unit 4: cell communication objectives: 2.c.1: organisms use feedback mechanisms to maintain their...

Unit 4: Cell CommunicationObjectives:• 2.C.1: Organisms use feedback mechanisms to maintain their internal

environments and respond to external environmental changes• 2.D.3: Biological systems are affected by disruptions to their dynamic

homeostasis• 2.D.4: Plants and animals have a variety of chemical defenses against

infections that affect dynamic homeostasis• 3.C.3: Viral replication results in genetic variation, and viral infection

can introduce genetic variation into the hosts• 3.D.2: Cells communicate with each other through direct contact with

other cells or from a distance via chemical signaling• 3.D.3: Signal transduction pathways link signal reception with cellular

response

Warm-UP: Compare the two types of communication in the models at right. What advantages are there to each? Disadvantages? Why would an organism benefit from being able to do each?

Due: Cell Communication POGIL

Unit 4 Test: 12/18/14

Homework: 10 Key Ideas 11.1

Unit 4: Cell Communication

Big Idea: The Signal Transduction Pathway is a series of events that begins with (1) a cell receiving an external signal (ligands) that (2) binds to ligand-specific receptors (integral proteins) which causes (3) cells to make changes that result (4) in a response.

3 MODELS:• Endocrine: Pancreas cells communicate to liver cells from a

distance via hormones in order to regulate blood sugar content• Paracrine: Neurons are cells that communicate through direct

contact using neurotransmitters.• Between Organisms: Antigens (virus particles) bind to

antibodies (receptors on immune system cells) cause the specific immune response

Signal Transduction Pathway

1. Signal (ligand)• a molecule that “fits” the

receptor protein (ligand specific)• produced by other cells• effects only target cells • Examples:

• Endocrine: Hormone: insulin

• Paracrine: Neurotransmitter: adrenaline

• Between Organisms: Antigens (pieces of viruses): flu

2. Reception3. Transduction4. Response

http://learn.genetics.utah.edu/content/cells/insidestory/




1. Signal (ligand)2. Reception

• ligand binds to receptor protein• receptor protein is changed

3. Transduction4. Response

http://www.youtube.com/watch?v=FtVb7r8aHco





• receptor protein is changed

3. Transduction:• a series of intracellular (within cell)

changes• Examples:

• activation of “other” proteins by phosphorylation

• activation of DNA that results in new proteins

4. Response



• receptor protein is changed

3. Transduction4. Response: cellular change

• Examples:• release of new protein into

extracellular fluid• activation of integral

protein to allow it to function

• cell division


Warm-UP: Pancrease cells release insulin to target liver cells when blood sugar is high. Speculate: What do you think happens in the liver cells signal transduction pathway?

1. Signal2. Reception3. Transduction4. Response

Due: Key Ideas 11.1Homework: Key Ideas 45.2

Hormones

• ligands

• secreted into the circulatory system from glands

• communicate regulatory messages to targets around the body

• reach all parts of the body, but only target cells capable of responding (i.e. with protein receptors)

Endocrine: Pancreas cells communicate to liver cells from a distance via hormones in order to regulate blood sugar content

Hormones • ligands• secreted into the circulatory system

from glands• communicate regulatory messages

to target cells (i.e. cells with receptors) around the body

• 2 types:– proteins:

• target surface receptors• secreted by exocytosis• insulin and glucagon

– lipids:• target receptors on inside

of cell• diffuse across the cell

membrane• steroids: testosterone


Insulin/Glucagon Model: maintain glucose homeostasis

1. Signal: insulin produced by pancreas due to high blood sugar

2. Reception: Insulin receptor on liver cell3. Transduction:

• activation of glut 4 transporter• translocation of glut 4 into cell

membrane• activation of enzymes: glycogen

synthase, phosphofructokinase, fatty acid synthase

4. Response:• glucose diffusion by facilitated diffusion

through glut 4• glycogen polymerization by glycogen

synthase• glycolysis by phosphofructokinase• fatty acid synthesis by fatty acid

synthase



1. Signal: insulin produced by pancreas due to high blood sugar

2. Reception: Insulin receptor on liver cell3. Transduction:

• activation of glut 4 transporter• translocation of glut 4 into cell

membrane• activation of enzymes: glycogen

synthase, phosphofructokinase, fatty acid synthase

4. Response:• glucose diffusion by facilitated diffusion

through glut 4• glycogen polymerization by glycogen

synthase• glycolysis by phosphofructokinase• fatty acid synthesis by fatty acid

synthase


http://upload.wikimedia.org/wikipedia/commons/c/ce/Insulin_glucose_metabolism_ZP.svg


1. Signal: glucagon produced by the pancreas due to low sugar

2. Reception: glucagon receptor on muscle cell3. Transduction:

• activation of glut 4 transporter• translocation of glut 4 and fatty acid

transporter into cell membrane• activation of enzymes: glycogen

phosphorylase4. Response:

• glucose diffusion by facilitated diffusion through glut 4

• glycogen dehydration by glycogen phosphorylase


Team1. Insulin just having

binded to insulin receptor

2. Insulin binding causes transduction

3. Transduction due to insulin causes response: decrease in blood glucose levels

4. Glucagon just having binded to glucagon receptor

5. Glucagon binding causes transduction

6. Transduction due to glucagon causes response: increase in blood glucose levels

Insulin Glucagon Whiteboard

Guiding Questions:1. Is the person’s blood sugar hyperglycemic

(high), hypoglycemic (low), or at homeostasis (just right)?

2. What has happened to: glucose molecules, integral proteins, enzymes?

3. Why has the cell responded this way? How does what’s shown help an organism maintain homeostasis?

Terms to Consider Drawing/Using:phospholipid, integral protein, activation, ligand, ligand receptor, glut 4 transporter, blood, glucose, fatty acid transporter, enzyme, fatty acid synthase, glycogen synthase, glycogen, glucagon, insulin, insulin receptor, glucagon receptor, glycogen phosphorylase

Warm-UP: What could go wrong with this Signal Transduction Pathway? Identify 2 possibilities AND suggest a solution that a medical researcher might investigate.

Homework: Diabetes Drawings

http://upload.wikimedia.org/wikipedia/commons/c/ce/Insulin_glucose_metabolism_ZP.svg

Warm-UP: Neurons communicate via paracrine signaling. Explain, using the model.

http://www.youtube.com/watch?v=x4PPZCLnVkA

Homework: Concept 48.1 10 Key Ideas



Warm-UP: Many drugs work by mimicking neurotransmitters. For example, morphine (a pain killer) mimicks endorphins, a neurotransmitter. Use the model to explain how this works.

Homework: Watch a youtube on neurons. Write down some key ideas as you watch (see my website links for ideas).

Neurons: nerve cells

Signal Transduction Pathway:

1. Signal: neurotransmitter2. Reception: neurotransmitter

receptor/gated ion channel3. Transduction: voltage-gated

ion channels send electrical signal down axon

4. Response: neurotransmitter is released to the next neuron

Paracrine: Neurons are cells that communicate through direct contact using neurotransmitters.

Before Signal is received:

• “Resting” membrane potential= -70mV

• “Net” negative• Active Transport: Na+/K+

pumps use ATP to pump more + out than in


1. Signal: adrenaline from previous neuron

2. Reception: adrenaline gated ion channel (adrenaline receptor) opens

• Na+ and K+ diffuse with their concentration gradients

• More + in than out (remember, there were more Na+ out than in, so a net diffusion in)

• “Action” membrane potential= -30mV


3. Transduction: • Voltage gated Na+ channels are

stimulated to open• Na+ diffuse with their

concentration gradients faster• Even more + in than out• “Action” membrane potential

= -50mV


3. Transduction • Voltage gated Na+ channels are



= -50mV• Voltage gated Na+ channels stimulate

neighboring channels to open• “electrical” signal is transferred

down the cell’s axon








down the cell’s axon• Resting membrane potential is

returned= -70mV• Voltage gated K+ channels are

stimulated to open• K+ diffuse with their concentration

gradients: more + out than in• Voltage gated Ca+ channels open

• Ca+ diffuses in, causing vesicles containing neurotransmitter to be released







down the cell’s axon• Resting membrane potential is

returned= -70mV• Voltage gated K+ channels are


gradients: more + out than in







down the cell’s axon• Voltage gated Ca+ channels open

• Ca+ diffuses in, causing vesicles containing neurotransmitter to be released

• Resting membrane potential is returned= -70mV• Voltage gated K+ channels are


gradients: more + out than in

4. Response: More adrenaline is released into the synapse

• Next neuron is stimulatedOR

• Muscle contracts



Before “NEXT” Signal is received:

• “Resting” membrane potential is reestablished= -70mV

• “Net” negative• Active Transport: Na+/K+

pumps use ATP to pump more + out than in

Neuron Signal Transduction Pathway Movie

Using a whiteboard, make a “movie” showing a neuron in the different parts of the signal transduction pathway assigned to your team.

Requirements: your “movie” must be labeled, careful, and show a minimum of 15 steps from beginning to end of the “box”.

Parts to consider drawing/labeling: cell membrane, adrenaline, K+, Na+, Ca+, Vesicle, Na+/K+ pump, adrenaline gated ion channel, voltage gated Na+ channel, voltage gated K+ channel

1

2

3

45

6

7

8. Show the end of the neuron with the response

Warm-UP: When athletes sweat, they drink electrolytes to replenish their lost ions. How does this help neuron function? Use the model to explain.

Homework: Neuron Function Handout

Warm-UP: When ADULTS drink alcohol, alcohol binds to K+ voltage gated channels and keeps them open, causing a hyperpolarization (making the resting membrane potential even more negative). How does this hurt neuron function? Use the model to explain.

Homework: Neuron Poster due Thursday

Stamp: Neuron Function

• ligand• K+• Na+• Ca+• Vesicle• Na+/K+ pump• ligand gated channel• Na+ voltage gated

channel• K+ voltage gated channel• signal• reception

• transduction• response• neurotransmitter• resting membrane

potential• action potential• vesicle• exocytosis• active transport• facilitated diffusion

Neuron Poster: Draw and label a neuron. Add the following parts:

Team:1. Loss of ions due to sweating

during exercise2. Slight decrease in pH of

surrounding fluid due to increase in carbonic acid

3. Cocaine acts as competitive inhibitor for Na+ voltage gated ion channel

4. Lack of calcium in diet5. Alcohol opens voltage gated K+

channels: causes “hyperpolarization”

6. Lack of ATP due to lack of oxygen in brain cell

http://ocw.mit.edu/ans7870/SP/SP.236/S09/lecturenotes/drugchart.htm

Neurons Whiteboard: Draw and explain what would be different if:

Key Questions1. Which parts of the neuron are

stopped?2. Which part of the Signal

Transduction Pathway is directly affected? Indirectly affected? Signal, Reception, Transduction, Response

3. Describe the overall impact this will have on neuron activity.

Parts to have drawn/labeled: Ligand, K+, Na+, Ca+, Vesicle, Na+/K+ pump, Ligand Gated channel, Na+ voltage gated channel, K+ voltage gated channel

http://ocw.mit.edu/ans7870/SP/SP.236/S09/lecturenotes/drugchart.htm

Warm-UP: The immune response uses a whole group of signal transduction pathways. Use the model of a macrophage engulfing a virus by endocytosis to explain one of these signal transduction pathways.

Homework: Neuron Poster due tomorrow

Viruses:• not cells• not alive

– can’t reproduce themselves (obligate intracellular parasites)

– require host– don’t eat

• very small• parts

– nucleic acid – protein coat (called a

capsid)• nucleic acid may be:

– DNA: DNA virus – RNA: RNA virus (a

retrovirus)

Between Organisms: Antigens (virus particles) bind to antibodies (receptors on immune system cells) cause the specific immune response

Viruses: Life Cycle:

1. virus bonds to protein receptors on host cell membrane

2. viral genome enters the host cell either by injecting DNA through protein channels or endocytosis

3. host cell polymerizes viral proteins and DNA

4. viral proteins and DNA assemble into new viruses

5. new viruses exit cell either by lysing host cell or exocytosis http://www.youtube.com/watch?v=K7yku3sa4Y8


http://www.youtube.com/watch?v=K7yku3sa4Y8

http://www.youtube.com/watch?v=K7yku3sa4Y8






5. new viruses exit cell either by lysing host cell or exocytosis


Warm-UP1. How do viruses hurt you? 2. Why do some viruses, like the flu, only hurt

temporarily, while others, like polio, cause permanent damage?

http://www.youtube.com/watch?v=hJM6M3AMwSs

DUE NOW: Neuron Poster










5. new viruses exit cell either by lysing host cell or exocytosis


Warm-UP

1. How do you fight viruses?

2. Why are viruses so hard for medicine to beat?

Homework: Immunity POGIL

1.5 µm

The Immune Response

1. Non-specific: • macrophages • attach to and ingest by

endocytosis• kill foreign bodies

indiscriminately b.c. the signal is general

• Ex: presence of a capsid causes macrophages to attach

2. Specifica. Cell-Mediated Responseb. Humoral Response


http://www.youtube.com/watch?v=JnlULOjUhSQ



1.5 µm


The Immune Response

1. Non-specific: • macrophages • attach to and ingest by

endocytosis• kill foreign bodies

indiscriminately b.c. the signal is general

• Ex: presence of a capsid causes macrophages to attach

2. Specifica. Cell-Mediated Responseb. Humoral Response

1.5 µm

Warm-UP: Describe the Signal Transduction Pathway in the helper T cell. How might a breakdown in this part of the immune system affect the rest of the immune response?

Due for a Stamp: Immune System POGIL; Stamp Sheets DUE NOW

Homework: ELISA pre-lab questions

1.5 µm


1. Non-specific: 2. Specific

a. Cell-Mediated Response: T cells• made in the thymus gland• 2 kinds:

• helper T cells1. Signal: virus, antigen, or

antigen presenting cells (macrophage or infected cell)

2. Reception: “correct” T cell: all T cells possible are present at birth; T cells with antigen specific receptor for present virus/antigen receives signal

3. Transduction: production of cytokines

4. Response: release of cytokines (signal that causes killer T cells and B cells to respond)

b. Humoral Response

1.5 µm



a. Cell-Mediated Response: T cells• made in the thymus gland• 2 kinds:

• killer T cells• attach to infected cells• release perforin (a

nonspecific integral protein)• causes lysis of infected cells

b. Humoral Response

1.5 µm



a. Cell-Mediated Responseb. Humoral Response: B cells

• made in the bone marrow• 2 types

• active:1. Signal: virus/antigen/antigen

presenting cell2. Reception: “selection” of

“correct” B cell3. Transduction: cell division;

production of antibodies4. Response: release of

antibodies

1.5 µm



a. Cell-Mediated Responseb. Humoral Response: B cells

• made in the bone marrow• 2 types

• memory: “correct” B cells are cloned and stored in case of 2ndry exposure

1.5 µm



a. Cell-Mediated Responseb. Humoral Response: antibodies

• bind to virus and act as competitive inhibitor to stop virus from infecting more cells

Meow. . . Meow. . . Meoooow! Obviously, it is time for your cat Garfield to come in. You go to the back door and see your big orange cat sitting on the back porch with a gift for you. Usually the gift he brings is small and furry such as a mouse or shrew. He is a very successful hunter and uses the nearby field as his hunting ground. His gift today is definitely unusual, it’s a dead pigeon. There are no signs of obvious trauma to the pigeon. You realize that Garfield was lazy and just brought you a dead bird that he simply found. Your next thought is, “How did it die?” Then you remember hearing in the news about a disease called the bird or avian flu. You get a little worried because you’ve heard that this type of flu may spread from wild birds to other animals like pigs, cats, and possibly humans. You decide that you had better call the county health department to let them know what you found. You are told to wrap the bird up in plastic to prevent contamination, and bring it, as well as Garfield, to the health department so they can be tested for bird flu.

Lab: ELISA: Enzyme-linked Immunosorbent Assay

Lab: ELISA: Enzyme-linked Immunosorbent Assay

Question: Does Garfield have antibodies for H5N1?

http://www.pbs.org/wgbh/nova/body/pandemic-flu.html http://www.youtube.com/watch?v=Rpj0emEGShQ

http://www.pbs.org/wgbh/nova/body/1918-flu.html

http://www.pbs.org/wgbh/nova/body/pandemic-flu.html



http://www.youtube.com/watch?v=Rpj0emEGShQ

http://www.youtube.com/watch?v=Rpj0emEGShQ



Pipetting Practice1. Adjust your micropipette:

a. 50.0 uL, 5.0 uL, or 125 uL

2. Make drops of your volume:a. 1st stopb. Into the solutionc. Released. Out of the solutione. Eject: to the 2nd stopf. Perfection?: TOUCH the drop to “unstick” the last bit

3. REMINDERS– No double dipping– Close tip box lids– Keep your hands, breath, etc. to yourself– Sterilize everything: before, during, and after– Small volumes DO NOT equal no volume: Use a microcentrifuge!

Warm-UP:

Sketch the model. Label it with the following:

H5 AntigenAntibody for H5Antibody for Antibody for H5PeroxidasePeroxidase Substrate

Homework for tomorrow: Analysis and Conclusion for lab due (I will collect)

Unit Test Thursday. Be ready to study in class tomorrow.

Tips for Tips• Using your micropippeter:

a. 1st stopb. Into the solutionc. Released. Out of the solutione. Eject: to the 2nd stopf. Perfection?: TOUCH the drop to “unstick” the last bit

• Ensure you have the “right” micropipette and tip for the job.

• Do not cross-contaminate your wells. Spread out. Keep track of what you’re doing.

• Use new “transfer” pipettes when you’re unsure if you’ve contaminated something. No double dipping

• Small volumes DO NOT equal no volume

BEFORE YOU LEAVE:• RECORD COLOR CHANGE on your chart of your 96 well

plate • CLEAN UP:

– Garbage:• transfer pipettes• paper towels• used tips• used 96 well plate

– On front table• colored minitubes (epitubes)• micropipettes in tub• tip box

• Homework for tomorrow: Analysis and Conclusion for lab due (I will collect)

• Unit Test Thursday. Be ready to study in class tomorrow.

Make sure to label: heavy chain, light chain, disulfide bonds, VDJ segments

HRP (Horseradish Peroxidase)

• peroxidase enzyme • catalyzes the reduction of hydrogen peroxide

(in the wash) to water• Substrate: TMB• Product: blue color

high blood sugar after a meal

insulin produced and excreted by pancreas

insulin receptor has not yet received the signal

activation of glut 4 transporter

activation of enzymes: glycogen synthase, phosphofructokinase, fatty acid synthase

blood glucose lowers as glucose diffuses by facilitated diffusion through glut 4

glycogen polymerization by glycogen synthaseglycolysis by phosphofructokinasefatty acid synthesis by fatty acid synthase

high blood sugar after a meal

insulin produced and excreted by pancreas

insulin receptor is broken and cannot receive the signal

glucose concentrations remain high in the blood: hyperglycemia

Before Signal is received

“Resting” membrane potential= -70mV

“Net” negative

Active Transport: Na+/K+ pumps use ATP to pump more + out than in

Voltage gated Na+ channels are stimulated to open

Na+ diffuse with their concentration gradients faster

Even more + in than out

“Action” membrane potential = -20mV

Na+

K+

outside of cell

inside of cell

Signal: adrenaline from previous neuron

Reception: adrenaline gated ion channel (adrenaline receptor) opens

• Na+ and K+ diffuse with their concentration gradients

• More + in than out • membrane potential “creeps”

towards threshold potential = -55mV

Resting membrane potential is -30mV

Voltage gated K+ channels are stimulated to open

K+ diffuse with their concentration gradients: more + out than in

Na+

K+

outside of cell

inside of cell

1.5 µm

Humoral Response

B cells secrete antibodies

antibodies bind to virus and act as a competitive inhibitor to stop virus from infecting more cells

1.5 µm

Humoral Response

“correct” B cells are cloned and stored in case of 2ndry exposure

“correct” antibodies bond to virus before host cells are infected.

host avoids being sick

1.5 µm

Non-specific

macrophages

attach to and ingest by endocytosis

kill foreign bodies indiscriminately b.c. the signal is general

Label: Primary Response

1. virus infects the person

2. macrophages kill some virus

3. helper T-cells release cytokines, which activates B cells and cytotoxic T-cells

4. B-cells are actively secreting antibodies

5. Viruses are being eliminated


Secondary Response

Same except:• more T and B cells

with the matching antibody

• less time for T and B cells to be activated

• antibodies secreted faster

• less virus replicated; less cells infected


insulin binds to receptor

glucose diffuses IN

insulin released

glycogen synthase is made

glut4 added to cell membrane

glucoseglycogen

vesicle binds to membrane, releases

neurotransmitter

neurotransmitter binds to ligand gated Na+ /K+

channel

voltage gated K+ channel opens

voltage gated Na+ channel opens

neurotransmitter released

Ca2+ diffuses IN, binds to vesicle

Na+ diffuses IN slowly, approaching threshold

potential

Na+ diffuses IN quickly: depolarization

K+ diffuses OUT quickly: repolarization

macrophage and infected host cell present antigen

helper T cell binds to antigen presenting cell

B cell releases antibodies

cytotoxic T cell bonds to infected host cells

infected host cells lyse

virus attaches to host cell

cytotoxic T cell divides

infected host cell produces more virus

macrophage kills virus by endocytosis

virus enters host cell

antibodies bond to virus

virus enters host

virus antibody complex is excreted by host

cytotoxic T cell releases perforin

B cell divides

helper T cell releases cytokines

unit 4: cell communication objectives: 2.c.1: organisms use feedback mechanisms to maintain their...

Documents

liver cells

pancrease cells

pancreas cells

target cells examples

immune system cells

external signal ligands

receptor protein ligand

release of new protein