New User Special Price Expires in

Let's log you in.

Sign in with Facebook


Don't have a StudySoup account? Create one here!


Create a StudySoup account

Be part of our community, it's free to join!

Sign up with Facebook


Create your account
By creating an account you agree to StudySoup's terms and conditions and privacy policy

Already have a StudySoup account? Login here

Biology 2000

by: Audrey Notetaker

Biology 2000 200001

Marketplace > Boston College > Biology > 200001 > Biology 2000
Audrey Notetaker
GPA 3.9

Preview These Notes for FREE

Get a free preview of these Notes, just enter your email below.

Unlock Preview
Unlock Preview

Preview these materials now for free

Why put in your email? Get access to more of this material and other relevant free materials for your school

View Preview

About this Document

Cell signaling and energy (enzymes)
Molecules and Cells
Danielle Taghian
Class Notes
25 ?




Popular in Molecules and Cells

Popular in Biology

This 5 page Class Notes was uploaded by Audrey Notetaker on Friday March 4, 2016. The Class Notes belongs to 200001 at Boston College taught by Danielle Taghian in Spring 2016. Since its upload, it has received 25 views. For similar materials see Molecules and Cells in Biology at Boston College.

Similar to 200001 at BC


Reviews for Biology 2000


Report this Material


What is Karma?


Karma is the currency of StudySoup.

You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!

Date Created: 03/04/16
Chapter 11: Cell communication  2/29/16  Cell needs receptor to receive signal  If receptor isn't in cytosol then nothing changes, if it is then it enterns through nuclear  pore into nucleus  Target gene DNA is what hornome receptor.  Hormone­gene bonding alters gene expression  Every cell has the same DNA sequence, but it is the expression of these genes via the  hormone­receptor complex that allows the gene to be expressed in the gene Signal processing  Not all hormones/peptides can diffuse.   Receptor protein embedded in lipid bilayer allow signal transduction pathway o Hormone binds to receptor, signal is sent through cytosol and amplified o G proteins: can bind GDP (guanasine diphosphate) or GTP (guanasine  triphosphate) triggers a cell response; inside on periphery of membrane (attached  to membrane with a lipid tail). Receptor has G protein bound to it  GPCR ­ G protein coupled receptor  When signal binds to receptor it changes the G protein making it detach  and go from GDP to GTP which activates the protein and it splits to bind  to enzyme (transmembrane protein) which produces the second messenger  Second messenger: molecules made in the cell that carry signals to  trigger a cell response o Enzyme­linked receptor: triggers protein activation within cell  Intrercellular signal is sent ­­> transmembrane protein receptor in bilayer (ectodomain;  pokes inside and outside of bilayer) ­­> signal is tranduced to intracellular signal ­­>  signal is picked up by other molecules with amplifies it ­­> cell activity changes causing  the cell to respond cAMP is a secondary messenger that can stimulate the activity of protein kinase A and other  proteins o First messenger ­­> receptor ­­> G protein ­­> enzyme (adenylyl cyclase (catalyzes the  conversion of ATP to cyclic AMP (cAMP))) ­­> secondary messenger (cAMP) ­> protein kinase A ­­> target proteins  BE ABLE TO DRAW THIS PROCESS IP3 (inasonal triphosphate) and Ca2+ ­ secondary messengers DRAW THIS PROCESS o Signal molecule ­­>receptor ­­> g protein activation ­­> phospholipase C enzyme to  cleave PIP2 to DAG (dyasal glycerol) and IP3 (second messenger) ­­> diffuse through  cytosol and binds to smooth ER ­­> smooth ER stores calcium and IP3 acts as a gated  channel which allows Ca to leave ER as second messenger ­­> proteins are activated in  cytosol ­­> cellular response Amplification: a single hormone can stimulate the production of many secondary messengers RTKs (receptor tirosine kinases): are enzyme linked, not G protein linked. Able to phosphorylate other proteins.   It's a dimer (has two pieces to it). Two pieces must collide in order for it to be activated.  Signal binds to one part and the other is attracted to it and then it dimerizes (comes  together)  Ectodomain: outside part that receives signal  Transmembrane: holds receptor in membrane  Signal transduction o Signal binds and it dimerizes ­­> RTK autophosphorylates (adds a phosphate  group to itself) ­­> Ras protein (a G protein because it is GDP when innactive and  GTP when active) with one subunit is activated (GTP) because it's bound to RTK  via bridging proteins ­­> RAS protein activates a protein by bringing in the  protein to activate the other protein Chapter 11: Signaling 3/2/2016 Adenylyl cyclase (in the membrane) catalyzes the conversion of ATP to cyclin AMP (cAMP) Kinase: an enzyme that phosphorylates other proteins Receptor tyrosine kinase (RTK): only phosphorylate the amino acid tyrosine (has a free OH  group for phosphate group to be added to). auto phosphorylates and then acts as a docking site  for other proteins (Ras) 1 Signal binds outside of cell to a transmembrane receptor 2 Conformational change triggers receptor phosphorylation inside of cell 3 Causes Ras (not a kinase) to bind GTP and remove GDP; Ras in now activated 4 Acivates Ras triggers a phosphorylation cascade (every protein after Ras is a kinase):  kinases are sequentially activated Signal responses: signal transduction changes activity of target cell at a distance (cells are far  apart) Gene expression ­ a change in which genes are being expressed in the cell Activation/deactivation ­ of a particular target protein that already exists in the cell Signal deactivation: allow cell to remain sensitive to changes in order to stop producing  secondary messengers   G proteins convert GTP back to GDP; changes the shape so cannot bind anymore   Extracellular signal is no longer produced  Phosphatases: enzymes that remove phosphate groups from proteins (may not always  inactivate a protein) Crosstalk: integrates diverse signals a cell receives ­ interactions between signaling pathways.  Elements or products from one pathway may afeect another Adjacent cells: gap junctions, desmosomes MAKE A MAP FOR A RECEPTOR TYROSINE KINASE PATHWAY AND A GPROTEIN  COUPLED RECEPTOR PATHWAY Chapter 8: Energy 3/4/2016 Kinetic: energy in movement Potential: energy in position; more unstable = higher Ep Further electron is from nucleus the more Ep Free energy: amount available to do work *spontaneous reactions have lower potential energy and higher entropy than the reactants  Potential energy drops when electros are held more tightly in products than reactants o Unequal electronegativities = low Ep o Equal electronegativities = high Ep Gibbs free­energy change: indicates whether a reaction is spontaneous or requires energy Delta G = delta H ­ T delta S ­G = spontaneous (exergonic)         +G = requires energy (endergonic)         G=0  = reaction at  equilibrium Enzymes don't effect the delta G of reaction Catalysis: acceleration of chemical change in order for reaction to happen Enzymes bring molecules together so that they may react; lowers activation energy *reaction rates depend on the kinetic energy of the reactants and the activation energy (Ea)  required to achieve the transition state *Delta G does not say anything about speed of reaction Induced fit model: when the enzyme binds to the substrate, causing the enzyme to change shape Enzyme catalyzed reaction steps 1.  initiation, reactants are corrently oriented and bind to active site 1 Transition state facilitated: enzyme facilitated chemical reaction 2 Termination: products are released from enzyme Enzyme phosphorylation: causes a conformation change in the protein Cofactors: inorganic ions that bind to enzyme to make it change shape Coenzymes: organic molecules bind to active site to help with correct shape of enzyme active  site for substrate Competitive inhibition: a molecule similar to substrate that fits into active site and prevents the  actual substrate from binding with enzyme Allosteric regulation: binding sites other than active site that a molecule binds to change shape of enzyme to either activate or deactivate it Limiting the rate of catalysis ­ when substrate concentration is low the speed of enzyme  catalyzed reaction is linear; at high substrate concentration the reaction rate plateaus at maximum speed  


Buy Material

Are you sure you want to buy this material for

25 Karma

Buy Material

BOOM! Enjoy Your Free Notes!

We've added these Notes to your profile, click here to view them now.


You're already Subscribed!

Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'

Why people love StudySoup

Jim McGreen Ohio University

"Knowing I can count on the Elite Notetaker in my class allows me to focus on what the professor is saying instead of just scribbling notes the whole time and falling behind."

Janice Dongeun University of Washington

"I used the money I made selling my notes & study guides to pay for spring break in Olympia, Washington...which was Sweet!"

Steve Martinelli UC Los Angeles

"There's no way I would have passed my Organic Chemistry class this semester without the notes and study guides I got from StudySoup."


"Their 'Elite Notetakers' are making over $1,200/month in sales by creating high quality content that helps their classmates in a time of need."

Become an Elite Notetaker and start selling your notes online!

Refund Policy


All subscriptions to StudySoup are paid in full at the time of subscribing. To change your credit card information or to cancel your subscription, go to "Edit Settings". All credit card information will be available there. If you should decide to cancel your subscription, it will continue to be valid until the next payment period, as all payments for the current period were made in advance. For special circumstances, please email


StudySoup has more than 1 million course-specific study resources to help students study smarter. If you’re having trouble finding what you’re looking for, our customer support team can help you find what you need! Feel free to contact them here:

Recurring Subscriptions: If you have canceled your recurring subscription on the day of renewal and have not downloaded any documents, you may request a refund by submitting an email to

Satisfaction Guarantee: If you’re not satisfied with your subscription, you can contact us for further help. Contact must be made within 3 business days of your subscription purchase and your refund request will be subject for review.

Please Note: Refunds can never be provided more than 30 days after the initial purchase date regardless of your activity on the site.