1. Biology I Chapters 23 & 24
Bacteria and Viruses

2. Do Now
In two lines, explain the difference between prokaryotes and eukaryotes.
Prokaryotic
Does not have a nucleus or membrane-bound organelles.
Eukaryotic
Has a nucleus and membrane-bound organelles.

3. Do Now
What are the two metabolic pathways by which cells obtain energy from nutrients?
Aerobic Respiration
Fermentation

4. Review What are the two kingdoms that prokaryotes compose?
Archaeabacteria
Eubacteria

5. Prokaryotes
Prokaryotes-single-celled organisms that do not have a membrane-bound nucleus.
Prokaryotes are the most numerous organisms on Earth.
3.5 billion years

6. Classification Eubacteria=Bacteria Archaebacteria=Archaea
The phylogenetic relationship is based on comparisons of ribosomal RNA sequences.
Bacteria can be classified according to their:
Type of cell walls
Methods of obtaining energy
Gram-staining characteristics

7. Classification
rRNA analysis shows that Archaea are more closely related to eukaryotes than they are to bacteria.

8. Do Now
What is used to distinguish Archaea from Bacteria?

9. Archaea
Archaea differs from bacteria in the makeup of their cell walls.
Peptidoglycan-a protein-carbohydrate compound found in bacterial cell walls

10. Archaea
Methanogens-convert hydrogen gas and carbon dioxide into methane gas
Halophiles-“salt-loving”-live in environments that have very high salt concentrations
Thermoacidophiles-live in very acidic environments that have very high temperatures

12. Bacteria Most known prokaryotes are bacteria.
They occur in many shapes and sizes and have distinct biochemical and genetic characteristics.

13. Bacilli-rod-shaped Cocci-sphere-shaped Sprilla-spiral-shaped
Bacteria
Bacilli-rod-shaped
Cocci-sphere-shaped
Sprilla-spiral-shaped

14. Strept-chains Staph-grapelike cluster
Bacteria
Strept-chains
Staph-grapelike cluster

15. Bacteria
The procedure used to distinguish between two types of bacterial cell wall composition is called gram-staining.

16. Bacteria
Gram-negative bacteria-have cell walls that are complex and have relatively small amounts of peptidoglycan.
Stain red

17. Bacteria
Gram-positive bacteria-simpler cell walls that have more peptidoglycan
Stain purple

18. Cyanobacteria-use photosynthesis to get energy from sunlight

19. Structure and Function
Cell Wall-gives shape and protects the cell from toxic substances
Cell membrane-acts as a selective barrier
Cytoplasm-a semifluid solution that contains ribosomes, DNA, small organic and inorganic molecules, and ions.

20. Structure and Function
Capsule-an outer covering that protects the cell against drying out
Pilli-short, hairlike protein structures on the surface of bacteria that help to attach the bacteria to surfaces
Endospores-a thick-coated, resistant structure used by the bacteria when the environment gets harsh

21. Flagella-long, whip-like tail
Movement
Flagella-long, whip-like tail

22. Nutrition
Photoheterotroph-Uses light energy but gets its carbon from other organisms
Chemoheterotroph-obtains both energy and carbon from other organisms
Photoautotroph-uses light energy and gets carbon from CO2
Chemoautotroph-obtain their energy from inorganic molecules, rather than from the sun

23. Do Now
What form of asexual reproduction do bacteria do when the cell membrane pinches in two to form two identical daughter cells?

24. Reproduction
Binary fission-a form of asexual reproduction when the cell membrane pinches in two to form two identical daughter cells.

25. DNA Exchange
Transformation-occurs when a prokaryote takes in DNA from its outside environment.

26. Conjugation-the process by which two prokaryotes bind together and one cell transfers DNA to the other cell.

27. Transduction-a virus obtains a small part of DNA from a host prokaryote.

28. Pathology Pathology-the scientific study of disease
Pathogen-bacteria and other organisms that cause disease
Exotoxin-toxic substances that bacteria secrete into their environment.
Endotoxin-toxic substances that are not released until the cell dies

29. Antibiotics
Antibiotic-affect bacteria by interfering with certain cellular activities
Prevent bacteria from making cell walls
Broad-spectrum antibiotic-antibiotics that can kill more than one kind of organism
Antibiotic resistance-the evolution of populations of pathogenic bacteria that antibiotics are unable to kill.

30. Foodborne Illnesses
Many foodborne illness can be avoided by selecting, storing, cooking, and handling food properly.

31. Bacteria in Industry Buttermilk, Sour cream, Yogurt, Cheese
Sauerkraut, Pickles, Coffee, Soy sauce,
Acetone, Antibiotics, and Insulin.

32. Bioremediation-uses bacteria to break down pollutants Crash Course
Liquid wastes
Outflow

33. Do Now
In the 1970s, many biotechnologists worked to develop a biodiesel that was an alternative to petroleum diesel. The results of their research was a biodiesel fuel that can be burned by most regular diesel engines and releases up to 50% less carbon emissions than petroleum diesel. If the majority of diesel-burning vehicles in the United States begin using biodiesel, what would be the most likely environmental impact?
A. The amount of acid rain falling on the country will increase.
B. Air quality across the country will improve.
C. There will be no environmental impact.
D. The amount of polluted runoff flowing into the ocean will decrease.
Answer B

34. Do Now
List four characteristics of living things.

35. Characteristics of Living Organisms
Cellular organization
Reproduction
Metabolism
Homeostasis
Heredity
Responsiveness
Growth & development

36. Virus
Virus-a nonliving particle made up of nucleic acid and a protein coat or nucleic acid and a lipid-protein coat
Viruses are not living organisms, they are of interest to biologists because they cause many diseases in living organisms and they are useful tools for genetic research, and because they are active in living cells.

37. Viruses Why viruses are considered non-living:
Cannot reproduce by themselves
Are not made up of cells
Cannot carry out metabolism by themselves

38. Characteristics of Viruses
Viruses do not have cytoplasm or organelles
Cannot carry out cellular functions
Have genetic material
Reproduce only in living cells.

39. Classification
Viruses are classified according to whether they contain RNA or DNA, the shape of their genome, and whether they have a membrane envelope.

40. Structure
A typical virus consists of a protein coat and a nucleic acid core.
Capsid-a protein coat-surrounds some viruses;
Protective outer coat

41. Lytic Cycle
Lytic Cycle-a virus invades a host cell, produces new viruses, and ruptures the host cell when releasing newly formed viruses.
Destroys host cell
Bacteriophage (Phage) a virus that infects a bacteria

43. Lysogenic Cycle
Lysogenic Cycle-Viral DNA become integrated into the host cell’s DNA
Temperate Virus-a virus whose replication includes the lysogenic cycle

45. Overview

46. Origin
Most scientists think that early viruses originated from existing cell parts.

47. Viral Diseases Types of Viral Diseases
Hepatitis
SARS
Shingles
The clearing of forests for housing is associated with the emergence of viruses not previously seen in humans

48. Can be spread by: Mosquitoes Ticks Humans
Viral Spread
Can be spread by:
Mosquitoes
Ticks
Humans

49. Vaccine
Antibiotics are ineffective against viral infections because antibiotics interfere with cellular processes that viruses do not perform.
Vaccination and vector control have been the most successful at fighting viral diseases.