Download Week 3 Agenda and Notes

Week 4 Notes
“Required” Extra Credit Assignment:
a) Look at the recycle symbols and report what symbols
mean, what the number within the symbol indicates,
etc.
b) Find/list 15 products that are made with recycled
material
The Cell
Definition: can reproduce itself without help from other
entities
Bacteria, Archaea: Unicellular (but can form “associations”
called colonies)
Eukarya: unicellular and multicellular (need some sort of
“bonding”/adhesion - -> tissue)
Cells
Sizes
Shapes
Color: presence of pigment
10 micrometers – 0.09 m (ostrich egg)
Metric System v English System
Meter
1 m = 100 centimeters (cm)
= 1000 millimeters (mm)
= 1,000,000 microns (µm)
= 1,000,000,000 nanometers (nm)
Shape: cubes, rectangular, spherical
Cell – take in nutrients, exude waste
Cell size: surface area to volume ratio
Microscope – tool for biologists
Cellular structure
Light Microscope
Focus – sharp image
Magnification –
Ocular Lens
10x
Objective Lens
10x, 40x, 100x
X
Ocular lens magnification
Objective Lens magnification =
Total Magnification
Cell prep – clean slide -> place specimen on slide, place
cover slip over specimen
Electron Microscopes
Transmission EM – allows for view of cross-sections
Scanning EM – allows for view of surface of material
Prokaryotic Cells (Bacteria, Archaea) – lacks true nucleus;
does not contain organelles; lack true compartmentalization
Glycocalyx: gel coating
Cell Wall : shape and support
Spherical (round)
Rod (E. coli)
Spiral
Plasma Membrane (bilayer): regulation of materials into
the inside and outside the cell
Mesosome – extension of plasma membrane into the cell
– allows for increase in surface area
Flagellum: for motility (motion)
Pilus: extensions of PM
Sex Pilus: extension that will allow for exchange of
genetic material
Fimbriae – bristle-like appendages that help in adhesion
of cell to surface
Inclusion bodies – for storage of nutrients
Nucleoid – area where bacterial chromosome are found
(usually toward the center of the cell) (bacteria: have one
chromosome, usually circular)
Ribosomes – small particles suspended in cytoplasm:
responsible for the site of protein synthesis
Shape of cells
Round – Cocci
Rod – Bacillus
Spiral – Spirilla
Rigid or flexible
Colony – cluster of cells
Cell Structure
Cell Envelope: glycocalyx, cell wall, plasma membrane,
mesosomes
Cytoplasm: semifluid solution: enzymes, nucleoid,
plasmid (circular DNA)
Cyanobacteria: bacteria that can photosynthesize just
like plants; contain extensive internal membranes called
thylakoids
Appendages: flagella, fimbriae, pilus
Archaea – different shapes than bacteria, lobed, plateshaped or irregularly shaped
- live in extreme habitats: hot or salty environments
Eukaryotic Cells
Unicellular
Multicellular
Organelles – membrane-bound
Compartmentalization
Organize
Double membraned organelles
Keep separate enzymes
(biocatalyst) that may not function
outside the organelle
Nucleus, Mitochondrion, Chloroplast
Animal cell v Plant cell
Plant cell: cell wall (gives support and shape);
Green plants contain chloroplasts (are the
organelles responsible for photosynthesis)
Central Vacuole
Animal Cell
Cell Structure
Nucleus – double-membraned (protect the genes!)
Nuclear envelope
Nucleolus – located inside the
nucleus/responsible for the synthesis of
ribosomes
Nuclear pores – tiny channels that allow for
communication between the nucleus and the cytoplasm
Nucleoplasm: (like cytoplasm but for nucleus)
Chromatin – contains genetic material (DNA); later
condense to form the chromosomes
Ribosomes: non-membrane bounded particles which
function in protein synthesis; can be in groups called
polyribosomes
Endomembrane System
Endoplasmic Reticulum (ER)
Smooth ER: does not have any ribosomes associated
with the SER; sight of lipid synthesis (fatty acids, steroids,)
Rough ER: does have ribosomes associated with the
RER; sight of protein synthesis
Golgi Apparatus: series of membranous sacs: packaging
and distributing the synthesized macromolecules; fold
into 3-Dim; proteins can combine with sugars
(glycoproteins) or phospholipids
secretory vesicles
transport vesicles
Lysosomes – membrane-bound vesicles that contain
digestive enzymes; housekeeping organelles (break down
cellular debris, foreign material); come from the Golgi
apparatus
Abnormal Lysosomes: Tay-Sachs disease
Apoptosis – programmed cell death
Vesicles
Incoming
Secretory
Peroxisomes and Vacuoles
Peroxisomes: membrane-bound vesicles that contain
enzymes (e.g., break down H2O2); lots found in the liver
Lorenzo’s Oil
Study biology!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Vacuoles: membranous sacs; store substances
Plants: water, sugars, salts and water-soluble pigments
Central Vacuole – functions to control storage of
nutrients and waste products; can change size
Paramecium (animal) – contain contractile vacuoles:
collect excess water and expel it outside the cell
turgidity
Energy-Related Organelles
Chloroplasts – site of photosynthesis
Double-membraned organelle
Site of photosynthesis; contains chlorophyll
Grana- sac
Thylakoid – stacks found in grana
Stroma – like the “cytoplasmic matrix” of the cell
Mitochondria
Double-membraned organelle
Site of aerobic cellular respiration
Krebs cycle (Tricarboxylic Acid Cycle)
Electron Transport System
Powerhouse of the cell -> produces ATP
Outer membrane
Inner membrane
Folds – cristae (site of electron support, TCA cycle)
Cytoskeleton – provides support and shape of the cell
Actin Filaments (7 nm in diameter): formerly called
microfilaments; play structural role; seen in microvilli of
intestinal cells
Involved with movement
Actin and myosin with ATP: motion
Intermediate Filaments (larger than actin filaments – 8-11
nm in diameter)
Anchor organelles
Involved with forming cell junctions
Microtubules – cylinders of protein 25 nm in diameter
Composed of tubulin, a protein
MTOC: microtubule organizing center: in the centrosome
(near the nucleus)
Self-assembly
See spindles in mitosis (cell division)
Centrioles
9+0
See mitosis chapter
Dynein (a motor molecule) side arms
Cilia and Flagella – surrounded by plasma membrane
Provides motility; membrane bound cylinders
Cilia: shorter than flagella
Both have “9+2” microtubule pairs
Each has a Basal body: ring of 9 microtubule triplets
with no central microtubules
Cilia of inner ear
Plant Cell
Plant Cells differ from Animal Cells with respect to the
following:
Plant Cells contain
A Cell Wall
Central Vacuole
Chloroplasts
Modification of Cell Surfaces
Allow cells to communicate, adhere to each other
Animals:
Anchoring/adhesion junctions
Desmosome – single point of attachment between adjacent
cells
Intermediate filaments
Tight junctions: zipperlike fastening; serve as barriers -> prevent
leakage
Blood-brain barrier
Kidney cells/tubules – keep urine within
Gap junction – allows cell communication
Heart muscle and smooth muscle -> flow of ions
Extracellular Matrix
Collagen and Elastin
Fibronectins and laminins – adhesive proteins – form highways
Cartilage – flexible
Bone – hard
Plant Cell Walls
Plasmodesmata – numerous narrow membrane-line channels
that pass through cell wall
Tight Junction
Gap Junction
Anchoring Junction - intermediate filaments involved
Plasmodesmata – plant cells