Chapter 10 Section 1 Bacteria and Archaea Bellringer
Chapter 10 Bacteria and Viruses
Table of Contents
Section 1 Bacteria and Archaea
Section 2 Bacteria’s Role in the World
Chapter 10 Section 1 Bacteria and Archaea
Bellringer
What are the two kingdoms of bacteria?
What are three shapes of bacteria?
Write your answers in your science journal.
Chapter 10 Section 1 Bacteria and Archaea
Objectives
• Describe the characteristics of prokaryotes.
• Explain how prokaryotes reproduce.
• Relate the characteristics of archaea.
Chapter 10 Section 1 Bacteria and Archaea
Some Characteristics of Bacteria and
Archaea
• The domains Bacteria and Archaea consists of single-celled organisms. These two domains consist of the oldest forms of life on Earth.
• The Shape of Bacteria Bacilli are rod shaped.
Cocci are spherical. Spirilla are long and spiral shaped. Each shape helps bacteria in a different way.
Chapter 10 Section 1 Bacteria and Archaea
Chapter 10 Section 1 Bacteria and Archaea
Some Characteristics of Bacteria and
Archaea, continued
• No Nucleus!
All bacteria and archaea are singlecelled organisms that do not have a nucleus. An organism that does not have a nucleus is called a prokaryote.
• Prokaryote Reproduction Prokaryotes reproduce by a process called binary fission, in which one single-celled organism splits into two single-celled organisms.
Chapter 10 Section 1 Bacteria and Archaea
Chapter 10 Section 1 Bacteria and Archaea
Comparing Cell Division in Prokaryotes and Eukaryotes
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Visual Concept
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Chapter 10 Section 1 Bacteria and Archaea
Some Characteristics of Bacteria and
Archaea, continued
• Endospores contain genetic material and proteins and is covered by a thick, protective coat. Some bacteria become inactive and form endospores in poor environmental conditions.
• When conditions improve, the endospores break open and the bacteria become active again.
Chapter 10 Section 1 Bacteria and Archaea
The Domain Bacteria
• The domain Bacteria has more individuals than all other domains combined do.
• Classification of Bacteria Bacteria are classified by the way they get food. Most bacteria are consumers.
• Cyanobacteria are producers. Cyanobacteria usually live in water and contain the green pigment chlorophyll.
Chapter 10 Section 1 Bacteria and Archaea
The Domain Archaea
• The three main types of archaea are heat lovers, salt lovers, and methane makers.
• Harsh Environments Archaea often live where nothing else can. Most archaea prefer environments where there is little or no oxygen.
Chapter 10 Section 2 Bacteria’s Role in the World
Bellringer
Are harmful bacteria more of a problem or less of a problem to people now than they were 200 years ago? Name some major historical events involving the spread of bacteria. How would your life change if you had to worry about getting clean water each day?
Record your answer in your science journal.
Chapter 10 Section 2 Bacteria’s Role in the World
Objectives
• Explain how life on Earth depends on bacteria.
• List three ways bacteria are useful to people.
• Describe two ways in which bacteria can be harmful to people.
Chapter 10 Section 2 Bacteria’s Role in the World
Good for the Environment
• Nitrogen Fixation Nitrogen-fixing bacteria take in nitrogen from the air and change it to a form that plants can use.
Chapter 10 Section 2 Bacteria’s Role in the World
Good for the Environment, continued
• Recycling Decomposer bacteria break down dead plant and animal matter, which makes nutrients available to other living things.
• Cleaning Up Using microorganisms, such as bacteria, to change harmful chemicals into harmless ones is called biomediation. Biomediation can be used to clean up hazardous waste and oil spills.
Chapter 10 Section 2 Bacteria’s Role in the World
Good for People
• Bacteria in Your Food Many common foods, such as cheese, yogurt, and sour cream, are made with the help of bacteria.
• Making Medicines Medicines used to kill bacteria and other microorganisms are called antibiotics.
Many antibiotics are made by bacteria.
Chapter 10 Section 2 Bacteria’s Role in the World
Good for People, continued
• Insulin In the 1970s, scientists discovered how to put genes into bacteria so that the bacteria would make human insulin.
• Genetic Engineering changes the genes of bacteria, or any other living thing. Scientists can now engineer bacteria to make many products, such as insecticides, cleansers, and adhesives.
Chapter 10 Section 2 Bacteria’s Role in the World
Harmful Bacteria
• Pathogenic bacteria are bacteria that cause disease by getting inside a host organism and taking nutrients from the host’s cells.
• Diseases in Other Organisms Bacteria cause diseases in other organisms as well as in people.
Pathogenic bacteria attack plants, animals, protists, fungi, and even other bacteria.
Chapter 10 Section 3 Viruses
Bellringer
Are viruses living? What are the characteristics of living things? Can you think of anything that would be difficult to classify as living or nonliving?
Write your answer in your science journal.
Chapter 10 Section 3 Viruses
Objectives
• Explain how viruses are similar to and different from living things.
• List the four major virus shapes.
• Describe the two kinds of viral reproduction.
Chapter 10 Section 3 Viruses
It’s a Small World
• Viruses are tiny. They are smaller than the smallest bacteria. About 5 billion virus particles could fit in a single drop of blood.
Are Viruses Living?
• Like living things, viruses contain protein and genetic material. But viruses don’t act like living things. They can’t eat, grow, break down food, or use oxygen.
Chapter 10 Section 3 Viruses
Classifying Viruses
• Viruses can be grouped by their shape, the type of disease they cause, their life cycle, or the kind of genetic material they contain.
• Four Main Shapes The four main shapes of viruses are shown on the next slide.
Chapter 10 Section 3 Viruses
Chapter 10 Section 3 Viruses
A Destructive House Guest
• Viruses attack living cells and turn them into virus factories. Viruses reproduce using the lytic cycle.
• A Time Bomb Some viruses put their genes into a host cell, but new viruses are not made right away.
New cells get copies of the virus’s genes when the host cell divides. The genes stay inactive for a long time before they make copies of the virus.
Chapter 10 Section 3 Viruses
Chapter 10 Section 3 Viruses
Lytic Cycle
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Visual Concept
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Chapter 10 Section 3 Viruses
A Destructive House Guest, continued
• Treating a Virus Antibiotics do not kill viruses, but scientists have recently developed antiviral medications that stop viruses from reproducing.
• Because many viral diseases do not have cures, it is best to prevent a viral infection from happening in the first place. Vaccinations give your immune system a head start in fighting off viruses.
Chapter 10 Bacteria and Viruses
Concept Map
Use the terms below to complete the concept map on the next slide.
Bacteria
Archaea decomposers prokaryotes nucleus consumers producers
Chapter 10 Bacteria and Viruses
Chapter 10 Bacteria and Viruses
