*Discovering God's Creation Science 9-12: Biology*

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Discovering God's Creation Science

Biology explores living things from the visual and microscopic perspectives. Learn how plants feed from their morningstars and which animals have multiple hearts. Discover why all of our blood doesn't settle in our feet when we stand up! Explore cell structures and DNA! Biology offers to homeschoolers an exciting new perspective on the intricate living organisms that God created.

My Courses
1: *Discovering God's Creation Science 9-12: Biology*
2: *Discovering God's Creation Science 9-12: Forensics-Crime Scene Investigation*
3: *Heritage Social Studies 8: American History 2*
4: *Heritage Social Studies 9-12: American Government*
5: *Jubilee English 1: Phenomenal Phonics*
6: *Living Word Bible 3: Life of Christ*
7: *Victory Math 2: From Training to Triumph*
           1.1
:::BACTERIA:::

Bacteria are an abundant, widespread and prolific (reproduce in great quantities) family of organisms belonging to kingdom Monera. They live everywhere - in air, water, soil, milk, and even in the human body.

Bacteria are commonly despised because they are best known as causers of disease. However, there are many which are directly and indirectly useful to man, and some are actually necessary for life's activities.

A typical bacterial cell has a cell wall made of cellulose or other material, surrounded by a thin, slimy gelatinous capsule. They have no nuclei; instead, their chromatin granules are often clumped together to resemble one large chromosome

Bacteria are very small; usually less than 1/25,000 of an inch, a unit of measurement called a micron. They vary from 0.15 to 5 microns in length. Fifteen hundred of the rod-shaped bacteria hardly reach across the head of a pin. Since they are visible under the microscope, bacteria have been seen to have various and distinct shapes. Some have no powers of locomotion, and are carried from place to place by the air, by water and other liquids, and by plants and animals. Others have flagella with which they move about in a liquid medium.

The surface soil, especially if it is rich in organic matter, contains many kinds of bacteria; but at a depth of ten feet they usually become scarce. Ordinary earth may yield from 10,000 to 100,000,000 in a gram if it has become polluted. Soils that have not been cultivated have fewer. The condition that really determines how many bacteria will be found in the soil is the amount of organic matter it contains.

The bacterium in soil breaks down parts of dead plants and animals, facilitating soil enrichment. This is an important process that is necessary for plant growth and survival.

CONDITIONS OF GROWTH

Like all other living organisms, bacteria must have all the proper conditions before they can grow and multiply. Their food is chiefly plant or animal matter. However, they cannot make use of food except in the presence of warmth and moisture. Most bacteria require oxygen in addition, which they get from the surrounding air.


When food, air, warmth, or moisture is not sufficient, bacteria cease to grow and go into a resting state (encystment). That is, they change their form, and surround themselves with a substance that protects the soft protoplasm from being harmed by freezing, heating, or drying.

Bacteria, being living cells, must carry on all life processes. Characteristically, they have a cell wall that surrounds a cell membrane. Under favorable conditions, they reproduce by binary fission (splitting in half after maximum growth). They get their food from other plants and animals.

Conditions favorable to growth and reproduction of bacteria are:
1. Moisture
2. Oxygen usually from air
3. Moderate heat
4. Lack of direct sunlight 
5. Prepared food
6. Proper chemical environment

Unfavorable conditions for growth and reproduction are, then:
1. Dryness 
2. Oxygen 
3. Extreme heat or cold
4. Direct sunlight
5. Lack of food

There are some hardy forms of bacteria that adapt themselves to withstand unfavorable conditions, sometimes temporarily and sometimes for many years. Their cell walls become very hard, developing into spore cases or cysts. The cell within the spore case is quiescent until conditions are favorable again. In some measure, it resembles a bear, hibernating during the long, cold, unfavorable winter.

APPEARANCE OF BACTERIA

Bacteria are grouped into three classes according to their shape: 
(1) round (the cocci
(2) rod-shaped (the bacilli
(3) those that are shaped like a cork
(4) screw (the spirilla). 

The spirilla and the bacilli often have on one or both ends tiny thread-like hairs called flagella by which they move.

 

Types of bacteria

Rickettsiae are like bacteria in that they reproduce by fission. They are like viruses in their need for living tissue in order to grow. The diseases caused by rickettsiae, including typhus fever, are carried by insects and other animals. 

Please place Disk 1 for Biology into your computer now. Click on Video 23 to watch a movie titled "Understanding Bacteria."

Some examples of the numerous life forms living on our body made visible by scanning electron microscopes. Excerpt from the documentary "The invisible world"

 

Read this site to get more in depth information on the general structure of bacterial cell.

Now explore this fantastic interactive bacterial cell. Click here for a great model of a bacteria cell. Explore the descriptions for each part!

Bacteria Rule! Test your knowledge of bacteria and learn about how helpful these microscopic life-forms can be.

Bacteria are pretty small; so small it can sometimes be hard to get a grasp on.  Try this interactive size comparison with other microorganisms to get an idea of just how little they can be.

Play Bacteria Jeopardy.  You only need one player.  Test yourself and have fun! See how much you've learned and how much more you would like to learn.

 

Let's see the affects of Bacteria with this activity called Sour Power.
 

Background
You can kill most of disease-producing bacteria in milk by heating it to 143° F (62° C) and then keeping it at that temperature for 30 minutes. This process is called pasteurization. Today "flash pasteurization" is commonly used instead, in which milk is heated at a higher temperature of 160° F (71° C) and maintained for 15 seconds. In this activity, you'll explore how the growth of additional bacteria after pasteurization is slowed in colder temperatures.

What You Need
  • two clear plastic cups
  • pasteurized milk
  • refrigerator
What To Do
  1. Pour a small amount of milk in each of two cups.
  2. Place one cup in a warm area, such as on a sunny windowsill.
  3. Place the other cup in a refrigerator.
  4. What do you think will happen to the milk in each cup over the next week? Write your predictions on the worksheet.
  5. Over the week, check both cups each day and write your observations in the worksheet chart. At the end of the week, answer the final worksheet question.

 

 

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