Cell Structure Review

http://en.wikipedia.org/
wiki/Cell_(biology)

“fundamental
units of life...”

Figure 1-1d Essential Cell Biology (© Garland Science 2010)

Figure 1-1b Essential Cell Biology (© Garland Science 2010)

Figure 1-1a Essential Cell Biology (© Garland Science 2010)

Figure 1-1c Essential Cell Biology (© Garland Science 2010)

Figure 1-1e Essential Cell Biology (© Garland Science 2010)

Structure-Function
Relationship

Number of cells
in a human body

Bright field, 400x
Hematoxylin stained

Bright field, 1000x
Hematoxylin stained

Phospholipid bilayer
+ membrane proteins
+ cholesterol

Surfaces are important!
They are the parts of an object
that are readily accessible
by things outside the object.

Heat exchange
happens via surfaces.

Gas exchange
happens via surfaces.

Peripheral
MembraneText

Proteins

http://en.wikipedia.org/wiki/
Peripheral_membrane_protein

“...a specialized subunit within a cell
that has a speciﬁc function,
and is usually separately enclosed within
its own lipid bilayer.”

wiki/Organelle

Table 4.2a
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

TABLE 4.2 EUKARYOTIC CELL STRUCTURES AND THEIR FUNCTIONS
Structure Description

Plasma Membrane
The plasma membrane is a phospholipid bilayer embedded with proteins that
Phospholipid encloses a cell and separates its contents from its surroundings. The bilayer results
Protein from the tail-to-tail packing of the phospholipid molecules that make up the
membrane. The proteins embedded in the lipid bilayer are in large part responsible
for a cell’s ability to interact with its environment. Transport proteins provide
channels through which molecules and ions enter and leave the cell across the
plasma membrane. Receptor proteins induce changes within the cells when they
come in contact with specific molecules in the environment, such as hormones, or
with molecules on the surface of neighboring cells.

Cholesterol

Nucleus

Nuclear envelope Every cell contains DNA, the hereditary material. The DNA of eukaryotes is isolated
within the nucleus, a spherical organelle surrounded by a double membrane
structure called the nuclear envelope. This envelope is studded with pores that
control traffic into and out of the nucleus. The DNA contains the genes that code
for the proteins synthesized by the cell. Stabilized by proteins, it forms chromatin,
Nucleolus the major component of the nucleus. When the cell prepares to divide, the
chromatin of the nucleus condenses into threadlike chromosomes.

Nuclear pore

The hallmark of the eukaryotic cell is compartmentalization, achieved by an
extensive endomembrane system that weaves through the cell interior. The
Endoplasmic Reticulum membrane network is called the endoplasmic reticulum, or ER. The ER begins at
the nuclear envelope and extends out into the cytoplasm, its sheets of membrane
Rough ER weaving through the cell interior. Rough ER contains numerous ribosomes that give
it a bumpy appearance. These ribosomes manufacture protein destined for the ER
or for other parts of the cell. ER without these attached ribosomes is called smooth
ER, which often functions to detoxify harmful substances or to aid in the synthesis
of lipids. Sugar side chains are added to molecules as they pass through the ER.
Delivery of molecules to other parts of the cell is via vesicles that pinch off from the
borders of the rough ER.

Ribosome

Smooth ER

Golgi Complex
Transport vesicles

At various locations within the cytoplasm flattened stacks of membranes occur.
Animal cells may contain 20, plant cells several hundred. Collectively, they are
Lysosome referred to as the Golgi complex. Molecules manufactured in the ER pass to the
Golgi complex within vesicles. The Golgi sorts and packages these molecules and
also synthesizes carbohydrates. The Golgi adds sugar side chains to molecules as
they pass through the stacks of membranes. The Golgi then directs the molecules
to lysosomes, secretory vesicles, or the plasma memrane.

Secretory
vesicles

Table 4.2b Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Structure Description

Mitochondrion Mitochondria are bacteria-like organelles that are responsible for extracting most
Of the energy a cell derives from the food molecules it consumes. Two membranes
Intermembrane space Outer Encase each mitochondrion, separated by an intermembrane space. The key
membrane energy-harvesting chemical reactions occur within the interior matrix. The energy is
Used to pump protons from the matrix into the intermembrane space; their return
Across this membrane drives the synthesis of ATP, the energy currency of the cell.
Inner
membrane

Matrix

The green color of plants and algae results from cell organelles called chloroplasts
Chloroplast rich in the photosynthetic green pigment chlorophyll. Photosynthesis is the
sunlight-powered process at converts CO2 in the air to the organic molecules
Outer membrane of which all living things are composed. Chloroplasts, like mitochondria, are
composed of two membranes separated by an intermembrane space. In a
chloroplast, the inner membrane pinches into a series of sacs called thylakoids,
Inner membrane which pile up in columns called grana. The chlorophyll-facilitated light reactions
of photosynthesis take place within the thylakoids. These are suspended in a
Granum semiliquid substance called the stroma.

Thylakoid

Stroma

The cytoplasm of all eukaryotic cells is crisscrossed by a network of protein fibers
Cytoskeleton called the cytoskeleton that supports the shape of the cell and anchors organelles
Actin filament to fixed locations. The cytoskeleton is a dynamic structure, composed of three
kinds of fibers. Long actin filaments are responsible for cellular movements such
as contraction, crawling, and the “pinching” that occurs as cells divide. Hollow
microtubule tubes, constantly forming and disassembling, facilitate cellular
movements an are responsible for moving materials within the cell. Special
motor proteins move organelles around the cell on microtubular “tracks.” Durable
Microtubule intermediate filaments provide the cell with structural stability.

Intermediate filament

Centrioles Centrioles are barrel-shaped organelles found in the cells of animals and most
protists. They occur in pairs, usually located at right angles to each other near
the nucleus. Centrioles help assemble the animal cell’s microtubules, playing
a key role in producing the microtubules that move chromosomes during cell
division. Centrioles are also involved in the formation of cilia and flagella, which
are composed of sets of microtubules. Cells of plants and fungi lack centrioles, and
cell biologists are still in the process of characterizing their microtubule-organizing
centers.

Microtubule triplet

Why is having organelles
advantageous?

The Nucleus
“information center”

Nuclear Envelope
Endoplasmic Reticulum
Golgi Apparatus
Lysosomes
Vacuoles
Vesicles
Cell Membrane
wiki/Endomembrane_system

“...the set of membranes that
form a single functional and
developmental unit, either being
connected together directly, or
exchanging material through
vesicle transport.”

wiki/Endomembrane_system

Endoplasmic
Reticulum
where proteins are made
and processed

Endoplasmic_reticulum

Vesicles
containers for storage,
transport and digestion

The Golgi Complex
where proteins are processed,
sorted and packaged

Mitochondrion

Movement
into and out of
the cell

The wandering
around of molecules

wandering
The
of
around molecules

The
wandering
molecules
around

of

Fig. 4.21 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Hypertonic Isotonic Hypotonic
Solution Solution Solution

Human Red Blood Cells
Shriveled cells Normal cells Cells swell and
eventually burst

0.55 µm 0.55 µm 0.55 µm
Plant Cells

Cell body shrinks Flaccid cell Normal turgid cell
from cell wall

(all): © David M. Phillips/Visuals Unlimited

http://www.npr.org/
2011/03/18/13462204
4/tracing-the-immortal-
cells-of-henrietta-lacks

In 1951, an African-American woman named Henrietta Lacks
was diagnosed with terminal cervical cancer. She was
treated at Johns Hopkins University, where a doctor named
George Gey snipped cells from her cervix without telling her.
Gey discovered that Lacks' cells could not only be kept alive,
but would also grow indeﬁnitely.

For the past 60 years Lacks' cells have been cultured and
used in experiments ranging from determining the long-term
effects of radiation to testing the live polio vaccine. Her cells
were commercialized and have generated millions of dollars
in proﬁt for the medical researchers who patented her tissue.
Lacks' family, however, didn't know the cell cultures existed until more than 20 years
after her death. Medical writer Rebecca Skloot examines the legacy of Lacks'
contribution to science — and effect that has had on her family — in her new book, The
Immortal Life of Henrietta Lacks.

Skloot is a freelance science writer and a contributing editor at Popular Science. She
has written feature stories for The New York Times, Discover Magazine, and RadioLab.
http://www.npr.org/
2011/03/18/134622044/tracing-
the-immortal-cells-of-henrietta-lacks

Cell Structure Review

Recommandé

Recommandé

Contenu connexe

Tendances

Tendances (20)

Similaire à Cell Structure Review

Similaire à Cell Structure Review (20)

Plus de Albert

Plus de Albert (20)

Dernier

Dernier (20)

Cell Structure Review