MC

MC	*Biology*	*Standard:* 02
*Objective:* 01. Describe the fundamental chemistry of living cells.
*ILO:*

The six elements that make up 99.9% of all living things include

a. C, K, O, N, Ca and S

b. C, P, S, H, O and N

c. C, P, K, I, O and N

d. N, O, P, H, S and T

Correct Answer: b

MC	*Biology*	*Standard:* 02
*Objective:* 01. Describe the fundamental chemistry of living cells.
*ILO:*

Which chemical elements would you expect to find in abundance in a living cell?

a. hydrogen, neon, argon

b. carbon, oxygen, hydrogen

c. iron, magnesium, calcium

d. sodium, potassium, sulfur

Correct Answer: b

MC	*Biology*	*Standard:* 02
*Objective:* 01. Describe the fundamental chemistry of living cells.
*ILO:*

Fats are important energy storage compounds because they:

a. readily breakdown to form glucose.

b. provide immediate energy.

c. contain more energy per gram than carbohydrates or proteins.

d. are liquid at normal body temperatures.

e. don't require nitrogen.

Correct Answer: c

MC	*Biology*	*Standard:* 02
*Objective:* 01. Describe the fundamental chemistry of living cells.
*ILO:*

What are the building blocks of protein molecules?

a. polymers

b. fatty acids

c. glucose molecules

d. amino acids

Correct Answer: d

MC	*Biology*	*Standard:* 02
*Objective:* 01. Describe the fundamental chemistry of living cells.
*ILO:*

Which of the following describes the function of proteins?

a. energy formation and storage

b. energy used in muscles and reaction

c. structural use and enzyme formation

d. heredity and genetic code carriers

Correct Answer: c

MC	*Biology*	*Standard:* 02
*Objective:* 01. Describe the fundamental chemistry of living cells.
*ILO:*

What is the most common food storage compound in plants?

a. glucose.

b. starch.

c. sucrose.

d. cellulose.

e. fat.

Correct Answer: b

MC	*Biology*	*Standard:* 02
*Objective:* 01. Describe the fundamental chemistry of living cells.
*ILO:*

Identify three organic compounds by how they react to the following tests. Place the correct letter on the line by the compound.

a. turns orange when boiled in Benedict's solution

b. turns black when iodine is added

c. turns purple when Bieuret's reagent is added

d. turns yellow in the presence of bromthymol blue

e. leaves a grease mark when rubbed on brown paper

1. Starch _____

2. Triglyceride lipid _____

3. Glucose _____

Correct Answers:

1. b

2. e

3. a

MC	*Biology*	*Standard:* 02
*Objective:* 01. Describe the fundamental chemistry of living cells.
*ILO:*

The solubility of water is due to

a. the presence of oxygen

b. the uneven distribution of its electrons

c. its ability to bond with lipids

d. its basic pH

Correct Answer: b

MC	*Biology*	*Standard:* 02
*Objective:* 01. Describe the fundamental chemistry of living cells.
*ILO:*

The properties of water make it very valuable to living systems. Which of the following statements regarding water is not true?

a. it covers more than 75% of the earth's surface

b. it expands slightly when it freezes

c. it is the greatest solvent in the world

d. it modifies temperature extremes

e. it makes up about 50% of your body

Correct Answer: e

MC	*Biology*	*Standard:* 02
*Objective:* 01. Describe the fundamental chemistry of living cells.
*ILO:*

Which characteristic of water allows it to support the weight of objects more dense than water?

a. capillary action

b. surface tension

c. specific heat

d. evaporation

e. adhesion

Correct Answer: b

MC	*Biology*	*Standard:* 02
*Objective:* 01. Describe the fundamental chemistry of living cells.
*ILO:*

Match the appropriate term with its description by writing the correct letter on the line to the left of the description. A letter may be used once, more than once, or not at all.

a. solute

b. solvent

c. evaporation

d. hydrophilic starch, gelatin, wood, etc. causing them to swell

e. hydrophobic

f. imbibition

g. ionization

h. neutral

_____ 1. having an affinity (attracted to) for water

_____ 2. cooling influence that occurs with a change from liquid to gas

_____ 3. characteristic of oil that keeps it from mixing with water

_____ 4. movement of water into substances such as starch, gelatin, wood, etc. causing them to

swell

_____ 5. a substance in which another is dissolved

Correct Answers:

1. d

2. c

3. e

4. f

5. b

MC	*Biology*	*Standard:* 02
*Objective:* 01. Describe the fundamental chemistry of living cells.
*ILO:*

Match the appropriate term with its description by writing the correct letter on the line to the left of the description. A letter may be used once, more than once, or not at all.

a. adhesion

b. capillary action

c. cohesion

d. condensation

e. evaporation

f. freezing

g. hydrogen bond

h. polar

i. specific heat

j. surface tension

_____ 1. attraction of like molecules.

_____ 2. having an unequal distribution of electrons

_____ 3. movement of water through tiny spaces

_____ 4. attraction between two polar molecules

_____ 5. change from a gas to a liquid

_____ 6. the amount of energy required to raise the temperature of 1 cm³ of water one degree

Celsius

Correct Answers:

1. c

2. h

3. b

4. g

5. d

6. i

MC	*Biology*	*Standard:* 02
*Objective:* 01. Describe the fundamental chemistry of living cells.
*ILO:*

Which of the following statements are true of enzymes?

a. they are lipids

b. they will react with most body chemicals

c. they can only be used once

d. they usually slow down reactions and prevent overheating of the cells

e. they usually speed up chemical reactions

Correct Answer: e

MC	*Biology*	*Standard:* 02
*Objective:* 01. Describe the fundamental chemistry of living cells.
*ILO:*

pH Scale

1 - 6 = Acid

7 = Neutral

8 - 14= Alkaline

The enzyme graphed above will work best in

a. an alkaline medium

b. an acid medium

c. a neutral medium

d. a carbohydrate medium

Correct Answer: b

I	*Biology*	*Standard:* 02
*Objective:* 01. Describe the fundamental chemistry of living cells.
*ILO:*

This chart shows the percentage amount of macromolecules found in a body tissue.

Which tissue type would this cell be from?

a. fat

b. muscle

c. bone

d. blood

Correct Answer: b

E	*Biology*	*Standard:* 02
*Objective:* 01. Describe the fundamental chemistry of living cells.
*ILO:*

Describe the function of carbohydrates, lipids, proteins and nucleic acids in cells.

Sample Answer:

Carbohydrates supply cells with energy, lipids make up cell membranes and also store energy, proteins provide cell structure and make-up enzymes, and nucleic acids are the building blocks of DNA which carries genetic information.

E	*Biology*	*Standard:* 02
*Objective:* 01. Describe the fundamental chemistry of living cells.
*ILO:*

Food storage in plants is usually in the form of starch. Food storage in animals is usually in the form of lipids. Why is it an advantage for animals to store their food in the form of lipids rather than starch?

Sample Answer:

Lipids contain about 2.5 times more energy per gram than starch (lipids have a higher ratio of C-H bonds which have the highest energy of all covalent bonds). Animals, unlike plants, cannot make their own food and have to actively search for it. Because of their active lives, they have high energy requirements and they must store energy in a concentrated form that will add minimal weight or volume to their bodies so they can still be mobile.

Scoring Guide:

Comparison of energy per gram in lipids versus starch 40%

AnimalsÕ need for high energy without sacrificing mobility 40%

Correct spelling, punctuation and language use 20%

E	*Biology*	*Standard:* 02
*Objective:* 01. Describe the fundamental chemistry of living cells.
*ILO:*

Compare (state similarities and differences) multiple aspects of two macromolecules. Include (but do not limit yourself to) energy content, function in living organisms, basic structure, and relationships between the two.

Scoring Guide:

4 additional, appropriate, and correct information related to the two chosen

macromolecules present and correct

relationships between molecules appropriate and described

3 similarities and differences addressed (at least 2 of each)

description of relationship between the two chosen macromolecules attempted

2 attempt at comparison of the following:

energy content

function in living organisms

basic structure

addressed and statements made are correct

1 some aspects of major macromolecules addressed and correct

0 unacceptable

all information given incorrect and severely limited

E	*Biology*	*Standard:* 02
*Objective:* 01. Describe the fundamental chemistry of living cells.
*ILO:*

Explain why a razor blade, with a density greater than water, will "float" on water. Include an explanation of cohesion and surface tension. Give an example of this principle demonstrated in nature.

Sample Answer:

Water molecules cling to each other as a result of hydrogen bonds. This attraction of water molecules to each other is called cohesion. Surface tension is a film-like surface on water caused by cohesion. If an object is small enough and does not break the surface it will float on that film-like surface. If it should break the surface it will quickly sink to the bottom. Surface tension enables certain insects to walk on the water's surface and not sink and some animals such as snails and flatworms can cling to the underside of the film.

The film provides a surface for feeding for many insects and, in addition, better access to oxygen for some aquatic organisms. Surface tension is the reason that water beads form into a spherical shape.

Scoring guide:

clear explanation of why a razor blade will float on water 40%

explanation of cohesion and surface tension 20%

example in nature 20%

correct spelling, punctuation and language usage 20%

E	*Biology*	*Standard:* 02
*Objective:* 01. Describe the fundamental chemistry of living cells.
*ILO:*

After 30 minutes of active exercise the body temperature would exceed 120 degrees F if it were not for our "cooling system" of evaporation. Explain the principle of evaporation and why it is such an effective mechanism for cooling our body. Include an explanation of the heat of vaporization.

Sample Answer:

Water on the surface of the skin evaporates as the heat of the body causes the hydrogen bonds to break between water molecules and they escape the liquid state and enter the air as a gas. The heat of vaporization is the amount of heat energy required to convert 1 gram of liquid to 1 gram of gas. Water has a very high heat of vaporization because of the strength of the hydrogen bonds between the water molecules in the liquid state. The heat from the surface of the body that breaks the hydrogen bonds is changed to energy of motion as the water molecule escapes leaving an "absence of heat" or a loss of kinetic energy of the remaining fluid, causing a cooling effect on the surface of the skin, thus maintaining your body temperature at a safe level.

Scoring guide:

explanation of evaporation 40%

explanation of heat of vaporization and its relationship to evaporation 40%

correct spelling, punctuation and language usage 20%

E	*Biology*	*Standard:* 02
*Objective:* 01. Describe the fundamental chemistry of living cells.
*ILO:*

Diagram the molecular structure of water. Indicate the areas of positive and negative charge. What causes polarity in water, what characteristics of water result from its polarity and what influences do these characteristics have on living systems?

Sample Answer:

Diagram of a Water Molecule

The electrons shared by oxygen and hydrogen in the water molecule are not shared equally. The oxygen atom has a stronger affinity for electrons, so the electrons shared spend more time around the oxygen atom, making that side of the water molecule slightly positive and leaving the hydrogen atom with a slightly negative charge. The unequal distribution of the electrical charge on a molecule is called polarity. Because water is polar it will readily form hydrogen bonds with other polar molecules, the positive side of one molecule being attracted to the negative side of an adjacent molecule. The polarity of water results in cohesion and adhesion. These characteristics result in surface tension, the film-like surface on water; the movement of water in plants; capillary action, that provides for the movement of water through small spaces making soil water available to roots and providing for the uptake of water by seeds allowing for germination. The polarity of water makes it a good solvent in which all of the chemical reactions sustaining life occur. Because of the force of the hydrogen bonds it takes a lot of energy to change the temperature of water. This moderates temperature changes and makes water a very stable environment. It also requires a lot of energy to convert water from a liquid to a gas resulting in its value as an evaporative cooling system.

Scoring guide:

diagram of a water molecule showing areas of positive and negative charge 20%

explanation of polarity 20%

description of characteristics of water resulting from its polarity and the influence

on living systems 40%

correct spelling, punctuation and language usage 20%

P	*Biology*	*Standard:* 02
*Objective:* 01. Describe the fundamental chemistry of living cells.
*ILO:*

Title: Organic Substances

Description: Students will design and perform an experiment related to the properties of organic substances. The lab can be quite extensive or relatively short in duration depending on the number of substances tested and the number of tests desired by the teacher.

Time Required: Variable, one period needed for students to design lab and one or two more periods depending on the amount of tests.

Student Background: Students should know what organic substances are and what a property is. They should be familiar with safety practices in the lab and basic experimental techniques.

Note to Teacher: This lab is written with an inquiry approach. If more structure is desired, add a list of materials, write the procedure by spelling out which tests youÕd like the students to perform and put headings on the data table.

Heating substances is a good property to test but does involve some risk. Hot plates work best but are often in limited supply. If open flame is used, care should be taken to use small quantities of substances in heat resistant glassware. Oil may spatter and can create fire hazards. Students may be asked to bring substances from home to test if desired. The types of properties students may test for include:

a. reaction to water, acid or base

b. reaction to heat

c. appearance, feel or texture

d. result when rubbed on paper towel (fat test)

e. reaction to Benedicts solution and heat (sugar test) ∆ this does not work for sucrose

Materials:

Organic substances:

carbohydrates such as flour, crackers, sugar, potato, corn chips

lipids like vegetable oil, butter, lard

proteins: egg white, tofu, beef jerky, hard cheese, and powdered soy protein

Lab ware:

beakers, test tubes, tongs, evaporating dish or crucible, heat source, wire or ring stand, and test tube rack

Lab Chemicals:

dilute acid (HCl) or vinegar dilute base (NaOH) or ammonia, water, litmus paper, Benedicts solution, iodine

Procedure:

1. Allow students time the first day to investigate ways they might test for properties of organic molecules. They may find help in their text, the library, the Internet, or from reference materials.

2. Students should begin their write-up and identify who will bring what substances. If you wish to supply the food substances, tell students what will be available. Students may bring substances that are mixtures of macromolecules as most foods are and they will be harder to classify.

3. Tell students how many properties or tests they should do on each food.

4. The second day of the lab should be devoted to testing the properties of the substances. Depending on the number of foods and tests, this may take additional days.

5. Summarize the class results and allow time to finish analysis questions.

Student Response Sheet Name _____________________________

Title: Organic Substances

Purpose: To design and test foods for the macromolecules they contain.

Materials: (list what your group will need)

Procedure: (explain what tests your group will do)

3ÉÉ.

Hypothesis:

Data:

Tests Performed

Macromolecule type

Analysis:

1. In general, what did the proteins seem to have in common?

2. In general, what did the carbohydrates seem to have in common?

3. In general, what did the fats seem to have in common?

4. Which tests seemed most specific for the substance being tested?

5. Why?

6. Why might tests like these be performed in the food industry?

7. Foods are made from cells or products of cells. Why might plant cells be high in carbohydrates?

Conclusion:

P	*Biology*	*Standard:* 02
*Objective:* 01. Describe the fundamental chemistry of living cells.
*ILO:*

Title: Testing for Sugars, Starch, Fats and Protein

Materials available at each test station:

5 or 6 common food items (egg, potato, peanuts or walnuts, apple, etc.)

hotplate wax pencil

250ml beaker brown paper

12 small test tubes Biuret reagent

Benedict solution eyedroppers

iodine test tube holder

Time required: 30 - 45 minutes

Directions: After having become familiar with the standard tests for the presence of starch, sugar, fats & oils, and proteins, demonstrate your ability to perform these tests to identify the presence of these compounds in the following foods. If a particular food tests positive for a substance, indicate (+) for slight amounts, (++) for moderate amounts and (+++) for large amounts. If a substance is absent, indicate (-). After completing the food tests, answer the questions below.

*Food Item*	*Sugar*	*Starch*	*Fats/Oils*	*Protein*
Egg white
Potato
Walnuts
Apple
Beans

Questions:

1. Describe a positive test for sugar.

2. Describe a positive test for starch.

3. Describe a positive test for oils and fats.

4. Describe a positive test for proteins.

5. How does your body use the starch that you eat?

6. How does your body use the protein that you eat?

7. According to the American Heart Association, what percent of your daily food intake should consist of carbohydrate?_________; protein?_________; fat?________.

Correct Answers:

1. Sugar, boiled in Benedict solution will turn orange.

2. Starch will turn purple or black in the presence of iodine.

3. Oil or fat will leave a permanent translucent spot on brown paper.

4. Biuret reagent will turn purple when mixed with protein.

5. Starch that you eat is broken down by digestion (hydrolysis) to smaller compounds (monosaccharides and disaccharides) that are used for energy, as building blocks for making other compounds or if taken in greater quantity than the body can use, they may be converted to fat.

6. Proteins are broken down by digestion to their amino acid monomers, which are used as building blocks to form your own body proteins.

7. The American Heart association suggests a diet consisting of approximately 50% carbohydrate; 30% protein; 20% or less fat.

Scoring guide:

Test results for food items 50%

Questions 40%

Spelling, punctuation and language usage 10%

P	*Biology*	*Standard:* 02
*Objective:* 01. Describe the fundamental chemistry of living cells.
*ILO:*

What Type of Munchies?

All organisms are composed of four types of organic materials: carbohydrates, lipids, proteins, and nucleic acids. Common foods contain these organic materials. The body uses food substances to meet its needs for these raw materials.

Objective: Identify four basic food materials, by using standard tests, on an unknown food substance.

Conducting the Investigation

Working individually, each student is to use the materials at the laboratory station to perform their tests for different food materials. The sample may contain one, two, three, or four different food materials. Use the testing and identification table for directions to conduct the test and identify the results.

Cautions: Benedicts solution, and Biuret solution are corrosive and toxic ∆ If body is contacted wash immediately with water. Eye protection must be worn at all times during this activity!!!

When you are finished:

Empty test tubes into sink.

Clean-up test tubes, using test tube brush and soap solution.

Reorganize materials.

Materials:

unknown sample of food material

3 test tubes

Beryl pipet with iodine solution

Beryl pipet with Benedicts solution

Beryl pipet with Biuret solution

Beryl pipet to make spot

brown bag paper

toothpicks for stirring

boiling water bath

test tube holder

Testing ∆ Identification Table

Substance	Test	Positive Result
Reducing Sugar	Heat sample + 2 droppers full of benedicts solution in boiling water bath	Orange-red color upon heating
Starch	Mix sample + 1 drop of iodine solution	Purple-black color appears
Protein	Mix sample + 1 dropper full of biuret solution	Rose-violet color appears
Fat	Place 1 drop of sample on brown bag paper ∆ allow to dry	Hold up to light spot, appears translucent

Your results:

List the substance/substances found in the unknown food sample.

Give evidence to support your inferences for each substance found.

Scoring Guide:

Found all substance and give correct evidences 100%

Missing one substance and/or correct evidence 80%

Missing two substances and/or correct evidences 60%

Missing more than two substances and/or correct evidences 40%

Teacher Notes:

Students may have been given previous experiences testing different food materials, but it is not required for this performance test.

Organization: The teacher should arrange individual test stations with the following materials at each station.

40 mLs unknown sample food material per student

(A sample food material can be prepared by making two liters of solution containing any or all of the following: 100 grams of table sugar, 20 mL of gelatinized starch, 20 mL of vegetable oil, 40 mL of gelatinized Knox gelatin)

3 micro-test tubes

Beryl pipet with iodine solution (Note: Eye droppers may be substituted for Beryl pipets)

Beryl pipet with benedicts solution

Beryl pipet with biuret solution

empty Beryl pipet to make spot

brown paper bag

toothpicks for stirring

boiling water bath (250 mL beaker ∆ water ∆ hot plate)

test tube holder

test tube brush (cleanup)

soap solution (cleanup)

Test Solutions: Commercially prepared solutions of benedicts solution, Biuret solution, and LugolÕs iodine solution may be purchased from Carolina, Wards, or Flinn.

soap and water mixture for cleanup

Time Needed: 20 to 30 minutes

What Type of Munchie?

Name ___________________________ Period ____________ Date ________________

Objective: In this test you will have the opportunity to perform several scientific tests on two unknown substances to determine what they contain: fat, simple sugar, complex sugars or protein.

Conducting the Investigation

Work individually and use the materials at the laboratory station to perform four tests for each of the mystery substances that you are given. A sample may contain one, two, three, or four different food materials. Use the chart for directions on how to conduct the tests and where to identify the results.

Begin by getting two unknown substances from your teacher. Perform four tests on each unknown substance. Record your observations in the boxes of the data table.

Cautions: Benedicts solution, and Biuret solution are corrosive and toxic ∆ If body is contacted wash immediately with water. Eye protection must be worn at all times during this activity!!!

When you are finished:

Empty test tubes into sink.

Clean-up test tubes, using test tube brush and soap solution.

Reorganize materials.

Benedicts Test

1. Fill a test tube 1/4 full of unknown substance. Label the test tube.

2. Add 2 droppers full of Benedicts solution to the test tube.

3. Place the test tube in a hot water bath for 3-5 minutes.

6. Record results below.

LugolÕs Test

1. Fill a test tube 1/4 full of unknown substance. Label the test tube.

2. Add 1 dropper full of LugolÕs solution to the test tube.

3. Record results below.

Biuret Test

1. Fill a test tube 1/4 full of the unknown substance. Label the test tube.

2. Add one dropper full of 10% NaOH solution to the test tube. CAUTION: This chemical is poisonous and corrosive!

3. Add one dropper full of 1% Copper Sulfate solution to the test tube and mix well with a toothpick.

4. Record results.

Brown Paper Test

1. Place 2 or 3 drops of unknown substance on a square of brown paper.

2. Spread the unknown substance around on the paper.

3. Allow the substance to dry.

4. Record results.

Unknown substance _______

What is unknown substance _______ composed of? ______________________________

P	*Biology*	*Standard:* 02
*Objective:* 01. Describe the fundamental chemistry of living cells.
*ILO:*

Title: Water Experiments

Time: Work in small groups during a 45 - 50 minute class period.

Materials available:

open glass tubes of different diameters glass slides

3 x 5 index cards thermometer

food coloring string or rubber bands

tape gauze or cloth

wax pencil eyedropper

razor blades detergent

pebbles beakers

culture dishes soil

Directions:

1. Using your choice of the materials above, design and carry out an experiment that demonstrates capillary action and the relationship between adhesion, cohesion, the diameter of a column of water and the height of a column of water. Explain the value of capillary action to living systems.

and/or

2. Using your choice of the materials above, design and carry out an experiment that demonstrates the cooling effect of evaporation and the relationship of temperature, wind and humidity on the rate of evaporation. Explain the value of evaporation to living systems.

and/or

3. Using your choice of the materials above, design and carry out an experiment that demonstrates the effect of pollution on surface tension. Use your data to make a graph showing the relationship between the amount of pollution and surface tension. Give some examples of surface tension in nature and its value to living systems.

and/or

4. Using your choice of the materials above, design and carry out an experiment that demonstrates that water stores heat. Use your data to construct a graph that demonstrates the heat-holding capacity of water versus land. Explain the value of water's high specific heat to living systems.