Download lytic cycle.

Chapter 10
Section 1 Bacteria
Objectives
• Describe the characteristics of bacteria.
• Explain how bacteria reproduce.
• Compare and contrast eubacteria and archaebacteria.
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
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 menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 10
Section 1 Bacteria
Characteristics of Bacteria
• Bacteria make up the kingdoms Eubacteria and
Archaebacteria. All bacteria are single-celled
organisms.
• 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 menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 10
Section 1 Bacteria
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 10
Section 1 Bacteria
Characteristics of Bacteria, continued
• No Nucleus! All bacteria are single-celled organisms
that do not have a nucleus. An organism that does not
have a nucleus is called a prokaryote.
• Bacterial Reproduction Bacteria reproduce by a
process called binary fission, in which one singlecelled organism splits into two single-celled
organisms.
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 10
Section 1 Bacteria
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 10
Section 1 Bacteria
Characteristics of Bacteria, 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 menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 10
Section 1 Bacteria
Kingdom Eubacteria
• The kingdom eubacteria has more individuals than
all of the other five kingdoms combined.
• Eubacteria Classification Eubacteria are classified
by the way they get food. Most eubacteria are
consumers.
• Cyanobacteria are producers. Cyanobacteria
usually live in water and contain chlorophyll.
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 10
Section 1 Bacteria
Kingdom Archaebacteria
• The three main types of archaebacteria are heat
lovers, salt lovers, and methane makers.
• Harsh Environments Archaebacteria often live
where nothing else can. Most archaebacteria prefer
environments where there is little or no oxygen.
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
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 menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
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 menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
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 menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
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 menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
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 menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
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 menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
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 menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
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 menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 10
Section 3 Viruses
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
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-the Lysogenic cycle 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 “go lytic”
making huge numbers of copies of the virus.
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 10
Section 3 Viruses
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
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
•Listen to this Virus rap and complete the crossword!
http://www.sciencemusicvideos.com/im-a-virus/
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.