Microbiology chapter 5 lecture guided answers, exam 2

13. Describe two ways in which fungal spores arise.

Asexual fungal spores are produced by mitosis. 2n → 2n cells (Diploid = 2n) Sexual fungal spores are produced by meiosis. 2n → 1n cells (Haploid = 1n)

5. List and give the function of the two kinds of external structures of eukaryotic cells. Also give examples of each.

Glycocalyx - cellular communication and recognition (Glycoproteins, Glycolipids) Appendages - used for cellular movement (Cilia and Flagella)

4. List the structures found in eukaryotic cells that are not found in prokaryotic cells. Why are these structures not found in prokaryotic cells?

Nucleus, Endoplasmic Reticulum (both rough and smooth), Golgi Apparatus, Mitochondria, Chloroplasts, Vacuoles, Lysosomes, Etc... Prokaryotic cells do not have membrane bound organelles.

20. What are the benefits of the cyst stage for protozoans?

The cyst is much more resistant to changes in the environment (temp, pH, osmotic pressure, nutrient availability, etc.) The cyst is not reproductive, but it allows the protozoan to survive.

3. Describe the endosymbiosis theory. What evidence supports this theory?

The endosymbiosis theory states that larger cells endocytosed smaller cells that had the ability to make ATP. It was a symbiotic relationship because both cells benefited from this intimate relationship. The larger cell obtained ATP, the smaller received protection from the external environment. Evidence of this theory - mitochondria and bacterial cells are similar - both have ribosomes that are 70S (with 50S and 30S subunits) and have their own DNA.

6. What structures form the boundary of the eukaryotic cell? Describe the chemical composition of each of these structures.

Cell Membrane - consists of a bilayer of phospholipids

14. List two detrimental and two beneficial activities of fungi (from the viewpoint of humans).

Detrimental activities: decompose food (bread, raspberries); cause disease (athlete's foot and other mycoses) Beneficial activities: produce food (bread, alcohol); make antibiotics (Penicillium makes penicillin antibiotics, Cephalosporium makes cephalosporin antibiotics)

1. Which type of cell has membrane bound organelles, including a nucleus?

Eukaryotic

9. Differentiate between Heterotrophic and Autotrophic.

Heterotrophs - have an external food source; cannot make their own food energy Autotrophs - have an internal food energy source; Photosynthesis is used (get energy and carbon from inorganic chemicals)

22. List the two major groups of helminths and then the two subgroups of one of these groups.

Platyhelminthes - flat worms Cestodes (tape worms) and Trematodes (flukes) Aschelminthes - round worms Nematodes

2. Which type of cell does not have membrane bound organelles or a nucleus

Prokaryotic

21. List the four types of protozoa and give an example of a disease caused by each group:

Protozoa group Disease Sarcodina (Amoeba) Amoebiasis (caused by various Amoeba) Naeglaria fowleri goes to brain tissue. Most cause diarrhea. Mastigophora (Flagella) Trypanosoma causes African and S. American Sleeping sickness that affects central nervous system Trichomonas vaginalis - Trichomoniasis (or Trich) is a STD Ciliophora (Cilia) Balantidium coli causes diarrhea Sporozoa/Acomplexian (Spores) Toxoplasma gondii causes Toxoplasmosis transmitted to babies from mothers through contact with cat feces Plasmodium falciparum causes Malaria transmitted by Anopheles mosquito and causes blood infection

12. Differentiate among the terms saprobe and parasite.

Saprobes - organisms which are free-living do not require a nutritional relationship with other organisms. Typically are decomposers whose job is to decompose dead organic matter. Parasites - two organisms who are in a close, intimate nutritional relationship which is required of one or both organisms and which benefits one (the parasite), while harming the other (the host). Saprobes and parasites can be decomposers, but the parasite is trying to decompose the host while it is still alive. Parasites do not have a choice - the relationship is obligatory.

10. Which type of organism (Heterotroph (H) or Autotroph(A) are the following:

a. Fungi ____H____ b. Protozoan ____H____ c. Protista ___Both__ d. Algae ____A____ e. Helminths ____H____

7. List the internal structures of the eukaryotic cell and give the function of each.

a. Nucleus contains instructions to make a new organism, controls the activities of the cell b. Nucleolus site for ribosomal RNA synthesis and is a collection area for ribosomal subunits c. Chromosome consists of DNA associated with protein d. Nuclear Membrane regulates what goes into and out of the nucleus e. Endoplasmic Reticulum a series of tunnels used in transport and storage of substances in the cell f. Rough Endoplasmic Reticulum originates from the nuclear membrane, site of protein synthesis g. Smooth Endoplasmic Reticulum site of lipid processing, synthesis, and storage h. Golgi Body(apparatus or complex) site in the cell where proteins are modified and sent to their final destination i. Mitochondria site of cellular aerobic respiration; ATP synthesis j. Chloroplasts- the site of photosynthesis k. Ribosomes synthesis of proteins l. Cytoskeleton a flexible framework of molecules that anchors organelles, provides support, and permits shape changes and movement in some cells m. Vacuole stores nutrients or water needed by the cell n. Lysosome breaks down cellular debris to be reused

19. Define the following terms related to protozoa:

a. Trophozoite - Active, feeding stage (or adult) b. Cyst - Dormant, survival stage

11. Describe the following features of fungal anatomy and terms related to fungi.

a. Yeasts - single cell form of fungi b. Hyphae - multinucleated filamentous form of fungi c. Pseudohypha - several budding yeast cells attached to each other form a chain d. Mycelia - a lawn of hyphae filaments e. Septate - having crosswalls in hyphae f. Nonseptate - having no crosswalls in hyphae g. Dimorphic - exists in two forms (yeast and hyphae)

17. What algal characteristic places organisms informally into the algae group?

• Color of pigment expressed

18. List three means of motility by protozoa

• Flagella - long hair-like structure which propels like a motor on a boat to move the microbe in a linear fashion • Cilia - short hair-like structures that cover the entire surface of the protozoan and beat in sync to move in a particular direction • Pseudopods - (fake feet) ectoplasm streams in one direction producing an extension of the cell membrane

8. What characteristics identify an organism as part of Kingdom Fungi?

• Most are unicellular or colonial, but a few are multicellular (mushrooms and puffballs) • Decomposers - saprophytic - live off of dead animals and plants • Soil or aquatic habitats • Microscopic or macroscopic organisms • Reproduce asexually and sexually by forming spores • Dimorphic - can exist in two forms: yeast (unicellular) and mold (filamentous) • Have a unique cell wall structure with chitin as the carbohydrate of structure

16. What protozoan characteristic places organisms informally into the protozoan group?

• Motility - structure used to disseminate or transport microbes

15. What characteristics identify an organism as part of Kingdom Protista?

• Single celled or multicellular, heterotrophic or autotrophic, cell wall or no cell wall - no defining characteristic - Nature's Junk Drawer of classification