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

Week 7 LIFE102 Notes

by: Sydney Dingman

Week 7 LIFE102 Notes Life 102

Marketplace > Colorado State University > Biology > Life 102 > Week 7 LIFE102 Notes
Sydney Dingman
GPA 3.7

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

Covers Friday of Week 6 and all of week 7
Attributes of Living Systems
Erik N Arthun
Class Notes
life, Biology
25 ?




Popular in Attributes of Living Systems

Popular in Biology

This 8 page Class Notes was uploaded by Sydney Dingman on Sunday March 6, 2016. The Class Notes belongs to Life 102 at Colorado State University taught by Erik N Arthun in Winter 2016. Since its upload, it has received 31 views. For similar materials see Attributes of Living Systems in Biology at Colorado State University.


Reviews for Week 7 LIFE102 Notes


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: 03/06/16
Week 7 LIFE 102 Notes 2/26/16, Module 8 cont.  Glycolysis: Sugar splitting, small amount of ATP is made and glucose is oxidized (loss of electrons)  Reduction is the gain of electron, cannot have reduction without oxidation.  Before the citric acid cycle can begin: o Pyrubate must be converted to acetyl Coenzyme A (Acetyl CoA), which links glycolysis to the citric acid cycle.  Major point of digesting food is to steal electrons and those electrons are used to pump hydrogen ions across a membrane  Step 2: Citric Acid Cycle o Occurs in the mitochondrial matrix o Completes the break down of pyruvate to CO2 o The cycle oxidizes organic fuel derived from pyruvate, generating 1 ATP, 3 NADH, and 1 FADH2 per turn o Pay attention to the electron shuttles; it is where the important energy is located o Fuel is oxidized in the citric acid cycle  During oxidative phosphorylation, chemiosmosis couples electron transport to ATP synthesis o Following glycolysis and the citric acid cycle, NADH and FADH2 account for most of the energy extracted from food o These two electron carriers donate electrons to the electron transport chain, which powers ATP synthesis via oxidative phosphorylation o The electron transport chain is in the inner membrane (cristae) of the mitochondrion o Electrons drop in free energy as they go down the chain and are finally passed to O2, forming H2O  Step 3: Electron Transport Chain o Electrons are transferred from NADH or FADH2 to the electron transport chain o Electrons are passed through a number of proteins to O2 o The electron transport chain generates no ATP directly o It breaks the large free-energy drop from food to O2 into smaller steps that release energy in manageable amounts  Chemiosmosis: The energy-coupling mechanism o Electron transfer in the electron transport chain causes proteins to pump H+ from the mitochondrial matrix to the intermembrane space o H+ then moves back across the membrane passing through the protein ATP synthase o ATP synthase uses the exergonic flow of H+ to drive phosphorylation of ATP o This is an example of chemiosmosis, the use of energy in a H+ gradient to drive cellular work  Cells can produce ATP in alternative ways o Aerobic respiration needs O2 for ETC o If there was no oxygen, the process of glycolysis would be connected to  Anaerobic respiration  Uses electron transport chain with a final electron acceptor other than O2, for example sulfate  Fermentation  An extension of glycolysis (repeats glycolysis)  Allows continuous substrate-level phosphorylation and recycles NADH  NAD+  Uses substrate level phosphorylation instead of an electron transport chain to generate ATP  Alcohol fermentation o Pyruvate is converted to ethanol in two steps, with the first releasing CO2  Lactic acid fermentation o Pyruvate is reduced (gaining of electrons) by NADH, forming lactate (gives somewhat sour taste) as an end product, with no release of CO2  We need empty electron shuttles 2  Only get 2 ATP, not efficient, but better than nothing o Pyruvate is a key intersection in catabolism  Energy movement through ecosystems o Energy flows into ecosystems as sunlight and leaves as heat through photosynthesis and respiration 2/29/16, Chapter 10, Photosynthesis  In photosynthesis light energy is converted into chemical energy  CO2+H2O(light)[CH2O]+O2Carbohydrates  Types of feeders o Autotrophs:  Self feeders  Producers of all organic compounds in the biosphere o Photoautotrophs  Produce energy from light o Heterotrophs:  Other feeders  Consumers of organic molecules from organisms  Photosynthesis o Plants, algae and some prokaryotes o Supports all life on Earth by:  Converts light energy to the chemical energy of food  Location of photosynthesis o Leaves: major locations of photosynthesis  Green color from chlorophyll, the green pigment within chloroplasts  CO2 enters and O2 exits the leaf through microscopic pores called stomata o Chloroplasts: the sites of photosynthesis in plants  The chlorophyll is the membranes of thylakoids  Chloroplasts also contain stroma, a dense interior fluid 3  Tracking atoms through photosynthesis o Light+6 CO 2+12 H 2OC 6H12O +6 O 2+6 H 2O o Chloroplasts split H2O into hydrogen and oxygen, incorporating the electrons of hydrogen into sugar molecules and releasing oxygen as a by-product o Energy flow on our planet is a cycle  How does photosynthesis work? o 2 processes: Light Reactions and Calvin Cycle  Light Reactions: light energy is captured in the thylakoid membrane  Acts as the input of energy  Calvin Cycle: CO2 is “fixed” and reduced to sugars in the stroma o Photosynthesis consists of light reactions (the photo part) and Calvin cycle (the synthesis part)  The light reactions  Split H2O  Release O2  Reduce NADP+ to HADPH  Generate ATP from ADP by photophosphorylation  The Calvin cycle (in the stroma) forms sugar from CO2, using ATP and NADPH  The Calvin cycle beings with carbon fixation, incorporating CO2 into organic molecules  How can light energy be captured? o Light: radiation energy from the sun o Light behaves as though it is made of discrete particles called photons  Interactions between leaves and light o Photons of light energy interact with chlorophyll molecules and other pigments in chloroplasts o Light is:  Reflected 4  Transmitted  Absorbed  Plants: molecules that can absorb light  Chlorophyll: photosynthetic pigment  How does light absorption work? o Unit of light: photon o When a photon hits any molecule, it can push an electron into a higher energy level  exited state  electrons fall back, emitting heat/radiation  Excitation of an e- from a chlorophyll molecule (see slide 16 of chapter 10 notes) o Chlorophyll excitation in a chloroplast does not allow the electron to fall back down after it is excited, and it is captured by another molecule (primary electron acceptor) 3/2/16, Module 10 cont.  Chlorophyll excitation in a chloroplast o Electron doesn’t fall back down, but is captured by another molecule  Photosystem (PS): cluster of pigment molecules working together o 2 types of photosystems: PS I and PS II  Work together in photosynthesis o Each PS has:  Reaction center: central Chl molecule that receives all captured light energy  Primary electron acceptor: molecule that accepts excited e- from reaction center  Photosystems o Consists of a reaction center complex surrounded by light- harvesting complexes o The light-harvesting complexes (pigment molecules bound to proteins) transfer the energy of photons to the reaction center o A primary electron acceptor in the reaction center accepts excited electrons and is reduced 5 o Solar-powered transfer of an electron from a chlorophyll a molecule to the primary electron acceptor is the first step of light reactions  Linear Electron Flow o During the light reactions, there are two possible routes for electron flow: cyclic and linear o Linear electron flow, the primary pathway, involves both photosystems and produces ATP and NADPH o A photon hits a pigment and its energy is passed among pigment molecules until it excites P680 o An excited electron from P680 is transferred to the primary electron acceptor o P680+ is a very strong oxidizing agent  It pulls very hard on electrons o H20 is split by enzymse and the electrons are transferred from the hydrogen atoms to P680+ thus reducing it to P680 o O2 is released as a by-product o this reaction o Each electron “falls” down an electron transport chain from primary electron acceptor of the PSII and PSI o Energy released by the fall drives the creation of a proton gradient across the thylakoid membrane o Diffusion of H+ (protons) across the membrane drives ATP o In PSI (like PSII), transferred light energy excites P700, which loses an electron to an electron acceptor o P700+ (P700 that is missing an electron) accepts an electron passed down from PSII via the electron transport chain  Linear Electron Flow o Each electron “falls” down an electron transport chain from the primary electron acceptor of PSI to the protein ferredoxin (Fd) o The electrons are then transferred to NADP+ and reduce it to NADPH o The high energy electrons of NADPH are available for the reactions of the Calvin cycle o Linear electron flow, the primary pathway, involves both photosystems and produces ATP and NADPH using light energy 6 o The electrons of NADPH are available for the reactions of the reaction cycle o KNOW HOW THE ATP IS MADE AND THE TWO PRODUCTS OF THE REACTION  Comparison of Chemiosmosis in Chloroplasts and Mitochondria o Chloroplasts and mitochondria generate ATP by chemiosmosis, but use different sources of energy o Mitochondria transfer chemical energy from food to ATP o Chloroplasts transform light energy into chemical energy of ATP  Summary of light reactions o Light energy  Chemical energy/ NADPH and ATP o Low-energy Light energy high energy e- o Flow of high-energy e- to NADPH is via an ETC  ATP produced o Oxygen formed as by-product form splitting of H2O to e- + H+ + O2  The Calvin Cycle uses the chemical energy of ATP and NADPH to reduce CO2 to sugar o The Calvin cycle, like the citric acid cycle, regenerates its starting material after molecules enter and leave the cycle o The cycle builds sugar from smaller molecules by using ATP and the reducing power of electrons carried by NADPH o CO2 is fixed and reduced to sugar (CHO) o Carbon enters the cycle as CO2 and leaves as a sugar names glyceraldehyde 3-phosphate (G3P) o For net synthesis of 1 G3P, the cycle must take place three times, fixing 3 molecules of CO2 o The Calvin cycle has 3 phases  Carbon fixation  Reduction  Regeneration of the CO2 acceptor o The Calvin cycle uses the chemical energy of 9 ATP and 6 NADPH to reduce CO2 to sugar  Calvin cycle and Light reactions are codependent, can’t have one without the other 7  Importance of Photosynthesis o The energy entering chloroplasts as sunlight gets stored as chemical energy in organic compounds o Sugar made in the chloroplasts supplies chemical energy and carbon skeletons to synthesize the organic molecules of cells o Plants store excess sugar as starch in structures such as roots, tubers, seeds, and fruits o In addition to food production, photosynthesis produces O2 in our atmosphere  Energy Movement through ecosystems o Energy flows into an ecosystem as sunlight leaves as heat o Photosynthesis and respiration 8


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

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."

Kyle Maynard Purdue

"When you're taking detailed notes and trying to help everyone else out in the class, it really helps you learn and understand the I made $280 on my first study guide!"

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.