Chapter 10 Overview

Section 1 Bacteria Kingdom reference: Archaebacteria and

Eubacteria Section 2 Bacteria’s role in the world Bacteria and plants Bacteria role in medicine Bacteria as poison producers

Chapter 10 Overview

Section 3 Viruses The discovery of Viruses Vaccines

Vocabulary for Section 1

Binary Fission Endospore

Section 1 Bacteria

They are the smallest and simplest organisms on earth.

They are also the must abundant. A gram of earth, which is about the size

of your pencil eraser, can contain as many as 2.5 million bacteria.

All organisms fit into one of the six Kingdoms we discussed last chapter.

Section 1 continued The two Kingdoms that bacteria fall under are

Archaebacteria and Eubacteria. These two Kingdoms contain the oldest forms of

life on earth, in fact for 2 billion years they were the only life forms on earth.

Bacteria are single cell organisms and their cells contain no nucleus. They are prokaryotic cells which you should already know.

Prokaryotes are able to perform cellular respiration, move around, and reproduce. Because of these abilities they can function as independent organisms.

Section 1 continued

Prokaryotes reproduce by a simple cell division called

Binary Fission: The process is the DNA replicates before cell division. The DNA and its copy attach to the inside of the cell membrane. As the cell grows and the membrane grows longer, the loops of DNA become separated. When the cell is about double in size, the membrane pinches inward. A new cell wall forms, separating the two new cells and their DNA.

Section 1 continued

Endospores Bacteria that grow a thick protective

membrane to protect them from an unfavorable environment. Once they are released from the harsh environment the endospores will break open and become active once again.

Section 1 continued The most common shapes of Bacteria Bacilla

• Rod shaped bacteria. Have a large surface area, which helps them absorb nutrients, but they can also dry out easily

Cocci• Spherical bacteria. They are more resistant to drying

out than rod shaped bacteria. Spirilla

• Long spiral shaped bacteria. This is the least common shape for bacterium. Spirilla move easily in a corkscrew motion, using flagella at both ends.

This is a picture of the worlds larges bacteria from the intestines of a surgeonfish. About the size of a pin head.It’s name is Epulopiscium.

CocciSpherical bacteria. They are more resistant to drying out than rod shaped bacteria.

SpirillaLong spiral shaped bacteria. This is the least common shape for bacterium. Spirilla move easily in a corkscrew motion, using flagella at both ends.

Lactobacillus acidophilus (lack-toe-bah-sill-us acid-off-ill-us): one of the bacteria gang wanted for turning milk into yogurt.

Saccharomyces cerevisiae (sack-arrow-my-seas sair-uh-vis-ee-ay): a.k.a. baker's yeast. Wanted for making bread rise.

Streptomyces (strep-toe-my-seas): soil bacteria wanted for making streptomycin, an antibiotic used to treat infections.

Pseudomonas putida (sue-doe-moan-us poo-tea-dah): one of many microbes wanted for cleaning wastes from sewage water at water treatment plants.

Escherichia coli (Esh-er-ish-e-ah coal-eye): one of many kinds of microbes that live in your gut. Wanted for helping you digest your food every day.

Section 1 continued Kingdom Eubacteria This Kingdom is the largest and contains more different

types of organisms than any of the other five Kingdoms. Eubacteria are classified by the way they obtain food. Consumers obtain nutrients from other organisms Parasites obtain food by invading other organisms to

obtain food. Producers make their own food and some use the

process of photosynthesis. They contain chlorophyll.

Section 1 continued Kingdom Archaebacteria They thrive in places where no other living things are

found. 3 types of Archaebacteria Methane Makers, excrete methane gas. Found in

swamps and landfills. Heat lovers live in places like ocean rift vents where the

temperatures reach 360 degrees Celsius. Salt lovers live in places where the salt concentration is

very high like the Dead Sea.

Section 1 Review

Draw and label the three main shapes of bacteria.

Describe the four steps of binary fission. How do eubacteria and archaebacteria differ? Many bacteria cannot reproduce in cooler

temperatures and are destroyed at high temperatures. How do humans take advantage of this when preparing and storing food?

Section 1 Review Answers 1. The drawings should resemble the pictures on page

226. 2. The cell grows, the DNA replicates, the DNA

molecules separate as the cell grows, and the cell splits in two.

3. Eubacteria and archaebacteria are genetically different. Their cell walls are also chemically different.

4. Humans store food in refrigerators and freezers to slow bacterial growth. Humans also cook food at high temperatures, which helps kill many bacteria.

Section 2Bacteria’s Role In the World

Vocabulary for Section 2 Bioremediation Antibiotic Pathogenic Bacteria

Section 2 Continued

Some bacteria cause disease and because of this they got a bad reputation.

Bacteria do many things that are important to us humans.

Life as we know it could not exist without bacteria. They are vital to our environment and we benefit from them in several ways.

Section 2 Continued Nitrogen-fixing(1st helpful use) Nitrogen is an essential element for all

organisms because it is a component of proteins and DNA.

Plants must have nitrogen in order to grow properly.

You would think this to be easy as 75% of our air is made of nitrogen.

Plants, however, cannot take in nitrogen from the air and must get it in a different form.

Section 2 Continued Nitrogen-fixing bacteria consume nitrogen in the air and

change it into a form that plants can use. Recycling(2nd helpful use) Breaking down dead organic matter, decomposing

bacteria make nutrients available again to living things. Cleaning up(3rd helpful use) Bacteria are being used to combat pollution. Bioremediation is the use of bacteria and other

microorganisms to change pollution into harmless chemicals.

It is used to clean industrial wastes, as well as spills.

Section 2 Continued Bacteria is good for people Genetically engineered bacteria is used for

many things such as medicines, insecticides, cleansers, adhesives, foods.

Fighting bacteria with bacteria Although some bacteria cause disease, other

bacteria make chemicals that treat diseases. Antibiotics are medicines used to kill bacteria

and other microoganisms. Many bacteria have been genetically engineered to make antibiotics in large quantities.

Section 2 Continued

Insulin Again, genetic engineering to the rescue

in making human insulin. Scientist put genes carrying the genetic code for human insulin into E. coli bacteria. The bacteria produce human insulin, which can be separated from the bacteria and given to diabetics.

Section 2 Continued

Feeding Time People breed bacteria for food! Every time you eat cheese, yogurt, buttermilk

or sour cream, you also eat a lot of lactic acid bacteria. Lactic acid bacteria digest the milk sugar lactose and convert it into lactic acid. The lactic acid acts as a preservative and adds flavor to the food.

Section 2 Continued

Harmful Bacteria Pathogenic Bacteria

• These bacteria invade the host and obtain nutrients from the hosts cells.

Some diseases caused by bacteria are: Dental cavities, ulcers, strep throat, food

poisoning, TB, etc. Pathogenic Bacteria also attack plants,

protists, fungi, and even other bacteria.

Section 3 Viruses

Vocabulary for Section 3 Virus Host

Section 3

It’s a small world About 5 billion of them could fit into a

drop of blood Because of size and ever changing

nature, scientist don’t know how many types of viruses exist.

There could be billions

Section 3, Continued Alive or Not ? They don’t eat, breath, grow, move, or perform

any biologic functions. A virus cannot live on its own. It can however reproduce (in the host) and

control its host. A host is an organism that supports a parasite. Using the host’s cell as a miniature factory,

viruses instruct the cell to produce viruses rather than healthy new cells.

Some of the more common Viruses-The flu virus

Some of the more common Viruses-Ebola

Some of the more common Viruses-Rota virus

So Exactly what is a Virus

Plain and simple It is some form of genetic material

enclosed in a protein coat.

How Destructive HIV is a virus that causes AIDS. The one thing they share with living things is that they

reproduce. Their reproductive cycle is called the lytic cycle. In this cycle stage 1 is to find a host cell. Stage 2, the virus enters the cell or injects genes into the

cell. Stage 3, once the genes are injected into the cell, the cell

becomes a virus factory. Stage 4, The new viruses break out of the host cell ready

to find a new host and repeat the cycle.

Is that all there is? No Some viruses don’t go straight into the lytic cycle. These

viruses inject their genes into the host cell, but no new viruses are made right away.

So What? When the host cell divides, each new cell has a copy of

the virus’s genes. This is called the lysogenic cycle. The viral genes can remain inactive for a long time until a

change in the environment, or stress to the organism causes the genes to launch into the lytic cycle.

Just when you thought you were safe!!

Section 3 Review

What would happen if one generation of measles viruses never found a host?

Describe the four stages of the lytic cycle.

Do you think modern transportation has had an effect on the way viruses are spread? Explain.

Review Answers

Measles would die out. Viruses cannot reproduce themselves without a host.

See page 235 for #2 People and livestock are much more

mobile now, and thus, able to bring viruses to new places.