Transcript A Tour of the Cell - Ursuline High School

4-2 Parts of the
Eukaryotic Cell
Part 2
Mitochondria
the
Site of Cellular
Respiration, or the place
where energy is released
from food and stored in ATP
the “Powerhouse” of the cell.
Mitochondria
have
their own DNA.
can reproduce themselves.
may have been independent
cells at one time.
Ribosomes
contain
no membranes.
are made up of 2 pieces
made of protein and RNA.
make or synthesize proteins.
Ribosome Locations
Free in the cytosol…..
they make proteins for use in
the cytosol.
When Attached to the
Endoplasmic Reticulum…..
they make proteins that are
exported from the cell.
When
Ribosomes
Endoplasmic Reticulum
is
often called ER.
is made of stacks of flattened
sacks.
is a highway system or path for
moving molecules through the
cell
is involved in the production of
proteins, sugars, fats, etc.
Rough ER
When
ribosomes
are attached to
ER, we call it
Rough ER
RER makes
proteins for
export
Smooth ER
 is
Endoplasmic
Reticulum without
Ribosomes…..
 is responsible for
making lipids and
hormones,
 in muscles regulates
Calcium levels,
 in liver cells breaks
down toxins and
drugs.
Golgi Apparatus
AKA Golgi bodies or Golgi Complex
Structure:
parallel array of
flattened sacs arranged in a
stack. (looks like a stack of
Pita bread)
3 to 20 per cell.
Likely an outgrowth of the ER
system.
The
Golgi Apparatus package and
modify proteins and lipids into
vesicles (small, spherical shaped
sacs that bud form the Golgi
apparatus). The vesicles often
merge and merge with the plasma
membrane to release contents to
the outside of the cell.
Lysosome
Vesicles
from the Golgi
apparatus that contain digestive
enzymes. They breakdown food,
cellular debris and foreign
invaders such as bacteria.
Important in cell death.
Not present in plant cells.
Peroxisomes
Organelles
that breakdown
various substances. During
digestion 0xygen is produced
and combines with H2O to form
Hydrogen Peroxide…. a toxin.
Peroxisomes break down
Hydrogen Peroxide.
Nucleus
Most
conspicuous organelle.
usually spherical, but can be
lobed or irregular in shape.
Function of the Nucleus
Control
center for the cell.
Contains the genetic
instructions.
Structure of the Nucleus
Nuclear
Envelope
Nuclear pores
Nucleolus
Chromatin
Nuclear Envelope… the
outer boundary of the nucleus
Double
membrane separated
by a 20-40 nm space.
Inner membrane supported
by a protein matrix (braces)
which gives the shape to the
nucleus.
Nuclear Pores
Regular
“holes” through both
membranes.
100 nm in diameter.
Allows materials in/out of
nucleus.
Nucleolus
Dark
area in the nucleus.
0 - 4 per nucleus.
Storage area for ribosomes.
Chromatin
Chrom:
colored, tin: threads
DNA and Protein in a “loose”
format (stringy form of DNA) Will
eventually form the cell’s
chromosomes.
Chromosomes
 Rod-shaped
bodies made up of coiled DNA.
 The DNA is wrapped around proteins called
histones.
 The histones are coiled into nucleosomes
Histone
Chromatin
Molecules
Nucleosome
To be continued…….
go to
Cell Biology Part 3
To be continued…….
go to
4-2, Part 3