Name __________________________________ Test Date_________________
CELL STRUCTURE AND FUNCTION
I. DISCOVERY OF CELLS
A. History of Microscopes
The invention and development of the microscope in the 1600’s enabled
scientists to discover and study cells - basic unit of structure and function in
in all living things
1. Anton von Leeuwenhoek – was the first to try stacking several
lenses_ together to view tiny objects. He looked at pond water_ through
his lenses and became known as the first scientist to describe living cells
as seen through a microscope.
2. Robert Hooke - In 1665, he used a _microscope_ to examine thin
slices of cork and then described what he saw and called them _cells__.
He chose the name “cells” because the chambers he saw reminded him of
the rooms in a monastery which were called cells.
B. Cell Theory
Nearly a century after Hooke’s findings, several other scientists discoveries led
to the formation of the _cell theory_.
1. Matthias Schleiden (botanist) & Theodor Schwann (zoologist) –
together they reached the conclusion that ____all____
living things were composed of cells_.
2. Rudolf Virchow – elaborated on Schleiden & Schwann’s proposal and
added “omnia cellula e cellula” : all cells come from cells_
These discoveries, confirmed by other biologists, are summarized in the
cell theory, a fundamental concept in Biology…..
The cell theory states that:
a. All organisms are ____composed of cells______
b. Cells are the smallest working units of life.
c. All cells come from ____pre-existing cells________
II. TYPES OF CELLS
Living organisms are made of either _prokaryotic__ or _eukaryotic_cells –
the two major kinds of cells which can be distinguished by _structural
organization__
PROKARYOTIC
_Bacteria_____; Divided into two
kingdoms, _Archaebacteria____ and
_Eubacteria________
_No_ true nucleus; Lack nuclear
envelope
Genetic material present
in_nucleoid___________ region
EUKARYOTIC
All organisms other than _bacteria______;
Found in kingdoms _Protista____,
_Fungi__, _Plantae___, and
_Animalia______
_True____ nucleus surrounded membrane
known as nuclear envelope
Genetic material contained
within_nucleus______________
__Lack_ membrane-bound organelles
_Contain____ membrane-bound organelles
A. Prokaryotic Cells – All Unicellular
1. Eubacteria – “True” Bacteria; Ex. include E.coli,Streptococcus.
2. Archaebacteria – “Ancient” bacteria; live in extreme environments (salty,
hot, acidic); Ex. methanogens
B. Eukaryotic Cells – Found in Unicellular and Multicellular organisms
1. Protista – ex. Amoeba, Euglena, Paramecium
2. Fungi - ex. Penicillium, yeasts, molds, mushrooms.
3. Plants – ex. Mosses, ferns, flowering plants.
4. Animals – ex. Sponges, worms, snails, insects, mammals.
III.
C. Microscopes - There are several types of modern microscopes:
1. Compound light microscope – More than one _lens (ocular & objective)________
uses light bent through lenses to magnify objects.
2. Electron Microscope – Uses _beams of electrons_________ . This enhances the
resolution and magnification to allow researchers to study _cell structures____.
There are two types of electron microscopes:
a. Transmission Electron Microscope or _TEM______________- electrons are
Transmitted _through_____the specimen; used to study _internal___ cell
structures.
b. Scanning Electron Microscope or _SEM_____ - uses electrons to trace the
_surface_____ of the specimen; provides _depth___ of field or 3-D view.
III. CELL BOUNDARIES
A. Cell Wall
Cell Walls are the outer most boundary in _bacteria_, _plants_, and
_fungi_. They are not found in __animal cells_____. The primary function
of the cell wall is to _provide support and structure__.
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Plants have cell walls made of _cellulose___
Fungi have cell walls made of _chitin____.
Eubacteria have cell walls made of _peptidoglycan_____.
The cell walls of _Archaebacteria___ are composed of other
_polysaccharides_____.
B. Cell Membrane
Every cell is surrounded by the cell membrane. Its function is to maintain
homeostasis__ in the cell by separating and protecting the cell from its
environment. It also regulates exchange with the environment. The cell
membrane is also called the __plasma membrane_. It is _selectively
permeable_ which means that it allows some substances to pass through;
acts a barrier to others.
IV. INSIDE A EUKARYOTIC CELL
Within the cell membrane, the cell is composed of the nucleus with its
corresponding structures, the _nucleolus_ and _nuclear envelope__.
The cytoplasm includes all the rest of the material inside the cell membrane.
The cytoplasm includes two components:
Cytosol – a semi-gelatinous substance that contains dissolved nutrients and
wastes
Organelles – means “little organs”. Each has a specific role in the overall
function of the cell.
Illustration
Structure
Type of Cell
Characteristics & Function
_Control center____ of the cell. Contains
Nucleus
Euk
most of cell’s DNA; stored as
_chromatin___ (_DNA_______ wrapped in
_protein_____)
Small, dense region in the nucleus.
Nucleolus
Euk
Involved in the synthesis of
_ribosomes_____ which are required for
_protein______ synthesis.
Nuclear
Double membrane, each consisting of a
Envelope
Euk
_phospholipid bilayer__. Perforated by
nuclear _pores______ which allow
_RNA______ to leave the nucleus
Tiny, non-membrane bound organelles
Ribosomes Pro + Euk located on _endoplasmic reticulum_____
(bound) or suspended in _cytosol_______
(free). Free ribosomes help manufacture
_proteins_____ that will stay in the cell;
bound ribosomes help make proteins that
will transported out of cell
Extensive network continuous with
_nuclear envelope______. Called “rough”
Rough
Euk
due to presence of _ribosomes____ all
Endoplasmic
along the membrane. Function of the rough
Reticulum
ER is to _modify____ and transport
_proteins_____. Most of these proteins are
packaged into _vesicles_____ (bubbles or
sacs made from membrane) and shuttled
to the _Golgi apparatus________
Euk
Similar to rough ER in structure, except
Smooth
that it lacks _ribosomes______. Smooth
Endoplasmic
ER functions in the synthesis of
Reticulum
_lipids_____, metabolizes _glycogen___,
detoxifies _poisons_____ and _toxins___.
Also stores _calcium__needed for muscle
contractions.
Golgi
apparatus
Euk
Lysosome
Euk –
Animal
Cells
Vacuole
Euk
Mitochondria
Chloroplast
Centrioles
Euk
Flattened, round sacs that look like a sack
of _pancakes______. Receives, modifies,
and ships products by way of
_vesicles_______ into the
_cytosol_________
Found in _animal ___ cells only??
Membrane-bound sacs containing
_hydrolytic enzymes___ that break down
_biomolecules_______ and _recycle____
used cell components. Also used as
defense against _bacteria________ and
_viruses______
Sacs that may be used as _storage_____
for water, ions, wastes. Plants have a
large central vacuole.
Double-membrane organelle with inner
folds called _cristae_____. Uses
_glucose_______ to manufacture energy in
the form of _ATP_____. Mitochondria have
their own _DNA____.
Euk –
Found in _plant____ cells. Contain green
Plant Cells pigment called _chlorophyll_________
and their own _DNA__________.
Chloroplasts harvest energy from the
_sun____ to produce _glucose____
through _photosynthesis______.
Euk –
Animal
Cells
Found only in _animal__ cells. Bundles of
_microtubules________ that play a role in
_cell division_____.
Cytoskeleton
Euk
VI. THE PROKARYOTIC CELL
Cell wall - 6
Cell membrane - 4
DNA - 3
Cytosol - 8
Ribosomes - 5
Capsule - 7
Pili – 2
Flagella - 1
8
Network of _protein____ fibers known as
_microtubules______ and
_microfilaments_________. Anchor
_organelles______ and provide
_support______. Also provide motility for
some cells in the form of _cilia______ or
_flagella________. More extensive
cytoskeleton found in _animal____ cells.
VII. THE EUKARYOTIC CELL
KEY TO EUKARYOTIC CELL LABELING
A. nucleus
B. nuclear envelope
C. chromatin
D. nucleolus
E. mitochondria
F. Golgi apparatus
G. rough endoplasmic reticulum
H. ribosome
I. vacuole
J. cytosol
K. cytoskeleton
L. cell membrane
M. smooth endoplasmic reticulum
N. centrioles
O. lysosome
P. cell wall
Q. chloroplast