Category: My Classroom Material

Caught Red-Handed

 

Caught Red-Handed  

 

Introduction:

Bacteria are everywhere. They have evolved the ability to inhabit almost every surface on the planet; however, they are invisible to the naked eye due to their small size. Bacteria have been found living in the deepest part of the ocean, in volcanic vents, in boiling hot springs, and even deep in polar ice caps. Many species of bacteria live inside of other organisms in a harmless commensalistic way such as the intestinal bacteria, Escherichia coli. Bacteria can reproduce at very rapid rates whenever conditions are favorable, as often as every 20 minutes doubling in number. The bacterial population is kept in check by the natural defenses of the host, such as the immune system and proper washing habits. When these natural defenses fail, bacteria can quickly become a problem. Some bacteria produce poisons or toxins that can be life-threatening if the bacterial population isn’t controlled by our natural defenses.

The United States Centers for Disease Control (CDC) states that the best way to prevent bacterial spread and infection is through the use of proper sanitary techniques. Perhaps the most critical step in this prevention is the use of proper hand washing. When improperly washed, your hands are one of the most easily colonized areas of your body and many of our behaviors involve the use of our hands.  Proper hand washing requires the use of water as hot as you can stand, soap, and lots of rubbing. The soap and water serve to destroy bacteria, and the rubbing helps slough off dead skin cells along with lots of bacteria.

Objective:

Students will examine:

  1. The spread of bacteria through surface contact
  2. Surface washing techniques to reduce the spread of bacteria

Materials (Part A):

Black light, Glo-Germ powder, lotion or Glo-Germ oil, hand soap, water, paper towels, pencil, lab sheet

Procedure (Part A):

  1. Choose one student in the lab group and have them spread a SMALL AMOUNT of Glo-Germ powder or lotion evenly over the entire surface of their hands. Be sure to include hard to clean areas such as around & under the fingernail.
  2. Have another student use the Black light to check your hands for the fluorescent “germs”.
  3. Estimate the percentage of your hand that you have covered with Glo-Germ powder and record this percentage in your data table 1 under time “0”.
  4. Wash your hands for 10 seconds and then recheck your hands with Black light and record the percentage of “germs” remaining.
  5. Repeat step 5 for washing times of 30 seconds, 60 seconds, and 120 seconds.
  6. Return Glo-Germ powder, lotion, or oil to lab cart. 

Data Table 1

 

Time of Wash in Seconds Percent of Hand Covered with “germs”
0 (initial observation)
10
30
60
120

 

Materials (Part B):

Tennis ball, “play” money, stuffed toy, pencil, lab sheet

Procedure (Part B):

  1. Choose a different member of your lab group and use the Black light to check their hands for the presence of germs.  IF they are “infected”, have them thoroughly wash their hands to remove the “germs”.
  2. Record the percentage of their hand that is covered with “germs”.
  3. Pick up the basket from the lab cart with your materials for part B.
  4. Handle the tennis ball for at least 20 to 30 seconds.
  5. After handling the tennis ball, have your hands rechecked with the Black light for “germs”.
  6. Record this percentage in data table 2.
  7. Return to your lab table and handle each of the other items ONE AT A TIME, checking for “germs after EACH item and recording this percentage in table 2.
  8. Return the black light and basket with handled items to the lab cart.

Data Table 2

 

Name of Item Percent Coverage
Initial Hand Coverage
Tennis Ball
“Play” money
Toy

 

Questions:

  1. If almost every surface we touch is inhabited by bacteria, why don’t bacterial infections occur more often?
  2. Name 3 ways you  might prevent the spread of bacteria each day.
  3. Name several bacterial diseases.
  4. Name and describe the 3 shapes of bacteria.
  5. Are all bacteria harmful? Explain your answer.
  6. What effect, if any, did increased washing time have on the percentage of “germ” coverage on your hands?
  7. Name 3 areas of your home that are most susceptible to bacterial contamination. Explain steps you could take in each of these areas to prevent the spread of bacteria to other places in your home.

Optional:

Create a graph based on the data from table 1.

Title _____________________________

 

Calorimetry lab

Calorimetry – Measuring the energy in Foods

Introduction:
There are two processes that organisms use to make usable energy. The process by which autotrophs convert sunlight to a usable form of energy is called photosynthesis. Photosynthesis supports all life on earth. Products from photosynthesis include food, textiles, fuel, wood, oils, and rubber. During photosynthesis, light energy is used to make organic compounds from inorganic water and carbon dioxide. Photosynthesis goes through light dependent reactions and the light independent reactions which include the Calvin cycle.
The process where heterotrophs break down food molecules to release energy for work is called cellular respiration. Cellular respiration is the reverse of photosynthesis; the reactants of one are the products of the other. The reactants of cellular respiration are glucose and oxygen, and the products are carbon dioxide, water, and energy.  Cellular respiration breaks down glucose to form carbon dioxide and water, while releasing energy usable by the cells. The first step, glycolysis is the process  that converts glucose to pyruvate and releases a small amount of cellular energy.  The second step may be aerobic or anaerobic depending on the amount of oxygen available.  Aerobic respiration is the breakdown of pyruvate in the presence of oxygen.  A larger amount of cellular energy or ATP is produced during the Kreb’s cycle and electron transport chain. Anaerobic respiration is the breakdown of food molecules in the absence of oxygen. Less ATP is produced by anaerobic respiration or fermentation.

Hypothesis:
If the heat given off by a burning pecan is measured by how much the temperature increases in a given amount of water, then the number of calories of energy stored in the nut during photosynthesis can be determined.

Materials:
Items needed for the lab included a large paper clip, a 100 ml graduated cylinder, thermometer, 2 soft drink cans, electronic balance, butane lighter, plastic tray, scissors, paper, and pencil.

Procedure:
Use a graduated cylinder to measure 100 ml of water and add this to an empty soft drink can. Cut holes on two sides of a second soft drink can so there is room to place a large bent paper clip.  Measure and record the mass of one pecan using the electronic balance. Bend a large paper clip to make a “nut stand” and measure and record  the mass of this clip. Place the pecan on the nut stand and put the stand inside the cut-out drink can.  Use a thermometer to measure and record the temperature of the water in the second can.  Place this can on top of the can with the nut. Use a butane lighter to ignite the nut. Record the temperature of the water when the nut is completely burned. Complete the data table by calculating the  the total calories in the pecan.

Data:    

Data Table 1
Before Burning After Burning Difference
Mass of Nut 1.7 g 0.1g 1.6g
Temperature of Water 20 40.1 20.1
Mass of Paper Clip 1.4g 1.4g 0g

 

Data Table 2
Mass of pecan 0.1 g
Temperature change of 100 ml of water 20.1
Calories required to produce temperature change in 100 ml water 2010
Calories per gram contained in the pecan 1182.4

Error Analysis:
Errors may have occurred in several ways during this experiment. One error that may have occurred is that some of the energy may have been lost during the burning. Some of the pecan’s energy was lost as light instead of heat energy. Also some of the heat measured in the water could have been due to the butane lighter used to ignite the pecan.

Conclusion:
The temperature of the 100 ml of water in the can above the burning pecan was changed by the energy given off by the pecan when it was burned.  The energy given off by the burning pecan was great enough to increase the water temperature by 20.1 degrees Celsius. The mass of the unburned pecan was 1.7g. It takes 100 calories to raise the temperature of 1 ml of water by 1 degree Celsius. The temperature of 100 ml of water was recorded to have increased by 20.1 degrees Celsius; therefore, the total number of calories in the pecan equals 20.1 x 100 or 2010 calories. Since the nut had a mass of 1.7g, the number of calories per gram equals 2010 divided by 1.7 or 1182.4 calories per gram.
The increase of temperature in the water showed that energy had been stored in the pecan. In this experiment, the amount of calories of heat energy stored in a pecan during photosynthesis was measured by a process known as calorimetry.

 

Structure & Function of the Cells

 

STRUCTURE AND FUNCTION OF THE CELL

All Materials © Cmassengale

I. All Organisms are Made of Cells

 

A. The cell is the basic unit of structure & function

 

B. The cell is the smallest unit that can still carry on all life processes

C. Both unicellular (one celled) and multicellular (many celled) organisms are composed of cells

D. Before the 17th century, no one knew cells existed

E. Most cells are too small to be seen with the unaided eye

 

F. In the early 17th century microscopes were invented & cells were seen for the 1st time

G. Anton Von Leeuwenhoek, a Dutchman, made the 1st hand-held microscope & viewed microscopic organisms in water & bacteria from his teeth

 

Leeuwenhoek’s microscope consisted simply of:

  • A) a screw for adjusting the height of the object being examined
  • B) a metal plate serving as the body
  • C) a skewer to impale the object and rotate it
  • D) the lens itself, which was spherical

 

 

H. In 1665, an English scientist named Robert Hooke made an improved microscope and viewed thin slices of cork viewing plant cell walls

 

I. Hooke named what he saw “cells”

J. In the 1830’s, Matthias Schleiden (botanist studying plants) & Theodore Schwann (zoologist studying animals) stated that all living things were made of cells

 

K. In 1855, Rudolf Virchow stated that cells only arise from pre-existing cells

 

L. Virchow’s idea contradicted the idea of spontaneous generation (idea that nonliving things could give rise to organisms)

M. The combined work of Schleiden, Schwann, & Virchow is known as the Cell Theory

 

Schwann Schleiden Virchow

 

 

II. Principles of the Cell Theory

 

A. All living things are made of one or more cells

B. Cells are the basic unit of structure & function in organisms

C. Cells come only from the reproduction of existing cells

 

III. Cell Diversity

 

A. Not all cells are alike

B. Cells differ in size, shape, and function

 

C. The female egg cell is the largest cell in the body & can be seen without a microscope

relative sizes of cells and their components

D. Bacterial cells are some of the smallest cells & are only visible with a microscope


E.coli Bacterial Cells

E. Cells need surface area of their cell membrane large enough to adequately exchange materials with the environment (wastes, gases such as O2 & CO2, and nutrients)

 

F. Cells are limited in size by the ratio between their outer surface area & their volume

 

G. Small cells have more surface area for their volume of cytoplasm than large cells

H. As cells grow, the amount of surface area becomes too small to allow materials to enter & leave the cell quickly enough

I. Cell size is also limited by the amount of cytoplasmic activity that the cell’s nucleus can control

J. Cells come in a variety of shapes, & the shape helps determine the function of the cell (e.g. Nerve cells are long to transmit messages in the body, while red blood cells are disk shaped to move through blood vessels)

 

IV. Prokaryotes

 

A. Prokaryotic cells are less complex

B. Unicellular

C. Do not have a nucleus & no membrane-bound organelles

 

D. Most have a cell wall surrounding the cell membrane & a single, looped chromosome (genetic material) in the cytoplasm

 

E. Include bacteria & blue-green bacteria

 

F. Found in the kingdom Monera

 

 

V. Eukaryotes

 

A. More complex cells

B. Includes both unicellular & multicellular organisms

 

C. Do have a true nucleus & membrane-bound organelles

 

D. Organelles are internal structures in cell’s that perform specific functions

 
a. Nucleus b. Chloroplast c. Golgi d. Mitochondria

 

E. Organelles are surrounded by a single or double membrane

 

F. Entire eukaryotic cell surrounded by a thin cell membrane that controls what enters & leaves the cell

G. Nucleus is located in the center of the cell

H. The nucleus contains the genetic material (DNA) & controls the cell’s activities

I. Eukaryotes include plant cells, animal cells, fungi, algae, & protists

J. Prokaryotes or bacteria lack a nucleus

K. Found in the kingdoms Protista, Fungi, Plantae, & Animalia

 

 

VI. Cell Membrane

 

A. Separates the cytoplasm of the cell from its environment

B. Protects the cell & controls what enters and leaves

 

C. Cell membranes are selectively permeable only allowing certain materials to enter or leave

D. Composed of a lipid bilayer made of phospholipid molecules

 

E. The hydrophilic head of a phospholipid is polar & composed of a glycerol & phosphate group and points to the aqueous cytoplasm and external environment.

F. The two hydrophobic tails are nonpolar point toward each other in the center of the membrane & are composed of two fatty acids

G. When phospholipids are placed in water, they line up on the water’s surface with their heads sticking into the water & their tails pointing upward from the surface.

H. The inside of the cell or cytoplasm is an aqueous or watery environment & so is the outside of the cell. Phospholipid “heads” point toward the water.

I. Phospholipid “tails” are sandwiched inside the lipid bilayer.

J. The cell membrane is constantly breaking down & being reformed inside living cells.

K. Certain small molecules such as CO2, H2O, & O2 can easily pass through the phospholipids

 

VII. Membrane Proteins

 

A. A variety of protein molecules are embedded in the cell’s lipid bilayer.

B. Some proteins called peripheral proteins are attached to the external & internal surface of the cell membrane

C. Integral proteins or transmembrane proteins are embedded & extend across the entire cell membrane. These are exposed to both the inside of the cell & the exterior environment.

D. Other integral proteins extend only to the inside or only to the exterior surface.

E. Cell membrane proteins help move materials into & out of the cell.

F. Some integral proteins called channel proteins have holes or pores through them so certain substances can cross the cell membrane.

G. Channel proteins help move ions (charged particles) such as Na+, Ca+, & K+ across the cell membrane

H. Transmembrane proteins bind to a substance on one side of the membrane & carry it to the other side. e.g. glucose

 

I. Some embedded, integral proteins have carbohydrate chains attached to them to serve as chemical signals to help cells recognize each other or for hormones or viruses to attach

 

 

VIII. Fluid Mosaic Model

 

A. The phospholipids & proteins in a cell membrane can drift or move side to side making the membrane appear “fluid”.

B. The proteins embedded in the cell membrane form patterns or mosaics.

C. Because the membrane is fluid with a pattern or mosaic of proteins, the modern view of the cell membrane is called the fluid mosaic model.

 

IX. Internal Cell Structure & Organelles of Eukaryotes

A. Cytoplasm includes everything between the nucleus and cell membrane.

 

B. Cytoplasm is composed of organelles & cytosol (jellylike material consisting of mainly water along with proteins.

 

C. Eukaryotes have membrane-bound organelles; prokaryotes do not

 

D. Mitochondria are large organelles with double membranes where cellular respiration (breaking down glucose to get energy) occurs

1. Energy from glucose is used to make ATP or adenosine triphosphate

 

2. Cells use the ATP molecule for energy

3. More active cells like muscle cells have more mitochondria

 

4. Outer membrane is smooth, while inner membrane has long folds called cristae

 

5. Have their own DNA to make more mitochondria when needed

E. Ribosomes are not surrounded by a membrane & are where proteins are made in the cytoplasm (protein synthesis)

 

1. Most numerous organelle

2. May be free in the cytoplasm or attached to the rough ER (endoplasmic reticulum)

F. Endoplasmic reticulum are membranous tubules & sacs that transport molecules from one part of the cell to another

1. Rough ER has embedded ribosomes on its surfaces for making proteins

2. Smooth ER lacks ribosomes & helps break down poisons, wastes, & other toxic chemicals

3. Smooth ER also helps process carbohydrates & lipids (fats)

4. The ER network connects the nucleus with the cell membrane

 

G. Golgi Apparatus modifies, packages, & helps secrete cell products such as proteins and hormones

1. Consists of a stack of flattened sacs called cisternae

 

2. Receives products made by the ER

 

H. Lysosomes are small organelles containing hydrolytic enzymes to digest materials for the cell

1. Single membrane

2. Formed from the ends of Golgi that pinch off

 

3. Found in most cells except plant cells

I. Cytoskeleton consists of a network of long protein tubes & strands in the cytoplasm to give cells shape and helps move organelles

 

1. Composed of 2 protein structures — microtubules, intermediate filaments, & microfilaments

 

2. Microfilaments are ropelike structures made of 2 twisted strands of the protein actin capable of contracting to cause cellular movement (muscle cells have many microfilaments)

3. Microtubules are larger, hollow tubules of the protein called tubulin that maintain cell shape, serve as tracks for organelle movement, & help cells divide by forming spindle fibers that separate chromosome pairs

 

Cytoskeleton Element  General Function
Microtubules Move materials within the cell
Move the cilia and flagella
Actin Filaments Move the cell
Intermediate Filaments Provides mechanical support

 

 

J. Cilia are short, more numerous hair like structures made of bundles of microtubules to help cells move

 

1. Line respiratory tract to remove dust & move paramecia


Cross section of Cilia & Flagella

K. Flagella are long whip like tails of microtubules bundles used for movement (usually 1-3 in number)

1. Help sperm cells swim to egg

L. Nucleus (nuclei) in the middle of the cell contains DNA (hereditary material of the cell) & acts as the control center

 

1. Most cells have 1 nucleolus, but some have several

2. Has a protein skeleton to keep its shape

3. Surrounded by a double layer called the nuclear envelope containing pores

4. Chromatin is the long strand of DNA in the nucleus, which coils during cell division to make chromosomes

 

5. Nucleolus (nucleoli) inside the nucleus makes ribosomes & disappears during cell division

 

M. Cell walls are nonliving, protective layers around the cell membrane in plants, bacteria, & fungi

1. Fungal cell walls are made of chitin, while plant cell walls are made of cellulose

 

2. Consist of a primary cell wall made first and a woody secondary cell wall in some plants

 

N. Vacuoles are the largest organelle in plants taking up most of the space

1. Serves as a storage area for proteins, ions, wastes, and cell products such as glucose

 

2. May contain poisons to keep animals from eating them

3. Animal vacuoles are smaller & used for digestion

O. Plastids in plants make or store food & contain pigments to trap sunlight

1. Chloroplast is a plastid that captures sunlight to make O2 and glucose during photosynthesis; contains chlorophyll

a. Double membrane organelle with an inner system of membranous sacs called thylakoids

 

b. Thylakoids made of stacks of grana containing chlorophyll

2. Other plastids contain red, orange, and yellow pigments

3. Found in plants, algae, & seaweed

X. Multicellular Organization

 

A. Cells are specialized to perform one or a few functions in multicellular organisms

B. Cells in multicellular organisms depend on each other

 

C. The levels of organization include:
Cells –> Tissues –> Organs –> Systems –> Organism

D. Tissues are groups of cells that performs a particular function (e.g. Muscle)

 

E. Organs are groups of tissues working together to do a job (e.g. heart, lungs, kidneys, brain)

F. Systems are made of several organs working together to carry out a life process (e.g. Respiratory system for breathing)

G. Plants have specialized tissues & organs different from animals

1. Dermal tissue forms the outer covering of plants

2. Ground tissue makes up roots & stems

3. Vascular tissue transports food & water

4. The four plant organs are the root, stem, leaf, & flower

 

H. Colonial organisms are made of cells living closely together in a connected group but without tissues & organs (e.g. Volvox)

Calorimetry Sample Lab 3 PreAP

 

The Heat Is On    

 

Introduction:

Energy comes in a variety of forms: light, heat, motion, electricity, and so forth. The energy in food is measured in units of Calories. A Calorie is defined as the quantity of heat it takes to raise the temperature of 1 kg of water 1 degree Celsius. The energy in food is defined in terms of heat because the quantity measured is heat produced upon burning the food. Burning in the presence of oxygen is the process of combustion. Complete combustion results in the production of energy as well as carbon dioxide and water.

Plants utilize sunlight throughout photosynthesis to convert carbon dioxide and water into glucose and oxygen.  This certain glucose has energy stored in its chemical bonds that can also be used by other organisms.  This stored energy can be released whenever these chemical bonds are broken in metabolic processes for instance cellular respiration.  When this experiment partakes you will have to measure the amount of energy that is available for use from types of nuts, preferably pecan because they have the most oil to burn.  The process you are doing is known as calorimetry.

Hypothesis:

            If calories are measured by the heat given off from the burning nut changing the temperature in the given amount of water, then the energy stored in the nut can be measured.

Materials:

The materials needed to construct this experiment are a large paper clip, thermometer, soft drink can, soft drink can with openings cut into the side, one whole pecan, matches, water, pencil and paper, scissors, plastic tray, graduated cylinder, calculator, and a electronic balance.

Methods:

            First, carefully cut out two openings along the side of a soft drink can.  This will serve as your support for the second drink can that will contain water and sit on top. Then bend a large size paper clip so that a nut can be attached on one end and the other end will sit flat inside the cut out soft drink can.  Next, use the graduated cylinder to accurately measure 100g of water. Pour this water into the uncut soft drink can.  Then use the thermometer to measure the temperature©.  Record this temperature on the data table.  Mass the nut (g) that you will burn and record this mass on your data table.  Next, attach the nut to the bent end of your paper clip and carefully set the clip and nut into the cut-out soft drink can on bottom.  Make sure the cans are sitting on a flat, nonflammable surface!  Carefully light the nut using a match and record the change in water temperature as the nut burns.  Record the final water temperature as the nut burned.  Then measure the mass (g) of the remaining nut and record this in the data table.  Complete the data table by calculating the change in mass of the nut and the temperature of the water.  If you have enough time repeat this experiment with a different type of nut but remember to always start with cold water and to take the initial and final water temperature and mass of the nut.

Results:

Data Table 1

Nut used pecan

Before Burning

After Burning

Difference
Mass of nut (g) 1.4 g .1 g 1.3 g
Temperature of water © 22 © 41 © 19 ©

Data Table 2

Mass of the burned pecan 1.3 g
Temperature change of 100mL of water 19 degrees C
Calories required to produce temperature change in 100mL of water 1900 calories
Calories per gram contained in the pecan 1357.1

 Questions:

  1. What is the relationship between matter and energy? The more the matter the more the energy.
  2. What do we call stored energy and where is energy stored in compounds such as glucose? We call it glycogen, and its stored in the bonds.
  3. Discuss what happened to the energy stored in the nut? It was released by the heat.
  4. Why was the mass of the less after burning?  The oils in the nut were evaporated.
  5. How do our bodies make use of this process? They break down the glucose to form energy known as glycogen.

Error Analysis:

Errors could have occurred if all the oils were not all evaporated during the process of burning of the pecan.  Also if you didn’t use the correct amount of water this could have caused an inaccurate measurement.

Discussion and Conclusion:

The temperature of the can with 100mL of water in it changed from the energy stored in the pecan.  The temperature of the water started out being 22 degrees C and as the pecan burned it released the energy and heated the water to 41 ©.  Also the mass of the pecan before it was burned was 1.4g and after burning was .1g.  One calorie equals the heat required to change the temperature of 1 gram of water 1degree C.  In this experiment, the temperature change was 19degrees C which meant 1900 calories were produced to change the temperature of the water.  With the mass of the nut before burning and the amount of calories required to change the temperature gave me the information to find that my pecan had 1357.1 calories in it.

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Cell Analogy

 

Cell City Analogy
By Shannan Muskopf

In a far away city called Grant City, the main export and production product is the steel widget. Everyone in the town has something to do with steel widget making and the entire town is designed to build and export widgets. The town hall has the instructions for widget making, widgets come in all shapes and sizes and any sizes and any citizen of Grant can get the instructions and begin making their own widgets. Widgets are  generally produced in small shops around the city, these small shops can be built by the carpenter’s union (whose headquarters are in town hall).

After the widget is constructed, they are placed on special carts which can deliver the widget anywhere in the city. In order for a widget to be exported, the carts take the widget to the postal office, where the widgets are packaged and labeled for export. Sometimes widgets don’t turn out right, and the “rejects” are sent to the scrap yard where they are broken down for parts or destroyed altogether. The town powers the widget shops and carts from a hydraulic dam that is in the city. The entire city is enclosed by a large wooden fence, only the postal trucks (and citizens with proper passports) are allowed outside the city.

 

Match the parts of the city (underlined) with the parts of the cell.

1. Mitochondria _____________________________________________
2. Ribosomes _____________________________________________
3. Nucleus _____________________________________________
4. Endoplasmic Reticulum _____________________________________________
5. Golgi Apparatus _____________________________________________
6. Protein _____________________________________________
7. Cell Membrane _____________________________________________
8. Lysosomes ____________________________________________________________
9. Nucleolus _____________________________________________

** Create your own analogy of the cell using a different model. Some ideas might be: a school, a house, a factory, or anything you can imagine**