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Cells (Lab)
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CHELSIE ROSE
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History of Cell Study
Robert Hooke
- discovered
cell
Anton Van Leeuwenhoek
- famous in observing one celled organisms
RJH Dutrochet
(1824) - all living things are made of cells and increase in
size
and
divide
(one of the first clear statement)
Dujardin
(1835) - French zoologist recognized the universality of
protoplasm
within plant cells and named it
Max Schultz
- called protoplasm the
physical
basis of heredity
Rudolf Virchow
- studied the life of cells and concluded that "every cell comes from a pre-existing cell" (cell theory/doctrine)
Significance of Cells
Unit of structure and function,
function
,
growth
,
reproduction
Contain the
units heredity
Cell shape
Spherical
Polyhedral
Ovoid
Ellipsoid
Cylindrical
Tubular
Prismatic
Lamelliform
Fiber-like
Stellate
Cell size
1mm
-
parenchyma
cells
1-3 mm -
fibers
of wood & phloem of
angiosperm
2-8mm - fibers of
wood
& phloem of
gymnosperm
20-50mm
- certain
monocotyledon
Prokaryotic Cell
Cell lacks true
nucleus
1-10
um in diameter
DNA is in a single
chromosome
located in the
nucleoid
region
Internal
membrane does not compartmentalize with few organelles
Eukaryotic cell
Have
true
nucleus
10-100 um in diameter
Membrane-bound
compartment that houses DNA within chromosomes
Organelles-
small membranous bodies structure suits their functions
ORGANELLES
Cell
Wall
Plasma or Cell Membrane
Ribosomes /
Microsomes
Endoplasmic reticulum
Golgi apparatus /
Dictyosomes
Vacuoles and vesicles
Peroxisomes
/ Microbodies
Mitochondrion
Chloroplast
Cytoskeleton
Nucleus
Cell Wall
Composition:
cellulose
fibrils
Function: for
support
and
protection
Plasma or Cell Membrane
Composition:
Bilayer
of
phospholipids
with embedded
proteins
Function:
passage
of molecules into and out of the cell
Ribosomes / Microsomes
Composition:
proteins
&
RNA
in 2 subunits (60 - 40)
Function:
protein
synthesis
Endoplasmic reticulum
Composition: membranous
flattened
channels and
tubular
canals
Function:
transport
system, protein synthesis-
rough
ER
Golgi apparatus / Dictyosomes
Composition: stack of membranous
saccules
Function:
processing
and
packaging
of molecules, e.g. glycoproteins
Vacuoles and vesicles
Composition: membranous
sacs
Function:
storage
of substances
Peroxisomes / Microbodies
Composition: membranous vesicle containing specific
enzymes
Function: various
metabolic
tasks
Mitochondrion
Composition: inner membrane (
cristae
) within outer membrane
Function:
cellular
respiration
Chloroplast
Composition: inner membrane (
grana
) within 2 outer membrane
Function:
photosynthesis
Cytoskeleton
Composition: microtubules,
microfilaments
Function:
shape
of cell and
movements
of its parts
Nucleus
Composition: nuclear envelope surrounding the nucleoplasm,
chromosome
and nucleoli
Function: cellular respiration and control of
photosynthesis
Cells -
smallest
living unit, most are microscopic
Principles of Cell Theory
All living things are made of
cells
Smallest living unit is the cell
All cells arise from preexisting cells (this principle discarded the idea of
spontaneous
generation)
Prokaryotic cells
1st cell type on Earth
Cell type of
bacteria
and
archaea
No membrane bound nucleus
Nucleoid
= region of DNA concentration
Organelles not bound by membranes
Eukaryotic cells
Nucleus bound by
membrane
Include fungi,
protists
, plants, animal cell
Possess many
organelles
Cytoplasm
Viscous
fluid containing organelles
Components: Interconnected filaments &
fibers
, Fluid =
cytosol
, Organelles (not nucleus),
Storage
of substances
Nucleus
Control
center of cell
Double
membrane
Contains chromosomes and
nucleolus
DNA
Hereditary
material
Chromosomes
:
DNA
,
proteins
, form of cell division
Chromatin