Virus, Bacteria, Protists, and Fungi

1
Virus, Bacteria,Protists, and Fungi

• Chapters 19-21

2
What a virus is and isnt.

• A virus is not a cell.
• No nucleus, cell membrane, ribosomes,
  mitochondria, chloroplasts, etc.
• A virus is very small.
• 3000 poloviruses could be contained in the period
  at the end of this sentence.
• A virus is not complex.
• Genes Humans (100,000), Bacteria (1000), a
  Virus just 5!

3
Viral Structure

• Nucleic Acid
• DNA or RNA, but not both.
• Protein Coat (capsid)
• Protects the nucleic acid from its environment.
• Envelope
• Only found in viruses that infect animals.
• Spike-like projections that recognize animal
  cells and bind to the cell surface.

4
Section 19-2
Tobacco Mosaic Virus
T4 Bacteriophage
Influenza Virus
5
Viral Replication

• Viruses dont reproduce, they replicate.
• Viruses cannot replicate on their own.
• Host cells.
• Lytic Cycle.
• When the virus enters the cell it immediately
  begins to replicate, rapidly killing the cell.
• Lysogenic Cycle.
• Viral DNA is inserted into the host cells DNA.
  This DNA, called a PROPHAGE, may be reproduced
  several times and eventually reactivates.

6
Lytic and Lysogenic Infections
7
Are viruses alive?

• Properties of Life
• Highly organized. Yes or no?
• Use energy. Yes or no?
• Grow and develop. Yes or no?
• Reproduce. Yes or no?
• Respond and adapt. Yes or no?
• Most scientists would say NO.

8
Figure 19-11 Viruses and Cells
Section 19-2
9
What are vaccinations?

• The process of injecting a person with a harmless
  (weakened or dead) form of a virus to stimulate
  the immune system to produce cells and proteins
  that will destroy that type of virus.

10
Bacterial Structure

• Figure 14.10
• Flagella
• Cell Membrane
• Ribosome
• Pili
• Chromosome
• Cell Wall

11
The Structure of a Eubacterium
Section 19-1
12
Survival/Reproduction

• Binary Fission the process by which bacteria
  replicate chromosomes and the cell divides.
• Power of doubling (1 penny doubled 20 times)
• 1048576 cents or 10,485.76
• Average bacteria doubles every 15-20 minutes
• Endospores
• Thick-walled reproductive structures that can
  resist heat, drought, and radiation, sometimes
  living centuries before breaking open.

13
Classifying Bacteria

• Archaebacteria (ancient)
• Methanogens produce methane.
• Thermophiles heated conditions
• Halophiles salty conditions
• Eubacteria
• True Bacteria live in much less harsh
  environments than archebacteria. Many types and
  ways to classify.

14
Classifying Bacteria, cont.

• Shapes
• Spheres (cocci), rods (bacilli), spirals
  (spirilla), chains (streptococci), clusters
  (staphylococci).
• Cell Wall Composition
• Gram-positive, Gram-negative.
• Nutrition (autotroph, heterotroph)
• Respiration (aerobes, anaerobes)

15
The Roles of Bacteria

• Decomposers.
• Breakdown dead material.
• Convert (fix) nitrogen into usable forms for
  plants.
• Symbiosis.
• You scratch my back Ill scratch yours.
• Bacteria can be harmful.
• Slides of deadly bacteria.

16
Section 19-3
Common Diseases Caused by Bacteria
Disease
Pathogen
Prevention
Regular dental hygiene Protection from tick
bites Current tetanus vaccination Vaccination Prop
er food-handling practices Maintaining good
health Clean water supplies
Tooth decay Lyme disease Tetanus Tuberculosis Salm
onella food poisoning Pneumonia Cholera
Streptococcus mutans Borrelia burgdorferi Clostrid
ium tetani Mycobacterium tuberculosis Salmonella
enteritidis Streptococcus pneumoniae Vibrio
cholerae
17
Section 19-3
Common Diseases Caused by Viruses
Type of Virus
Nucleic Acid
Disease
Cancer Cancer, AIDS Respiratory
infections Chickenpox Smallpox
Oncogenic viruses Retrovirus Adenoviruses Herpesvi
ruses Poxviruses
DNA RNA DNA DNA DNA
18
Protists

• Common characteristic EUKARYOTES
• Very diverse (20 new kingdoms?)
• Three general categories
• Animal-Like Protists (p. 355-357)
• Plantlike Protists (p. 358-361)
• Funguslike Protists (p. 362-364)

19
Concept Map
Section 20-1
Protists
are classified by
which include
which
which
which
20

• Animallike Protists Protozoans
• A. Zooflagellates
• B. Sarcodines
• C. Ciliates
• 1. Internal Anatomy
• 2. Conjugation
• D. Sporozoans

Section 20-2
21
Figure 20-4 An Amoeba
Section 20-2
22
Figure 20-5 A Ciliate
Section 20-2
23
Section Outline

• Plantlike Protists Unicellular Algae
• A. Chlorophyll and Accessory Pigments
• B. Euglenophytes
• C. Chrysophytes
• D. Diatoms
• E. Dinoflagellates

Section 20-3
24
Section 20-3
Euglena
Chloroplast
Carbohydrate storage bodies
Gullet
Pellicle
Contractile vacuole
Nucleus
Eyespot
Flagella
25

• Plantlike Protists Red, Brown, and Green Algae
• A. Red Algae
• B. Brown Algae
• C. Green Algae
• 1. Unicellular Green Algae
• 2. Colonial Green Algae
• 3. Multicellular Green Algae

26
Section Outline

• Funguslike Protists
• A. Slime Molds
• 1. Cellular Slime Molds
• 2. Acellular Slime Molds
• B. Water Molds

Section 20-5
27
Figure 20-23 The Life Cycle of an Slime Mold
Section 20-5
MEIOSIS
FERTILIZATION
Zygote
Germinating spore
Spores
Mature sporangium
Feeding plasmodium
Young sporangium
Mature plasmodium
Haploid (N) Diploid (2N)
28
Fungi

• 3 Common characteristics
• Cell wall are chitin. Same covering as insects.
• Made of individual filaments, called hyphae.
  Tubes full of cytoplasm and nuclei.
• Masses of hyphae combine to form the mycelium.
  This is the body of the fungus.

29
(No Transcript)
30
Hyphae Structure
Section 21-1
Hyphae Without Cross Walls
Hyphae With Cross Walls
31
The Life Cycle of a Basidiomycete
Section 21-2
FERTILIZATION
HYPHAE FUSE
Haploid Diploid
MEIOSIS
32
(No Transcript)
33
How does a fungus eat?

• Heterotrophs
• Diffusion most fungi absorb small organic
  nutrients from their environment.
• Saprophytic they absorb nutrients from dead or
  decaying organic matter.

34
(No Transcript)