Cell
2
12
The Cell
Anatomy:
Physiology:
The two categories of cells are prokaryotic
cells and eukaryotic cells. Prokaryotic cell
lack membrane bound organelles and their
Genetic material is not surrounded by a
nuclear membrane, while Eukaryotic cells
have their Genetic material surrounded by a
nuclear membrane. Prokaryotic organisms are
classified within the domains Archaea and
Bacteria, whereas eukaryotic organisms are
classified within the domain Eukarya.
The genetic material, usually DNA, sends
information via the messenger RNA [mRNA].
Ribosomes of the cell read the information on
the mRNA to from protein frameworks which
are further modified within the cytoplasm by
other organelles such as, for the eukaryotic cell,
the golgi apparatus. The final product remains
within the cell or for eukaryotic cells may form other
organelles [such as lysosomes or peroxisomes]
or transported by secretory vesicles to exit
the cell.
The structures of cells are unique with specific
functions. Eukaryotic cells, for the most part
tend to be larger than prokaryotic cells. All
cells have a plasma membrane, cytoplasm
and genetic material. Prokaryotic organisms
are classified within the domains Archaea
and Bacteria, whereas eukaryotic organisms
are classified within the domain Eukarya. The
structures of cells are unique with specific
functions. Eukaryotic cells, for the most part tend
to be larger than prokaryotic cells.
Cell
Eukaryotic
Prokaryotic
Prkarya
Archaea
Prkarya
Bacteria
Animal
Plant
Fungi
Protists
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13 © 2019 Damaris-Lois Y Lang, Content illustrations and diagrams are licensed under a Creative Commons Attribution-NonCommercial 4.0
International License.
CELL
STRUCTURE
EUKARYOTES
PROKARYOTES
BACTERIA
ARCHAEA
Size
~0.5–1 μM
~0.5–1 μM
~5–20 μM
Surface area-tovolume ratio
High
High
Low
Nucleus
No
No
Yes
Genome
characteristics
• Single chromosome
• Single chromosome
• Multiple chromosomes
• Circular
• Circular
• Linear
• Haploid
• Haploid
• Haploid or diploid
• Lacks histones
• Contains histones
• Contains histones
Cell division
Binary fission
Binary fission
Mitosis, meiosis
Membrane lipid
composition
• Ester-linked
• Ether-linked
• Ester-linked
• Straight-chain fatty acids
• Branched isoprenoids
• Straight-chain fatty acids
• Bilayer
• Bilayer or monolayer
• Sterols
• BilayerW
Cell wall
composition
• Peptidoglycan, or
• Pseudopeptidoglycan, or
• Cellulose (plants, some algae)
• None
• Glycopeptide, or
• Chitin (molluscs, insects,
• Polysaccharide, or
• Protein (S-layer), or
crustaceans, and fungi)
• Silica (some algae)
Motility
structures
Rigid spiral flagella
composed of flagellin
• None
• Most others lack cell walls
Rigid spiral flagella composed of Flexible flagella and cilia
archaeal flagellins
composed of microtubules
Membranebound
organelles
No
No
Yes
Endomembrane
system
No
No
Yes (ER, Golgi, lysosomes)
Ribosomes
70S
70S
• 80S in cytoplasm and
rough ER
• 70S in mitochondria,
chloroplasts
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Sporangiospores are produced in a sporangium (Figure 24.9).
Eukaryotic
Fungi
635
635
(a) Apicomplexans are parasitic protists. They have a characteristic apical complex that enab
ells. (b) Plasmodium, the causative agent of malaria, has a complex life cycle typical of apic
dification of work by CDC)
which include Paramecium and Tetrahymena, are a group of protists 10 to 3,000 micrometers in
n rows, tufts, or spirals of tiny cilia. By beating their cilia synchronously or in waves, ciliates ca
ements and ingest food particles. Certain ciliates have fused cilia-based structures that function l
ns. Ciliates
Fungi also are surrounded by a pellicle, providing protection without compromising agility
includes
protists that have organized their cilia into a plate-like primitive mouth, called an oral gr
Figure 24.9 This bright field light micrograph shows the release of spores from a sporangium at th
pture
anda digest
bacteria (Figure
23.15).
captured
in the
oraloften
groove
enters
a food
vacuo
called
sporangiophore.
The organism
is aFood
Mucor
sp. fungus,
a mold
found
indoors.
(credit:
m
h digestive
enzymes.
byRussell)
an exocytic vesicle that fuses at a specific r
by Dr. Lucille
Georg,Waste
CDC; particles
scale-bar are
dataexpelled
from Matt
e, called the anal pore. In addition to a vacuole-based digestive system, Paramecium also uses
Reproduction
ichSexual
are osmoregulatory
vesicles that fill with water as it enters the cell by osmosis and then contrac
e cell.
4.5
Fungal
hyphae
may be (a) septated
or (b) coenocytic
= "common";
= "cell") with of
many
nuclei In fungi, sexual reproduct
Sexual
reproduction
introduces
genetic(coenovariation
into -cytic
a population
fungi.
n a single hypha. A bright field light micrograph of (c) Phialophora richardsiae shows septa that divide the
response to adverse environmental conditions. During sexual reproduction,
credit c: modification of work by Dr. Lucille Georg, CDC; scale-bar data from Matt Russell)
two mating types are pro
Heterothallic m
ngal hyphae may be (a) septated or (b) coenocytic (coeno- = "common"; -cytic = "cell") with many nuclei
mating types are present in the same mycelium, it is called homothallic, or self-fertile.
ngle hypha. A bright field light micrograph of (c) Phialophora richardsiae shows septa that divide the
ive
in environments
that
are
moist
andmycelia
slightly
and can grow
with
without
light. They vary in
but
compatible,
to reproduce
sexually.
c: different,
modification
of work
by Dr.
Lucille
Georg, acidic,
CDC;
scale-bar
data
fromorMatt
Russell)
gen requirement. Most fungi are obligate aerobes, requiring oxygen to survive. Other species, such as the
mycota that reside in the rumen of cattle, are are obligate anaerobes, in that they only use anaerobic respiration
nxygen
environments
moist and
acidic,
and can grow
with
or without
light.This
They
vary in
will disrupt that
their are
metabolism
or killslightly
them. Yeasts
are intermediate,
being
faculative
anaerobes.
means
equirement.
Most
fungiofare
obligate
requiringbut
oxygen
to survive.
Other species,
such
as the
grow best in the
presence
oxygen
using aerobes,
aerobic respiration,
can survive
using anaerobic
respiration
when
anotthat
reside The
in the
rumen
of cattle,
areyeast
are fermentation
obligate anaerobes,
in that
use anaerobic respiration
available.
alcohol
produced
from
is used in wine
andthey
beeronly
production.
n will disrupt their metabolism or kill them. Yeasts are intermediate, being faculative anaerobes. This means
best in the presence of oxygen using aerobic respiration, but can survive using anaerobic respiration when
mals, fungi are heterotrophs; they use complex organic compounds as a source of carbon, rather than fix carbon
vailable. The alcohol produced from yeast fermentation is used in wine and beer production.
rom the atmosphere as do some bacteria and most plants. In addition, fungi do not fix nitrogen from the
re. Like animals, they must obtain it from their diet. However, unlike most animals, which ingest food and then
nternally in specialized organs, fungi perform these steps in the reverse order; digestion precedes ingestion. First,
ungi are heterotrophs; they use complex organic compounds as a source of carbon, rather than fix carbon
mes are transported out of the hyphae, where they process nutrients in the environment. Then, the smaller molecules
he
atmosphere
as do some
bacteria
and most
plants.
Inarea
addition,
fungi do As
notwith
fixanimal
nitrogen
by this
external digestion
are absorbed
through
the large
surface
of the mycelium.
cells,from
the the
ke
animals,
they
must
obtain
it
from
their
diet.
However,
unlike
most
animals,
which
ingest
food
and
then
aride of storage is glycogen, rather than starch, as found in plants.
lly in specialized organs, fungi perform these steps in the reverse order; digestion precedes ingestion. First,
mostly saprobes (saprophyte is an equivalent term): organisms that derive nutrients from decaying organic
transported
out of the hyphae,
where
they process
nutrients
in the environment.
Then,Fungal
the smaller
molecules
5ehey
Paramecium
primitive
mouth
an plant
oralmaterial.
groove)
to
ingest
food, and an anal pore
obtainProtist
their nutrientshas
from a
dead
or decomposing
organic(called
matter: mainly
exoenzymes
s
external
digestion
are
absorbed
through
the
large
surface
area
of
the
mycelium.
As
with
animal
cells,
the
down insoluble
polysaccharides,
such as the to
cellulose
and ligninexcess
of dead wood,
into readily
absorbable
eoofbreak
vacuoles
allow
the organism
excrete
water.
Cilia
enable the organism to m
storageThe
is glycogen,
rather than
as foundarein thus
plants.
molecules.
carbon, nitrogen,
and starch,
other elements
released into the environment. Because of their
micrograph”:
modification
of ecological
work by
dataas from
Russell)
etabolic
pathways, fungi
fulfill an important
roleNIH;
and arescale-bar
being investigated
potentialMatt
tools in
ly saprobes (saprophyte is an equivalent term): organisms that derive nutrients from decaying organic
ation. For example, some species of fungi can be used to break down diesel oil and polycyclic aromatic
btain
their nutrients from dead or decomposing organic matter: mainly plant material. Fungal exoenzymes
ons (PAHs). Other species take up heavy metals, such as cadmium and lead.
k down insoluble polysaccharides, such as the cellulose and lignin of dead wood, into readily absorbable
gi areThe
parasitic,
infecting eitherand
plants
or animals.
Smut
and
elm disease
affect
plants, whereas
athlete’s their
ules.
other
elements
are from
thusDutch
released
into the
environment.
Because
© 2013nitrogen,
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and
illustrations
textbook
produced
by OpenStax
is licensed
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Creative Commons Attribution
15carbon,
andidiasis
(thrush)
are
medically
important
fungal
infections
in
humans.
In
environments
poor
in
nitrogen,
ic pathways,License
fungi 3.0
fulfill
anThis
important
role and are being investigated as potentialsome
tools in
license.
is availableecological
for free at http://cnx.org/content/col11496/1.8
ort to predation of nematodes (small non-segmented roundworms). Species of Arthrobotrys fungi have a number
Prokaryotic
Chapter 4 | Prokaryotic Diversity
Bacteria
Archaea
Figure 4.26 Sulfolobus, an archaeon of the class Crenarchaeota, oxidizes sulfur and sto
granules.
Another genus, Thermoproteus, is represented by strictly anaerobic organisms with an
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CNX,85
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illustrations
textbookand,
produced
by OpenStaxare
is licensed
underThermoproteus
a Creative Commons Attribution
16
°C.and
They
havefrom
flagella
therefore,
motile.
has a cellular
me
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Plant Cell
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Animal Cell
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Fill out the table
Structures
Cell
Organelles
Molecules
Atoms
Work Overflow
19
Sketch and Label / Illustrations
Functions/ Roles
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(condensed)
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Extracellular
Intracellular
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Personal Notes:
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