Classification and Taxonomy

Question 1

Describe how a typical Phylogenic Tree of Life is organized.

Answer 1

It is a tree of life based on the similarities and differences between the small subunit rRNA gene sequences of different organisms. The tree is separated into three separate domains that link together as one to show that they all evolved from a common ancestral cell type. There are three main branches, on the left is bacteria, in the middle is archaea, and on the right is eukarya. Archaea and bacteria contain all prokaryotic organisms while eukarya contains all eukaryotic organisms. The tree is skewed to show that there is a closer evolutionary relationship between archaea and eukarya than they have to bacteria. The closer organisms are in the tree, the more closely related they are. Also, the closer the branch is to the common ancestral cell type, the more ancient they are.

Question 2

Compare and contrast cellular microbes and acellular microbes

Answer 2

Cellular microbes can either be unicellular or multicellular. Cellular microbes are considered living as they can carry out the basic functions of life. On the other hand, acellular microbes do not contain any cells. They are considered nonliving as they lack basic cell features. Acellular microbes are often infectious particles. Like acellular microbes, some cellular microbes such as bacteria, protozoa, and fungi can cause disease.

Question 3

Give multiple examples of cellular microbes

Answer 3

Prokaryotes:
- Bacteria and Archaea
Eukaryotes:
- Protozoa and Fungi

Question 4

Give multiple examples of acellular microbes

Answer 4

o Viruses
o Prions
o Viroids

Question 5

Examples of diseases caused by cellular microbes

Answer 5

o Candida albicans (caused by fungi)
o E.coli (caused by gram negative bacteria)
o Staphylococcus Aureus (caused by gram positive bacteria)

Question 6

Examples of diseases caused by acellular microbes

Answer 6

o Kuru (caused by a prion)
o Influenza virus (caused by a virus)
o Potato spindle tuber viroid

Question 7

Compare and contrast prokaryotic and eukaryotic microbes.

Answer 7

Prokaryotic microbes are all unicellular and have cell walls that contain either pseudopeptidoglycan (Archaea) or peptidoglycan (Bacteria). Eukaryotic microbes have a nucleus, membrane-bound organelles, and can be multicellular. They can lack a cell wall (Protozoans and Animalia), have cell walls made up of chitin (Fungi), or cell walls made up of cellulose (Plantae). Both prokaryotic microbes and eukaryotic microbes can cause disease. Bacteria, fungi, and protozoa can all cause disease. Furthermore, some eukaryotic microbes can also be single-celled. For instance, protozoa and fungi. Lastly, a type of bacteria, cell wall-less bacteria lack a cell wall like protozoans and Animalia.

Question 8

Examples of prokaryotic microbes

Answer 8

o Bacteria
o Archaea

Question 9

Examples of eukaryotic microbes

Answer 9

o Protozoa
o Fungi

Question 10

What are diseases caused by prokaryotic microbes?

Answer 10

o E.coli (caused by gram negative bacteria)
o Mycobacterium tuberculosis (caused by acid-fast bacteria)
o Mycoplasma pneumoniae (caused by cell wall-less bacteria)

Question 11

What are diseases caused by eukaryotic microbes?

Answer 11

o Giardia lambia
o Candida albicans

Question 12

What are the major defining characteristics of bacteria?

Answer 12

Can be harmless or helpful, some have been classified as pathogens. Unicellular prokaryote with cell walls that are made of peptidoglycan. Some are photosynthetic and others are non-photosynthetic.

Question 13

What are some examples of bacteria?

Answer 13

• Gram + example
o Staphylococcus Aureus
• Gram – example
o E.coli
• Cell wall-less example
o Mycoplasma pneumoniae
• Acid fast example
o Mycobacterium tuberculosis

Question 14

What are the major defining characteristics of archaea?

Answer 14

prokaryotic, unicellular organisms with cells walls that contain pseudopeptidoglycan. None have been shown to be human pathogens. They are also extremophiles (can live in extreme environments)

Question 15

What are some examples of archaea?

Answer 15

1) Halophiles
2) Methanobacterium
3) Thermoproteus
4) Pyrodicticum

Question 16

What are the major defining characteristics of protozoa?

Answer 16

Unicellular, diverse group. Some are photosynthetic while others feed on organic material. Some can be parasitic while others can be free-living. Most are harmless but some are pathogens.

Question 17

What are some examples of protozoa?

Answer 17

o Giardia species
- Giardia lambila: cause severe diarrhea
o Plasmodium species
o Trypanosoma
o Trichomonas

Question 18

What are the major defining characteristics of fungi?

Answer 18

They can be unicellular or multicellular. They are not photosynthetic and their cell walls are made up of chitin. They can be microscopic like yeasts and molds or macrobes like mushrooms.

Question 19

What are some examples of fungi?

Answer 19

o Candida albicans (vaginal yeast infections and oral thrush)
o Pneumocystic jirovecii
o Trichophyton
o Tinea

Question 20

What are the major defining characteristics of viruses?

Answer 20

acellular, nonliving microorganisms that consist of proteins and genetic material (DNA or RNA). They can infect all types of cells, but many viruses do not cause disease

Question 21

What are some examples of viruses?

Answer 21

o Influenza virus
o Measles
o Rubella
o Ebola virus

Question 22

What are the major defining characteristics of viroids?

Answer 22

acellular particles that consist only of single stranded RNA without a protein coat. They are plant pathogens that can cause losses of important food crops that are grown in fields and orchards

Question 23

What are some examples of viroids?

Answer 23

o Potato spindle tuber viroid
o Tomato planta macho viroid
o Avocado sunblotch viroid
o Peach latent mosaic viroid

Question 24

What are the major defining characteristics of prions?

Answer 24

rare misfolded rogue form of a normal protein found in the cell. They can be infectious- can cause other proteins to become misfolded. They are the toughest pathogens to destroy.

Question 25

What are some examples of prions?

Answer 25

o Mad cow disease
o Scrapie in sheep
o Kuru
o Fatal Familial Insomnia

Question 26

What are the major defining characteristics of plantae?

Answer 26

Kingdom of multicellular, photosynthetic organisms. The cell walls of these organisms are made up of cellulose.

Question 27

What are some examples of plantae?

Answer 27

• Mosses
• Trees
• Flowers
• Herbs

Question 28

What are the major defining characteristics of animalia?

Answer 28

Kingdom of multicellular organisms that lack a cell wall. They are heterotrophic, meaning they use organic molecules for their energy.

Question 29

What are examples of animalia?

Answer 29

• Mammals
• Worms, leeches
• Fish
• Insects

Question 30

What makes the Fungi different from the other groups of organisms?

Answer 30

They can be multicellular or single-celled organisms that have cell walls made up of chitin. Chitin is the substance that insect exoskeletons are made out of. They are also saprophytes, signifying that they decompose decaying material.

Question 31

What makes these 2 groups (Plantae and Animalia) different from all the other groups?

Answer 31

They are multicellular, Plantae can be photosynthetic, with cell walls made up of cellulose. Animalia are heterotrophs and lack a cell wall. A heterotroph uses organic molecules for its energy. These two groups consist of larger organisms such as flowers, cows, fish, and grass that can be seen with the naked eye. The other groups are often microscopic or small. The other groups, except archaea, can cause disease to organisms in the Plantae and Animalia groups. They also can be found living in the Plantae and Animalia groups.