DNA arranged
into long thin
threads known as
chromosomes
In most cells
the
chromosomes
are arranged in
homologous
pairs
Surrounded
by nuclear
envelope
This has pores to
allow communication
between the nucleus
and cytoplasm
Plasma membrane
Sea of
phospholipids -
arranged as a
bilayer
Intrinsic and
extrinsic
proteins float
within the
phospholipids
Selectively permeable
barrier - controls
movement of
substances between the
internal and external
environments
Lysomes
Formed by
the golgi
apparatus
Contain
digestive
enzymes -
proteases and
lipases
Important to protect the
cell from the effect of
these enzymes before they
are released at the cell
surface membrane or into
a phagocytic vesicle
Mitochondria
Mostly protein,
but also contains
some lipid, DNA
and RNA
Power house of
the cell
Energy is stored in high
energy phosphate bonds
of ATP
Mitochondria convert energy from the
breakdown of glucose into adenosine
triphosphate (ATP)
Responsible for
aerobic respiration
Metabolic activity of a cell is
related to the number of cristae
(larger surface area) and
mitochondria
Ribosomes
Small organelles
often attached to the
ER but also found in
the cytoplasm
Large (protein) and small
(rRNA) subunits form the
functional ribosome
Subunits bind with
mRNA in the cytoplasm
This starts translation
of mRNA for protein
synthesis (assembly of
amino acids into
proteins
Free ribosomes make proteins used in the cytoplasm.
Responsible for proteins thatgo into solution in
cytoplasm or form important cytoplasmic, structural
elements
Ribosomal ribonucleic
acid (rRNA) are made in
nucleus of cell
Endoplasmic reticulum
Rough ER
Have ribosomes attached
to the cytosolic side of
their membrane
Found in cells that
are making proteins
for export (enzymes,
hormones, structural
proteins, antibodies)
Thus, involved in
protein synthesis
Modifies proteins by the addition of
carbohydrates, removal of signal
sequences
Phospholipid synthesis
and assembly of
polypeptides
Smooth ER
Have no ribosomes attached
and often appear more
tubular than the rough ER
Necessary for steroid
synthesis, metabolism
and detoxification, lipid
synthesis
Numerous in the liver
Golgi apparatus
Stack of
flattened sacs
surrounded by
membrane
Receives protein-filled vesicles from the rough ER (fuse
with Golgi membrane)
Uses enzymes to modify these
proteins (e.g. add a sugar
chain, making glycoprotein)
Adds directions for destination of protein package - vesicles
that leave Golgi apparatus move to different locations in cell
or proceed to plasma membrane for secretion
Involved in processing, packaging, and secretion
Other vesicles that leave
Golgi apparatus are
lysosomes