Metabolic+Processes


 * Red-ox reactions are how energy is obtained biologically.
 * NAD+ and FAD are most common oxidation agents in the body

Oxidation

 * chief mechanisms by which chemical potential is released
 * this energy comes from reduced compounds:
 * Carbohydrates: broken down into simple sugars (1st Choice)
 * Lipids : high ratio of hydrogen and oxygen atoms (2nd Choice)
 * Even proteins (amino acids) in a pinch (3rd Choice)

Redox reactions involve flow of electrons
Oxidation Reduction
 * loss of electron
 * remove Hydrogen
 * add oxygen
 * gain of electron
 * gain Hydrogen
 * lose Oxygen

Redox in Biological systems: When and How

 * redox reactions occur at
 * moderate temperatures
 * eg) reaction for aldehyde to alcohol at room temperature requires strong enzymes and extremely high pressure while body temperature allows it to occur more easily.
 * in the presence of enzymes
 * in small steps to minimize energy

(Oxidized form) (Reduced form)
 * eg) NAD+ + H2 > NADH + H+
 * Nicotinamide adenine dinucleotide: the __reduced__ version carries __2 electrons__ from enzyme to enzyme
 * it can shuttle 1 proton
 * in this example above, the electrons most likely come from an energy source like glucose


 * Eg) FAD + H2 ---> FADH2
 * Flavin adenine dinucleotide: the __reduced__ version __carries electrons__ from enzyme to enzyme.
 * it has the ability to carry 2 protons too

Photosynthesis: Anabolic Process (making complex molecules from simple ones)

 * how energy gets into ecosystems
 * helps in carbon fixation
 * 6 H2O + 6 CO2 + Energy (UV light) > 6 O2 + C6H12O6

Cellular Respiration: Catabolic Process (breaking down complex molecules)

 * performed by every living organism
 * 6 O2 + C6H12O6 > 6 H2O + 6 CO2 + Energy (ATP)

Cellular Respiration

 * ** Glycolysis Phase 1 = Energy investment phase, Catabolism of Glucose **
 * Overview
 * In --> 1 molecule of glucose goes in (one 6-Carbon Molecule)
 * In --> 2 molecules of ATP
 * Out --> 2 molecules of PGAL (G3P in text) (two 3-Carbon molecules)
 * Out --> 2 molecules of ADP
 * Stage 1 is the same in both aerobic respiration and anaerobic fermentation


 * ** Glycolysis Phase 2 = Energy pay off Phase, Catabolism of PGAL **
 * Remember this reaction happens twice, so the 2 ATPs made will actually result in a total of 4 ATPs [[image:wilsonsbi4u1-02-2013/photo (42).JPG width="560"]]
 * Overview
 * Inorganic phosphate is added to each of the 2 PGALs
 * NAD+ acts as an oxidizing agent
 * It gains a hydrogen and an electron and therefore, is reduced.
 * NAD+ + 2 H > NADH + H+
 * 4 ATP molecules and 2 pyruvic acid molecules are made
 * For every molecule of glucose which undergoes glycolysis, two 3-phsophoglyceraldehyde are made. So, phase 2 occurs 2 times per glucose molecule.

Homework

 * Read 3.1 and 3.2
 * Complete pg 145 #3-5, 8, 12
 * Review for __#|Quiz__ on Tuesday

Helpful Resources

 * Explanation: []
 * Animation: []

= Metabolic Processes - Sunjeev Uthayakumar - Oct. 7, 2013 = Molecules in: -2 PGAL, 2 NAD+, 2 Pi, 4 ADP Molecules out: -2 pyruvic acid -2 NADH (used elsewhere by cell) -4 ATP -2 H2O Note: 2 ATP __in__ during phase 1; 4 ATP __out__ in phase 2 Therefore, a net gain of 2 ATP.
 * Glycolysis Phase 2 Summary** (What goes in must come out)

1 glucose + 2 ATP + 2 NAD+ --> 2 NADH + 4 ATP + 2 pyruvic acid Net energy gain 2 ATP and 2 NADH (1 glucose molecule is broken down into 2 pyruvate molecules)
 * Glycolysis Summary: Phase 1 and 2**



__What's the Point of Glycolysis__? -to break down a glucose molecule into 2 pyruvate molecules in the cytoplasm of a cell

The fate of pyruvate (which pathway to choose?) __#|Options__: -cellular respiration (aerobes) -alcoholic fermentation (yeast) -lactic acid fermentation (energy-deprived muscles)

>
 * Homework**
 * Clothes Pin Activity Questions
 * Study for Glycolysis Phases __#|Quiz__ tomorrow
 * Links**
 * []
 * []

=**Metabolic Processes - Thanusika Ramanathan - October 8th, 2013**=

__**Recap of the beginning of class**__
 * Handed in Clothes Pin Activity Questions
 * Glycolysis Quiz (Students were asked to draw out Phase I and Phase II of the glycolysis process on a sheet of paper).

__**Aerobic Respiration Overview**__ __Pathways of Pyruvate__ options:
 * 1) Cellular Respiration (Aerobes)
 * 2) Alcoholic Fermentation (Yeast)
 * 3) Lactic Acid Fermentation (Oxygen deprived muscles)

The path the pyruvate should go to is acetyl-CoA which is located in the mitochondria. The other two pathways are located in the cytoplasm.

__Pyruvate to CO2 and H2O__ The two steps above are a part of __Oxidative Decarboxylation__, which is the process of producing CO2 as a waste product, in the removal of the carboxyl group (COOH) of pyruvate.
 * Pyruvates produced from glycolysis are transported through the outer and inner __mitochondrial__ membrane.
 * Pyruvate is broken down into Acetyl-CoA
 * Acetyl-CoA is fed into the Kreb Cycle
 * In the Kreb Cycle, various reduced co-enzymes (NADH and FADH2) are formed.
 * In a pathway called the electron transport chain, NADH and FADH2 are used in the chemiosmotic synthesis of ATP.

__**Oxidative** **Decarboxylation**__ (Redox Reaction) Below, is a small diagram illustrating the process of Oxidative Decarboxylation.
 * Production of CO2 through the removal of a carboxyl group in the pyruvate.
 * Glucose --> 2 Pyruvates + 2NAD+ --> 2Acetyl-CoA + 2NADH + 2CO2
 * Coenzyme A and NAD+ goes IN
 * CO2, NADH and H+ comes OUT




 * The pyruvate are transported into the mitochondrion and this reaction occurs there. Eventually, the "Acetyl" is converted into Hydrogen, CO2 and water in Kreb's cycle,
 * The Hydrogen's are combined with O2 to form H2O.
 * ATP is produced from ADP using chemiosmotic synthesis of ATP in the Electron Transport Chain.


 * __Kreb Cycle = TCA (Tricarboxylic Acid Cycle)= CItric Acid Cycle__**
 * The Oxidation of Acetyl groups to form CO2
 * Located in the mitochondrial matrix
 * Synthesis of ATP, NADH, and the nucleotide base FAD (Increases Cell's ATP producing potential)
 * Increases Cell's ATP producing potential
 * Acts as a passage for metabolites that might be needed for other processes than energy production, such as, the biosynthesis of amino acids, proteins or enzyme cofactors.
 * For every Acetyl-CoA entered --> 3NADH + 1FADH2 + 1ATP
 * Acetyl-CoA + 3NAD+ + FAD + ADP + Pi --> 2CO2 + 3NADH + H+ + FADH2 + ATP + CoA
 * All the Carbon present in glucose is oxidized and released as CO2
 * 2 rounds of Kreb Cycle for every Pyruvate molecule



Need Help? []

[] [] []

Homework! Read and make notes on 4.2 Pages 174-177 Study for Kreb Cycle Quiz on Wednesday Blueprint of Enzyme Model is due on Thursday

==

P. 179 - Electron Transport Chain (ETC)


-the point of the ETC is to extract energy from NADH and FADH2 and make it available for ATP synthesis -ETC allows the transfer of electrons from NADH and FADH2 to O2 -ETC consists of four protein complexes: complex I (NADH dehydrogenase), complex II (succinate dehydrogenase), complex III (cytochrome complex), and complex IV (cytochrome oxidase) -ubiquinone (UQ) and cytochrome (cyt c) shuttle electrons across the four protein complexes -oxygen goes to the mitochondria to pull electrons away from complex IV -as oxygen interacts with complex IV, it removes __a pair__ of electrons -therefore, for every oxygen gas (O2) molecule that we breath in, four electrons are pulled through the elctron transport chain and two water molecules are produced -then, complex IV replaces the two electrons that it lost by taking two away from complex III, which in turn takes two electrons from complex I

Homework

 * Draw Figure 7 on page 178 into notes
 * Read pages 177-181
 * Kreb Cycle quiz on Wednesday
 * Enzyme blueprint due on Thursday

Links

 * []
 * https://www.khanacademy.org/science/biology/cellular-respiration/v/electron-transport-chain

==

Metabolic Processes- Lahina Sivanantharajah
October 10th, 2013

Today we had an ISP

__**Homework:**__
 * Read and make notes from page 190-194 on Lactic acid
 * Do the __#|review__ questions on page 194 #1-10
 * Study for the Kreb cycle __#|quiz__ on Wednesday
 * The blueprint of the enzymes are due on Thursday

=__**Metabolic Processes - Thanusika Ramanathan - October 15, 2013**__=

__Recap of today:__ The day was spent as an independent study period, in which students were asked to with their partners on their Electron Transport Chain presentation, that were to begin the following day. Students had to design a captivating performance that would not only entertain but also educate their fellow peers on the steps involved in the Electron Transport Chain. Some creative performances involved making the process into a story, lyrics of a song/rap, or into an interpretive dance.

__ Homework! __ Prepare for ETC Presentations that are tomorrow Enzyme Model Blueprint due Thursday
 * Kreb Cycle Quiz tomorrow **

Metabolic Processes - Abisheha Yogaratnam
October 16th, 2013

Today, we had a quiz on the Electron Transport Chain. We also presented our ETC skits.


 * Reminder: ENZYME MODEL BLUEPRINTS ARE DUE TOMORROW!**

**Metabolic Processes** - Megan Lin
October 17th, 2013

Recap of Today: - Handed in Enzyme Model Blueprints - Presented the rest of the ETC skits - Received unit tests back

//Some things to Review://
 * []
 * []
 * []

__//Homework//__ //(If you haven't already done it////) ://
 * Read and make notes on page 190-193
 * Do questions #1-10

Metabolic Processes - Sahana Nirmaiyan - October 18, 2013
**Regulation of Cellular Respiration**


 * Mostly Negative Feedback Inhibition

1. Glycerol-3-phosphate shuttle

 * Transports NADH with the cost of an ATP
 * Theoretically, you'll end up with 36 ATP/glucose molecule
 * There are A LOT of these shuttles

2. Malate-aspartate shuttle
 * Transports NADH without use of ATP
 * You'll theoretically end up with 38 ATP/glucose molecule
 * There are very few of these shuttles

Alternatives to Glucose

 * Stored Carbohydrates
 * Short term, 1st used
 * Animals store glucose as glycogen, Plants store it as cellulose
 * Lipids
 *  [[image:http://smartcoup-a.akamaihd.net/items/it/img/arrow-10x10.png height="10"]] are the major source
 * <span style="background-color: #ffffff; color: #222222; font-family: arial,sans-serif; line-height: 1.5;">They are broken down into glycerol and fatty acids
 * <span style="background-color: #ffffff; color: #222222; font-family: arial,sans-serif; line-height: 1.5;">Glycerol is converted into PGAL and then enters into glycolysis II (if you enter at glycolysis II, you don't miss any direct ATP)
 * <span style="background-color: #ffffff; color: #222222; font-family: arial,sans-serif; line-height: 1.5;">Fatty acids undergo **beta oxidation** to become acetyl-CoA (miss making NADH and ATP)
 * <span style="background-color: #ffffff; color: #222222; font-family: arial,sans-serif; line-height: 1.5;">Proteins
 * <span style="background-color: #ffffff; color: #222222; font-family: arial,sans-serif; line-height: 1.5;">Normally not used for energy, can be used during starvation
 * <span style="background-color: #ffffff; color: #222222; font-family: arial,sans-serif; line-height: 1.5;">They are hydrolyzed before being oxidized
 * <span style="background-color: #ffffff; color: #222222; font-family: arial,sans-serif; line-height: 1.5;">Amino group is removed and leaves as ammonia which is later disposed. The remaining molecule enters as pyruvate or acetyl-CoA or a part of the Kreb cycle; depends on the R group and enzymes that convert them


 * <span style="background-color: #ffffff; color: #222222; font-family: arial,sans-serif; line-height: 1.5;">Liver stores excess glucose as glycogen (glycogenesis) and fat (lipogenesis) and converts amino acids into glucose (gluconeogenesis, the opposite of glycolysis)
 * <span style="background-color: #ffffff; color: #222222; font-family: arial,sans-serif; line-height: 1.5;">Adipose tissue stores (lipogenesis) and breaks down (lipolysis) fats
 * <span style="background-color: #ffffff; color: #222222; font-family: arial,sans-serif; line-height: 1.5;">Brain can only use glucose

<span style="background-color: #ffffff; color: #222222; font-family: arial,sans-serif;">Homework

 * <span style="background-color: #ffffff; color: #222222; font-family: arial,sans-serif; line-height: 1.5;">Pg. 189 #3, 4, 6-10
 * <span style="background-color: #ffffff; color: #222222; font-family: arial,sans-serif; line-height: 1.5;">Copy diagram on page 184 and draw in where lipids and proteins enter
 * <span style="background-color: #ffffff; color: #222222; font-family: arial,sans-serif; line-height: 1.5;"> [[image:http://smartcoup-a.akamaihd.net/items/it/img/arrow-10x10.png height="10"]] on Enzyme Model
 * <span style="background-color: #ffffff; color: #222222; font-family: arial,sans-serif; line-height: 1.5;"> [[image:http://smartcoup-a.akamaihd.net/items/it/img/arrow-10x10.png height="10"]] on group project about fermentation

<span style="background-color: #ffffff; color: #222222; font-family: arial,sans-serif;">Useful links

 * <span style="background-color: #ffffff; color: #1155cc; font-family: arial,sans-serif; line-height: 1.5;">@http://www.pearsonhighered.com/mathews/ch15/c15secm.htm
 * <span style="background-color: #ffffff; color: #1155cc; font-family: arial,sans-serif; line-height: 1.5;">@https://www.boundless.com/biology/cellular-respiration/other-pathways-involving-glycolysis-and-the-citric-acid-cycle/feedback-inhibition-regulates-cellular-respiration/

=Metabolic Processes - Sunjeev Uthayakumar - Oct. 21, 2013= Today we discussed the procedures for the Catalase lab (which we are going to be doing on Wednesday). There is a template online (search: SBI4UKING and the Microsoft Word document). Use this template by writing the method for all six procedures and filling out numbers in the charts.

Homework:

 * Research about your fermentation topic
 * Work on enzyme model
 * Catalase lab procedure is due tomorrow (before 4 pm)

=__**Metabolic Processes - Thanusika Ramanathan - October 22, 2013**__= Today in class we had a supply teacher, so we worked on our fermentation presentations. Students were expected to in their alloted groups of 2-3 people on the given topics, assigned on Friday.

__**Homework**__ REMINDER: MAKE SURE TO SEND MS. WILSON YOUR CATALASE LABS BY __**4:00P.M. TODAY!**__ Prepare for fermentation presentation Remember to bring signed report cards if you have satisfactory mark or lower.

= Metabolic Processes - Abisheha Yogaratnam - October 23, 2013 =

Today in class, we began our potato lab. We will be continuing the lab on Friday.

REMINDER: - There is no class tomorrow. - Enzyme models are due next Monday, October 28th.

Metabolic Processes - Sahana Nirmaiyan - October 25, 2013
Today we performed the second part of the enzyme lab.

**Homework:**

 * __ Enzyme Model is due Monday __
 * Complete Fermentation Presentation - Presentations are Monday
 * Over the weekend, post your results for the enzyme lab on the wiki.
 * Type out and hand in the purpose, materials (in two columns), procedures for the two lab situations you did, and observation tables for the enzyme lab - Due Monday

=October 28- Jenn Lindeman= //**__Lab Report Due Monday November 4__**// __Purpose:__ - what is the enzyme used - what factors are tested - what you are testing for __Materials:__ - table, 2 columns - hydrogen peroxide (3%) - HCl (0.01n) __Procedure:__ -numbered steps - PAST tense -do not start a sentence with digests __Post lab questions:__ -add 4 graphs - average everyone's data __Conclusion:__ - NO personal nouns

All calculations --> 2 diget places (0.0076) Rate of reation --> mL/sec

=October 29- Jenn Lindeman= - Supports the energy transformations of the entire biosphere - The means by which the energy from sunlight is made available to living systems - The conversion of light-energy to chemical-energy via the chloroplasts of Eukaryota cells - Generates 100 billion metric tons of sugar annually - The process via which energy enters out biosphere - It is responsible for the capture of inorganic molecules (CO2 and H2O) and fixing them in simple organic molecules - Accomplished using energy obtained by sunlight
 * __//Phtosyn//__thesis Overview**


 * __Van Helmont__** --> Planted a tree and over a 5 year span fed it distilled water and afterwards measured the tree and soil mass to see if the tree ate the soil or gained the new mass from the water.
 * __Priestly__** --> Tested the production/consumption of gas by a plant. He put a plant in a jar with a mouse and it lived, without the plant the mouse died and vice verse... without the mouse the plant died.
 * __Ingen-Housz__** --> Plants need sunlight and the green parts undergo photosynthesis.
 * __Senebier__** --> Plants need a particular gas, CO2.


 * __Van Neil__** -->

October 31, 2013
Today, we took notes on photosynthesis and the breakdown of the process.

Breakdown of the process: Stage 1: Capturing light energy Stage 2: Synthesizing ATP and NADPH Stage 3: Calvin Cycle (carbon fixation)
 * Stages 1,2 are light dependent reactions (require light to function)
 * Stage 3 does not require light directly and thus is considered light independent

__Properties of light__ - visible light is a small part of the electromagnetic spectrum - white light can be separated into the different colours (wavelengths) of light by passing it through a prism - energy is inversely proportional to the wavelength: longer wavelengths have less energy than do shorter ones - the longer the wavelength of visible light, the more red the colour - likewise, the shorter wavelengths are towards the violet side - wavelengths longer than red are referred to as infrared while those shorter than violet are altraviolet

__Light and Pigments__ - light has energy and that can be transferred or captured by an electron in a chemical bond - the electron is then "excited" to a higher energy state - this excitation can be passed from one electron to another until an electron actually leaves the bond - the source molecule is now said to be the "oxidized" - photosynthesis pigment molecules have many alternating single-double bonds between their carbon atoms - these are ideal for capturing light energy and in turn losing electrons that are transferred to other molecules

__Pigment Molecules__ - light energy is "captured" by pigment molecules - the energy absorbed by the pigment causes and electron to be excited to a higher energy level - occurs in the double C=C bonds or "Pi" bonds - usually an "excited electron" falls back down to its original energy level, it releasing the exact amount and wavelength of light it originally absorbed - in photosynthesis, the electron does not just fall back down to its ground state and release the energy, instead the energy is used to power the Red-Ox reactions of photosynthesis

__Carotenoids__ - Beta carotene is a carotenoid pigment - this pigment reflects orange light, providing the orange colour associated with carrots and leaves in the fall - carotenoids absorb blue light - they have a system of alternating double and single carbon bonds in their structure - when light strikes the pigment, excited electrons are passed along its length, and in plants will be collected by an "electron acceptor"

__Chlorophyll__ - Chlorophyll a and b are different only in the "R" group


 * THE REST OF THE NOTE WILL CONTINUE TOMORROW

__Homework:__ Read 5.1 and 5.2 and do questions #2-5 on pg. 219

=**Photosynthesis**= =Lahina **Sivanantharajah**= =**November 1st, 2013**=


 * Light Reactions**
 * Occur in the Thylakoid
 * 2 pathways
 * A) Non-cyclic**


 * Main pathway
 * Involves both photosystems
 * Uses 2 ADP, 2 NADP + ,2 H2O, and light ( 4 photons) to make 2 ATP, 2 NADPH and O2

( Copy figure 3 on page 221)
 * Steps: **
 * Photosystem 2 (P680) absorbs a photon, exciting the chlorophyll and causing it to be oxidized ( lose an electron).
 * The electrons from the oxidized chlorophyll are transferred to the primary acceptor of P680.
 * The oxidized chlorophyll, initiates the splitting of 2 water molecules at the water splitting complex (Z complex) to make 4 H+ and O2 and releasing 4 electrons. The oxygen gas diffuses out of the cell.
 * The electrons travel from the primary acceptor of P680 to plastoquinone (PQ) to the cytochrome complex then to plastocyanin and then to the photosystem 1 in a series of redox reactions. This sets up and maintains a hydrogen ion gradient across the thylakoid membrane allowing for the production of ATP.
 * Light is absorbed by photosystem 1 (700) exciting the chlorophyll and causing it to be oxidized ( lose and electron) and transferring its electron to the primary acceptor.
 * The electrons fro the primary acceptor of P700 travel to ferrodoxin and then to NADP+ reductase where NADP+ is reduced by the electrons to form NADPH in the stroma which is used in the Calvin cycle.

( copy Figure 6 on page 225)
 * B) Cyclic**
 * Occurs when oxygen levels and NADPH levels are high.
 * Only involves Photosystem 1 (P700)
 * NADPH is not formed as the electrons are cycled back to P680 not NADP+ reductase.
 * Steps:**
 * 1) Light is absorbed by photosystem 1 (P700) exciting the chorophyll and causing it ti be oxidized ( lose an electron) and transferring its electron to the primary acceptor.
 * 2) The electrons from the primary acceptor of P700 travel to ferrodoxin to plastoquinone (PQ) to the cytochrome complex to plastocyanin in a series of redox reactions. This sets up and maintains a hydrogen ion gradient across the thylakoid membrane allowing for the production of ATP.
 * 3) The electrons cycle back to P700 to keep the process going.

Links:[|video]
 * Homework:**
 * 1) Textbook questions : page 228 #3-6
 * 2) Quiz on Thursday
 * 3) Catalase Lab due Thursday

=Photosynthesis: Calvin Cycle= =Sharyse Bell= =Monday, November 4th, 2013=

Phase 1: Carbon Fixation

 * CO2 is added to Ribulose biphosphate (5C) via the enzyme called Rubisco
 * this big enzyme works slowly
 * most plant enzymes can process around 1000 substrate molecules per second
 * Rubisco does 3 substrates/second
 * therefore to make up for this slow process, the plant needs lots of Rubisco
 * Half of the protein in a leaf = Rubisco
 * the 6C intermediate is very unstable so it splits into two 3C molecules called 3-phosphoglycerate (PGA)
 * Since the final product of this first phase are 3C molecules, the Calvin Cycle is also called C3 photosynthesis
 * C3 plants undergo this form of carbon fixation

Phase 2: Reduction Reactions/Reverse of Glycolysis

 * PGA is phosphorylated via ATP to form 1, 3-bisphosphoglycerate
 * NADPH is used to reduce 1, 3-bisphosphoglycerate to glyceraldehyde 3-phosphate (G3P/PGAL)
 * One G3P (sugar) leaves the Calvin Cycle as a final product per cycle
 * It takes 2 G3P to become glucose or larger sugars

Phase 3: Reforming of RuBP

 * The remaining G3P are rearranged to form RuBP
 * Rubisco is the enzyme that helps with this formation
 * To rearrange G3P, ATP is used
 * With RuBP again, the cycle can continue to fix CO2

Classwork:

 * (5.2 should be read) pg 228 # 8-10
 * read pg 229-230 "Calvin Cycle Journal" & do pg 230 # 1-4

Homework:

 * read section 5.4
 * Catalase lab report due Thursday
 * Quiz on Thursday

=**Alternatives to photosynthesis**=
 * November 11th 2013**
 * Name: Andrew Samuel R**
 * __ C4 __** (due to slow Rubisco these plants need to retain the leaving of CO2)
 * Recall: Rubisco is used for Carbon fixation in Calvin cycle + Isomerization in reduction phase to form 1,5-bisphosphate (RuBP)
 * When [O2] > [CO2], Rubisco oxidizes RuBP instead of fixing it with carbon
 * Oxidation of RuBP= photorespiration
 * When photorespiration occurs, it decreases carbohydrate production (since it is decreasing PGA production in the Calvin Cycle)
 * Optimal temperature for photosynthesis = 15 to 25 ˚C
 * Optimal temperature for Photorespiration=30 to 47 ˚C
 * In normal conditions about 20%= photorespiration
 * In tropical conditions it can rise to 50% ( 50% of Calvin Cycle going each time)
 * In more tropical conditions, plants have evolved to counteract this situation
 * Example of C4 plants are sugarcane and corn

1. Bundle sheath cells around a vein 2. Mesophyll cells around bundle sheath cells (deeper in cell, not as much photorespiration)
 * __Adaptation #1__**
 * They have an enzyme = Phosphoerolpyruvate carboxylase (PEP carboxylase)
 * This enzyme catalyzes to addition of CO2 to 3C molecule (Phoshoenolpyruvate-PEP, traps the CO2) which converts H to a 4C molecule (oxaloacetate-OAA)
 * __Adaptation #2__**
 * Unique leaf anatomy - It has two types of cells

In the mesophyll cell
 * __C4 Plants__**

1) PEP caarboxylase fixes CO2 to phosphoenolpyruvate to form oxaloacetate 2) Oxaloacetate isomerizes and becomes malate 3) Malate diffuses into bundle sheath cells through a connection called Plasmodesmata. During this transition phase, malate is decarboxylated forming pyruvate. This builds up carbon dioxide in the bundle sheath cells.

In the Bundle-Sheath cell 4) Pyruvate diffuses back into the mesophyll cells where it using ATP molecule, it isomerizes back to phosphoenolpyruvate so it can be used again 5) Meanwhile CO2 is used in the Calvin Cycle

These adaptations were favoured in C4 plants (in tropical areas) to keep the concentration of CO2 high in the bundle sheath cells so that CO2 outcompetes O2 when binding to Rubisco (i.e. Photorespiration is minimizes, and photosynthesis is maximized)
 * __ Main Idea: Why do C4 plants have this process? __**


 * __ CAM Plants __**
 * Crassulacean acid metabolism
 * Run the Calvin cycle and C4 cycle in same cells but at different times of the day
 * Live in regions that are hot and dry during the day, but cool at night
 * Ex. Cactus; have fleshy leaves or stems, have low surface-to-volume ratio, and less stomata
 * These plants only open their stomata at night to release the O2 that was accumulated from photosynthesis during the day. They then allow CO2 to enter
 * The CO2 that enters is fixed by a C4 pathway into malate, which accumulates over night and stored in the form of malic acid in cell vacuoles.
 * Daylight initiates the second phase of the CAM process
 * When the sun rises and temperature increases the stomata close, this reduces water loss and cuts off the exchange of gas
 * Malic acid diffuses from cell vacuoles into the cytosol
 * The malate is oxidized to pyruvate and high concentration of CO2 is released
 * High concentration of CO2 favours the carboxylase activity of Rubisco
 * This allows the Calvin Cycle to continue efficiently with little loss of CO2 from photorespiration
 * Pyruvate produced by malate breakdown accumulates during the day, but is converted to malate during the night
 * This requires ATP

Homework: Page 234 #1-9 Catalase Lab due THURSDAY

REMINDER: QUIZ THRUSDAY (includes fermentation, Kreb cycle, glycolysis, up to cellular respiration) DOES NOT INCLUDE PHOTOSYNTHESIS

Name: Andrew Samuel November 11th 2013 = = =*Study Period*=

Catalase Lab due THURSDAY

REMINDER: QUIZ THRUSDAY (includes fermentation, Kreb cycle, glycolysis, up to cellular respiration) DOES NOT INCLUDE PHOTOSYNTHESIS