Kingdom Monera and Nature Study #206: Bacteria

Sam's notebook page (10th grade)

What is included in the Kingdom Monera?

Kingdom Monera is basically Bacteria -the tiny little living things -so small that 1,000 of them would fit easily side-by-side in a dot on this "i". Bacteria are prokaryotic which means that they are single-celled organisms that are not "membrane-bound." The DNA strand, which is a single circular strand, is not bound inside a nucleus but is simply suspended in the cytoplasm. They also only have one type of organelle - ribosomes. The first way we separate the organisms in kingdom Monera is by their cell walls. If a bacterium has a complex cell wall (Gram-negative) it belong to phylum Gracilicutes. If the cell wall is rather simple (Gram-positive), it belongs to phylum Firmicutes. If they have no cell wall, they belong into phylum Tenericutes. Some bacterial posses a cell wall, but the compounds which form these walls are different than those of the phylums Gracilicutes and Firmicutes, than it is in the phylum Mendosicutes.

In phylum Firmicutes, the classes are determined by their shape.

Bacteria come in three basic shapes.

The shape of the bacterium is in its name. For instance, Staphylococcus pharyngitis is the name for strep throat, and from the name, you can tell that the bacteria are spherical (cocci). They are sometimes in colonies, not just a single bacterium by itself. There are other ways in which we categorize bacteria, however.

Bacteria can be aerobic or anaerobic, meaning they may or may not need oxygen.

Phylum Gracilicutes have three classes, which are based on their metabolism. Class Scotobacteria is composed of the non-photosynthetic bacteria. Many pathogenic bacteria can be found here.

Heterotrophic bacteria get their food from other sources. If they are decomposers, they are saprophytic; they feed on non-living things.

If heterotrophic bacteria are parasitic, they feed on a living host. Autotrophic bacteria make their own food either by photosynthesis (energy from sunlight) or by chemosynthesis (chemical reactions which release energy). Class Anoxphotobacteria, is composed of photosynthetic bacteria that do not produce oxygen, and Oxyphotobacteria, as you can probably tell from its name, is composed of photosynthetic bacteria that produce oxygen.

Bacteria can be aerobic or anaerobic, meaning they may or may not need oxygen.

We also took this opportunity to complete a nature study of bacteria, the object being a lesson to enforce cleanliness. We made up some unsweetened gelatin according to the directions on the packet. We poured some into four little disposable cups and let it cool. I then invited the boys to place their unwashed hands on the gelatin in two of the cups. I then got them to wash their hands and do the same with the second set of cups of gelatin. We covered the two plates and left them in a cool, dark place for a few days.

This is one of the cups that was touched with dirty hands. Can you see the cloudy spots throughout the gelatin? It is a bit hard to see. These are the places with bacterial colonies. The ones with washed hands did not have them. (I neglected to get pictures of them, since they didn't change.) We then explored the questions in Lesson 206 of the Handbook of Nature Study.  

Most people think of bacteria as harmful, and they can be, but there are also friendly bacteria. These are found in milk and yogurt, as the process of making yogurt involves culturing milk with live and active bacterial cultures. There are also friendly bacteria in your own body, including the ones that are responsible for the digestion of your food.

It is so much fun to collect a water sample from a nearby pond and see if you can identify the interesting microscopic creatures found there...

but if you don't have access to a pond and/or microscope, you can use this as your virtual pond. 

What can you identify?
Culturing pond water, or adding things to the jar of pond water in hopes of encouraging microorganisms to grow and reproduce, can produce even more interesting creatures to see, sketch and study. You can add a small amount of hay, rice, egg yolk or soil (or try adding each to four separate jars.) Take the jars and place them in an area of subdued light and leave them for about 3 to 5 days.

Some are Monera but some are Protista, which we will get to next time.

sources and inspiration:

• Exploring Creation with Biology, Jay Wile
• Handbook of Nature Study, Anna Botsford Comstock, Lesson 206: Bacteria
• Sahm I Am!
• Virtual Pond Dip
• Homeschooler's Resources (lots of videos)
• Healthy Habits at Totally Tots, Glitter Germs at Kids Activity Blog, or Glo Germs

related posts:

• The Plague Spreads

Introduction to Biology

The four criteria for life:
1. All life forms contain deoxyribonucleic acid (DNA).
2. All life forms have a method to extract energy from their surroundings and convert it into energy that is useful to them.
3. All life forms can sense changes in their surroundings and respond to those changes.
4. All life forms reproduce.
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Classifying Living Things

Living things can be classified into one of five kingdoms. Each kingdom can then be further classified into a phylum. Each of the phyla can be further classified into a class. Each class can be further divided into an order. Each order can be further divided into a family. Each family can be further divided into a genus, and each genus can be further divided into a species.

model of a Eukaryotic Animal Cell

Characteristics Used to Separate Organisms into Kingdoms

The first and most basic way of dividing organisms is based on whether they have  prokaryotic or eukaryotic cells. Prokaryotic cells are not "membrane-bound." The DNA strand, which is a single circular strand, is not bound inside a nucleus but is simply suspended in the cytoplasm. The Eukaryotic cell, on the other hand, has distinct, membrane-bound organelles.

Using a Biological Key
The steps are written out in a Biological Classification Key. One of the living things we used a Biological Key to classify was a tiger. Begin by determining if something is microscopic, or macroscopic (visible w/ the naked eye). We can see the tiger without the aid of a microscope, so the tiger is macroscopic. To the right of the word microscopic is the number 3. So we skip to question #3.
3. Autotrophic or heterotrophic? A tiger cannot make it's own food (like plants can, for example), so it is heterotrophic. To the right of heterotrophic, we see the number 5. So we skip to #5.
5. Decomposer or Consumer? A tiger is a consumer of food, not like fungi which is a decomposer. To the right of the word "consumer" are the words "kingdom Animalia" and the number 6.
That is our first classification, so in their notebook, the kids wrote the kingdom: "Animalia" and moved on to question 6.
6. Backbone or no backbone? Tigers have backbones, and that gives us our next classification of phylum: Chordata. They write it in their notebooks, and we see we should go to number 22.
22. Jaws or beak, or no jaw or beak? Tigers have a jaw, and the next number we go to is 23.
23. Skin covered with scales or no scales on skin? No scales on skin, so we go to 26.
26. No scales, no hair, no feathers; skin is slimy, orfeathers or hair. Tigers have hair; we go to 28, which further distinguishes between hair and feathers.
28. Hair or feathers? They have hair, and that means our next classification is class: Mammalia. Write that in the notebook and next is 29.
29. Hooves or no hooves? No hooves; go to 31.
31. Carnivore or herbivore? What do you think? Carnivore! On to 32.
32. Teeth or no teeth? (like an insect.) Tigers have teeth, so the next classification is order: Carnivora.
This is the last one for this key, since the key we are using only goes thru kingdom, phylum, class, order.
Our classification for a tiger is:
kingdom: Animalia; phylum: Chordata; class: Mammalia; order: Carnivora.

Another fun activity is the Pasta Biological Key.

Introduction to the Microscope

  Learning how to use a microscope is not as easy as one might think, and it is why high school students are expected to take biology with a lab. What do you do if you do not own or can't afford a microscope? The next best thing is a virtual microscope. Either way, students need to learn the name of each part, and the basics of how to focus. The most classic beginning microscope lab assignment is to look at a cheek cell. It is pretty fascinating to see a cell from your own body.

 

The Environmental Factor in Genetics and Its Effect on Radish Leaf Color

"...an organism's characteristics are not wholly determined by genetics. There are environmental factors...that influence the makeup of an organism. With all the talk of Punnett squares and the emphasis on phenotypes that are completely determined by genetics, it is important to remind ourselves that genetics is not the only thing at play. We can observe the effect that the environment has on a genotype to make its phenotype change." -Jay Wile, Exploring Creation with Biology

We planted 60 radish seeds in two egg cartons, wetting the soil. We covered one egg carton with a box to keep out light and let one have sunlight. When half of the seeds sprouted, we examined them daily. The cotyledons (the two leaves in the sprout) were either yellow or green.

We discovered that those seeds in the light had some yellow cotyledons to begin with but turned green over time. Those left in the dark continued to stay yellow, and in fact, even the ones that were green to start with, turned yellow over time. By the end of a week of observation, all of the cotyledons in the egg carton in the dark were yellow and all of the cotyledons in the egg carton in the light were green.

Genetic traits can be influenced by environmental conditions.

The Fragility of an Enzyme

Your students might have heard that their stomachs use enzymes to break down food, but they may not understand how they work. Enzymes are a special class of proteins that can attach themselves to particular molecules and actually pull on it, stretching the bond that holds the molecules together, a part of digestion. Enzymes, however, are very fragile and break down soon after they are formed. For this reason, people must a regular supply of protein. 

To illustrate just how fragile an enzyme can be, you can perform this demonstration. You will need some fresh pineapple (not canned), a blender, three bowls and Jell-O gelatin (It doesn't matter what flavor.)

Take some pieces of the fresh pineapple (skin removed) and crush it in the blender until it is a thick pulp.

Prepare the Jello, following the directions on the package until you get to the point where you need to put it in the refrigerator.. Take about a tablespoon of the pulpy mixture and put it into one of the bowls. Pour about 1/3 of the Jello to the bowl and stir it around. Mark this bowl as Room Temperature Pineapple.

Take the rest of the pineapple pulp and heat it on the stove on high for about 3 minutes, stirring constantly.  Take about one tablespoon of this mixture and put it in the second bowl. Pour 1/3 of the Jello mixture on top and stir. Label this Heated Pineapple.

Pour the rest of the Jello into the third bowl and label it Control. 

Put them all in the refrigerator for  a few hours.

After a Few Hours

The control bowl should, of course, look like regular jello.

The bowl marked room temperature pineapple should, on the other hand, be as runny as it was when you put it in the bowl. Pineapple contains an enzyme that stops the reaction which causes jello to gel. You may have noticed that Jell-O warns of this reaction on the side of their boxes, and suggests that you do not use fresh pineapple (as well as a few other fruits).

The bowl marked heated pineapple should look pretty much like the control jello.

The heat that was added to this pineapple was enough to destroy the enzyme 

This is also why you can use canned pineapple in jello. The enzyme has been destroyed during the pineapple's processing.

Because enzymes are so fragile and break down soon after they are formed, new enzymes, made from protein have to replace the old ones in a continual process. This is one reason why it is so important to have protein regularly in our diet.

Osmosis and Diffusion...what is the difference?

You can do the following demonstrations in order to show the difference between osmosis and diffusion. You will need:  a potato, a knife to cut it, some salt and some sugar, a tablespoon, three cups, some plastic wrap, a napkin and some tape. 

Put a tablespoon of sugar into the center of a unfolded napkin and then fold up the napkin around the sugar and  tape it shut so that no sugar and spill out. Put the napkin bundle into one of the cups and fill the cup with water. Cover with plastic wrap and let sit for two hours.

Cut the potato along it's width so that you can get two circular slices about 1/2 inch thick. Grasping the potato slices by their edges, they should be difficult to bend. Take one of the cups and add salt to the cup until the salt can no longer dissolve in the water. Take one slice and put it into the cup of salt-water. Take the other slice and add put it in the remaining up and fill it with plain water. Cover both cups with plastic wrap and let them sit for two hours.

After Two Hours

Remove the plastic wrap from the cup with the sugar bundle and then the sugar bundle and taste the water. What does it taste like?

It should taste sweet because the sugar should have found its way out of the napkin and into the water. The water molecules were able to travel through the tiny holes in the napkin and start filling the napkin with water. When in its solid form, sugar was too large to get through the tiny holes in the napkin, but  as the water got inside the napkin, the sugar began to dissolve. When dissolved, the sugar molecules cold individually get through the holes in the napkin. Thus the sugar moved from inside the napkin, where the concentration of sugar was high, into the water outside the napkin, where the concentration was low. This is diffusion.

Diffusion-The movement of molecules from an area of high concentration to an area of low concentration.

Remove the plastic wrap from the remaining two cups. Take each potato slice, one at a time and holding them from the edges as before, try to bend them again. How does it bend as compared to the first time? 

The potato in the glass of plain water should have been even more difficult to bend than before. A potato gets it's firmness or rigidity from the water that it in it. Diffusion allowed the water to move into the potato in the glass of plain water. You might even notice that the slice got a little larger. It got stuck a little in the bottom of our plastic cup.

The potato slice in the glass of salt water should, on the other hand, have become easy to bend and rubbery because diffusion could not occur, and in fact, this potato slice even lost water! The cells in the potato are surrounded by a semipermeable membrane and this membrane allows some molecules to pass through but  not others. It allows the water to pass through but not the salt. Salt, however, is attracted to water, which is why is dissolves in water in the first place. The attraction between the salt and the water molecules is enough to pull the water out of the potato and into the salt-water solution. This is osmosis. 

Osmosis-The tendency of a solvent to travel across a semipermeable membrane into areas of higher solute concentration.

Thanksgiving Week Science: Yeast and Making Bread

We do a lot of baking at our house, and many of our favorites use yeast as a leveaning agent. Yeast is a member of the fungi family, cousins to mushrooms, molds and mildew. Yeast must have three things in order to grow -moisture, food, and warmth. Once they have these three conditions, they reproduce, which is called budding.

"When a yeast buds, the nucleus of the cell reproduces inside a single cell. A section of the cell wall and plasma membrane then swell to form a pouch...This pouch is called a bud. The bud continues to grow until it is about the same size as the parent cell and then the two cells seperate." -Exploring Creation with Biology, Wile ("Experiment" 4.2)

The yeast begins to feast on the sugars, breaking them down into alcohol and carbon dioxide. The carbon dioxide pushes its way out of the dough, causing the dough to rise. When the dough is put into the oven, the yeast are killed and the alcohol evaporates.

Since one of the products of fermentation is alcohol, yeasts are also used to put the alcohol into alcoholic beverages.

Mix one packet of yeast with one cup of warm water in a glass. Add one tablespoon of sugar or honey. Stir gently. Let the mixture stand for five to ten minutes. As the mixture stands, you should be able to see bubbles forming -in fact a whole layer of foam caused by the bubbles will form and grow as time goes on.
If you have a microscope, ou could place a drop of he yeast solution on a slide (and coverslip) and observe the budding process. You might even see chains of budding yeast.

If you wish, you can now use your yeast to make bread, rolls or pizza dough.