1. Viruses, Bacteria, & Protists
The Single Cell:
Viruses, Bacteria, & Protists

2. What do you notice as the levels go from atom to organism?
Once at the organism level how do we organize?
Why are levels of organization important?

3. Viruses, Bacteria, & Protists
Structure:
Viruses, Bacteria, & Protists

4. What is a Virus? DNA or RNA
½ to 1/100 the size of the smallest bacteria
DNA or RNA
Only contains instructions for making a copy of the virus. No genes for protein synthesis, viruses don’t process any food or water, they aren’t aerobic or anaerobic they have no metabolism
Some viruses have only four genes
Classification on basis of nucleic acid
DNA viruses: - Herpes simplex virus (HSV)
RNA viruses: - influenza virus

5. Structure of a Virus? Proteins determine the viruses shape:
Envelope
Lipid bilayer
Capsid
Genetic material
Envelope – additional layer
surrounding the capsid
Capsid - a shell of protein
surrounding nucleic acid
Proteins determine the viruses shape:
Polyhedral - papilloma virus
The protein arrangement also determines what cell can be infected by the virus and how the virus infects the cell.
with projections - HIV
helical - tobacco mosaic virus
Polyhedral head w/cylindrical tail w/ leg fibers

6. What are Bacteria? The Extremists! Kingdom Archebacteria Prokaryote
Extreme environment
No free O2
High salt or sulfur concentration
Some produce methane
These are bacteria with a twist, the reason they get their own kingdom is because of the environment where they live,
The archaebacteria are prokaryotes that live in extreme environments where there is no free oxygen like deep on the ocean floor near the volcanic vents, in sulfur springs or in the dead sea or great salt lake in Utah. There are even archaebacteria that live in swamps or even in the gut of some animal that produce methane
The Extremists!

7. What are Bacteria? Can be found just about anywhere Kingdom Eubacteria
Human pathogens
Decomposers
Symbiotic living
Prepare food
Make antibiotics
These are the bacteria we are familiar with. The ones that give us strep throat, streptococcus pyrogenes, the ones that live in our guts and help us digest food, E. coli, and there are may that work as decomposers. Bacteria can be found on just about all surfaces. Only 1% are harmful.
Can be found just about anywhere

8. Structure of Bacteria Prokaryotic cells lack a nucleus and membrane
bound organelles
The definition of prokaryote is not membrane bound organelles. They have no mitochondria or chloroplast to produce food or energy instead Prokaryotes us parts of their plasma membrane that are folded inward inside the cell to perform metabolic activities like cellular respiration and photosynthesis.
Common shapes among prokaryotes are spheres, rods, & spirals

9. Unicellular, multicellular, colonial
What are Protists?
Kingdom Protista
All organisms that are neither animals, plants, bacteria or fungi are called 'protists'
Unicellular, multicellular, colonial
Eukaryotic
Aquatic environments
The most diverse kingdom.
Protists are put into three groups

10. What are Protists? Plant like Protists - Algae
Live in fresh or salt water
Reproduction & metabolism similar to plants
Animal like Protists - Protozoa
Aquatic
All are single celled
Metabolism similar to animals
Grouped according to how they move
Pseudopod
Ciliate
Sporazoan
Green algae prefer fresh water, there are also red and brown algae and a lot of them live in salt water.
Algae are responsible fro producing more than 70% of the oxygen we breath
Some algae are multicellular like kelp
Some are singled celled but live in colonies like the volvox
Algae are also very important as the foundation of may aquatic food webs
Flagellate
Fungus like Protists –
plasmodium, slime mold, downy mildew
Behavior & metabolism similar to fungus

11. Inside story “A Typical Bacteria Cell”
page 503 of green text book
Divide page 23 in half
On the top half draw a bacteria cell
label plasmid, chromosome, cell wall, plasma
membrane, pilus, ribosomes, and flagellum
Below your picture draw a VINN diagram to compare and contrast prokaryotic cells and Eukaryotic cells

12. Describe three advantages to
Warm- up
Describe three advantages to
being a
Eukaryotic cell.

13. Viruses, Bacteria, & Protists
Reproduction:
Viruses, Bacteria, & Protists

14. Viral Reproduction Lytic Cycle
The viruses attaches to a host cell and deposits its DNA
The viral DNA instructs the host cell to use its own enzyme raw material & energy to only make new viruses
The new viruses burst from the host cell – killing it – & are able to go infect other cells
Attachment
Entry
Replication
Assembly
Release
The recognition and attachment of the virus to the receptor site is like two pieces of a puzzle fitting together.
Each virus can usually attach to only a few kinds of cells

15. Viral Reproduction Lysogenic Cycle
The viral DNA is integrated into the host cells chromosome - provirus
Every time the host cell replicates it also replicates the viral DNA
Once activated, the provirus enters the lytic cycle replicates and kills the host cell
Not all viruses kill the host cell – at least not right away
Attachment
Entry
Provirus formation
Replication
Assembly
Release

16. Bacterial Reproduction
Most prokaryotes have a single, circular, double-stranded DNA chromosome condensed in the nucleoid region of the cytoplasm
Many bacteria have an additional small ring of DNA – The Plasmid – prokaryotes can survive without the plasmid the genes for essential functions are on the chromosome. Plasmids sometimes contain genes for resistance and other special issues

17. Bacterial Reproduction ASEXUAL
No cell cycle like seen in Eukaryotes
No mitosis or meiosis
Prokaryotes reproduce mostly
asexually via binary fission,
making DNA almost continuously
Translation and transcription
occur simultaneously
Allows for rapid response to Environment – ADAPTATION

18. Bacterial Reproduction SEXUAL
Conjugation, one cell directly transfers DNA to another
But the thing that is so special about the plasmid is that the bacteria can share their special powers with other bacterial cells no matter if they are the same or different species.
The plasmid replicates independently of the chromosome and can be transferred thru conjugation, just like in protists. This is the main way antibiotic resistance has increased.
Resulting in a bacterium with a new genetic composition

19. Plant Like Protist Reproduction
Asexual & Sexual
Fragmentation occurs when a filament breaks apart and each piece develops into another organism.
Spirogyra
Conjugation occurs when two filaments form conjugation tubes. The contents of one cell passes through the tube an fuses with a cell from the other filament. Fertilization occurs and a zygote is formed.
Some algae reproduce asexually, but some can reproduce either asexually or sexually, and some have different stages where they reproduce sexually in one stage and asexually in another.
(haploid)
(diploid)
Alternation of generations Sexual and asexual reproduction occurs during alternating periods in the life cycle of the plant like protist.

20. Fungus Like Protist Reproduction
Animal Like Protist Reproduction
Multiply asexually by fission. The cell divides into two individuals.
Paramecium undergoing fission.
Fungus Like Protist Reproduction
Plasmodium - Reproduces by haploid spores
Slim molds are haploid their entire life & reproduce by cell division

21. Warm up
Define homeostasis. In what types of situations would an organism require a homeostatic mechanism.

22. Viruses, Bacteria, & Protists
Metabolism:
Viruses, Bacteria, & Protists 22

23. Do viruses need to “eat”?
Do viruses need energy?
Do viruses need to “eat”?
Do viruses produce waste?
Do viruses have a metabolism?
HOST CELL DOES IT ALL!

24. Heterotrophic Bacteria
Use organic molecules as a food source
Parasites –
Unable to produce organic molecules
Obtain nutrients from living organisms
Excretes waste thru cell wall
Saprophytes –
Feed on dead organisms or organic waste
Break down nutrients locked in body tissues
of dead organisms
Excretes waste thru cell wall

25. Autotrophic Bacteria Photosynthetic autotrophs –
Use sunlight to make organic molecules
Photosynthetic autotrophs –
Contain chlorophyll
Excretes waste thru cell wall
Make organic molecules from inorganic ones
Cyanobacteria – usually blue/green, can
be red or yellow, found in ponds, streams & moist areas of land. Colonial, composed of chains of independent cells
Chemosynthetic autotrophs –
Obtain energy needed to make food from
Chemicals like sulfur & nitrogen
Excretes waste thru cell wall
NITROGEN FIXATION

26. Protists Animal like Plant like Fungus like
Heterotrophic – feed on other organisms or dead organic matter. Some are parasitic
Have specialized organelles used to release waste
Plant like
Able to perform photosynthesis
contain chlorophyll
Not all are green. Diatoms & dinoflagellates have yellow to brown chloroplasts. There are brown algae & red algae
Release waste thru cell wall
Fungus like
Green algae prefer fresh water, there are also red and brown algae and a lot of them live in salt water.
Algae are responsible fro producing more than 70% of the oxygen we breath
Some algae are multicellular like kelp
Some are singled celled but live in colonies like the volvox
Algae are also very important as the foundation of may aquatic food webs
Heterotrophic
Plasmodium Eats as it moves
Mildew Feed on dead organisms
Releases waste thru cell membrane

27. Viruses, Bacteria, & Protists
Gas Exchange:
Viruses, Bacteria, & Protists 27

28. Why is gas exchange important?
Do viruses need oxygen or carbon dioxide?
HOST CELL DOES IT ALL!

29. Bacteria Metabolism Obligate aerobes – require oxygen
Mycobacterium tuberculosis –
the organism that causes the lung disease tuberculosis
Obligate anaerobes –
require NO oxygen
There is a wide range of oxygen need in bacteria, some have to live in an oxygenated environment like the bacteria that causes tuberculosis, other bacteria like the one that causes syphilis require an oxygen free environment. And then there are some that can live in either or have a certain percentage of oxygen required.
Treponema pallidum – the bacterium that
causes syphilis

30. Bacteria Metabolism
Prokaryotes used infolded regions of the plasma membrane to perform many metabolic functions, including cellular respiration and photosynthesis.
Respiratory membranes in aerobes
Thykaloid membranes in photosynthetic bacteria
Autotroph
Heterotroph

31. Protists Metabolism Protists are eukaryotic cells
Have many specialized organelles including mitochondria or chloroplasts used in cellular respiration
Protists are aerobic – they require oxygen
Paramecium

32. Viruses, Bacteria, & Protists
Homeostasis:
Viruses, Bacteria, & Protists

33. What is HOMEOSTASIS? Why is it important? How do VIRUSES
maintain homeostasis?
They DON’T!
The Host Cell does it for them!!

34. When life gets rough some bacteria can form resistant endospores
Bacteria Homeostasis
The cell wall maintains the shape
of the cell, protects the cell, and
prevents the cell from bursting in
a hypotonic environment
When life gets rough some bacteria can form resistant endospores
The Gram + cells have a plasma membrane with a bunch of peptidoglycan stacked on top. Balloon demo
The Gram – cells have a plasma membrane a small amount of peptidoglycan and then another membrane
Endospores contain a bacterium’s DNA and a small amount of cytoplasm
Endospores are encased in a tough outer covering that resists drying out and extreme temperatures

35. Protist Homeostasis
Because the kingdom protista contains such a variety, several homeostatic behaviors exist
If you would keep Euglenoids in the dark they start feeding on organic matter and may loose their chloroplast. Sometimes classified as animal like other times classified as plantlike
Amoebas can grow to very large sizes. Some species are 5 mm long! They can survive by having many nuclei within their single cell.
Star-shaped contractile vacuoles are used to balance the amount of water in the cell.
Two nuclei contain the genetic information.

36. Cellular organization
Are viruses alive?
What are the characteristics of life?
Reproduction
Genetic information
Maintain Homeostasis
How do characteristics of viruses
compare to that of living organisms?
Metabolism
Cellular organization

37. NO Are viruses alive? How do characteristics of viruses
compare to that of living organisms?
No cell organization
Has genetic material
Once the virus drops off its genetic material it uses the metabolism of the host cell to make new viruses. A typical lytic cycle takes about 30 minutes and produces about 200 new viruses
The host cell is destroyed
Unable to reproduce with out a host cell
Use host cell’s
metabolism
Homeostasis?

38. Turn to page 523 in the Green text book
On the top half of the next odd page of your BIN draw a picture of the paramecium
Be sure to draw ALL of the organelles
Draw a food particle as it is consumed by the paramecium and trace it’s path thru the digestive system of the protist
Next to your drawing describe how the food is taken in by the paramecium and where in the digestive system the goes and what happens to the food at each point along the way.
Draw a contractile vacuole doing it’s job in your paramecium
Below your drawing explain why the job of the contractile vacuole is so important.
8. Describe how bacteria deal with unfavorable environmental conditions.