! Name! !!Section ! Unit%3:%Energy% …3...2!!!! ! chapter 2-8: Energy Flow in Living Things The total amount of energy that exists in the universe remains, constant, but energy can

! Name!__________________________________!!Section__________!Unit%3:%Energy%Reading:)BSCS)Text)Chapter)2.2)–)2.8)!1. Discuss!why!organisms!need!energy!and!how!they!obtain!it.!(2.2)!2. Describe!energy!flow!through!an!ecosystem.!(2.3)!3. Relate!the!first!and!second!laws!of!bioenergetics!to!their!implications!for!living!systems.!(2.4)!4. Explain!how!every!chemical!reaction!involves!either!a!net!absorption!or!net!release!of!energy.!(2.6)!5. Explain!the!role!of!enzymes!in!biochemical!reactions.!(2.6)!6. Explain!how!and!why!enzymes!can!be!affected!by!factors!such!as!temperature!and!pH.!(class!notes)!7. Define!activation!energy!and!describe!how!energy!changes!affect!whether!or!not!a!reaction!will!occur.!

(2.6)!8. Describe!how!chemical!reactions!are!illustrated!by!chemical!equations.!Identify!reactants!and!

products.!(2.7)!9. Distinguish!between!synthesis!and!decomposition!reactions!in!metabolism.!(2.7)!10. Explain!how!chemical!reactions!affect!chemical!bonds!in!reactions.!(2.7)!11. Explain!why!ATP!is!referred!to!as!“the!energy!currency”!of!the!cell.!(2.7)!12. !Summarize!the!importance!of!ATP!in!cellular!energy!transfer.!(2.7)!%Vocabulary%Energy!Heterotroph!Autotroph!Photosynthesis!Cellular!respiration!Decomposer!First!and!second!laws!of!

thermodynamics!Food!web!

Ecosystem!Keystone!species!EnzymeWsubstrate!complex!!Product!ATP/ADP!Metabolism!Endergonic!Exergonic!Activation!energy!

Catalysts!Enzyme!!Substrate!Active!site!Induced!fit!model!Denaturation!Reduction!Oxidatio

!! !LIGHT LIGHT

Simple Organic

Molecules (e.g. PGA)

+ Pi

ATP

Biosynthesis Anabolism Reduction

Endergonic

Degradatior Catabolism Oxidation Exergonic

2!

!!! !

chap te r 2 -8 : Energy Flow in L i v i n g Things The total amount of energy that exists in the universe remains,

constant, but energy can change from one form to another. For example, the chemical energy in gasoline can be released and transformed into heat energy and the energy of motion.

This type of transformation of energy occurs in many of the processes that fake place in living things. In this plate, we will examine the flow of energy through living things and identify the molecule that serves as the main energy source in all life processes.

' sThis plate shows how energy exists in different forms at different times in living things. As you encounter the terms, color the appropriate structures in the dia-

( All of the energy on the Earth comes from the sun (A); the sun's energy (A,) is what drives chemical reactions and the processes of life. This solar energy is trapped in a photosynthesizing organelle of the plant called the chloroplast (B); we discuss this organelle in detail later in the book.

A number of chemical reactions take place in the chloroplast to transform solar energy into chemical energy. Carbon dioxide (C) and water (D) are necessary for the process of photosynthe-sis (E), and the products of photosynthesis include carbohydrates (F), which are represented by a candy bar, and molecular oxy-gen (G). The bonds of the carbohydrates now contain some of the sun's energy; photosynthesis has transformed fhe sun's energy into the chemical energy of the carbohydrate. Oxygen is given off as a waste product of photosynthesis, and it is expelled from the plant cell into the atmosphere.

Having explained how the sun's energy is converted to the chemical energy found in carbohydrates, we \vill jVow, discuss another, transformation of energy Continue your readjhg belofy and focus on the right side of the diagram as we continue to study energy flow in living things

Plants, humans, and many other living things use carbohy-drates as their essential source of energy. Carbohydrates are transported to an organelle called the mitochondrion (H), where they are combined with oxygen molecules in the process of res-piration (I), illustrated by the arrow. During chemical reactions in the mitochondrion,_the energy from carbohydrates is released and used to form the energy-rich molecule adenosine triphos-phate (J). (Adenosine triphosphate is commonly abbreviated as ATP.) Carbon dioxide and water are byproducts of respiration; notice that they are both essential for photosynthesis. To summa-rize, the energy of the sun is first transformed into the energy of carbohydrates and then into the energy in the ATP molecule.

We will conclude with a brief examination of the ATP molecule Recall that the energy ,of the ATP molecule comes from the sun. As you read, color the appro¬

, priate structures in the diagram.

The adenosine triphosphate (ATP) molecule (J) is shown at the bottom of the plate. You should use a light shade to color the inte-rior of the box, and darker colors should be used for the components of ATP. These components include an adenine mole-cule (J,) and a ribose molecule (J2). Adenine is one of the four nitrogenous bases found in DNA and RNA, and ribose is a five-carbon carbohydrate. Attached to the ribose molecule are three phosphate groups (J3).

Living things use energy in the form of ATP, breaking it down into adenosine diphosphate (K) and an inorganic phosphate group. Adenosine diphosphate (ADP) contains adenine (J,) and a ribose molecule (J2), but only two phosphate groups (J3). During this breakdown, seven kilocalories of energy are given off for use by the cell.

In the following plates, we will study the processes by which ATP is created, such as glycolysis, the Krebs cycle, electron trans-port, and chemiosmosis.

The!picture!below!shows!how!energy!exists!in!different!forms!at!different!times!in!living!things.!As!you!encounter!the!terms,!color!the!appropriate!structures!in!the!diagram.!!

Having!explained!how!the!sun’s!energy!is!converted!to!chemical!energy!found!in!carbohydrates,!we!will!now!discuss!another!transformation!of!energy.!!Continue!your!reading!below!and!focus!on!the!right!side!of!the!diagram!aw!we!continue!to!study!energy!flow!in!living!things.!!

We!will!conclude!with!a!brief!examination!of!the!ATP!molecule.!Recall!that!the!energy!of!the!ATP!molecule!comes!from!the!sun.!!As!you!read,!color!the!appropriate!structures!in!the!diagram.!!!

3!

! !

Energy Flow: m CD ~5

CQ

O

< — i .

=5 CQ

Z3 CQ 00

7Kcal Energy

O Sun -.' A O Sun's Energy Ad

O Ch lo rop las t B O Carbon Dioxide C 0-Water , , D

Energy Flow in L i v ing Things O Photosynthesis E O Carbohydrates F O Oxygen G O Mitochondr ion H O Resp i ra t ion I

O Adenosine Triphosphate J O Adenine J :

O Ribose J2

O Phosphate Groups . .J 3

O Adenosine Diphosphate K

4!

!!!!!!!!!!!!!!

!!

!

!

The!Assignment:!!!• Color!and!cut!out!the!animals!from!the!next!page.!Use!them!to!

create!an!aquatic!food!web!using!the!“What!Do!I!Eat?”!chart.!!!• Create!a!food!web!showing!energy!transfer!through!the!aquatic!

ecosystem.!!• This!food!web!does!not!display!any!decomposers…!add!them!in!!!• Answer!the!questions!below!once!your!food!web!is!complete.!!

Analysis!Questions:!!1. What!would!happen!to!your!food!web!if!phytoplankton!died!out!

because!of!water!pollution?!!2. How!would!the!jellyfish!population!be!affected!if!sea!turtles!

were!removed?!!3. How!important!are!plankton!in!the!marine!food!web?!Explain!

your!answer!using!evidence!from!your!food!web.!4. Why!do!we!use!arrows!when!creating!a!food!web?!What!do!they!

represent?!!

!

It’s a Plankton Eat Plankton World Worksheet | http://askabiologist.asu.edu/experiments/plankton | Ask A Biologist 4

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Marine Organisms

It’s a Plankton Eat Plankton World Worksheet | http://askabiologist.asu.edu/experiments/plankton | Ask A Biologist 5

Phytoplankton

Zooplankton

Small fish

Shellfish

Jellyfish

Sea turtle

Large fish

Sea Lion

Sea Bird

Shark

Toothed whale

Baleen whale

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I use energy from sunlight to turn carbon dioxide gas into sugars.

I eat phytoplankton.

I eat zooplankton.

I eat zooplankton.

I eat small fish and zooplankton.

I eat jellyfish and small fish.

I eat small fish.

I eat small fish.

I eat small fish, jellyfish, and shellfish.

I eat small fish, large fish, and sea lions.

I eat small fish, large fish, and sea lions

I eat zooplankton.

# Name What do I eat?

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Objective%6:%What!factors!affect!enzyme!function?!%“Toothpickase”%Enzyme%Model%!The!Object:!!1.!!!Try!to!break!as!many!toothpicks!in!half!as!possible!in!two!minutes.!2.!!!Develop!a!model!for!enzyme!activity.!!!The!Rules:!1.!!Break!toothpicks!only!one!at!a!time.!2.!!Break!toothpicks!with!two!hands.!3.!!Break!toothpicks!completely!in!half.!The!Game:!1.!!Spread!toothpicks!on!table!surface!randomly.!2.!!When!teacher!instructs,!begin!breaking!toothpicks.!!3.!!You!will!stop!and!count!the!number!of!broken!

toothpicks!at:!• 10!seconds!• 30!seconds!• 60!seconds!• 120!seconds!

!!!The!Analysis:!!Answer!the!following!questions!with!your!lab!group.!1.!!!In!this!model,!how!did!we!represent!the:!! A.!!Enzyme!!! B.!!Substrate!!! C.!!Active!Site!!! D.!!Induced!Fit!Model!!!2.!!What!changed!during!the!reaction:!enzyme,!substrate,!or!both?!!Explain.!!!!!!!!!!!! !

Time%(seconds)%

#%of%broken%toothpicks%

Class%average%

0! 0! 0!

10!! ! !

30! ! !

60! ! !

120! ! !

8!

3.!!Create!a!graph!of!the!class!data.!!!

!!!!!!!!!!!!!!!!!!!!!!

!4.!!Calculate!the!rate!of!this!reaction.!(#toothpicks/time)!!!! A.!From!0!–!30!!seconds:!!!! B.!!From!0!–!60!seconds:!!!!! C.!!From!60!–!120!seconds:!!!!5.!Did!the!rate!of!reaction!remain!constant?!Why!do!you!think!this!happened?!!!!6.!!How!could!we!use!our!“toothpickase”!model!to!represent!doubling%the%substrate%concentration%in!an!enzymeWcatalyzed!reaction?!!!!!!6a.!!Sketch!the!graph!you!would!expect!to!see:!!!!!!

Amount!of!product!

9!

7.!How!could!we!use!our!“toothpickase”!model!to!represent!!doubling%the%enzyme%concentration!in!an!enzymeWcatalyzed!!reaction?!!!!!7a.!!Sketch!the!graph!you!would!expect!to!see:!!!!!!8.!!How!could!we!use!our!“toothpickase”!model!to!represent!!decreasing%the%temperature%of!an!enzymeWcatalyzed!!reaction?!!!!!!8a.!!Sketch!the!graph!you!would!expect!to!see:!!!!!!!!9.!!How!could!we!use!our!“toothpickase”!model!to!represent!!denaturing%the%enzyme%in!an!enzymeWcatalyzed!reaction?!!!!!!!9a.!!Sketch!the!graph!you!would!expect!to!see:!!!10.!!How!could!we!use!our!“toothpickase”!model!to!represent!enzymes%saturated%with%substrate%in!an!enzymeWcatalyzed!reaction?!!!10a.!!Sketch!the!graphs!you!would!expect!to!see:!!!!! !

Amount!of!product!

Amount!of!product!

Amount!of!product!

Amount!of!product!

Rate!of!reaction!

10!

Lab:!Factors!Influencing!Enzyme!Activity!%PreJLab%Questions%(Answer!in!your!notebook):%1.!Enzymes!are!proteins.!Review!the!structure!of!proteins.!Describe!the!primary,!secondary,!tertiary,!and!quaternary!structures!of!a!protein.!

!!2.!!What!is!protein!denaturation?!!Why!does!it!occur?!

%%Background%Enzymes!are!biological!catalysts!capable!of!speeding!up!chemical!reactions!by!lowering!activation!energy.!!!In!biochemical!reactions!the!enzyme!combines!reversibly!with!its!specific!substrate!to!form!an!enzymeJsubstrate%complex.!!One!result!of!this!temporary!union!is!a!reduction!in!the!energy!required!to!activate!the!reaction!of!the!substrate!molecules!so!that!the!products!of!the!reaction!are!formed.!!This!can!be!summarized!by!the!equation:!!

Enzyme!+!Substrate(s)!!!EnzymeWSubstrate!Complex!!!Enzyme!+!Product(s)!!

Note!that!the!enzyme!is!not!consumed!in!the!reaction!and!can!recycle!to!work!with!additional!substrate!molecules.!Enzymes!are!a!class!of!protein!molecules.!!Each!enzyme!is!specific!for!a!particular!reaction!because!its!amino!acid!sequence!is!unique,!which!causes!it!to!have!a!unique!3Wdimensional!structure.!The!active%site!is!the!portion!of!the!enzyme!that!interacts!with!the!substrate.!!!

!We!will!be!working!with!the!protein!enzyme%catalase!in!this!lab.!Catalase!contains!4!polypeptide!chains,!each!composed!of!more!than!500!amino!acid!monomers.!This!enzyme!occurs!universally!in!aerobic!organisms.!One!function!of!catalase!within!cells!is!to!prevent!the!accumulation!of!toxic!levels!of!hydrogen!peroxide!(H2O2),!which!is!formed!as!a!byWproduct!of!metabolic!processes.!!!!The!primary!reaction!catalyzed!by!catalase!is!the!decomposition!of!H2O2!to!form!water!and!oxygen:!!

2H2O2!!!2H2O!+!O2!(gas)!!In!the!absence!of!catalase,!this!reaction!occurs,!but!very!slowly.!A!primary!benefit!of!enzymes!is!they!allow!the!cell!to!carry!out!chemical!reactions!quickly!at!a!relatively!low!temperature.!In!this!experiment,!a!rate!for!this!reaction!will!be!determined.!!

Key%Idea:!For!a!reaction!to!occur,!a!substrate!must!come!in!contact!with!(bump!into)!an!enzyme.!!!• Any!factor!that!increases!these!collisions!may!speed!up!the!rate!of!an!enzymatic!reaction.!!!• Any!factor!that!blocks!or!changes!the!shape!of!an!active!site!may!interfere!with!the!enzymatic!reaction.!

!

11!

Much!can!be!learned!about!enzymes!by!studying!the!kinetics!(changes!in!rate)!of!enzymeWcatalyzed!reactions.!The!rate!of!a!chemical!reaction!may!be!studied!in!a!number!of!ways,!including!

A. Measuring!the!rate!of!disappearance!of!substrate,!in!this!example!H2O2.!B. Measuring!the!rate!of!appearance!of!product,!in!this!example!O2,!which!is!given!off!as!a!gas.!!C. Measuring!the!heat!released!or!absorbed!during!the!reaction.!!!!

!Predict:!Which!molecule!(reactant!or!product)!do!you!think!would!be!easiest!to!measure?!!!Materials%All!groups:!!• 50!mL!beaker!containing!catalase!solution!• reaction!chamber!• 10mL!graduated!cylinder!• 100!mL!graduated!cylinder!• 3%!hydrogen!peroxide!(H2O2)!• water!bath!!• transfer!pipette!• timer!

• !Additional!materials:!• hot!plate!• ice!• thermometer!• buffers!of!varying!pH:!4,!7,!10!• balance!• NaCl!(salt)!

!!Lab%Overview%1. Each!lab!group!will!complete!Part!A!of!the!lab.!!(Alternatively,!your!teacher!may!do!Part!A!as!a!

demonstration.)!Your!teacher!will!assign!an!additional!activity!to!each!group!form!Parts!B,!C,!D,!E!&!F.!2. At!your!lab!bench!you!will!find!a!square!bottle!with!a!medicine!dropper!top.!This!is!called!the!reaction!

chamber.!You!will!also!find!a!100mL!graduated!cylinder,!ring!stand!and!clamp,!and!a!plastic!pan!which!will!be!used!as!a!water!bath.!All!of!this!equipment!needs!to!be!assembled!into!our!experimental!apparatus,!as!described!and!illustrated!below.!

3. Fill!the!pan!3/4!full!of!tap!water.!Allow!the!water!to!come!to!room!temperature.!4. Submerge!the!100mLWgraduated!cylinder!to!fill!it!with!water.!Turn!the!graduated!cylinder!upside!down,!

keeping!the!open!end!under!water,!so!as!to!keep!it!filled!with!water.!Suspend!it!upside!down!in!the!clamp!on!the!ring!stand.!Adjust!the!height!of!the!clamp!on!the!ring!stand!so!the!open!end!of!the!graduated!cylinder!is!about!3cm!above!the!bottom!of!the!pan.!See!diagram!below.!

5. Place!a!thermometer!in!the!pan!and!record!the!temperature!of!the!water,!during!Part!A!of!the!lab.!____________________°C!

6. When!all!sections!of!the!lab!are!complete,!share!the!data!with!the!class!from!your!group’s!section.!Each!person!must!plot!the!data!for!all!parts!of!the!lab!on!his/her!own!graph!paper.!

%Procedure!We!will!measure!enzyme!activity!by!measuring!the!generation!of!oxygen!gas!–!a!product!in!the!reaction.!!!!!Day%1:%%Part%A.%Measuring%Enzyme%Activity!1. Sketch!a!prediction:!In!your!notebook,!

create!a!graph!of!what!you!predict!this!data!will!look!like.!!

2. Set!up!the!experimental!apparatus!as!illustrated!and!described!above.!

Name __________________________________ Period _________

Ms. Foglia • AP Biology Date ______________________

4 of 102004-2005

General Lab Procedure:

1. Work as a lab group of 3-4 members. Each lab group will complete Part A and Part B of the

lab. Your teacher will assign on an additional activity to each group form Parts C, D, E & F.

2. At your lab bench you will find a square bottle with a medicine dropper top. This is called the

reaction chamber. You will also find a 100mL graduated cylinder, ring stand and clamp,and a plastic pan which will be used as a water bath. All of this equipment needs to be

assembled into our experimental apparatus, as described and illustrated below.

3. Fill the pan 3/4 full of tap water. Allow the water to come to room temperature.

4. Submerge the 100mL graduated cylinder to fill it with water. Turn the graduated cylinder

upside down, keeping the open end under water, so as to keep it filled with water. Suspend

it upside down in the clamp on the ring stand. Adjust the height of the clamp on the ringstand so the open end of the graduated cylinder is about 3cm above the bottom of the pan.

See diagram below.

5. Place a thermometer in the pan and record the temperature

of the water, during Part A of the lab. ____________________°C

6. When all sections of the lab are complete, share the data with the class from your group’s

section. Each person must plot the data for all parts of the lab on his/her own graph paper.

Catalase Extraction & Filter Paper Disk Instructions

1. Ground fresh liver has been provided for each lab group. It has been ground with water in ablender. Use this mixture to dip your filter paper disks into.

2. Collect paper disks by punching holes in the filter paper provided to you.

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3. Obtain!a!reaction!chamber.!4. Obtain!a!bottle!of!3%!hydrogen!peroxide!(H2O2)!solution!and!a!10mLWgraduated!cylinder.!5. Obtain!a!small!amount!of!stock!catalase!(yeast)!solution!in!a!50mL!beaker.!You!will!need!1.0mL!of!yeast!

solution!for!each!trial.!When!you!are!ready,!you!will!add!it!to!the!vial!with!a!plastic!pipette.!6. Pour!10mL!of!hydrogen!peroxide!(H2O2)!into!the!reaction!chamber.!Pipette!in!1.0mL!of!stock!catalase!

solution!(yeast!solution)!and!IMMEDIATELY!stopper!the!reaction!chamber!tightly,!submerge!it!in!the!water!bath!and!place!the!plastic!tubing!into!the!bottom!of!the!graduated!cylinder,!so!all!the!bubbles!formed!in!the!reaction!chamber!are!captured!by!the!inverted!graduated!cylinder.!

7. Measure!the!gas!levels!in!the!graduated!cylinder!at!30Wsecond!intervals!for!5!minutes.!Record!the!levels!in!a!data!table!of!your!own!design.!

8. Plot!the!data!on!a!graph.!Don’t!forget!to!label!your!axes!and!title!your!graph.!!

Day%1%Homework:%%1.!!Create a graph of the class data. Make sure your axes are labeled and include a descriptive title. Remember -

the independent variable goes on the X-axis and the dependent variable goes on the Y-axis. 2. Sketch a prediction for each condition that will be tested tomorrow (Procedures B – F).

!Day%2:%%Investigating%Enzyme%Activity%Under%a%Variety%of%Conditions%Each)lab)group)will)conduct)one)of)the)following)experiments.))Class)data)will)be)shared)at)the)end)of)the)period.)))Before)you)begin:)Brainstorm outside factors that might affect your results regarding the amount of bubbles produced.

These factors are known as confounding factors. Explain how each of those factors is controlled in the current procedure or change the procedure so that it is controlled. The first one was done for you as an example. )

Variable How the procedure minimizes or eliminates this variable

The amount of catalase on the disk

Hold every disk in the solution for only 4 seconds, and then use the “touch and hold” procedure 2 times per disk side to drain excess solution.

Continue in your notebook with as many rows as needed.

!!Part%B.%The%Effect%of%Enzyme%Concentration%on%Enzyme%Activity%1. Repeat!the!experiment!from!Part!A!using!3!different!levels!of!enzyme!concentration:!75%,!50%,!and!25%!

concentration!of!enzyme!solution.!You!may!easily!do!this!by!using!the!following!procedures:!a. 75%!concentration:!Follow!the!procedure!from!Part!A,!but!use!0.75mL!catalase!solution!in!the!reaction!

chamber,!instead!of!1.0mL.!b. 50%!concentration:!Follow!the!procedure!from!Part!A,!but!use!0.50mL!catalase!solution!in!the!reaction!

chamber,!instead!of!1.0mL.!c. 25%!concentration:!Follow!the!procedure!from!Part!A,!but!use!0.25mL!catalase!solution!in!the!reaction!

chamber,!instead!of!1.0mL.!2. Repeat.!Conduct!a!total!of!3!trials.!3. Record!all!data!in!a!data!table!of!your!own!design.!4. Plot!this!data!and!the!data!from!part!A!on!the!same!graph.!!!Part%C.%The%Effect%of%Temperature%on%Enzyme%Activity%1. Repeat!the!experiment!from!Part!A!(5!minute!runs!with!1mL!catalase!solution),!using!3!different!

temperatures:!5°C,!37°C,!and!100°C!(boiled!catalase).!You!may!easily!do!this!by!using!the!following!procedures:!a. 5°C:!Set!up!your!reaction!vessel!and!water!bath!and!add!ice!to!the!water!bath!so!that!it!is!chilled!to!5°C!for!

5!minutes!before!running!the!experiment.!Keep!adding!ice!to!keep!the!temperature!at!5°C!or!colder.!b. 37°C:!Set!up!your!reaction!vessel!and!water!bath!with!heated!water!so!that!it!is!warmed!to!37°C!for!5!

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minutes!before!running!the!experiment.!Keep!adding!hot!water!to!keep!the!temperature!at!37°C.!c. 100°C!(boiled!catalase):!We!can’t!use!a!water!bath!of!boiling!water!since!that!may!injure!a!student,!so!

instead!of!keeping!the!reaction!vessel!in!boiling!water!during!the!experiment,!we!will!instead!boil!the!catalase!solution!for!5!minutes.!Then!after!the!catalase!solution!has!cooled!you!run!the!experiment!in!room!temperature!water!(but!with!already!boiled!catalase).!!!

2. Repeat.!Conduct!a!total!of!3!trials.!3. Record!all!data!in!a!data!table!of!your!own!design.!4. Plot!this!data!and!the!data!from!part!A!on!the!same!graph.!!Part%D.%The%Effect%of%pH%on%Enzyme%Activity%1. Repeat!the!experiment!from!Part!A!(5!minute!runs!with!1mL!catalase!solution),!using!3!different!hydrogen!

peroxide!solutions!at!3!different!pH!values:!pH!4,!pH!7,!and!pH!10.!You!may!easily!do!this!by!using!the!following!procedures!a. pH!4:!Make!a!1.5%!solution!of!H2O2!at!pH4!by!adding!5mL!of!H2O2!to!5mL!of!pH!4!buffer.!b. pH!7:!Make!a!1.5%!solution!of!H2O2!at!pH7!by!adding!5mL!of!H2O2!to!5mL!of!pH!7!buffer.!c. pH!10:!Make!a!1.5%!solution!of!H2O2!at!pH10!by!adding!5mL!of!H2O2!to!5mL!of!pH!10!buffer.!

2. Repeat.!Conduct!a!total!of!3!trials.!3. Record!all!data!in!a!data!table!of!your!own!design.!4. Plot!this!data!and!the!data!from!part!A!on!the!same!graph.!!Part%E.%The%Effect%of%Substrate%Concentration%on%Enzyme%Activity%1. Repeat!the!experiment!from!Part!A!(5!minute!runs!with!1mL!catalase!solution),!using!4!different!substrate!

concentrations:!0%,!0.3%,!1.5%,!and!3.0%.!You!may!easily!do!this!by!using!the!following!procedures!a. 0%:!Use!10mL!distilled!water!only.!b. 0.3%:!Prepare!this!by!adding!3mL!of!H2O2!to!7mL!of!distilled!water.!c. 1.5%:!Prepare!this!by!adding!5mL!of!H2O2!to!5mL!of!distilled!water.!d. 3.0%:!This!is!the!concentration!of!substrate!from!the!original!experiment!in!Part!A;!just!use!this!initial!

data.!2. Repeat.!Conduct!a!total!of!3!trials.!3. Record!all!data!in!a!data!table!of!your!own!design.!4. Plot!this!data!and!the!data!from!part!A!on!the!same!graph.!!Part%F.%The%Effect%of%Ionic%Concentration%on%Enzyme%Activity%1. Repeat!the!experiment!from!Part!A!(5!minute!runs!with!1mL!catalase!solution),!using!3!different!ionic!

concentrations:!10%!NaCl,!2%!NaCl,!and!0%!NaCl.!You!may!easily!do!this!by!using!the!following!procedures:!a. 10%!NaCl:!Make!a!1.5%!solution!of!H2O2!containing!10%!NaCl!by!dissolving!5g!of!NaCl!in!50mL!of!

water!then!add!5mL!of!this!solution!to!5mL!of!H2O2.!b. 2%!NaCl:!Make!a!1.5%!solution!of!H2O2!containing!2%!NaCl!by!dissolving!1g!of!NaCl!in!50mL!of!water!

then!add!5mL!of!this!solution!to!5mL!of!H2O2.!c. 0%!NaCl:!Prepare!this!by!adding!5mL!of!distilled!water!to!5mL!of!H2O2.!

2. Repeat.!Conduct!a!total!of!3!trials.!3. Record!all!data!in!a!data!table!of!your!own!design.!4. Plot!this!data!and!the!data!from!part!A!on!the!same!graph.!%Lab%WriteJup%Expectations!You!will!submit!a!formal!lab!report!describing!this!experiment.!!Be!sure!to!reference!your!lab!report!format!for!the!requirements!of!each!section.!Specific!details!are!given!below!to!help!you!write!your!analysis!section.!(Helpful!hint:!Many!of!these!same!topics!should!be!addressed!in!your!introduction!section.)!!

1. What are enzymes and what do they do? How do they work? (be specific) (1 pt) 2. What is catalase? Where is it normally found? What reaction does it affect? What is its substrate? (1 pt)

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3. We measured the rate of enzyme activity through the amount of gas exiting the reaction chamber. Why was this a good measure of catalase activity? In other words, what do bubbles have to do with enzyme speed? (1 pt)

4. Examine Graph A. a) What!is!the!rate!of!this!enzymatic!reaction!during!the!first!10!seconds?!(Show!calculations.)!b) What!is!the!rate!after!4!minutes?!(Show!calculations.)!c) Why!is!the!rate!after!4!minutes!different!from!the!initial!rate?!

For Every Experiment (B – F): 5. a. Look back at the original predictions you made. Make a conclusion – were your predictions correct or not?

NEVER use the word “prove”…you didn’t prove anything from one experiment… Also, to say that your results are “inconclusive” is OK. Do not exaggerate the clarity of your findings. (1 pt) b. Support your conclusion by analyzing data. Refer to specific data in this answer. (2 pt)

6. Provide possible BIOCHEMICAL explanations as to why you observed the trends you did. Your explanations should reveal your knowledge of biochemistry, tertiary structure, hydrogen bonding, enzyme structure, etc.

7. Draw!an!idealized!graph!to!illustrate!the!relationship!between!each!independent!variable!and!enzyme!activity!(5!graphs!total).!!For!each!graph!explain!why!you!would!see!this!trend!in!data.!

8. What!are!the!optimal!conditions!for!catalase?!!Do!all!enzymes!have!the!same!optimal!conditions?!Explain!your!answer.!

!For!Any!ONE!Experiment:!!9. Error analysis:

a) Look at your tables and pick one trial that is different from the other trials of the same treatment. This is called an outlier. Explain what makes that one trial an outlier. Refer to specific numbers in your data. (1 pt)

b) Identify two sources of error that alone or separately could explain why that trial turned out so differently. There should be one complete paragraph per error. Use the following guidelines: (3 pt)

" “Contamination” is not a good error; neither is dust or being more careful. Your errors should reveal your understanding of the process and the apparatus.

" You must identify problems with the procedure – things that you tried to control, but couldn’t or things you didn’t think to control, but should have.

" When you identify your two errors, you must connect each error directly back to your outlier. Don’t just say “it would have affected the data.” You must explain why it increased or decreased the oxygen production in that one trial (and only that one trial).

c) Why did we do 3 trials for every treatment? (1 pt)

15!%ATP— The Free Energy Carrier 1

ATP—The Free Energy CarrierHow does the ATP molecule capture, store, and release energy?

Why?A sporting goods store might accept a $100 bill for the purchase of a bicycle, but the corner store will not take a $100 bill when you buy a package of gum. That is why people often carry smaller denominations in their wallet—it makes everyday transactions easier. The same concept is true for the energy transactions in cells. Cells need energy (their “currency”) to take care of everyday functions, and they need it in many denominations. As humans we eat food for energy, but food molecules provide too much energy for our cells to use all at once. For quick cellular transactions, your cells store energy in the small molecule of ATP. This is analogous to a $1 bill for your cells’ daily activities.

Model 1 – Adenosine Triphosphate (ATP)

N

NN

N OCH2 O P O–

O–

O

NH2

OH OH

O P

O–

O

O P

O–

O

1. The diagram of ATP in Model 1 has three parts. Use your knowledge of biomolecules to label the molecule with an “adenine” section, a “ribose sugar” section, and a “phosphate groups” section.

2. Refer to Model 1.

a. What is meant by the “tri-” in the name adenosine triphosphate?

b. Discuss with your group what the structure of adenosine diphosphate (ADP) might look like. Draw or describe your conclusions.

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% %

2 POGIL™ Activities for AP* Biology

Model 2 – Hydrolysis of ATP

N

NN

N OCH2 O P O P O P O–

O O O

NH2

OH OH

H2O

N

NN

N OCH2 O P O P OH

O O

NH2

OH OH

+ HO P O–

O–O–O–O–O–O–

O

3. Model 2 illustrates a chemical reaction. Write the reaction as an equation, using the name or abbreviation of each of the two reactants and each of the three products.

4. Consider the structural formulas of ATP, ADP, and phosphate in Model 2 carefully. What happens to the atoms from the water molecule during the hydrolysis of ATP?

5. The word hydrolysis has two roots, hydro and lysis. Describe how this term relates to the chemi-cal reaction illustrated in Model 2.

6. Refer to Model 2.

a. Does the hydrolysis of ATP result in a net output, or a net input of energy?

b. Which molecule, ATP or ADP, has a higher potential energy? Explain your reasoning.

Energy

InorganicPhosphate

(Pi)

17!

% %

ATP— The Free Energy Carrier 3

7. Consider Model 2.

a. Is the process endothermic or exothermic?

b. Recall that all bonds require energy to break, but energy is released when bonds are formed. With this in mind, explain why it is incorrect to say that the phosphoester bond in ATP releases a large amount of energy when ATP turns into ADP.

Read This!The conversion of ATP to ADP is not only exothermic, but there is also an increase in entropy of the system. Therefore, the hydrolysis of ATP is exergonic, and provides free energy for many processes needed to sustain life.

8. The reaction in Model 2 is reversible.

a. Write a reaction for the process that is the reverse of Model 1.

b. This reaction is called phosphorylation. Explain why this name is appropriate for the reac-tion above.

c. Would you expect this reaction to be endergonic or exergonic? Explain your reasoning.

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% %4 POGIL™ Activities for AP* Biology

Model 3 – The ATP Cycle

ATP+ water

ADP+ phosphate

Energy Energy Respirationor photosynthesis

Cellular processes such as muscle contraction,

protein synthesis,cell division, etc.

9. Label the two large arrows in Model 3 with “hydrolysis” and “phosphorylation.” 9. Label the two large arrows in Model 3 with “hydrolysis” and “phosphorylation.” 9. Label the two large arrows in Model 3 with “hydrolysis” and “phosphorylation.”

10. When ATP is hydrolyzed, free energy is available.

a. According to Model 3, what does that energy get used for?

b. Name at least two other cellular processes that could be fueled by the hydrolysis of ATP that are not listed in Model 3.

11. After it is used, an ADP molecule is recycled back into ATP. What cellular, exergonic processes supply the energy needed for the phosphorylation of ADP?

12. In the Why? box at the start of this activity, an analogy was made between money and cellular energy.

a. What part(s) of the ATP cycle are analogous to earning money?

b What part(s) of the ATP cycle are analogous to spending money?

c. What would be analogous to saving money in the context of ATP?

19!%ATP— The Free Energy Carrier 5

Extension Questions13. Describe or draw a diagram of adenosine monophosphate (AMP).

14. If ADP were to be hydrolyzed in a similar manner to ATP, would you expect the reaction to be endergonic or exergonic? Explain your answer.

Read This!It is estimated that more than 2 × 1026 molecules of ATP are hydrolyzed in the human body daily. If each molecule was used only once you would need approximately 160 kg (350 lbs) of ATP daily. The repeated use of ATP molecules through the ATP cycle saves the body a huge amount of resources and energy.

ATP is synthesized in two ways:

Substrate-level phosphorylation—Energy released during a reaction, such as the breakdown of sugar molecules, is used directly to synthesize ATP. A small amount of energy is generated through this process.

Electron transfer (oxidative phosphorylation)—Energy from the movement of electrons from one molecule to another, via electron carriers, is used to synthesize ATP. Most cellular ATP is synthesized by electron transfer in the mitochondria.

15. Dinitrophenol (DNP) is an “uncoupler,” which means it interferes with the flow of electrons during electron transfer. Fifty years ago, DNP was given as a drug to help patients lose weight.

a. Why would taking DNP make someone lose weight?

b. Why would taking DNP be dangerous?

20!

Energy%Practice%problems%%Energy%Transfer%in%an%Ecosystem%%Part%A%–%Answer!the!questions!using!the!diagram!to!the!right.!!1.!!How!many!food!chains!make!up!the!food!web?!!2.!!Which!organism!is!an!herbivore?!3.!!Which!organism!is!an!autotroph?!4.!!Which!organism!is!an!omnivore?!5.!!Which!organism!is!a!tertiary!consumer?!!6.!!Finish!the!web:!Draw!in!arrows!showing!how!the!organisms!on!the!diagram!relate!to!the!decomposer.!!Summarize!your!answer.!!!

%%

%Part%B%–%Use!the!food!web!below!to!fill!in!the!table.!!List!all!organisms!as!autotrophs!or!heterotrophs!in!the!first!two!columns.!In!the!third!columns,!state!whether!each!heterotroph!is!a!primary,!secondary,!or!tertiary!consumer.!(Note:!If!an!organism!fits!into!more!than!one!category,!list!only!the!highest!order.!!!% %

Decomposer%

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Chemical%Reactions%

1. During a chemical reaction, bonds are ________________________.

2. Protein catalysts, or enzymes, act by lowering the ____________________ required for a reaction.

3. The reactants (starting molecules) of an enzyme-catalyzed reaction are known as _______________.

4. According to the induced fit hypothesis of enzyme catalysis, _____.

a. the binding of the substrate depends on the shape of the active site b. some enzymes change their structure when activators bind to the enzyme c. the binding of the substrate changes the shape of the enzyme's active site d. the active site creates a microenvironment ideal for the reaction

5. In the figure below, why does the reaction rate plateau at higher reactant concentrations?

6. Which graph (I or II) shows the reaction that absorbs energy?

7. Why are two pathways shown in graph II? What does line C represent?

Graph!I! Graph!II!

Rate of an enzyme-catalyzed reaction. (Note: enzyme concentration is constant.) !

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The following questions are based on the reaction A + B ! C + D shown in the accompanying figure.

8. In this reaction, the substrates are (A, B, C or D) _____________ and the products are (A, B, C or D)

__________.

9. Which has a higher free energy, the substrates or the products? ________________.

a. Is this reaction endergonic or exergonic?

Match the arrow on the diagram to the concept it represents. Which arrow represents the …

10. Activation energy required when no enzymes are present? ____

11. Activation energy required for the enzyme-catalyzed reaction in the figure? ____

12. Total energy given off during the reaction? ____

13. Which arrow in the figure would be the same in an enzyme-catalyzed and a non-catalyzed reaction? ____ The graph below shows enzyme activity at varying temperatures.

14. Describe what is meant by optimal temperature for enzyme activity.

15. Explain why most enzymes perform poorly at low temperatures.

The graph below shows enzyme activity at varying pH levels.

16. State the optimum pH for each of the enzymes: Pepsin: __________ Trypsin: __________ Amylase: __________

17. Pepsin acts on proteins in the stomach. Explain

how its optimum pH is suited to its working environment.

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18. The diagram below shows the structure of ATP.

a. Label the high-energy bonds.

b. Circle the portion of the molecule that makes up ADP.

c. ATP is a derivative of which type of monomer? ______________________

19. How does ATP enable the cell to store and transfer energy?

20. In which cellular organelle is ATP produced? _____________________ a. What is the name of the process by which ATP is produced? __________________

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Induced Fit Model of Enzyme Activity !

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! Name! !!Section ! Unit%3:%Energy% …3...2!!!! ! chapter 2-8: Energy Flow in Living Things The total amount of energy that exists in the universe remains, constant, but energy can

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