Dispatch Give 3 facts about enzymes What does denature mean? How are we going to denature our enzyme?

Announcements Next test Chapters 2-7. POK or chapter notes Pick up your grade report at lunch TODAY Meeting today after school so office hours after school tomorrow To redo Ecology POK, turn in chapter notes

Take out prelab

Denaturing Enzymes

Enzymes are proteins. Proteins are chains of amino acids.

Denature=weaken or kill an enzyme by breaking the amino acid bonds. When an enzyme is denatured, it slowly turns substrate to product or not at all.

What can cause an enzyme to denature? Animation http://www.biotopics.co.uk/other/aninac.html What can cause an enzyme to denature?

Enzyme: Catalase REACTANT H2O2 PRODUCTS O2 H20 What is the equation of this reaction?

http://bioweb.wku.edu/courses/Biol114/enzyme/enzyme2.asp

Denaturing Enzyme Temperature--Each enzyme has an optimum temperature at which it works best; making the enzyme too hot or too cold will denature it.

Denaturing Enzyme The pH--Each enzyme has an optimal pH that helps maintain its three-dimensional shape; making the enzyme too acidic or basic will denature it.

Base Acid

Denaturing Enzyme The salt concentration--Each enzyme has an optimal salt concentration; making the enzyme too salty will denature it.

Your job is to denature an enzyme in the lab and measure its rate of turning a substrate into a product.

H202 Catalase Water Oxygen Gas

Catalase Lab pg 53 Chicken liver has the enzyme catalase. The substrate is hydrogen peroxide (H2O2). The products are water (H2O) and oxygen gas (O2). catalase 2H2O2----------------------> 2H2O + O2

Materials: 5 test tubes 1 test tube rack 50 ml of catalase 1 ml lemon juice (acid) 1 teaspoon of salt 25 ml of H2O2

Control Hot Cold Acid Salt (Temperature) (pH)

Procedures pg 53 (cont) Copy and draw each step 1. Label 5 test tubes: Control, Hot, Cold, Acid, Salt 2. Place 10 cm of catalase (enzyme) into each test tube. 3. Make 3 hypothesis, one for temperature, one for pH, and one for salt. If_____________then If _____________then 4. Place the test tube labeled temperature in the hot water bath for 3 minutes. 5. Place the test tube labeled cold in the cold water bath for 3 minutes and the test tube labeled room temperature leave in the test tube rack. 6. Add 1ml of lemon juice to the one labeled acid. 7. Add 1 ml of salt to the one labeled salt. Get approval. 8. Add 5ml of H2O2 (substrate) to each of the 5 tubes. 9. Time the reaction with the stop watch and record the height of the bubbles in each tube in cm. Record in Data Table.

Laboratory Safety

T-1-- Lab Room 7 8 6 2 5 1

BEFORE THE LAB

Dress properly during a laboratory activity. Long hair, dangling jewelry, and loose or baggy clothing are a hazard in the laboratory.  Long hair must be tied back, and dangling jewelry and baggy clothing must be secured.  Shoes must completely cover the foot.  No sandals allowed on lab days.

Which shoe is appropriate?

Don’t touch, until told When first entering a science room, do not touch any equipment, chemicals, or other materials in the laboratory area until you are instructed to do so.

Where’s the safety equipment? Know the locations and operating procedures of all safety equipment including: first aid kit(s), and fire extinguisher.  Know where the fire alarm and the exits are located.

T-1: Fire Extinguiser is by the door, first aid is by the whiteboard

No food Do not eat food, drink beverages, or chew gum in the laboratory.  Do not use laboratory glassware as containers for food or beverages.

Know the directions Follow ALL written and verbal instructions carefully. If you do not understand a direction or a part of the procedure, ASK YOUR TEACHER BEFORE PROCEEDING WITH THE ACTIVITY!

Before the Lab—Answer in complete sentences 1) How do we dress for a lab? 2) What is the rule about food and gum? 3) Can you touch equipment before being told?

During the Lab

Be responsible Conduct yourself in a responsible manner at all times in the laboratory.

Work together Never work alone in the laboratory. No student may work in the science classroom without the presence of a teacher.

Authorized experiments only! Perform only those experiments authorized by your teacher. Carefully follow all instructions, both written and oral. Unauthorized experiments are not allowed.

Be preapred Be prepared for your work in the laboratory.  Read all procedures thoroughly before entering the laboratory.  Never fool around in the laboratory.  Horseplay, practical jokes, and pranks are dangerous and prohibited.

Keep your area organized Observe good housekeeping practices.  Work areas should be kept clean and tidy at all times.

Don’t wander Experiments must be personally monitored at all times.  Do not wander around the room, distract other students, startle other students or interfere with the laboratory experiments of others.

Goggles on at all times Any time chemicals, heat, or glassware are used, students will wear safety goggles. NO EXCEPTIONS TO THIS RULE

Ask for help If you do not understand how to use a piece of equipment, ASK THE TEACHER FOR HELP!

If there is a problem…

YELL FOR HELP If you or your lab partner is hurt, immediately (and loudly) yell out the teacher's name to get the teacher's attention.  Do not panic.

USE the eye wash If a chemical should splash in your eye(s) or on your skin, immediately flush with running water for at least 20 minutes.  Immediately (and loudly) yell out the teacher's name to get the teacher's attention. 

Notify of dangerous hazards Be alert and proceed with caution at all times in the laboratory.  Notify the teacher immediately of any unsafe conditions you observe

Report accidents or injuries Report any accident (spill, breakage, etc.) or injury (cut, burn, etc.) to the teacher immediately, no matter how trivial it seems.  Do not panic.

T-1: Fire Extinguiser is by the door, first aid is by the whiteboard

Know what to do in a drill Know what to do if there is a fire drill during a laboratory period; containers must be closed, and any electrical equipment turned off

If there is a problem… 1) What should you do if someone is injured? 2) Where is the first aid located? 3) What do you do if something gets in your eyes?

FOR GLASSWARE

Use clean, unbroken glassware Examine glassware before each use.  Never use chipped, cracked, or dirty glassware.

Don’t touch broken glass Never handle broken glass with your bare hands.  Tell the teacher immediately, the teacher will clean it up.

Do not immerse hot glassware in cold water. The glassware may shatter. Nothing hot in the sink Do not immerse hot glassware in cold water.  The glassware may shatter.

Be careful with the hot plate Do not operate a hot plate by yourself.  Take care that hair, clothing, and hands are a safe distance from the hot plate at all times.  Use of hot plate is only allowed in the presence of the teacher.

Use tongs for hot items Heated glassware remain very hot for a long time.  They should be set aside in a designated place to cool, and picked up with caution.  Use tongs or heat protective gloves if necessary.

Don’t watch a boiling test tube Never look into a container that is being heated.

Don’t touch hot plates or test tubes Do not place hot apparatus directly on the laboratory desk.  Always use an insulated pad.  Allow plenty of time for hot apparatus to cool before touching it.

ALWAYS think before you do something!!!! Always use your brain ALWAYS think before you do something!!!!

For glassware What things can happen to glassware that you should be aware of? How should you touch glassware that has been on the hot plate? Why shouldn’t you look at a boiling test tube?

CLEANING UP

Wash your hands Keep hands away from face, eyes, mouth, and body while using chemicals or lab equipment.  Wash your hands with soap and water after performing all experiments.

Dispose of chemicals Dispose of chemicals in waste containers, not down the sink

Cleaning What do you do with the chemicals that you have finished with? 2) What should you do before you leave the lab?

Get dressed Gloves Aprons