
Three

Chapter
Four

2

Cell
Sizes

• Smallest ‐ Bacteria• Largest
 ‐ Bird
egg• Longest ‐ Giraffe’s
Nerve
Cell• Most
Cells ‐ Diameter
of
0.7µm to

105
µm


3

Human height

Length of somenerve andmuscle cells

10 m

Frog egg

Chicken egg

Una

ided

eye

1 m

100 mm(10 cm)

10 mm(1 cm)

1 mm

Ligh

t mic

rosc

ope

Elec

tron

mic

rosc

ope

100 nm

100 µm

10 µm

1 µm

Most plant and animal cells

Viruses

NucleusMost bacteriaMitochondrion

10 nm

Lipids

Ribosome

Proteins

Mycoplasmas(smallest bacteria)

1 nmSmall molecules

0.1 nm Atoms

4

How
big
can
a
cell
get?

• Cells
are
limited
by
natural
laws• They
must
be
able
to
house
organelles(minimum
size)

• They
must
stay
within
a
certain
surface
areato
volume
raRo
(maximum
size)

5

Surface
Area

• L
x
W

6

Volume

• L
x
W
x
H

• Large
cell
=
smaller
SA/Vol
raRo

7

30 µm

30 µm 10 µm

10 µm

Surface areaof one large cube= 5,400 µm2

Total surface areaof 27 small cubes= 16,200 µm2

8

Cell
Structure

• Minimal
Cell1.

Plasma
membrane

2.

Cytoplasm

3.

GeneRc
informaRon

4.

Ribosomes

9

Two
Types
of
Cells

• ProkaryoRc• EukaryoRc

10

ProkaryoRc
Cells

• Average
2
µm
to
8
µm
long• No
nucleus– Nucleoid
(nuclear
region)

• Most
have
a
bacterial
cell
wall– PepRdoglycan

• Limited
organelles– Ribosomes

11

ProkaryoRc
Cells

• Variety
of
structures– Capsule

• Some
have
sRcky
outer
coat– Pili
or
flagella

• Used
for
movement

12

Nucleoid

Ribosomes

Plasma membrane

Cell wall

Capsule

Flagella

Bacterialchromosome

A typical rod-shapedbacterium

Pili

A thin section through thebacterium Bacillus coagulans(TEM)

13

EukaryoRc
Cells

• Average
10x
bigger
and
1000x
in
volume
asprokaryoRc

• Nucleus
present• Variety
of
membranous
cellular
organelles• Vary
in
cellular
metabolism

– Dependent
on
internal
cellular
membranes– Increase
areas
of
specializaRon

• Increase
in
SA
allows
for
more
reacRons
to
takeplace
at
one
Rme

14

Unicellular

• ProRsta– The
kingdom
being
reorganized

• Fungi– Yeast

15

MulRcellular

• Plant– No
centrioles– Cell
wall
(cellulose)– Chloroplast– Central
vacuole

16

Smooth endoplasmicreticulum

Rough endoplasmicreticulum

CYTOSKELETON:

NUCLEUS:Nuclear envelopeChromosomeNucleolus

Ribosomes

Golgiapparatus

Plasma membrane

Mitochondrion

Peroxisome

Cell wall

Central vacuoleMicrotubule

Intermediatefilament

Microfilament

Cell wall ofadjacent cell

Chloroplast

Plasmodesmata

17

MulRcellular

• Animal– Paired
centrioles– No
cell
wall– Flagella
in
some
(movement)– ContracRle
vacuole

18

Smooth endoplasmicreticulum

Roughendoplasmicreticulum

CYTOSKELETON:

NUCLEUS:Nuclear envelopeChromosomesNucleolus

Ribosomes

Golgiapparatus

Plasma membrane

Mitochondrion

Peroxisome

Centriole

Lysosome

MicrotubuleIntermediatefilamentMicrofilament

19

Organelles
and
FuncRons

• Four
Categories1.

Manufacturing

2.

Breakdown

3.

Energy
Processing

4.

Support,
Movement
and
CommunicaRon

20

Manufacturing

• Nucleus
–
control
center
of
the
cell– Nuclear
Envelope

• Double
membrane• Perforated
(pores)• Material
movement

– DNA• ChromaRn
strands• Strands
make
up
chromosomes

– Nucleolus• Contains
chromaRn,
RNA
and
protein• Manufactures
ribosome

21

Two membranes ofnuclear envelope Nucleus

Nucleolus

Chromatin

Pore

Endoplasmicreticulum

Ribosomes

22

Ribosomes

• Assemble
amino
acids
into
polypepRdes• Every
cell
has
ribosomes!

23

Cytoplasm

Endoplasmic reticulum (ER)

Free ribosomes

Bound ribosomes

RibosomesER

Smallsubunit

Diagram of a ribosome

TEM showing ERand ribosomes

Largesubunit

24

• Endoplasmic
ReRculum
(ER)– Rough
ER
(due
to
ribosomes)

• Makes
membrane
bound
proteins• Makes
secretory
proteins

– Smooth
ER• Synthesis
of
lipids• In
the
liver,
helps
regulate
blood
sugar• Drug
breakdown• Storage
of
calcium

– Amount
of
Smooth
ER
or
Rough
ER
in
the
cells
depends
onthe
funcRon
of
the
cell

25

Smooth ER

Nuclearenvelope

Ribosomes

Rough ER

26

Transport vesiclebuds off

Secretoryproteininside trans-port vesicle

Glycoprotein

Polypeptide

Ribosome

Sugarchain

Rough ER

1

2

3

4

27

• Golgi
Apparatus– Receives
and
modifies
substances
manufacturedin
the
ER

– Finishes,
sorts
and
ships
products– #
of
GA
depend
on
how
acRve
the
cell
is
insecreRng
proteins

– Receiving
and
Shipping
sides
(cis
and
trans)– Contents
may
either
leave
the
cell
or
become
partof
the
cell’s
organelles
or
membrane

28

Golgi apparatusGolgi apparatus

“Receiving” side ofGolgi apparatus

Transportvesiclefrom ER

New vesicleforming

“Shipping” sideof Golgi apparatus

Transportvesicle fromthe Golgi

29

Breakdown• Lysosomes

– DigesRve
enzymes
(hydrolyRc)
in
a
membranous
sac– Only
work
in
a
very
acidic
environment– “Stuff”
that
needs
to
be
broken
down
is
brought
into
themembranous
sac
(recycling)

– Engulfing
bacteria– Fusing
with
food
vacuoles– Embryonic
development
(programmed
cell
death)

30

Digestiveenzymes

Lysosome

Plasmamembrane

Food vacuole

Digestion

31

Lysosome

Vesicle containingdamaged mitochondrion

Digestion

32

• Peroxisomes– Contains
enzymes
in
a
membranous
sac
thatproduce
H2O2

– Help
survive
environmental
toxins
includingalcohol

– Help
the
cell
use
oxygen
to
break
down
faky
acids

33

• Vacuoles– In
plants,
can
be
a
large
lysosome

• Can
store
water,
chemicals,
pigments,
poisons
or
wasteproduct

– In
animals,
used
as
a
contracRle
vacuole
tomaintain
water
balance

34

Nucleus

Chloroplast

Centralvacuole

35

Nucleus

Contractilevacuoles

36

Energy
Processing

• Mitochondria– Energy
converRng
organelle– Cellular
RespiraRon

• ConverRng
chemical
energy
in
food
to
chemical
energyof
ATP
for
cellular
work

37

• Mitochondria
(conRnued)– Double
membrane
–
two
compartments
(outer

and
inner
membranes)

1. Intermembrane
space

‐
between
the
membranes
–
where
H+
build
upoccurs

2. Cristae

‐
increase
surface
area
for
ATP
producRon

‐
ATP
Synthase
is
embedded
here

3. Mitochondrial
matrix

‐
The
Citric
Acid
Cycle
is
located
here

38

Mitochondrion

Intermembranespace

Innermembrane

Cristae

Matrix

Outermembrane

39

Support,
Movement
&CommunicaRon

• Cilia– Microtubule
extending
from
cell– Short
and
many
present– Line
trachea
to
sweep
mucous
containing
debrisout
of
lungs

– Line
oviducts
to
move
the
egg
toward
the
uterus

40

Cilia

41

• Flagella– Fewer
in
number
but
longer– Sperm

42

Flagellum

43

• Both– Dynein
arms
for
movement
(9
+
2)
arrangement– Anchor
in
basal
body– Are
tubular
extensions
of
the
plasma
membrane– FuncRon
is
to
move
either
the
whole
cell
or
movematerial
across
cell
or
into
cell

44

Centralmicrotubules

Outer microtubuledoublet

Radial spoke

Dynein arms

Plasmamembrane

Triplet

Cross sections:

Flagellum

Basal body

Basal body

45

• Animal
Cell
Surfaces– Animal
and
other
eukaryotes
are
organized
intosingle
funcRonal
organisms

– These
are
held
together
with
cell
surfaces

46

• Extracellular
Matrix– Helps
hold
cells
together,
affects
cell
behavior
bycontacRng
proteins
in
plasma
membrane
andcytoskeleton
within
the
cell

47

EXTRACELLULAR FLUID

Microfilaments

Collagen fiber

Connectingglycoprotein

Integrin

Plasmamembrane

Glycoproteincomplex with longpolysaccharide

CYTOPLASM

48

Binds
Cells
Together

1. Tight
JuncRons‐
leak
proof
sheet‐
digesRve
or
nervous
system

2. Anchoring
JuncRons‐
rivets
with
cytoskeleton

3. CommunicaRng
(Gap)
JuncRons‐
allow
for
flow
of
water
and
chemicals‐
also
for
electrical
signals

49

Tight junctions

Anchoring junction

Gap junctions

Plasma membranesof adjacent cells

Extracellular matrix