Category: Curriculum Map

Cell Exploration Webquest

 
 

 

CELL EXPLORATION WEBQUEST

 

INTRODUCTION

Every living thing is composed of at least one cell. Bacteria, amoebae, and paramecia are made of one cell and are capable of the activities of life. Organisms made of one cell are unicellular. Most living things are made of more than one cell and are called multicellular. Cells of these organisms function together to accomplish life activities. How many cells do you think make up your body? The human body is made of trillions of cells.

In order to understand how the cell functions in your body, we have to take a look at how your body is organized. Since you are made of matter, and all matter is made of atoms, your body is a collection of atoms. These atoms combined in specific ways to form molecules. Some of the important molecules in your body are proteins, carbohydrates, lipids, salts, water, and nucleic acids. These molecules combined to form the structures that make up a cell. Since each cell is capable of the activities of life, it is the smallest unit of life.

Cells that are similar can function together. These collections of cells are called tissues. Some tissues that you may be familiar with are the muscle tissue that makes up your heart, epithelial tissue that makes up your skin, and connective tissue that holds your body together. Different groups of tissues can be arranged to form organs. Some organs that you may be familiar with are the stomach, intestines, heart, and lungs. For example, the stomach has epithelium to line the outside and inside surfaces for protection and the muscle tissue allows your stomach to squeeze and churn. Groups of organs can work together as an organ system to perform a specific function. The digestive system functions to breakdown and absorb food so that our bodies can use the energy. The pancreas, stomach, intestines, gall bladder, and esophagus are some of the organs that make up the digestive system. There are 13 systems in the human body that function together to produce an organism – YOU!

To review:

ATOMS ——> MOLECULES ——-> CELLS ——-> TISSUES ——-> ORGANS ——> SYSTEMS ——> ORGANISM
The focus of this activity is to learn more about the cell and how it functions in your body.

CELL SIZE

Cells are very small and you must use a microscope to look at them. Watch this video (click on “start animation”), then look at the size of cells and answer the following questions. To give you an idea about size, the length of a key on the keyboard is about 1 cm.

Question:
Answer:
A. Is a bacterium larger or smaller than an animal cell?
B. How many bacteria can fit into an animal cell?
C. Are plant cells larger or smaller than animal cells?

 

EUKARYOTIC CELL ORGANELLES

Since the cell is the fundamental unit of life, it must be capable of independent existence. Some of the necessary life activities are communication, metabolism, protection, and waste disposal. In order to carry out these jobs, the cell has different organs inside of it just like your body has organs. These “tiny organs” are called organelles. Different organs have different jobs and they need the proper supplies of ATP (cellular energy), proteins, oxygen, and other nutrients to carry out their jobs.
There are different types of cells that have different functions, but all cells have some common features. The things common to all cells are a cell membrane (plasma membrane), cytoplasm, and organelles. Take a look at a drawing of an animal cell. (Hold cursor over organelle to identify it.)

To understand how the cell carries out its functions, you should know more about the cytoplasm, cell membrane, and organelles. Click on each structure given in the table below to learn more about each cell part. Complete the table by writing a brief description and function for each part.

The things common to all cells are a cell membrane (plasma membrane), cytoplasm, and organelles. Remember that plant cells have three structures that animal cells don’t.  Now look at a drawing of a plant cell.  (Hold cursor over organelle to identify it.)

COMPLETE THE TABLE BELOW:

Structure
Description
Function
 CHLOROPLAST
 CELL WALL
CENTRAL VACUOLE 

 
PROKARYOTIC CELLS

 

        Remember that prokaryotic cells are only found in bacteria!  They’re simpler than eukaryotic cells.  Look at the bacterial cell, and complete the table below:

Structure
Description
Function

After you have read about  cells, take the cell quiz. Check your answer after you answer each question.

 

 

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Campbell Problem 9

Molecular Genetics Problem 9
9. What pattern of inheritance would lead a geneticist to suspect that an inherited disorder of cell metabolism is due to a defective mitochondrial gene?

 

The disorder would always be inherited from the mother because the mother’s mitochondrial gene is the only one that survives when the zygote is formed. The gamete from the mother contains all the information. The head of the father’s sperm is the only part that survives during fertilization. The tail of the sperm containing the male’s mitochondria (an their genes) is lost when the zygote begins development. Thus it is only from the mother that the disorder can be inherited.

 

Do Brain Cells Run Out of Gas?
Within each cell reside hundreds of tiny gas stations known as mitochondria. These essential organelles generate a large share of the fuel, a molecule called ATP, that cells use to power their biological machinery. There’s a suspicion, admittedly controversial, that problems with these energy-supplying mitochondria contribute to the progression of age-related neurodegenerative illnesses such as Alzheimer’s, Parkinson’s, and Huntington’s diseases, says Douglas C. Wallace of Emory University School of Medicine in Atlanta. In 1993, Wallace and his colleagues reported on comparisons of the mitochondrial DNA of Alzheimer’s patients and that of people without Alzheimer’s, who served as controls. This genetic material, which contains all the instructions necessary for mitochondria to function and replicate, is independent of the DNA found in a cell’s nucleus. Wallace’s group discovered that a particular mutation in mitochondrial DNA showed up in more than 5 percent of Alzheimer’s patients but in less than 1 percent of a random group of people with-out the disease. Studies on animals support the importance of mitochondria in brain disorders. When investigators destroy mitochondria or inhibit the activity of enzymes crucial to mitochondrial function in rats or mice, the rodents develop behavioral or physical attributes of Alzheimer’s, Huntington’s, and Parkinson’s diseases. &emdash; J. Travis

Science News: Aug. 5 • Vol. 148, No. 6

 

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Catalase Bi Sample Lab 2

 

 

Enzyme Rate of Reaction for Catalase

 

Introduction:
Life would not be possible without chemical reactions. Chemical reactions are responsible for speeding up the process. A chemical reaction is the process of breaking chemical bonds, forming new bonds or both. The four things that can speed up a chemical reaction is heat, increasing the concentration of reactants, decreasing the concentration of products, and enzymes. Enzyme is a catalase, most the time a protein. Enzymes can control the rate of a reaction, and they also lower activation energy. Enzymes are important in regulating chemical pathways, synthesizing materials needed by cells, releasing energy, and transferring information. Enzymes are involved in digestion, respiration, vision, movement, and thought. There are several things that can affect the function of enzymes like temperature, the pH, and the amount of reactant or product. Simple cells may have as many as 2000 different enzymes, each one catalyzing a different reaction. In this particular lab, your hands act as the enzyme “Catalase”. This enzyme, which is found in your cells, splits hydrogen peroxide, a byproduct made by your cells during cellular respiration,  into water and oxygen.

 

Hypothesis:
If  time is increased, then more hydrogen peroxide molecules will be split into water and oxygen

 

Materials:
The materials used in this lab were pencils, scissors, envelope, 100 paper hydrogen peroxide molecules, and a watch with a second hand so that a person would be able to keep time for the person tearing the strips.

 

Methods:
Take a paper template and cut out 100 hydrogen peroxide molecules. Place the cut out pieces into an envelope. Then have a person act as a catalase and take one piece of the paper molecules out of the envelope at a time and rip it in two and  place the pieces back into the envelope. Have a person hold the envelope person, while another student keeps track of the “tearing” time intervals (10, 20, 30 ,60, and 60 seconds). Count how many molecules are  ripped at the end of each time interval and record this number in your data table. When all time intervals and counts are completed, use the formula below to figure the reaction rate for catalase. Record this rate in  your data table.
M2 – M1 = reaction rate
T2 – T1

Results:

 

 

Time in seconds

  

Ripped Hydrogen Peroxide Molecules

  

Rate of reaction
 

0-10

 3 .3
 

10-30

 10 .35
 

30-60

 24 .47
 

60-120

 63 .65
 

120-180

 124 1.02

 

1. What is an enzyme? What are its functions in living things?
Enzymes are proteins in living systems. Enzymes can control the rate of a reaction, and they lower activation energy.

 

2. Name several things things that can affect the function of an enzyme?
Temperature, the amount of reactant or product and the pH.

3. Write the chemical equation for the breakdown of hydrogen peroxide by the enzyme catalase.
hydrogen peroxide + catalase yields water + oxygen

4. An enzyme’s efficiency increases with greater substrate concentration, but only up to a point. Why?
all of the active sites of the enzymes become filled with hydrogen peroxide molecules

 

5. If you were allowed to continue this lab and rip hydrogen peroxide molecules for 240 and 300 seconds. What would happen to the rate of reaction and why would this happen?
It would increase.

 

6. What can you say about the length of time and the rate of the reaction?
The less time, the more the reaction rate is lowered, and the more time, the more the reaction rate is higher.

 

7. What would happen to the rate of reaction if you remove the water  and oxygen molecules as soon as they are produced?
It would be faster.

 

Error Analysis:
All pieces must be returned to the envelope each time interval to correctly simulate what occurs within a cell.

 

Discussion and Conclusion:
As the time intervals increased, the reaction rate of catalase increased also. In a living cell, more hydrogen peroxide would be broken down by catalase over a longer period of time.

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Catalase Lab Sample 1

 

 

Enzyme Rate of Reaction for Catalase

 

Introduction:
Enzymes are an important part of life that regulate chemical reactions with in the body. Enzymes speed up chemical reactions in four different ways, one way is heat, another is increasing the rate of reactants, the third way is decreasing the amount of products and the fourth way is enzymes, which speed up reaction without themselves being used up. Enzymes are also involved in digestion, respiration, reproduction, vision, movement, thought, and also in the productions of other enzymes. Simple cells may have as many as 2000 enzymes with each one catalyzing a different reaction. An enzyme can speed up a reaction making it 10, 000,000,000 times faster. An enzyme is a catalyst. A catalyst is a chemical that reduces the amount of activation interim needed for a reaction. Without enzymes a reaction would take much longer than if it had and enzyme. Enzymes also the control the rate and direction of the reaction.
Without catalysts chemical reactions would take much longer that the average human life expectancy. So that would mean that in 76 years only a couple chemical reactions would take place. Since our bodies have enzymes though hundreds of chemical reactions a day. If our bodies didn’t have catalysts our bodily cells couldn’t function. Some bacteria, however, possess a defense mechanism which can minimize the harm done by the two compounds. These resistant bacteria use two enzymes to catalyze the conversion of hydrogen peroxide  back into diatomic oxygen and water. One of these enzymes is catalase and its presence can be detected by a simple test. The catalase test involves adding hydrogen peroxide to a cultures sample or an agar slant.

 

Hypothesis:
The reaction rate of catalase splitting hydrogen peroxide into water and oxygen will increase over time.

Materials:
The materials used consisted of 100 paper H2O2 molecules, a data table, paper, pencil, calculator, scissors, watch with a second hand, and an enzyme rate of reaction catalase worksheet.

Methods:
Cut out 100 hydrogen peroxide paper molecules. Double check to make sure there are only 100 paper molecules and place them in an envelope. Then one person will keep track of the time while another person acts as a catalase and tears the paper hydrogen peroxide molecules in half. The torn paper molecules should be returned to the envelope each time. Another person times the person acting as the catalase.  The time intervals in which the paper molecules are to be ripped are 10 seconds, 20 seconds, 30 seconds, and two different 60second periods of time. The results should be  recorded in a data table. The reaction rate for catalase is figured using the formula:
M2 – M1 = Reaction Rate
T2  –  T1

 

Results:

 

 

Time in Seconds Ripped H2O2 Molecules Rate of Reaction
0-10 5 .5
10-30 13 .4
30-60 31 .6
60-120 61 .5
120-180 91 .5

 

1. What is an enzyme? What are its functions in living things?
chemicals that reduce the amount of activation energy needed for reactions to occur; they are proteins in cells that control metabolic reactions

 

2. Name several things that can affect the functioning of an enzyme.
temperature, pH, and the amount of reactant or product

 

3. Write the chemical equation for the breakdown of hydrogen peroxide by the enzyme catalase.
H2O2   +   Catalase –>  H2O  + O2

 

4. An enzyme’s efficiency increases with greater substrate concentration, but only up to a point. Why?
once all active sites are filled, the enzyme’s reaction rate won’t continue increasing

 

5. If you were allowed to continue this lab and rip hydrogen peroxide molecules for 240 and 300 seconds, what would happen to the reaction rate and why would this happen?
there would be more molecules ripped because of the increased amount of time

 

6. What can you say about the length of time and the reaction rate?
The more time available, the faster the reaction will occur.

 

7. What would happen to the reaction rate if you removed the water and oxygen molecules as soon as they were produced?
The rate of reaction would go even faster

 

Error Analysis:
The counting of the time  may have been off a couple of seconds.

 

Discussion and Conclusion:
The data shows that the more time there is, the more hydrogen peroxide molecules will be ripped. The catalase in the lab ripped about 6 molecules every 5 seconds. The same thing occurs in a cell as more hydrogen peroxide is produced, catalase speeds up breaking down this waste into water and oxygen.

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