BIOLOGY CATALYST- FRIDAY, 12/20/13 – PERIOD 3

1. EMAIL ME YOUR LAB REPORT (gutierrezbr@elizabeth.k12.nj.us) p3 Subject. Save File As “LastName.FirstName.StepUpLabReport” during the first 5 minutes of class.

BIOLOGY AGENDA 12/20/13

• Catalyst

• Announcements

• Study all topics that have been covered. You will have a unit test on homeostasis next week

• Acids, bases, and pH Discussion

• Homeostasis Disturbance Project

DISTURBING HOMEOSTASIS – DUE JANUARY 3RDAssume the role of a healthcare provider (physician, nurse, health educator, etc.) whose job is to educate today’s youth on a cardiovascular, respiratory, or renal disease. Create one of the following to inform today’s youth on the disease, what type of treatment is available, and what lifestyle changes they can adopt to prevent this disease. Know your audience (young folks like yourselves) so figure out a way to catch your peers’ attention!

• Brochure

• Commercial

• Pamphlet

• Poster

• Other? ( must be approved by teacher)

YOUR PRODUCT MUST INCLUDE• Normal physiology

• Pathophysiology

• How body responds to disease • Be sure to mention HOW homeostasis is

disrupted• Risk Factors

• Treatment Options

• Prevention Tips

• Include visual aids and a works cited page

EVALUATION CRITERIA

1. Creativity (50 points)

2. Scientific Accuracy (100 points)

3. Organization and Neatness (50 points)

4. Includes all required elements (50 points)

GPOINTS

P3:

P7:

Your class can earn class points if:

everyone in class:

Comes to class quietly and on time

Stays focused and on task during class

Leaves classroom neat and organized

Students are teaching other students

Majority of class participates

Follows all classroom expectations and procedures

And more…

OBJECTIVES 12/19/13

We will be able to

1. Compare and contrast characteristics of acids and bases

2. Describe the pH scale

3. Explain the importance of maintaining acid-base homeostasis

WHAT ARE ACIDS AND BASES?

BRAINPOP VIDEO – PERIOD 3

http://www.brainpop.com/science/matterandchemistry/phscale/

Pay close attention. Take notes if you’d like.

ACIDS, BASES, AND PH

The separation of water molecules into ions causes solutions to be acidic, basic, or neutral.

The pH scale measures how acidic or basic a solution is.

• pH of 7—Neutral: Equal concentrations of H+ and OH-

• pH below 7—Acidic: Relatively high concentration of H+

• pH above 7—Basic: Relatively high concentration of OH-

ON ACIDS…AN ACID IS A SUBSTANCE THAT IONIZES IN WATER TO GIVE HYDROGEN IONS (H+)

Arrehenius Theory

ON BASES…A BASE IS A SUBSTANCE THAT IONIZES IN WATER TO GIVE HYDROXIDE IONS (OH-)

Arrehenius Theory

AN EXAMPLE OF THE REACTION OF HYDROCHLORIC ACID:

When the HCl breaks apart the free H+

is attracted to the H2O and forms a HYDRONIUM ION

HCl + H2O H3O+ + Cl-

SO WHO IS THE ARRHENIUS ACID GIVEN:

HCl

HCl + H2O H3O+ + Cl-

Why?Because it produces H+

AN EXAMPLE OF THE REACTION OF POTASSIUM HYDROXIDE:

When the KOH breaks apart it forms the HYDROXIDE

ION (OH-)

KOH + H2O K+ + 2OH-

SO WHO IS THE ARRHENIUS BASE GIVEN:

KOHKOH + H2O K+ + 2OH-

Why?Because it produces OH-

WHY CARE ABOUT ACIDS AND BASES?

1. Acid Rain –

1. Changing the pH of lakes and stream waters can affect aquatic life

2. Damages trees and building

2. Respiration Rates are regulated by pH of blood

CHARACTERISTICS OF ACIDS• Taste Sour

• Affect indicators (red=acid)

• Neutralize Bases

• Often produce hydrogen gas

• pH between 0 and <7

EXAMPLES OF ACIDS

HCl, hydrochloric acid CH3COOH, acetic acid

CHARACTERISTICS OF BASES

• Taste Bitter

• Feel Slippery

• Neutralize Acids (Antacids)

• Affect indicators (base=blue)

• pH between >7 and 14

• Dissolve grease (Drano, Windex)

EXAMPLES OF ACIDS

• HCl• H2SO4

• HNO3

• HF• Juices

REAL LIFE EXAMPLES OF BASES

NaOH, sodium hydroxide

NH4+, ammonia CaCO3,

calcium carbonate

PH TELLS YOU HOW ACIDIC A COMPOUND IS

PH SCALE

PH SCALE

WHY IS IT IMPORTANT FOR OUR BODY TO MAINTAIN PH?\

PH LAB OVERVIEW

Part A

• Testing the pH of common household products

Part B

• Systematically Increasing/Decreasing the Acidity of a Liquid

PROTOCOL

At this time, carefully read pages 184 – 188.

Summarize the “NEED TO KNOW” Background on Buffers found on page 188.

PRE-LAB INSTRUCTIONS

1. IN YOUR LAB NOTEBOOK, create a table that looks like the following:

Substance Predicted pH Actual pH

Lemon Juice

Dishwashing Soap

Baking Soda

Shampoo

Vinegar???

PRE-LAB INSTRUCTIONS

2. Using the graph paper provided, create a graph similar to that on page 186. (Figure 5.9)

• Use a ruler if you need to

PRE-LAB INSTRUCTIONS

3. Create a table that looks like the one on page 187. (figure 5.10)

LAB COMMENTS

• Only the sink by my desk will work. BE CAREFUL WHEN TURNING IT ON.

• Read the labels VERY carefully.

LAB SAFETY PRECAUTIONS

GOGGLES AND GLOVES MUST BE WORN AT ALL TIMES!

THE RESPIRATORY SYSTEM

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This “air-blood barrier” (the respiratory membrane) is where gas exchange occurs

• Oxygen diffuses from air in alveolus (singular of alveoli) to blood in capillary

• Carbon dioxide diffuses from the blood in

the capillary into the air inthe alveolus

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MICROSCOPIC DETAIL OF ALVEOLIAlveoli surrounded by fine elastic fibersAlveoli interconnect via alveolar poresAlveolar macrophages – free floating “dust cells”Note type I and type II cells and joint membrane

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LUNGS AND PLEURA

Pleural cavity – slit-like potential space filled with pleural fluid

Lungs can slide but separation from pleura is resisted (like film between 2 plates of glass)

Lungs cling to thoracic wall and are forced to expand and recoil as volume of thoracic cavity changes during breathing

Around each lung is a flattened sac of serous membrane called pleura

Parietal pleura – outer layerVisceral pleura – directly on lung

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NEURAL CONTROL OF VENTILATIONReticular formation in medulla

• Responsible for basic rate and rhythm• Can be modified by higher centers

• Limbic system and hypothalamus, e.g. gasp with certain emotions

• Cerebral cortex – conscious control

Chemoreceptors • Central – in the medulla• Peripheral: see next slide

• Aortic bodies on the aortic arch• Carotid bodies at the fork of the carotid artery: monitor O2 and

CO2 tension in the blood and help regulate respiratory rate and depth

The carotid sinus (dilated area near fork) helps regulate blood pressure and can affect the rate (stimulation during carotid massage can slow an abnormally fast heart rate)

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PERIPHERAL CHEMORECEPTORS REGULATING RESPIRATION

Aortic bodies*

• On aorta• Send sensory info to medulla

through X (vagus n)

Carotid bodies+• At fork of common carotid

artery• Send info mainly through IX

(glossopharyngeal n)

*

+

Respiration gas exchange pathway

1. Ventilation2. Diffusion between gas and blood3. Circulation4. Diffusion between blood and cells

Overview: Major functions - Uptake of O2, loss of CO2

Overall gas exchange consists of 4 steps in series:

nose

mouth

larynx

lung

right bronchus

diaphragm

pharynx

trachea

left bronchus

bronchiole

alveoli

Oxygen binds to the iron atom in hemoglobin that is in the ferrous (Fe2+) form. Each Hb molecule has 4 iron atoms and

they bind oxygen cooperatively; i.e., binding of the first increases the affinity of the second, etc.

CO2 reactions in the tissues

Important points:CO2 reactions in tissues

Only a small fraction of added CO2 is carried as dissolved CO2 even thought CO2 is 20-30 x more soluble than O2

Most reactions occur within RBC because of presence of hemoglobin and carbonic anhydrase.

Conversion of CO2 to bicarbonate (HCO3

-facilitated by hemoglobin buffering of H+ and by export of HCO3

- to plasma in exchange for Cl-

(the Chloride Shift).

Most CO2 carried finally as plasma HCO3

- even though the reactions occur primarily within the RBCs.

Note: Loss of O2 from hemoglobin cause CO2 curve to shift upward and to the left, increasing the amount of CO2 carried at any PCO2. This is known as the HALDANE EFFECT. Compare to Bohr Effect.

CO2 DISSOCIATION CURVE

CO2 + H2O H2CO3 HCO3- + H+

CO2 transport and PCO2 value has acid-base consequences

Low PCO2 result inRESPIRATORY ALKALOSIS

High PCO2 results inRESPIRATORYACIDOSIS