Biology Chapter 16: Microbiology

14. How do penicillin, tetracycline, and sulfa drugs kill bacteria?

-Penicillin: interferes with cell wall formation -Tetracycline: inhibits protein synthesis -Sulfa drugs: inhibits cell metabolism

15. Explain the four step process leading to antibiotic resistance in bacteria.

1. A course of antibiotic treatment is given 2. The most susceptible bacteria die first 3. A few chance mutants that aren't as readily affected continue to grow (natural selection) 4. Resistant forms reproduce and become prominent

6. The three basic shapes of bacteria, and their specific names are:

1. Cocci- spheres 2. Baccilli- rods 3. Spirilla- curves (spirals)

16. Give two mechanisms by which bacteria can resist the effects of antibiotics.

1. Mutations to prevent entry of drugs into the cells 2. Mutations that destroy/disable the drug

21b. What is the host cell of HIV (be specific)

Human white blood cell

30. Of what do AIDS victims die?

Opportunistic infections that can't be stopped by the weakened immune system and the dwindling helper T cells

1a. Explain three structural differences between prokaryotes in the Domain Archaea (Kingdom Archaebacteria) and the Domain Bacteria (Kingdom Eubacteria).

Peptidoglycan is found only in bacteria, interons are found in Archaea only, they have a different lipid composition. Bacteria: peptidoglycan present in cell wall structure, no introns, no ribosomal proteins, can be parasitic (cause infectious diseases) Archaea: no peptidoglyan in cell wall (has polysaccharides, pure proteins, or no cell wall), has introns, has ribosomal proteins, none are parasitic

5b. What part of the cell retains the violet stain?

Peptidoglycan layer

18. Most bacteria are not pathogenic. Give an example of how bacteria are helpful in an ecosystem.

In the ecosystem, bacteria aid in decomposing dead plants and animals and in converting nutrients to usable form, as in the nitrogen cycle

5c. If endotoxin were present in a bacterial species, where would it be located?

In the outer membrane

29. What system in the body is destroyed by HIV?

The immune system by damaging T cells

35. Mitochondria and chloroplasts evolved from ____. The theory that describes this process is called the _____ theory

Mitochondria and chloroplasts evolved from bacterial cells. This process is called the Endosymbiotic theory

28d. Antibiotic

Drugs that work against bacterial infection by interfering with some part of bacterial metabolism.

17b. What is a colony and how does it arise?

A colony is millions of bacteria all derived a single cell that grow and reproduce in the same spot. They grow in a circular shape

17cii. What was a material tested in your class that contained few bacteria?

A refrigerated egg

31. Why has it been difficult to develop a vaccine for AIDS?

A vaccine won't cure AIDS, but a vaccine might be developed to prevent HIV from causing AIDS. For a vaccine to work, the pathogen must be identifiable, and HIV has far too many forms for a single vaccine to target it.

17a. The gelatin-like substance (obtained from seaweed) used as a solid medium to grow bacteria is...

Agar

33. Miller and Urey's experiment simulating the earth's pre-life atmosphere produced _____, the monomers of proteins!

Amino acids

28c. Pathogen

An organism or particle that causes disease

17ci. What was a material tested in your class that had lots of bacteria?

An unrefrigerated egg

1b. Give three examples from the Archaea and Bacteria domains.

Archaea: -methanogens -thermoacidophiles -halophiles Bacteria: -Cyanobacteria -enterobacteria -gliding and bubbling bacteria

21a. What is the host cell of a bacteriophage?

Bacteria

17e. Why were plates not opened after the bacteria grew?

Because the colony and the bacteria may be pathogenic, or capable of causing disease

7. Describe the process of conjugation and the result for the bacterial cells.

Conjucation is one of the three ways bacteria can transfer its genes. The process involves the donor cell passing DNA to the recipient cell by the sex pilus, which forms a temporary bridge between two bacterial cells. A plasmid, containing DNA, passes through this bridge, from one cell to the other. Genetic information on the plasmid is thus passed from cell to cell.

10. The bacterial phylum that contains the type of organisms that introduced lots of oxygen into the early earth's atmosphere is ______. What biochemical process produced the oxygen?

Cyanobacteria. Photosynthesis produced the oxygen.

9. Name the helpful enteric bacteria in humans. To what phylum does it belong? In what two ways is this species helpful to us?

E. coli is the helpful enteric bacteria in humans. It belongs to the proteobacteria phylum. This species is helpful because: 1. Helps break down food 2. Makes a few vitamins, especially vitamin K

22. The genetic material for a virus is...

Either DNA or RNA

12. In what three ways can bacteria cause disease?

Endotoxin, exotoxin, and tissue destruction

11. Compare Endotoxins and Exotoxins.

Endotoxins: Gram Negative, lipid or carbohydrate molecules, found in the outer membrane, symptoms: fever and weakness, diseases: salmonella and typhoid Exotoxins: Gram Positive, protein molecules, found secreted out of the bacterial cell, symptoms: very toxic quick, diseases: bad strain of E. coli and botulism

32. Give the sizes of eukaryotic cells, bacterial cells, and viruses

Eukaryotic: 10-100 micrometers Bacterial: 1-10 micrometers Viruses: .2 micrometers

28a. Virulent

Extremely dangerous, usually spreading very quickly. When prophage becomes virulent, the lyric cycle begins. Virulent viruses rupture cells immediately.

17d. Name two bactericides that worked really well

Germ-X and diluted bleach worked really well for E-coli.

5a. What colors does the Gram stain procedure produce in Gram-negative and Gram-positive bacteria?

Gram-negative bacteria stains pink and Gram-positive stains purple since it has a thinker layer of peptidoglycan in their cell wall which retains the dye.

23. The capsid of a virus is made of...

Protein

34. The ____- First Hypothesis is favored because this type of macromolecule can store genetic information and act as an enzyme

RNA

25. What do viruses need to reproduce?

They need the host cell's metabolic machinery.

13. Antibiotics are produced by fungi and bacteria in nature. Why do they make these compounds?

To defend themselves against other microbes

8. Describe the process of transformation in bacteria

Transformation happens when a recipient bacterium picks up free pieces of DNA from its surroundings that were secreted by live prokaryotes or released by dead prokaryotes.. This process incorporates only a small amount of donor DNA into the chromosome of the recipient

24. Explain why bacteria are considered to be alive, while viruses are not.

Viruses are not considered living because they don't grow, don't have a cytoplasm, and don't use respiration to convert energy. They are also non-cellular and can only reproduce inside a living cell. They can only reproduce by using the metabolic machinery of the host cell. Bacteria are cellular organisms that can independently reproduce.

27. How are viruses and cancer related?

Viruses can cause cancer by inserting DNA into the host cells genome - this is a mutation to the host's DNA, because the host cell's DNA is altered by the insertion of the foreign DNA.

28b. Temperate

When a bacterial cell invaded by a virus divides as usual, producing new prophage as its own DNA is replicated. Temperate viruses integrate into the host chromosome

20. Label the basic structures of HIV

a. Envelope b. Spike c. Caspid d. RNA e. Reverse transcriptase

19. Label the basic structures of a bacteriophage

a. Head b. Tail c. Capsid (made of protein) d. Tail fibers e. DNA

2. Label the basic structures of a bacterium

a. Plasmid b. Fimbriae c. Sex pilus d. flagellum e. DNA f. cytoplasm g. ribosome h. cell wall

4. Label the outer layers of a Gram-positive bacterial cell

a. cell wall - thick layer of peptidoglycan which holds the purple stain b. membrane

3. Label the outer layers of a Gram-negative bacterial cell

a. outer membrane b. cell wall - thin layer of peptidoglycan that cannot hold the stain so the area appears pink c. membrane