(if a spherical cell)
10 times the diameter
100 times the surface area
1000 times the volume
is in paired chromosomes
DNA is in a nucleus contained in
additional structures such as
that are "live-in"
additional structures to help
organization and functioning
one tenth the size of a
is a loop
DNA floats in the cytoplasm
are anaerobic (poisoned by
some can live with oxygen or
some use oxygen
a lot of biochemical diversity
So What is in These Cells?
encloses the cell. Water and
nutrients are admitted through the
cell wall, and wastes are
expelled. Bacteria and plant
cells also have a protective cell
wall, but animals have a membrane
without a wall.
is the watery stuff that fills the
cell, provides a medium in which to
move the molecules around.
The cytoplasm is full of chemicals:
dissolved oxygen and / or carbon
dioxide, amino acids, simple sugars, molecules of
carbohydrates, proteins, or lipids
(fats). More than half of
the cell contents is water.
eukaryotes the inside of the cell is
full of membranes that guide and
contain and compartmentalize the cell
Ribosomes do protein
synthesis. I think of them as
being like workers in a fast food
place. When the cell needs
proteins, the ribosomes get
information about how to make the
proteins by copying a piece of the
DNA. That is like taking the
The proteins are made of amino acids,
which are floating in the
cytoplasm. The ribosome collects
the amino acids which fill the
order. It puts the amino acids
together correctly. That is like
assembling and packing up the
items on the order.
When the order is complete, the
protein folds up and is ready to
use. The folding up is the
The Nucleus contains the
DNA, the material that holds the
genetic code, the instructions for how
to make the cell and control its
processes. The nucleus is
contained in a membrane which keeps
all the DNA together. In Eukaryotes, ribosomes are made inside
the nucleus by a structure called the
The Vacuole is a
container within a single
membrane. It may hold water,
food, or wastes -- whatever the cell
is storing or transporting. In a
plant cell the vacuole stores
water. In plant cells, the
vacuole can occupy about 55% to 95% of
the cell volume. When the
vacuole is full of water it helps to
support the cell wall of the plant
and Chloroplasts are called
Mitochondria are found in
all eukaryotic cells. They are
the "energy factories" of
the cells, doing respiration..
They use oxygen as they work.
They process the glucose that the
chloroplasts make and release energy
that powers the entire cell.
They are small and oval shaped, and
were once free-living
Mitochondria have their own DNA and
their own small ribosomes. They
are enclosed in two membranes.
They divide themselves by binary
Chloroplasts are found
in algae and plants. They are
cyanobacteria that moved into
eukaryotic cells long ago. They
have their own DNA loops and their own
little ribosomes. They are enclosed by
three specialized membranes.
Chloroplasts do photosynthesis.
They capture the carbon in carbon
dioxide and link it to other atoms to
make organic compounds. They
release oxygen into the
atmosphere. What they do
benefits the whole cell.
Chloroplasts are larger than
mitochondria. It is their
productive work that makes much of the
life on earth possible by providing
oxygen and materials for the
construction of biomass (leaves,
twigs, roots, etc) that support
animals and decomposers.
Chloroplasts are well treated by the
plants. Plants supply the
chloroplasts with water and minerals,
and turn their leaves toward the sun
so that the chloroplasts can function
well. What a great
Other contents of the eukaryotic cell
include the endoplasmic reticulum
(membranes that create paths for the
movement of contents in the cell), the
Gogli body, and the cytoskeleton,
which provides support and helps in
to the Three Domains
Header by Viau
in Lily Pond
1996,1997, 1998, 1999,
2000, 2002, 2003.
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