1. Archaea, Bacteria, and Viruses
Unit 4 Earth’s Organisms Lesson 2

2. Bacteria Q & A
With your table, come up with 3 questions and answers about bacteria and their characteristics. The questions should be about information you’ve found in the textbook. We’ll share in a few minutes!

3. Cells
Tell me what you know about cells already.

4. Cells
Tell me what you know about cells already.
What does a cell do?

5. Cells Tell me what you know about cells already. What does a cell do?
Cells take in nutrients, convert nutrients to energy, carry about specific functions, and reproduce.

6. Cells Tell me what you know about cells already. What does a cell do?
Cells take in nutrients, convert nutrients to energy, carry about specific functions, and reproduce.
What are the simplest cells?

7. Cells Tell me what you know about cells already. What does a cell do?
Cells take in nutrients, convert nutrients to energy, carry about specific functions, and reproduce.
What are the simplest cells?
Prokaryotes, which are one-celled organisms that do not have a nucleus.

8. Bacteria and Viruses Venn Diagram
In your notebook and with your table, come up with a Venn diagram comparing characteristics of bacteria and viruses.

9. Bacteria and Viruses Venn Diagram
In your notebook and with your table, come up with a Venn diagram comparing characteristics of bacteria and viruses.
Underneath the diagram, list questions you have about bacteria and viruses. As we go through this powerpoint, see if you can find any answers to your questions.

10. Modeling Viral Replication
Let’s do a quick lab together that models the lytic cycle.

11. Introduction
Welcome to the lesson, "Archaea, Bacteria, and Viruses.“ In this lesson, you'll learn more about the properties and life processes of the organisms in the domains Archaea and Bacteria. You'll also learn how bacteria reproduce and viruses replicate.
EQ: What are microorganisms?
The vocabulary words for this lesson are archaea, bacteria, binary fission, virus, and host.

12. Vocabulary
Archaea: A domain made up of prokaryotes most of which are known to live in extreme environments that are distinguished from other prokaryotes by differences in their genetics and the makeup of their cell wall.
Bacteria: A domain made up of prokaryotes that usually have a cell wall and that usually reproduce by cell division.
Binary fission: A form of asexual reproduction in single-celled organisms by which one cell divides into two cells of the same size.
Virus: A microscopic particle that gets inside a cell and often destroys the cell.
Host: An organism from which a parasite takes food or shelter.

13. Sized Extra-Small
I’m going to draw a two-column chart on the board, with Prokaryotes and Eukaryotes as the two columns.

14. Sized Extra-Small
I’m going to draw a two-column chart on the board, with Prokaryotes and Eukaryotes as the two columns.
Under Prokaryotes, I’m going to write Bacteria and Archaea. Copy this down in your notebook.

15. Sized Extra-Small
I’m going to draw a two-column chart on the board, with Prokaryotes and Eukaryotes as the two columns.
Under Prokaryotes, I’m going to write Bacteria and Archaea. Copy this down in your notebook.
Prokaryotes usually have one cell, although a few have multicellular life stages. Eukaryotes have one or more cells. Which organism is usually larger, a prokaryote or a eukaryote and why?

16. Sized Extra-Small
Prokaryotes usually have one cell, although a few have multicellular life stages. Eukaryotes have one or more cells. Which organism is usually larger, a prokaryote or a eukaryote and why?
A eukaryote is usually larger because it can have many more cells.

17. Sized Extra-Small
Prokaryotes usually have one cell, although a few have multicellular life stages. Eukaryotes have one or more cells. Which organism is usually larger, a prokaryote or a eukaryote and why?
A eukaryote is usually larger because it can have many more cells.
I’m going to put the word Living above the entire chart, and the word Nonliving next to the chart. Under Nonliving, I’m going to write the word Viruses. We’ll come back to this chart throughout the lesson.

18. Interpreting Visuals
On page 294, look at the pictures of the prokaryotic and eukaryotic cells. What differences do you see between the two cells?

19. Interpreting Visuals
On page 294, look at the pictures of the prokaryotic and eukaryotic cells. What differences do you see between the two cells?
The prokaryotic cell does not have a nucleus or membrane-bound organelles.

20. Interpreting Visuals
On page 294, look at the pictures of the prokaryotic and eukaryotic cells. What differences do you see between the two cells?
The prokaryotic cell does not have a nucleus or membrane-bound organelles.
Are both these cells living? How do you know?

21. Interpreting Visuals
On page 294, look at the pictures of the prokaryotic and eukaryotic cells. What differences do you see between the two cells?
The prokaryotic cell does not have a nucleus or membrane-bound organelles.
Are both these cells living? How do you know?
Yes, all cells are living. Both prokaryotic and eukaryotic cells are able to move, get energy, and reproduce.

22. Beautiful Bacteria
Spherical bacteria do not dry out quickly. Where do you think such bacteria might be found?

23. Beautiful Bacteria
Spherical bacteria do not dry out quickly. Where do you think such bacteria might be found?
They could be in places that are both wet and dry. If they don’t dry out quickly, they can survive until the area becomes wet again.

24. Beautiful Bacteria
Spherical bacteria do not dry out quickly. Where do you think such bacteria might be found?
They could be in places that are both wet and dry. If they don’t dry out quickly, they can survive until the area becomes wet again.
Rod-shaped bacteria quickly absorb nutrients. Why might this be?

25. Beautiful Bacteria
Rod-shaped bacteria quickly absorb nutrients. Why might this be?
Because they have more surface area than spherical bacteria, they can absorb more nutrients from outside the cell. This might give them an advantage over other bacteria in nutrient-poor places.

26. Beautiful Bacteria
Some students think that all bacteria are harmful, or pathogenic. While it is true that bacteria can cause many illnesses, many species help other living things or cause no harm. For example, we have bacteria living inside our digestive tracts that aid in digestion. While we have found pathogenic (harmful) bacteria, scientists have not discovered pathogenic archaea.

27. Bacteria Reproduction
On page 298, look at the picture of binary fission. What happens during binary fission?

28. Bacteria Reproduction
On page 298, look at the picture of binary fission. What happens during binary fission?
The DNA is copied to make two loops. Then the cell divides so that one loop of DNA is in each cell.

29. Bacteria Reproduction
On page 298, look at the picture of binary fission. What happens during binary fission?
The DNA is copied to make two loops. Then the cell divides so that one loop of DNA is in each cell.
What happens during conjugation (as seen on page 299)?

30. Bacteria Reproduction
On page 298, look at the picture of binary fission. What happens during binary fission?
The DNA is copied to make two loops. Then the cell divides so that one loop of DNA is in each cell.
What happens during conjugation (as seen on page 299)?
Two cells join together. A plasmid is copied and then transferred from one cell to the other. The genes in the plasmid may be useful to a new cell.

31. Do the Math
Look at page 298 again. How did you figure out the answer to this question?

32. Do the Math
Look at page 298 again. How did you figure out the answer to this question?
I drew a diagram.

33. Do the Math
Look at page 298 again. How did you figure out the answer to this question?
I drew a diagram.
What if the question asked how many cells there were after 10 divisions?

34. Do the Math
Look at page 298 again. How did you figure out the answer to this question?
I drew a diagram.
What if the question asked how many cells there were after 10 divisions?
Instead of drawing, I could just write the number of cells for each generation. The cells double with each generation.

35. Bacteria
What are characteristics of bacteria?

36. Bacteria What are characteristics of bacteria?
They are almost all single-celled; lack a nucleus or organelles; are spherical, rod-shaped, or spiral-shaped; and live everywhere.

37. Alive or Not Alive?
Look at the different images of viruses on page Why might viruses have so many different shapes?

38. Alive or Not Alive?
Look at the different images of viruses on page Why might viruses have so many different shapes?
Their shapes might help them latch on to the different kinds of cells that they use to replicate themselves, or perhaps they are like bacteria in that their shapes help them survive in different conditions.

39. Why It Matters
The flu is transmitted easily from person to person. How do you think a flu pandemic today would be similar to or different from the 1918 flu pandemic?

40. Why It Matters
The flu is transmitted easily from person to person. How do you think a flu pandemic today would be similar to or different from the 1918 flu pandemic?
Because people travel more today, the flu would spread more quickly than it did in Today a vaccine could be developed more quickly after a new strain of the flu emerged. There are antiviral medicines available that might lesson the severity of the flu.

41. Why It Matters
The flu is transmitted easily from person to person. How do you think a flu pandemic today would be similar to or different from the 1918 flu pandemic?
Because people travel more today, the flu would spread more quickly than it did in Today a vaccine could be developed more quickly after a new strain of the flu emerged. There are antiviral medicines available that might lesson the severity of the flu.
If people recover quickly from the flu, why do we worry about flu pandemics?

42. Why It Matters
If people recover quickly from the flu, why do we worry about flu pandemics?
The flu can be dangerous to some people, such as pregnant women, the young and the old, or people who have other medical problems. Not all strains of the flu are the same as some can be deadly.

43. Viruses
Look on page What happens during the lytic cycle?

44. Viruses Look on page 303. What happens during the lytic cycle?
The virus attaches to a host. It enters the host or injects its genetic material into the host. The host’s cells replicate the virus’s genes. The new viruses burst out of the host cell, usually killing it, and the cycle begins again.

45. Viruses Look on page 303. What happens during the lytic cycle?
The virus attaches to a host. It enters the host or injects its genetic material into the host. The host’s cells replicate the virus’s genes. The new viruses burst out of the host cell, usually killing it, and the cycle begins again.
What are characteristics of viruses?

46. Viruses
What are characteristics of viruses?

47. Viruses What are characteristics of viruses?
They are microscopic, they are made of DNA or RNA and a protein coat, they are not living, they have different shapes, such as geometric forms, cylinders, and spheres.

48. Viruses What are characteristics of viruses? How do viruses replicate?
They are microscopic, they are made of DNA or RNA and a protein coat, they are not living, they have different shapes, such as geometric forms, cylinders, and spheres.
How do viruses replicate?

49. Viruses How do viruses replicate?
One method is a process called the lytic cycle, in which viruses attach to a host cell. The virus then either enters the cell or injects its genetic material into the host cell. The host cell replicates the DNA and viral proteins. Viruses are assembled inside the host cell. The new viruses burst out of the host cell, generally killing it when they do.

50. Summary
Members of the domains Bacteria and Archaea can be distinguished by differences in their genetics and chemistry.
Archaea and bacteria reproduce asexually by binary fission.
This involves making a copy of genetic information and then splitting to form two separate, identical organisms.
Binary fission and conjugation are two processes that bacteria undergo.

51. Summary Binary fission produces identical new bacteria.
Conjugation results in a change in genetic information in the recipient cell.
The donor cell does not receive new genetic information.
Viruses consist of nucleic acid with a protein covering.

52. Summary
Viruses come in a variety of shapes, including rods, spheres, crystals, and irregular, complex shapes.
Scientists do not consider viruses to be alive because viruses cannot undergo many life processes, including reproducing on their own.
When viruses replicate by the lytic cycle, they invade a cell, use it to make copies, and then burst out of the cell.
Viruses also replicate by the lysogenic cycle.

53. Tonight’s Homework
On a half-sheet of paper, make a two-panel flip chart that compares characteristics of bacteria and viruses, including how they reproduce.