Download Chapter 4 Notes – “THE CELL”

Name _______________________________________________________________________ Test Date _Fri, 9/23____
UNIT 2 - CELL STRUCTURE AND FUNCTION
I. DISCOVERY OF CELLS (pgs. 169 – 172)
A. History of Microscopes
The invention and development of the microscope in the 1600’s enabled scientists to discover and study cells –
_the smallest working unit of life_____________________________________.
1. Anton von Leeuwenhoek – was the first to try stacking _glass 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 reminded him
of _rooms in a monastery_____.
B. Cell Theory
Nearly a century later, several other scientist’s 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 & 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:
 All organisms are _made of cells_______________________
 Cells are the smallest working units of life.
 All cells come from _pre-existing cells through cell division__________
C. Types of Cells
All _organisms______ are composed of one of two types of cells:
 Prokaryotic – “__Before nucleus______”
 Eukaryotic – “__True nucleus_________”
D. 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.
COMPOUND LIGHT MICROSCOPE
The proper technique for carrying a microscope is to support _arm____ and the _base____ When viewing slides, the _light___
illuminates the field. To examine a slide, _place it on the stage___________ and hold the slide in place by using the _stage
clips________ Rotate the _nosepiece______ if necessary to lock the _low power objective (10X)_____ in place. The low
power objective is _always used first for focusing_____ and screening. Look through the _eyepiece__________ which
_contains the ocular lens______ and focus the image using the _coarse adjustment knob_______ After focusing with the
_coarse adjustment knob, _____ fine tune the image using the _fine adjustment knob_____________ The
_diaphragm_________ may be used to _increase the amount of light entering_______ the field of vision. If higher
magnification is needed to examine the specimen more closely, _rotate the nosepiece_ to the _high power
objective_(40X)____ When using the high power objective, ONLY the _fine adjustment knob_________ should be used for
focusing!!!! If you do not see a clear image, you must _return______ to _low power_____ and focus again using the _coarse
adjustment knob_______
II. TYPES OF CELLS (pgs. 172 – 173)
PROKARYOTIC
EUKARYOTIC
_Bacteria_____; Divided into two kingdoms,
_Archaebacteria____ and _Eubacteria________
_No_ true nucleus; Lack nuclear envelope and other
_membrane__-bound _organelles_____
Genetic material present in_nucleoid___________ region
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
2. Archaebacteria – “_Ancient__” bacteria; Live in _extreme____ environments (salty, hot, acidic)
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. CELL BOUNDARIES (pgs. 182 – 183)
A. Cell Wall
Cell Walls are the outermost boundary in _bacteria___, _fungi_____ and _plants_____. They are never present in
_animals____. The primary function of the cell wall is to _provide support & structure______.
 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 a cell membrane.
1. Function of Cell Membrane
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.
2. Composition of Cell Membrane
Composed of three types of biomolecules:
 Lipids – There are two lipids that make up the cell membrane: _phospholipids______ and
_cholesterol_________
 Phospholipid Bilayer – Phospholipids are composed of a _non-polar_____ glycerol backbone
with two fatty acid tails and a _polar____ phosphate head.
 Cholesterol - Found in the cell membranes of _animal cells___ to help stabilize them. Wedged
between the _non-polar fatty acid tales__________ of the phospholipid bilayer.
 Carbohydrates - Serve as “ID tags” to _identify cells____. There are two types:
 Glycolipids – Carbohydrate chain attached to _lipids________
 Glycoproteins – Carbohydrate chain attached to _proteins____
 Proteins - Embedded in the phospholipids bilayer. Serve as _channels___ and _pumps___for
transport of specific molecules across the cell membrane.
A – phospholipid bilayer
B – protein channel
C – glycoprotein
D – glycolipid
E -- cholesterol
F – polar phosphate head
G – non-polar fatty acid tails
IV. INSIDE A EUKARYOTIC CELL (pgs. 174 – 181)
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 – __Cell gel____; semi-gelatinous substance that contains dissolved nutrients and wastes
Organelles – “_Little organs____”; cell structures; each has a specific role in the overall cell function
V. EUKARYOTIC CELL STRUCTURES
Illustration
Structure
Type of Cell
Nucleus
Euk
Nucleolus
Euk
Nuclear
Envelope
Euk
Ribosomes
Pro + Euk
Rough
Endoplasmic
Reticulum
Smooth
Endoplasmic
Reticulum
Euk
Characteristics & Function
_Control center____ of the cell. Contains most of cell’s DNA;
stored as _chromatin___ (_DNA_______ wrapped in
_protein_____)
Small, dense region in the nucleus. Involved in the synthesis of
_ribosomes_____ which are required for _protein______
synthesis.
Double membrane, each consisting of a _phospholipid bilayer__.
Perforated by nuclear _pores______ which allow _RNA______
to leave the nucleus
Tiny, non-membrane bound organelles 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” due to presence of _ribosomes____ all along the
membrane. Function of the rough 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________
Similar to rough ER in structure, except that it lacks
_ribosomes______. Smooth ER functions in the synthesis of
_lipids_____, metabolizes _glycogen___, detoxifies
_poisons_____ and _toxins___. Also stores _calcium__needed
for muscle contractions.
Golgi apparatus
Euk
Lysosome
Euk – Animal
Cells
Vacuole
Euk
Mitochondria
Euk
Chloroplast
Euk – Plant
Cells
Centrioles
Euk – Animal
Cells
Cytoskeleton
Euk
VI. THE PROKARYOTIC CELL
Cell wall
Cell membrane
DNA
Cytosol
Ribosomes
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____.
Found in _plant____ cells. Contain green pigment called
_chlorophyll_________ and their own _DNA__________.
Chloroplasts harvest energy from the _sun____ to produce
_glucose____ through _photosynthesis______.
Found only in _animal__ cells. Bundles of
_microtubules________ that play a role in _cell division_____.
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
Structure
__________
Picture
Prokaryotic
Eukaryotic,
or Both?
General Characteristics and Functions
Control center of the cell. Contains genes that control cell activities. Contains
most of the cell's DNA, which is stored as chromatin (DNA wrapped in protein).
Nucleolus
Small, dense region in the nucleus. Involved in the synthesis of____________
which are important in protein synthesis. "Little nucleus"
Nuclear
Envelope
Double membrane, each consisting of a___________________ bilayer.
Perforated by nuclear _________ which allow______ molecules to leave the
nucleus.
Ribosomes
_________
Endoplasmic
Reticulum
___________
Endoplasmic
Reticulum
________
Apparatus
___________
Vacuole
Constructed in the_______________, these tiny, non-membrane bound
organelles are located in prokaryotic and eukaryotic cells. These organelles
function in ______________________________, and can be either free
(suspended in the cytosol), or bound (attached to rough ER). Free ribosomes aid
in the production of proteins that will ________________, and bound ribosomes
aid in the production of proteins that will be _________________out of the cell.
Extensive network continuous with the _______________. Appear "rough" due
to the presence of _____________ all along the membrane. Function of the
rough ER is to ______________________________. Most of these proteins are
packaged into _______________________(pieces of the membrane that act as a
protective sac) and shuttled to the ______________________________.
Similar to rough ER in structure, except that it ____________ribosomes. Smooth
ER functions in the synthesis of ___________________ (steroids), breaks down
___________________, and _______________, and poisons. Smooth ER (esp. in
muscle and liver cells) also stores ___ ions that are used for_______ contraction.
Flattened, round sacs with the appearance of pita bread. Golgi is sometimes
called the "UPS man" because it functions in _________________________, and
re-routing the products of the ER. Golgi is packed with _________________ that
aid in modifying the products before they are shipped out by way of
a____________________________into the cytosol.
Membrane bound bag of __________________________ that help to digest
macromolecules, as well as recycle used cell components. Lysosomes are made
from parts of the ER (enzymes) and Golgi apparatus (phospholipid membrane).
Also used as a defense against _____________________ and _______________.
Sacs that may be used as storage for ___________________________________
or wastes. Plants have a very large _________________ vacuole for maximum
water storage.
EUKARYOTIC CELLS KEY
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