Agenda 11/5

1) Grade free response questions 2) Pass back test corrections and photosynthesis quizzes3) Review for test using Big Idea Powerpoint4) Check out more review manuals – can stay at home,

have class set – will send some to Career Center and Library

5) Per. 6 inquiry

Homework Study for test tomorrow – focus on enzymes, cell

respiration, and photosynthesis (esp. lab concepts) but anything from 6-10 and prior tests is fair game.

Math questions are calculate mean, rates, and energy coupling

Note - Website updated with most recent Powerpoints

Agenda 11/6

Cells and Metabolism Unit Test- Good Luck!!!Check gradeTurn in test corrections

Homework – Chapter 11 Notes and concept checks due Friday, Ch. 12

due next Tuesday

Agenda 11/7

1) Standard Deviation calculations2) Cell signaling animations from online assignments

Homework – Chapter 11 Notes and concept checks (NOT 11.5) and

online assignments due FridayCh. 12 Notes and concept checks due next Tuesday Ch. 12 Online assignments due next WednesdayNOTE – MAKEUP TESTS WILL BE DURING CLASS

TOMORROW

Agenda 11/8

Finish cell signaling – put it all together

Homework –

Chapter 11 Notes and concept checks (NOT 11.5) and online assignments due tomorrow

Ch. 12 Notes and concept checks due next Tuesday

Ch. 12 Online assignments due next Wednesday

Cell signaling and Evolution

In yeast and bacteria, cell signaling is very similar to multicellular organisms

Yeast use it to find each other for sex Bacteria use it to aggregate as spores in

times of low nutrients

Cell signaling has remained important in the microbial world. Myxobacteria, soil-dwelling bacteria, use chemical

signals to communicate nutrient availability. When food is scarce, cells secrete a signal to

other cells leading them to aggregate and form thick-walled spores.

Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

Fig. 11.2 Fruiting body

Can classify cell signaling based on distance

Paracrine = local ex:growth factors & NT’s

Endocrine = far, hormone travels in blood to target cells

Direct Contact – impt. in embryo dvpmt and immune system

Three stages of cell signaling In reception, a chemical signal (ligand) binds to a

cellular protein, typically at the cell’s surface. In transduction, binding leads to a change in the

receptor that triggers a series of changes along a signal-transduction pathway.

In response, the transduced signal triggers a specific cellular activity.

Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

Fig. 11.5

Yesterday, we saw the different types of receptors - what were they? G protein-linked, tyrosine kinase, ligand-

gated ion channel, and intracellular

A G-protein-linked receptor consists of a receptor protein associated with a G-protein on the cytoplasmic side. The receptor consists of seven alpha helices

spanning the membrane. Effective signal

molecules include yeast mating factors, epinephrine, other hormones, and neurotransmitters.

Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

Fig. 11.6

© 2011 Pearson Education, Inc.

Animation: Signal Transduction Pathways Right-click slide / select “Play”

Signal Transduction

Protein kinases phosphorylate other proteins/enzymes which usually activates them (can deactivate though)

Have to have a way to turn off response -Protein phosphatases remove the phosphate group and inactivate the protein/enzyme to shut down the response

The balance of these 2 regulates the activities of the cell

Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

Fig. 11.11

Second messengers (small, non-protein signal molecules that diffuse) – what were the 2 we saw yesterday? cAMP and Calcium ions (usually Ca++ low in cell)

Certain microbes cause disease by disrupting the G-protein signaling pathways. The cholera bacterium, Vibrio cholerae, colonizes

the small intestine and produces a toxin that modifies a G protein that regulates salt and water secretion.

The modified G protein is stuck in its active form, continuously stimulating productions of cAMP.

This causes the intestinal cells to secrete large amounts of water and salts into the intestines, leading to profuse diarrhea and death if untreated.

Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

Cell Response 3 examples from yesterday= glycogen

phosphorylation, microtubule formation, transcription factors

Signal amplification

Wild type (with shmoos) Fus3 formin

Matingfactoractivatesreceptor.

Matingfactor G protein-coupled

receptor

Shmoo projectionforming

Formin

G protein binds GTPand becomes activated.

2

1

3

4

5

P

P

P

PForminFormin

Fus3

Fus3Fus3

GDPGTP

Phosphory- lation cascade

Microfilament

Actinsubunit

Phosphorylation cascadeactivates Fus3, which movesto plasma membrane.

Fus3 phos-phorylatesformin,activating it.

Formin initiates growth ofmicrofilaments that formthe shmoo projections.

RESULTS

CONCLUSION

Figure 11.17

Canine Ear Infection

Fine-Tuning of the Response

There are four aspects of fine-tuning to consider

Amplification of the signal (and thus the response) Specificity of the response Overall efficiency of response, enhanced by

scaffolding proteins Termination of the signal

© 2011 Pearson Education, Inc.

Specificity The response of a particular cell to a signal

depends on its particular collection of receptor proteins, relay proteins, and proteins needed to carry out the response.

Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

Fig. 11.18

Rather than relying on diffusion of large relay molecules like proteins, many signal pathways are linked together physically by scaffolding proteins. Scaffolding proteins may themselves be relay

proteins to which several other relay proteins attach.

This hardwiring enhances the speed and accuracy of signal transfer between cells.

Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

Fig. 11.19

Termination of the Signal

Inactivation mechanisms are an essential aspect of cell signaling

If ligand concentration falls, fewer receptors will be bound

Unbound receptors revert to an inactive state

© 2011 Pearson Education, Inc.

Build a Pathway Activity

Last paragraph of Ch. 11

Let’s read it, then go on to Ch. 12 Mitosis figures, p. 232-233 and cell cycle figures from Bio

Agenda 11/9 Finish Build a Pathway Cell cycle slides Mitosis Bioflix video and tutorials

Have book open to p. 232-233 I check Ch. 11 notes during this

Tests back – write your percentage on your test correction sheet

Homework- Ch. 12 Notes and concept checks due next Tuesday Ch. 12 Online assignments due next Wednesday

The Cell Cycle

• Interphase

• G1 phase

• S phase

• G2 phase

• Mitosis

M phase

• Cytokinesis

cell membrane or cell wall

divides

growth

growth and preparation for mitosis

The Cell Cycle

Cell Cycle Regulation