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Much of this chapter is covered in Biology so
the pacing will be rapid.
Focus on what is new to you while you review
what is already familiar.
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Cyto = cell
- ology = study of
Should use observations from several types
of microscopes to make a total picture of
how a cell is put together.
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Uses visible light to illuminate the object.
Relatively inexpensive type of microscope.
Can examine live or dead objects.
Occular Lens
Objective Lens
Stage with specimen
Light Source
 Ability
to detect two discrete
points as separate from each
other.
 As Magnification increases,
resolution decreases.
 LM working limits are
100 - 1000X.
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Miss many cell structures that are beyond the
magnification of the light microscope.
Need other ways to make the observations.
 Fluorescence:
uses dyes to make
parts of cells “glow”.
 Phase-contrast: enhances
contrasts in density.
 Confocal: uses lasers and special
optics to focus only narrow slides
of cells.
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Use beams of electrons instead of light.
Invented in 1939, but not used much until
after WWII.
TEM
SEM
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Much higher magnifications.
Magnifications of 50,000X or higher are
possible.
Can get down to atomic level in some cases.
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Need a Vacuum.
Specimen must stop the electrons.
High cost of equipment.
Specimen preparation.
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Sends electrons through thinly sliced and
stained specimens.
Gives high magnification of interior views.
Many cells structures are now visible.
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Specimen dead.
Specimen preparation uses extreme
chemicals so artifacts are always a concern.
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Excellent views of surfaces.
Produces 3-D views.
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Cell Fractionation
Chromatography
Electrophoresis
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Disrupt cells.
Separate parts by centrifugation at different
speeds.
Result - pure samples of cell structures for
study.
 Technique
for separating
mixtures of chemicals.
 Separates chemicals by size or
degree of attraction to the
materials in the medium.
 Ex - paper, gas, column,
thin-layer
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Separates mixtures of chemicals by their
movement in an electrical field.
Used for proteins and DNA.
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Robert Hooke - Observed cells in cork.
Coined the term "cells” in 1665.
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1833 - Robert Brown, discovered the
nucleus.
1838 - M.J. Schleiden, all plants are made
of cells.
1839 - T. Schwann, all animals are made
of cells.
1840 - J.E. Purkinje, coined the term
“protoplasm”.
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All living matter is composed of one or more
cells.
The cell is the structural and functional unit
of life.
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“Omnis cellula e cellula”
All cells are from other cells.
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Prokaryotic - lack a nucleus and other
membrane bounded structures.
Eukaryotic - have a nucleus and other
membrane bounded structures.
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Membrane
Cytosol
Ribosomes (but the size is different)
Prokaryotic
Eukaryotic
Nucleus
Eukaryotic
Prokaryotic
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Cell volume to surface area ratios favor small
size.
Nucleus to cytoplasm consideration (control).
Metabolic requirements.
Speed of diffusion.
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Membrane
Nucleus
Cytoplasm
Organelles
Animal Cell
Plant Cell
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Separates the cell from the environment.
Boundary layer for regulating the movement
of materials in/out of a cell.
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Cell substance between the cell membrane
and the nucleus.
The “fluid” part of a cell. Exists in two forms:
◦ gel - thick
◦ sol - fluid
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Term means "small organ” Formed body in a
cell with a specialized function.
Important in organizational structure of cells.
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Way to form compartments in cells to
separate chemical reactions.
Keeps various enzymes separated in space.
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Identify the major organelles
Give their structure
Give their function
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Practice problems
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Most conspicuous organelle.
usually spherical, but can be lobed or
irregular in shape.
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Nuclear membrane
Nuclear pores
Nucleolus
Chromatin
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Double membrane separated by a 20-40 nm
space.
Inner membrane supported by a protein
matrix which gives the shape to the nucleus.
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Regular “holes” through both membranes.
100 nm in diameter.
Protein complex gives shape.
Allows materials in/out of nucleus.
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Dark staining area in the nucleus.
0 - 4 per nucleus.
Storage area for ribosomes.
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Chrom: colored
- tin: threads
DNA and Protein in a “loose” format. Will
form the cell’s chromosomes.
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Control center for the cell.
Contains the genetic instructions.
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Structure: 2 subunits made of protein and
rRNA. No membrane.
Function: protein synthesis.
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Large:
◦ 45 proteins
◦ 3 rRNA molecules
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Small:
◦ 23 proteins
◦ 1 rRNA molecule
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Free in the cytoplasm - make proteins for use
in cytosol.
Membrane bound - make proteins that are
exported from the cell.
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Membranes that are related through direct
physical continuity or by the transfer of
membrane segments called vesicles.
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Often referred to as ER.
Makes up to 1/2 of the total membrane in
cells.
Often continuous with the nuclear membrane.
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Folded sheets or tubes of membranes.
Very “fluid” in structure with the membranes
constantly changing size and shape.
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Smooth ER: no ribosomes.
Used for lipid synthesis, carbohydrate
storage, detoxification of poisons.
Rough ER: with ribosomes.
Makes secretory proteins.
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Structure: parallel array of flattened cisternae.
(looks like a stack of Pita bread)
3 to 20 per cell.
Likely an outgrowth of the ER system.
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Processing - modification of ER products.
Distribution - packaging of ER products for
transport.
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Small sacs of membranes that bud off the
Golgi Body.
Transportation vehicle for the modified ER
products.
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Single membrane.
Made from the Golgi apparatus.
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Breakdown and degradation of cellular
materials.
Contains enzymes for fats, proteins,
polysaccharides, and nucleic acids.
Over 40 types known.
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Important in cell death.
Missing enzymes may cause various genetic
enzyme diseases.
Examples: Tay-Sachs, Pompe’s Disease
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Structure - single membrane, usually larger
than the Golgi vesicles.
Function - depends on the organism.
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Contractile vacuoles - pump out excess
water.
Food vacuoles - store newly ingested food
until the lysosomes can digest it.
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Large single vacuole when mature making up
to 90% of the cell's volume.
Tonoplast - the name for the vacuole
membrane.
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Water regulation.
Storage of ions.
Storage of hydrophilic pigments.
(e.g. red and blues in flower petals).
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Used to enlarge cells and create turgor
pressure.
Enzymes (various types).
Store toxins.
Coloration.
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Structure: single membrane.
Often have a granular or crystalline core of
enzymes.
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Specialized enzymes for specific reactions.
Peroxisomes: use up hydrogen peroxide.
Glyoxysomes: lipid digestion.
Enzymes in a
crystal
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Structure: 2 membranes. The inner
membrane has more surface area than the
outer membrane.
Matrix: inner space.
Intermembrane space: area between the
membranes.
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Folded into cristae.
Amount of folding depends on the level of
cell activity.
Contains many enzymes.
ATP generated here.
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Cell Respiration - the release of energy from
food.
Major location of ATP generation.
“Powerhouse” of the cell.
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Have ribosomes (small size).
Have their own DNA.
Can reproduce themselves.
May have been independent cells at one time.
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Structure - two outer membranes.
Complex internal membrane.
Fluid-like stroma is around the internal
membranes.
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Arranged into flattened sacs called
thylakoids.
Some regions stacked into layers called
grana.
Contain the green pigment chlorophyll.
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Photosynthesis - the use of light energy to
make food.
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Contain ribosomes (small size).
Contain DNA.
Can reproduce themselves.
Often contain starch.
May have been independent cells at one time.
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Group of plant organelles.
Structure - single membrane.
Function - store various materials.
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Amyloplasts/ Leucoplasts - store starch.
Chromoplasts - store hydrophobic plant
pigments such as carotene.
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General term for other substances
produced or stored by plant cells.
Examples:
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Crystals
Tannins
Latex
Resins
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Network of rods and filaments in the
cytoplasm.
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Cell structure and shape.
Cell movement.
Cell division - helps build cell walls and move
the chromosomes apart.
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Microtubules
Microfilaments
Intermediate Filaments
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Structure - small hollow tubes made of
repeating units of a protein dimer.
Size - 25 nm diameter with a 15 nm lumen.
Can be 200 nm to 25 mm in length.
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Protein in microtubules.
Dimer - a and b tubulin.
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Regulate cell shape.
Coordinate direction of cellulose fibers in cell
wall formation.
Tracks for motor molecules.
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Form cilia and flagella.
Internal cellular movement.
Make up centioles, basal bodies and spindle
fibers.
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Cilia - short, but numerous.
Flagella - long, but few.
Function - to move cells or to sweep
materials past a cell.
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Structure - 9+2 arrangement of
microtubules, covered by the cell membrane.
Dynein - motor protein that connects the
tubules.
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A contractile protein.
Uses ATP.
Creates a twisting motion between the
microtubules causing the structure to bend or
move.
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Usually one pair per cell, located close to the
nucleus.
Found in animal cells.
9 sets of triplet microtubules.
Help in cell division.
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Same structure as a centriole.
Anchor cilia and flagella.
Basal Body
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5 to 7 nm in diameter.
Structure - two intertwined strands of actin
protein.
Microfilaments
are stained green.
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Muscle contraction.
Cytoplasmic streaming.
Pseudopodia.
Cleavage furrow formation.
Maintenance and changes in cell shape.
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Fibrous proteins that are super coiled into
thicker cables and filaments 8 - 12 nm in
diameter.
Made from several different types of protein.
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Maintenance of cell shape.
Hold organelles in place.
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Very dynamic; changing in composition and
shape frequently.
Cell is not just a "bag" of cytoplasm within a
cell membrane.
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Nonliving jacket that surrounds some cells.
Found in:
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Plants
Prokaryotes
Fungi
Some Protists
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All plant cells have a Primary Cell Wall.
Some cells will develop a Secondary Cell Wall.
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Thin and flexible.
Cellulose fibers placed at right angles to
expansion.
Placement of fibers guided by microtubules.
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Thick and rigid.
Added between the cell membrane and the
primary cell wall in laminated layers.
May cover only part of the cell; giving spirals.
Makes up "wood”.
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Thin layer rich in pectin found between
adjacent plant cells.
Glues cells together.
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May be made of other types of
polysaccharides and/or silica.
Function as the cell's exoskeleton for support
and protection.
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Fuzzy coat on animal cells.
Helps glue cells together.
Made of glycoproteins and collagen.
Evidence suggests ECM is involved with cell
behavior and cell communication.
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Plants-Plasmodesmata
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Channels between cells through adjacent cell
walls.
Allows communication between cells.
Also allows viruses to travel rapidly between
cells.
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Animals:
◦ Tight junctions
◦ Desmosomes
◦ Gap junctions
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Very tight fusion of the membranes of
adjacent cells.
Seals off areas between the cells.
Prevents movement of materials around cells.
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Bundles of filaments which anchor
junctions between cells.
Does not close off the area between
adjacent cells.
Coordination of movement between
groups of cells.
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Open channels between cells, similar to
plasmodesmata.
Allows “communication” between cells.
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Answer: Why is Life cellular and what are the
factors that affect cell size?
Be able to identify cellular parts, their
structure, and their functions.
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http://multimedia.mcb.harvard.edu/anim_inn
erlife_hi.html
You may need to replay this several times to
catch all of the parts.