Download Lesson 1 – Introduction to Biotechnology

Middle School Curriculum
Unit 17: Biotechnology
Lesson 1: Overview of Biotechnology
STUDENT OBJECTIVES
1. Define biotechnology
2. Compare and contrast biotechnology and genetic engineering
3. Explain how biotechnology helps increase production
4. List uses of biotechnology in plant and animal science
5. Explain the historical uses of biotechnology
Agriculture QCC:…………………………………………………………………………20, 26
Language Arts QCC:…………………………..…………………………………………. 6-7, 16
7-7, 20
8-7, 20
Science QCC:…………………………..……………………………………………………... 6-1
7-1, 10
8-1
REFERENCES
Raven, Peter H. and George B. Johnson. Understanding Biology: Third Edition.
Dubuque, IA: Wm. C. Brown Publishers.
Osborne, Edward W. Biological Science Applications in Agriculture. Danville, IL:
Interstate Publishers, Inc.
Herren, Ray V. Exploring Agriscience (2nd Edition). Delmar Thomson Learning.
Lee, Jasper P. and Diana L. Turner. Agriscience and Technology. Danville, IL: Interstate
Publishers, Inc.
Biological Science Application in Agriculture: Plant Science.
EQUIPMENT, SUPPLIES, MATERIALS
See labs
PowerPoint presentation
TERMS TO FAMILIARIZE YOUR STUDENTS WITH
DNA
Codons
Chromosomes
Artificial insemination
Fermentation
Nucleotides
Genes
Cloning
Replication
Herbicides
Amino acid
Mutation
Teaching Procedure
A. Introduction
Georgia Middle School Agricultural Education Curriculum, Unit 17 Lesson 1
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Biotechnology is the management of biological systems for the benefit of humanity. It is
used in molecular biology and genetics. Another example of biotechnology seen in the news
recently is cloning. In this lesson, we will learn the basics of biotechnology so we can apply
them to the later lessons in this unit.
B. Motivation
1. Learn about biotechnology and its uses
2. Do lab activity where students construct sentences using the DNA codes given to them
3. Compare and contrast genetic engineering and biotechnology
C. Discussion
1. Question: What is DNA?
Answer: DNA is hereditary information for organisms stored in chromosomes. It is stored
as a sequence of nucleotides, which are composed of a five-carbon sugar, phosphate
group, and nitrogenous base. DNA is a recipe for making an organism because it contains
the necessary items to make that organism just like a recipe contains the ingredients to
make a cake.
2. Question: What is biotechnology?
Answer: The management of biological systems for the benefit of humanity. It is used in
a wide array of other science disciplines.
3. Question: What are some uses of biotechnology in plant and animal science?
Answer: Cloning is used in both animal and plant sciences. Plant science used herbicides
and now scientists are working on developing a plant that can withstand the herbicide. In
animals, genetic engineering allows us to check on who is the father of a child as well as
cracking the genetic code for humans.
4. Question: Compare and contrast genetic engineering and biotechnology.
Answer: Biotechnology encompasses all subjects of science, but genetic engineering
deals with genes. Genetic engineering involves gene splicing, replication, and transfer of
genes to other organisms. Biotechnology handles the bigger picture and genetic
engineering focuses more on smaller areas. Genetic engineering is an example of a
biotechnology. Using a wide array of methods, genetic engineering accomplishes the task
of multiplying the number of genes.
5. Question: List the historical uses of biotechnology.
Answer: The earliest biotechnology was used to make cheese and wine. Through the use
of bacteria, spoiled milk can be fermented to form cheese and grape juice fermented to
form wine. Yeast can be fermented to make bread as well (see attached lab activity).
Highly spoilable foods can now be kept for long periods of time thanks to certain
bacteria. Legend has it that Arabs were the first to use artificial insemination. Arabs
would sneak into enemy camps and collect the semen of the stallions. This semen would
then be used to impregnate the mares.
6. Question: How does biotechnology increase production?
Answer: Developing and using new forms of plants and animals, modifying to improve
their life processes, and improving the quality of food. Thanks to biotechnology foods
have a longer shelf life. A good example is the tomato because tomato pickers pick
tomatoes that are green so that as the tomatoes travel to stores…they ripen along the way!
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D. Lab Activity
This lab allows the students to practice their copying and replication of DNA. They need a basic
understanding of what is all involved in biotechnology before moving on to future lessons.
In order for students to understand how DNA replicates they need to understand how to copy
DNA.
Before class, create at least six DNA codes, containing six triplet codes in one DNA
code.
Examples of genetic codes: GTA ACT TGC TAG GGG ATT , CCC ATG CAT AAA GCT
CGT , and TTT ATC GTC TGA ATC AAA
Then, copy the DNA and put each triplet code on a piece of construction paper.
Example of copied genetic code: CAT TGA ACG ATC CCC TAA
On the back of each piece, put a word for the students to construct a sentence. Place each
piece of paper around the room, on tables or walls.
Example: CAT triplet code will have the word “the”. TGA have “goat”, ACG be “likes”,
ATC be “the”, CCC be “purple”, and TAA be “flowers.” So the sentence the students will
construct will be “The goat likes the purple flowers.” You can make the sentence longer by
adding more triplet codes.
When the students come in give each pair of students a DNA code, if one or more groups
has the same code that is fine! Instruct the students to first copy their DNA and then find the
appropriate answers around the room. When they are done with their DNA code, one student
from each group will report their answer to the teacher to see if their answer is correct.
After this exercise, have the students do this activity with RNA. Students keep the same
DNA sequence but now they are looking for the corresponding RNA strand. Before class, put up
the corresponding RNA codons.
From this they can find the t-RNA sequence. Hint: this is the same as their original
sequence except instead of thymine it will be uracil!
E. Other Activities
1. Video: “Nova Cracking the Code of Life” The video explains the structure and
function of DNA, what a gene is and what it does, and how proteins are produced. Item # ER-492212A in Carolina Catalog.
2. Teacher Activity:
DNA Mutations – on PowerPoint
Print the following sentence on the board: THE OLD RED DOG WAS TOO BIG FOR HIS
BED. Each word consists of three letters like the triplet code of DNA. If a mutation were to
cause a deletion of the D in OLD, the sentence would now read: THE OLR EDD OGW AST
OOB IGF ORH ISB ED. Obviously this is nonsense. If it were a DNA molecule, the resulting
protein would probably be ineffective. If the mutation caused an inversion of the word DOG, the
sentence would now read: THE OLD RED GOD WAS TOO BIG FOR HIS BED. In this case,
the sentence still makes sense, but the meaning is completely changed. A protein resulting from
such a mutation would have a different amino acid in one position of its sequence which could
have profound implications. This analogy could be extended by making other mutations, such as
reversing the sentence, inserting a new word or letter, substituting a different word somewhere
along the chain.
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***Simple mutations, such as deletions, can affect the animal only slightly such as a color
change or lack of a certain color pigment. Inversion and larger deletions or additions can change
the animal by a birth defect or worse things.
3. Extra Assignment – Bread and Yeast Fermentation provided as set of worksheets. One
set is for the teacher and the other for the student.
3. Optional Lab Activity
What kinds of food do we get from cows? Steaks, hamburger meat, milk, etc. Milk
goes into the formation of cheese and ice cream. Yogurt also is made from milk. In this lab,
students will make their own yogurt using whole milk.
Yogurt Production
Society uses more from an animal than we think. Milk from cows is not only used for drinking
but also for making cheese, ice cream and yogurt. In this lab, we will find out how people make
yogurt from milk.
Materials:
Half-pint carton of milk
500 ml beaker or Mason jar
Ring stand (optional)
Powdered milk
Heat source (Bunsen burner, hot plate, etc)
Thermometer (0-100° C)
Starter Yogurt culture (any non-flavored yogurt available at grocery store)
Incubator, yogurt maker, or heating pad and cooler
Refrigerator
Sugar
Jams or fruit
Procedure:
1. Pour the half-pint carton of milk into a beaker. Place the beaker in a ring stand (or on a hot
plate).
2. Add 11 g of powdered milk to the beaker and stir. Heat to 96° C, stirring constantly. Do not
boil, but scald it.
3. Cool milk to 46° C while continuing to stir.
4. Add 5 ml of starter yogurt culture to the empty milk carton. Pour the cooled milk into the
carton and staple shut. Label the carton with date and student name.
5. Place in an incubator at 39° C until it coagulates (6-8 hours). If you are using the heating pad
and cooler as your incubator, be sure to keep the temperature consistent. To find out the
temperature at each setting on the heating pad, tightly wrap the pad together and then stick a
thermometer in the center. Check the temperature at each setting for accuracy. Usually the “low”
setting is around 39° C.
6. Remove the carton from the incubator and cool to 10° C in a refrigerator overnight.
7. You may want the students to bring in their own jams to put into their yogurt. The teacher
needs to have some sugar on hand because the yogurt is a little tart at first.
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ACADEMIC CONNECTIONS
Language Arts
Middle School Connections in Agriculture Education
Language Arts QCC: Grade 6-7, 16
7-7, 20
8-7, 20
Name____________________________________ Period____ Date______________
Teacher’s Note: Have students participate in the lab activity related to DNA and RNA in the
lesson plan.
You are just beginning to learn about biotechnology and have completed the lab related to DNA.
Respond to the questions below in complete sentences.
1. How is the lab related to biotechnology?
2. How has biotechnology impacted agriculture?
3. Compare and contrast genetic engineering and biotechnology.
4. Name some current issues related to biotechnology and genetic engineering that you have
heard about in the last year.
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ACADEMIC CONNECTIONS
Science
Middle School Connections in Agriculture Education
Science QCC: Grade 6-1
7-1, 10
8-1
Name____________________________________ Period____ Date______________
You have learned exactly what DNA is.
DNA is hereditary information for organisms stored in chromosomes. It is stored as a
sequence of nucleotides, which are composed of a five-carbon sugar, phosphate group, and
nitrogenous base. DNA is a recipe for making an organism because it contains the necessary
items to make that organism just like a recipe contains the ingredients to make a cake.
Please use an overhead to allow students to see the following website:
http://www.cnn.com/interactive/specials/0006/genome.interactive/frameset.exclude.html
Read the information aloud to the class as you show the picture slide show.
Introduce the concept of a DNA ladder to the class.
DNA LADDERS
Materials needed:
black, red, green, blue, yellow markers or crayons.
Poster paper or large manilla paper
Follow the instructions carefully to complete your DNA ladders. DNA molecules always
follow a specific code, with the following elements: (G) guanine, (C) cytosine, (A) adenine
and (T) thymine. Guanine and Cytosine are always matched together. Adenine and thymine
are always matched together. For instance, one side of a DNA molecule has a basic sequence of
C so the opposite side is G. One side of a DNA molecule has a basic sequence of G so the
opposite side is C. One side of a DNA molecule has a basic sequence of A so the opposite side
is T. Here is another example:
Example:
C---G
G---C
This makes up part of a
A---T
DNA ladder. This is a very simple ladder.
T---A
Pass out the following worksheet of DNA ladders and allow the students time to complete the
sheet and turn it back into the teacher.
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Name:
Use the following colors for each element to complete this worksheet C=red G=green T=blue
A=yellow Use black for the dashes, this resembles the ladder.
Draw each DNA ladder using the color code. Match each side with the right element. You will
be amazed at how many different codes there are.
1.
G
C
G
T
A
2.
A
A
T
C
G
3.
G
T
C
T
A
NOW CREATE 5 OF YOUR OWN DNA CODES. DO YOU SEE HOW HUMANS ARE SO
DIFFERENT?
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Middle School Curriculum
Unit 17: Biotechnology
Lesson 1: Overview of Biotechnology
Bread making:
A concise look at the history, biology, and chemical processes of yeast
Teacher’s Edition
Opener:
Relate the following story:
A bakery in San Francisco was famous for its wonderful bread. The bakery
decided to franchise their bread, but the taste could never be duplicated outside the San
Francisco Area.
Ask the students to brainstorm what they think the possible reasons could be for
the variation.
Solution:
The recipe was always the same and every possible explanation for the difference
was tried (elevation, slightly varying ingredients across the country). This problem
caught the interest of the USDA who decided to find the solution. The bread was tested
and a new variety of yeast was discovered that added a particular taste. This yeast only
grew in that specific part of San Francisco and grew on the walls of the bakeries in that
area. When the bread was being made, the yeast present in the air landed in the bread
dough.
Procedure
Purpose:
To show how yeast causes bread to rise while simultaneously explaining the
chemical process of fermentation.
Distribute handout and proceed with experiment.
Materials: (Per group of 4)
Ziploc type bags, 2-gallon size
4 paper plates
Mini loaf pans, custard cups, or a muffin pan
Spatula
Measuring spoons and cup
2 cups all purpose flour (plus extra for kneading)
2 cups wheat flour
1 package of dry yeast or fast-acting yeast
1 c. water (boiling water will be supplied by teacher)
2 teaspoons honey
4 tablespoons nonfat dry milk
1-tablespoon vegetable oil
2-tablespoon salt
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1-teaspoon baking powder
1-teaspoon baking soda
Felt pen
Ruler
4 colored pencils
Safety glasses
Teacher’s Materials
(In addition to the above listed)
Hot plate or stovetop
3-4 quart saucepan
Butter for the taste testing if desired
Discussion:
Discuss the following topics during the first resting stage of the bread dough.
There is a coordinating handout which can be given to students.
Brief History of Yeast
Yeast has been used to make bread since before written history.
Historians generally believe that yeast was originally introduced into bread through
natural contaminants of flour and milk. Yeast floats in the air and lands on bread dough
while being prepared.
Leaven was a dough-type medium that was kept from one loaf of bread to the next to
begin the leavening process.
Yeast has also been used for many centuries in both beer and wine making.
Not until modern times that scientists discovered the existence of the yeast cells that are
actually responsible for fermentation.
Yeast as a Living Organism
Yeast is a unicellular fungus (and therefore not a plant) that lives in liquid or moist
habitats, primarily reproducing asexually by simple cell division or by budding of a
parent cell.
Special note: There are now five general kingdoms that organisms are divided into:
Monera, Protista, Plantae, Fungi, Animalia. At one time, it was taught that yeast was a
plant. This has changed in the past few years.
Yeast is classified into the division Ascomycota (sac fungi). The microorganism is
placed here because under certain conditions a single yeast cell can produce 4 spores.
The spores are much better adapted to survival under harsh conditions such as drought
and excessive heat than are vegetative cells.
Simple cell division occurs when the cell divides evenly creating an exact genetic
duplicate of itself. Budding also produces a duplicate, but cytoplasm and intracellular
apparatuses are not evenly divided between the mother and daughter cell.
Refer students to the picture provided on their handout. The yeast pictured here is
Saccharomyces cerevisiae, which is the most important form of yeast for commercial
production. This species is widely used in bread, beer, and wine.
Yeast produces energy to carry out daily metabolic function using anaerobic glycolysis,
or fermentation.
Refer students to the overall chemical equation for fermentation.
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2 CO2
Glucose → 2 pyruvate→ 2 Acetaldehyde →2 Ethanol
Yeast in Action
Yeast is used for beer, wine, bread, soy sauce
The first reaction in bread making involves combining a sugar source (glucose) with
warm water and yeast. The warm water acts as a catalyst. Flour is added in this step to
help trap the carbon dioxide (like a balloon filling with air)
The bread rests for 15 minutes during which it begins to rise
More flour, honey, and warm water are added to increase fermentation and volume.
The bread is kneaded to increase the elasticity of the dough and prevent the carbon
dioxide from escaping.
The bread rests again for 10 minutes after which the air is punched out. Why? To
prevent the extra carbon dioxide from causing the bread to “explode”
During the next rising phase the bread will double in size again due to fermentation.
During baking, more carbon dioxide is produced = final rise, and the ethanol is cooked
off.
Alternatives to Yeast
There are many chemicals that produce similar reactions to yeast.
Both baking powder and baking soda react to produce carbon dioxide.
Baking soda (NaNCO3) is a base that reacts with an acid to produce CO2. Recall the
volcano experiment - baking soda + vinegar.
In cooking there are several ingredients that will react with the soda: Sour milk, brown
sugar, honey, applesauce, vinegar, cream of tartar.
Baking powders contain mixtures of dry acid or acid salts and baking soda.
The type of baking powder generally used in cooking is double acting. It releases CO2
when moistened, and again when baked.
This receipt is for the purchase of the food materials used in this experiment. Your costs
should be similar. These materials are plenty for a class of 20-25 working in groups of 45.
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Breadmaking:
A concise look at the history, biology, and chemical processes of yeast
The Discovery of Yeast
Since before written history, man has been making food. For centuries, bread has been a
crucial foodstuff for people of all classes. How exactly bread making became known to ancient
man is not completely understood by scientists. However, the general agreement is that
contaminants accidentally entered food through natural means. For example, yeast may have
entered bread through contamination of flour. No matter how accidental its introduction was,
bread making very quickly became a staple to society.
To ancient people, the rising of bread must have seemed a mysterious and magical
process. During Biblical times, leaven, which was a dough-type media, was kept from one loaf
to the next. As bread was made, extra leaven was kept aside for incorporation into the next loaf.
During the 19th century, science was making miraculous discoveries about the world.
However, it was not until 1859 that a scientist, Louis Pasteur, discovered the presence of yeast in
bread and the mechanism, now known as fermentation, that solved the riddle of bread.
Yeast as a Living Organism
For many years, yeast was thought of as a plant. However, under the new five kingdom
classification, yeast is now placed in the kingdom Fungi. Yeast is a unicellular fungus that lives
in liquid or moist habitats, primarily reproducing asexually by simple cell division or by budding
of a parent cell. Simple cell division occurs when the cell splits evenly creating an exact
duplicate of itself. Budding also creates a genetic copy, but the cytoplasm and intracellular
apparatuses are not evenly divided between the mother and daughter cells.
More specifically, yeast is placed in the Ascomycota division, which contains sac fungi.
The sac fungi produce sacs filled with asexually produced spores. Yeast is placed in this division
because under certain conditions, a single yeast cell can produce four spores. The spores are
much better adapted to survival in harsh conditions, such as drought and excessive heat, than are
vegetative cells.
Figure 1 depicts a specific yeast known as Saccharomyces cerevisiae which is the most
important domesticated yeast in terms of production. S.cerevisiae is used in many food science
and production aspects such as beer, wine, and breadmaking. Interestingly, yeast is also used in
the production of soy sauce.
Because yeast is a living organism, it must have a way of creating energy to sustain its
daily metabolic functions. This microorganism utilizes anaerobic
glycolysis, or fermentation.
The overall process of fermentation reduces one molecule of
glucose to 2 molecules of ethanol and 2 molecules of carbon dioxide.
You may recall from biology that glycolysis reduces one molecule of
glucose into 2 molecules of pyruvate. In yeast, instead of putting the
two molecules of pyruvate into the Krebs Cycle for energy (which
requires oxygen), pyruvate is anaerobically transformed into ethanol.
The overall reaction for fermentation is shown below.
Fermentation
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glucose → 2 pyruvate → 2 acetaldehyde → 2 ethanol
The end of glycolysis and beginning of anaerobic fermentation occurs when the carbon dioxide
is formed between the pyruvate and acetaldehyde.
Yeast in Action
Yeast is still used in a variety of ways and in many different industries. Both the
production of beer and wine are dependant upon yeast as a source of fermentation. However, as
this lesson focuses on yeast in the bread making industry, we will concentrate our discussion to
this particular use.
When bread is made, yeast is combined with a sugar source (glucose) usually in the form
of granulated sugar; but honey, molasses, or brown sugar are also used. With sugar acting as a
fuel, warm water is added to increase the rate of fermentation. In this situation, heat acts as a
catalyst for the reaction. Generally at this point a small amount of flour is also added to help trap
the carbon dioxide that is beginning to be produced. As the bread rests, it begins to swell or rise.
The rising is simply the result of trapped carbon dioxide gas forcing the flour mixture to expand
just as a balloon swells when filled with air.
Usually, after a first rising, more sugar, flour, and warm water are added to continue the
fermentation process and increase the bulk of the bread. Kneading increases the elasticity of the
bread mixture further amplifying its ability to contain the carbon dioxide that is being produced.
After kneading, bread is left to rest for a second time; usually until it has doubled in size. The
process here is the same; fermentation produces carbon dioxide that is trapped inside the elastic
bread dough.
Baking occurs after a second resting period, which can last from 45 minutes to 2 days
depending on the type of yeast being used and the type of bread that is being cooked. During the
baking process, bread rises even higher. This final rise is caused by heat once again accelerating
the fermentation process and creating higher levels of carbon dioxide. When exposed to heat, the
starch in the flour gelatinizes hardening the bread into its permanent porous shape. Also during
baking the ethanol is burned off.
The result of all of this hard work by the yeast cells is a light, porous food source that is
found in many forms from croissant to bagels, rye bread to wheat, cookies to cakes. There is no
doubt that yeast plays a crucial role in many of the foods that we consume. The next time you
eat dinner, think about how many foods you are eating have yeast in them and perhaps what you
would be eating instead if yeast had never been discovered.
Alternatives to Yeast
Although yeast is primarily used in baking, there are several chemical substances that can
be used as an alternative to yeast. Both baking powder and baking soda are used. Both of these
substances undergo chemical reactions that release carbon dioxide gas.
Baking soda, or sodium bicarbonate, is a base. When it reacts with an acid, carbon
dioxide is released. You may recall doing an experiment in which you mixed baking soda and
vinegar to create a “volcano.” The same principle is at work here. The carbon dioxide is
trapped in the dough causing it to rise.
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Baking powder is a convenience item. It contains both baking soda and a dry acid or acid
salt. Most baking powders are double acting. This means that when the powder is moistened the
acid reacts with the base. The reaction occurs again when the dough is baked. As in both the
yeast and baking soda reactions, carbon dioxide is released and trapped in the bread dough
causing it to rise.
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Bread making:
An experiment with yeast fermentation
Student Activity Sheet
Materials:
4 paper plates
4 plastic bags
Mini loaf pans, custard cups, or a muffin pan
Plastic spatula
2 cups all purpose flour (plus extra for kneading)
2 cups wheat flour
1 package of dry yeast
1 c. water (warm and boiling water will be supplied by your teacher)
2 teaspoons honey
¼-cup nonfat dry milk (4 tablespoons)
1-tablespoon vegetable oil
2-tablespoon salt
1-teaspoon baking powder
1-teaspoon baking soda
Permanent pen
Ruler
3 colored pencils
Safety glasses
Note to Students:
The following lab requires you to make several measurements of dough
and bread. Be sure to make your measurements in centimeters. Any
measurements of curved surfaces should be made at the highest point.
Procedure:
In groups of 4:
*** Be sure to wash your hands ***
1.
Label each of the four plastic bags A, B, C and D with the permanent pen.
2.
Into each bag put the following ingredients:
Bag A
Bag B
Bag C
Bag D
¼ cup white flour
½ tsp. honey
3 tbsp. warm water
¼ pkg. of yeast
¼ white flour
½ tsp. honey
3 tbsp. boiling water
¼ pkg. of yeast
¼ white flour
½ tsp. honey
3 tbsp. warm water
1 tsp. baking soda
¼ cup white flour
½ tsp. honey
3 tbsp. warm water
1 tsp. bak. powder
3.
Close the bag, removing all air and sealing tightly. Place the bag on the table and
mix the ingredients by working the bag through your fingers for about 20 seconds
or until completely blended.
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4.
Be sure to note the appearance of the mixtures in the space provided. Allow the
bag to rest for 15 minutes.
Physical description:
A________________________________________
B________________________________________
C________________________________________
D________________________________________
Return to your seats for the duration of this period.
5.
Record any differences you see after the 15 minute resting period.
Physical Description:
6.
A______________________________________________
B______________________________________________
C______________________________________________
D______________________________________________
Add the following ingredients to your bags:
Bag A
Bag B
Bag C
Bag D
3 tbsp warm water
pinch of salt
1 tbsp dry milk
2 tsp honey
¾ tsp oil
3 tbsp warm water
pinch of salt
1 tbsp dry milk
2 tsp honey
¾ tsp oil
3 tbsp warm water
pinch of salt
1 tbsp dry milk
2 tsp honey
¾ tsp oil
3 tbsp warm water
pinch of salt
1 tbsp dry milk
2 tsp honey
¾ tsp oil
7.
8.
9.
10.
11.
Mix thoroughly using the same method as in step 3. Once the ingredients have
been completely combined, add 2 cup of wheat flour to each bag incorporating
slowly, mixing thoroughly.
Add the remaining white flour (1/4 cup) to the bags slowly until a stiff, doughlike consistency forms. You can vary the flour amount to a certain degree to
achieve the correct consistency.
Using the plastic spatula, push the dough away from the sides of the bag. Scrape
out as much dough as possible. Place dough on a lightly floured paper plate.
Repeat steps 8 and 9 for each bag.
Knead for 5 minutes or until dough is smooth and elastic. If you find your dough
is sticking to the surface add flour as necessary.
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12.
13.
14.
Cover the dough with the plastic bag and let sit for 10 minutes. Measure the
height of the dough as it sits on the table both before and after the 10 minutes.
Record below along with any observations.
Height of Dough A ____________cm, after 10 minutes ________________cm
Height of Dough B ____________cm, after 10 minutes ________________cm
Height of Dough C ____________cm, after 10 minutes ________________cm
Height of Dough D ____________cm, after 10 minutes ________________cm
Observations:______________________________________________________
______________________________________________________
______________________________________________________
Punch down the dough (remove the air by pressing down on the dough).
Shape into a ball and place the plastic bag over the dough and allow it to rise for
20 minutes. Make the same measurements as in step 12 and record below.
Height of Dough A ____________cm, after 20 minutes ________________cm
Height of Dough B ____________cm, after 20 minutes ________________cm
Height of Dough C ____________cm, after 20 minutes ________________cm
Height of Dough D ____________cm, after 20 minutes ________________cm
Observations:______________________________________________________
______________________________________________________
______________________________________________________
Use the remaining time to begin work on your study sheet
15.
Place each ball of dough in a labeled muffin pan (or other pan) and bake for 10-12
minutes at 375F or until golden brown. Measure the height of each roll after it is
removed from the oven. Be very careful, the rolls are hot!!
Height of Roll A
Height of Roll B
Height of Roll C
Height of Roll D
16.
___________cm
___________cm
___________cm
___________cm
THE FUN PART!!!! Taste each roll and record observations such as preference
(both on taste and visual appearance).
Observations_______________________________________________________
__________________________________________________________________
__________________________________________________________________
__________________________________________________________________
__________________________________________________________________
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Bread making:
An experiment with yeast fermentation
Data Sheet
Graph your results on the following chart connecting the data points to create a line graph.
Key (record your color used)
_____ Roll A
_____ Roll B
_____ Roll C
_____ Roll D
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Bread making:
An experiment with yeast fermentation
Study Sheet
Answer the following questions briefly and in complete sentences. Refer to your notes
and handout as needed.
1.
What kingdom and division is yeast placed in and why?
2.
What is yeast?
3.
Who discovered yeast?
4.
How did early man discover yeast?
5.
What are the two chemical results of fermentation? What happens to these
compounds during baking?
6.
Why did dough B not rise? Be sure to include support for your reason.
7.
Which bread dough rose the highest? Why do you think this occurred?
8.
During which part of the rising process did the bread show the most change in
volume?
Georgia Middle School Agricultural Education Curriculum, Unit 17 Lesson 1
Updated May 2004
9.
Why did dough A not continue to rise throughout the baking process?
10.
Why is increasing the elasticity of the bread dough important? How did you
achieve this?
11.
What is the purpose of flattening the bread dough before allowing it to rise the
final time?
12.
Which bread did you prefer? Relate this to the industry’s current process of
breadmaking.
13.
You are a USDA consultant. A baker in Florida calls you with a problem: none
of his bread rose during baking and his bakery is about to go bankrupt. You go
visit his bakery and find that he stores all of his ingredients in a tin storage shed
outside of his bakery. Upon seeing this you know exactly why his bread did not
rise. What do you tell him?
How does this lab pertain to our discussion on biotechnology? (Hint: think about
the first time bread was made and what was needed.)
14.
Breadmaking Experiment written by Jennifer A. Moore
Georgia Middle School Agricultural Education Curriculum, Unit 17 Lesson 1
Updated May 2004
Summary
Conclusion
Biotechnology involves all subjects of science. DNA plays a big part in it as the
primary factor for which it revolves around. Biotechnology has many real-world
applications with the development of yogurt, cheese, wine, and so forth. Many students
eat the item that biotechnology provides, which explains how biotechnology benefits
humans.
Evaluation
Written quiz
Georgia Middle School Agricultural Education Curriculum, Unit 17 Lesson 1
Updated May 2004