Download Cell Communication

 Get ready for lab quiz
 14 days until AP BIO Final
-75 questions
-Photo/cellular respiration
-Cell communication + cell cycle (Chapters 11-13)
-Ecology
-Cell
-Evolution
-Labs
-Water and Chemistry of Life
-Colored book CAN be used on FINAL
Monday, May 14th at 8am
AP Biology Exam
Lab Quiz—Photo + Cellular Resp
1. In the cell respiration lab, the role of KOH
was___________________
2. In the cell respiration lab, we
measured_________________________
3. Oxygen is needed by living organisms
to____________________
4. In the chromatography lab, the pigments were
found in the spinach leaf were________
5. The reason that pigments had different Rf
values is________________
Lab Quiz—Photo + Cellular Resp
1. In the cell respiration lab, the role of KOH was to make
CO2 a solid; reduce the volume
2. In the cell respiration lab, we measured the O2
consumed
3. Oxygen is needed by living organisms to collect the
electrons in the ETC
4. In the chromatography lab, the pigments were found in
the spinach leaf were chlorophyll a, chlorophyll b,
xanthophyll, and carotene
5. The reason that pigments had different Rf values is that
they have different properties and react differently with
the chromatopraphy paper AND have high/low
soluability in the solvent
Averages for Lab Report—2 LABS DUE
FRI
Averages from Chromatography Lab
Chlorophyll a=0.249
Chlorophyll b=0.370
Xanthophyll=0.446
Carotene=1
OIL RIG
OIL=Oxidized Involves Losing electrons
RIG=Reducing Involves Gaining electrons
Oxidized or Reduced?
NAD +  NADH
O2 H2O (cellular
respiration)
H2O in photosynthesis
Dispatch
1) How do you think one part of the
body communicates with the other
over SHORT distances? Over
LONG distances?
2) What do you think the jar is
representing? Open jar=2
Phosphates (ADP); Closed jar=3
Phosphates (ATP)
Cell Communication
http://video.search.yahoo.com/search/v
ideo;_ylt=A0oGdWOXyBFPwhsAQ5VX
NyoA?p=dominoes%20knocking%20o
ver&fr=yfp-t-701&fr2=piv-web
The Cellular “Internet”
 Within multicellular organisms, cells must
communicate with one another to coordinate
their activities
 A signal transduction pathway is a series of
steps by which a signal on a cell’s surface is
converted into a specific cellular response
 Signal transduction pathways are very similar in
all organisms, even organisms as different as
unicellular yeasts and multicellular mammals
Local (Short-Distance) Signaling
 Cells may communicate by direct contact
 Plasmodesmata in plant cells
 Gap junctions in animal cells
 Animal cells can also use cell-cell recognition
 Membrane-bound surface molecules can interact and
communicate
Local (Short-Distance) Signaling
 Messenger molecules can also be secreted by the signaling cell
 Paracrine signaling:
 One cell secretes (releases) molecules that act on nearby “target” cells
 Example: growth factors
 Synaptic Signaling:
 Nerve cells release chemical messengers (neurotransmitters) that
stimulate the target cell
How do you think one part of the
body communicates with the
other over LONG distances?
Long-Distance Signaling
 Endocrine (hormone)
signaling
Specialized cells
release hormone
molecules, which travel
(usually by diffusion
through cells or
through the circulatory
system) to target cells
elsewhere in the
organism
The body needs more of protein X.
DNARNAProtein X
How do we turn on transcription?
Phosphorylation
The protein being phosphorylated GAINS
a phosphate
A molecule that is phosphorylated has an
increased chemical reactivity; it is primed
to do cellular work.
The Three Stages of Cell Signaling
 There are 3 stages at the “receiving end” of a
cellular conversation:
1. Reception
2. Transduction
3. Response
Stage 1: Reception
 The target cell “detects” that there is a signal molecule
coming from outside the cell
 The signal is detected when it binds to a protein on the cell’s
surface or inside the cell
 The signal molecule “searches out” specific receptor proteins
 The signal molecule is a ligand
• It is a molecule that specifically binds to another one (think enzymes!)
Stage 2: Transduction
This stage converts the signal into a form
that can bring about a specific cellular
response
One signal-activated receptor activates another
protein, which activates another molecule, etc.,
etc.
These act as relay molecules
Often the message is transferred using protein
kinases, which transfer phosphate groups from
ATP molecules to proteins
Stage 2: Transduction
Stage 3: Response
 The signal that was
passed through the signal
transduction pathway
triggers a specific cellular
response
 Examples: enzyme action,
cytoskeleton
rearrangement, activation
of genes, etc., etc.
 Diagram example:
transcription of mRNA
The Specificity of Cell Signaling
 The particular proteins
that a cell possesses
determine which signal
molecules it will respond
to and how it will respond
to them
 Liver cells and heart cells,
for example, do not
respond in the same way
to epinephrine because
they have different
collections of proteins
Animation
http://bcs.whfreeman.com/thelifewire/conte
nt/chp15/15020.html
1) What is flight or fight?
2) What is glycogen?
Word bank: signaling molecule, cell receptor, signal
transduction pathway, nuclear signaling, cascade,
phosphorylation, ATP, protein, response, nucleus, mRNA,
second messenger