Microbiology Lecture Exam 3

Eukaryotes are single-celled or multicellular organisms that possess a membrane-bound nucleus and organelles. This means that their DNA is enclosed within a nucleus, which separates it from the rest of the cell. Additionally, eukaryotes have various specialized structures called organelles that perform specific functions within the cell. This distinguishes them from prokaryotes, which lack a nucleus and organelles. Eukaryotes include a wide range of organisms, such as plants, animals, fungi, and protists.

Eukaryotes are organisms that have complex cells with a nucleus. They can be found in various environments and play important roles as environmental indicators and producers. Additionally, some eukaryotes can also be pathogenic, meaning they have the potential to cause diseases in other organisms. Therefore, the statement that eukaryotes are good environmental indicators, producers, and can be pathogenic is true.

Algae can indeed be single-celled or multicellular, and they are commonly found in both fresh and salt water. However, algae are not typically pathogenic, meaning they do not cause diseases in humans or animals. Therefore, the statement that algae can be pathogenic is false.

Algae contains chlorophyll, a pigment that is responsible for trapping sunlight during the process of photosynthesis. Chlorophyll absorbs light energy from the sun and converts it into chemical energy, which is used by algae to carry out various metabolic processes. This pigment gives algae its green color and is essential for their survival and growth.

Carotene is a pigment found in algae that is known for its red/yellow color. It is a type of carotenoid, which is responsible for the vibrant colors in plants, fruits, and vegetables. Carotene is an important pigment in algae as it helps in photosynthesis by absorbing light energy and converting it into chemical energy. The presence of carotene gives algae its characteristic red/yellow hue, making it easily identifiable.

Xantophyll is a pigment found in algae and diatoms that is noted for its yellow color. It is responsible for the yellow hues observed in these organisms. Xantophyll is a type of carotenoid pigment, which is a class of pigments found in various plants and algae. It plays a vital role in photosynthesis, absorbing light energy and transferring it to chlorophyll molecules. Additionally, xantophyll acts as an antioxidant, protecting cells from damage caused by reactive oxygen species.

Phycobilin is a pigment found in algae that is known for its red color. It is responsible for the red coloration observed in certain types of algae. Phycobilins are light-absorbing pigments that play a crucial role in photosynthesis by capturing light energy and transferring it to chlorophyll. These pigments are structurally diverse and can vary in their specific shade of red, ranging from a bright red to a deep maroon. Due to their distinctive red color, phycobilins are often used as natural dyes and colorants in various industries.

Spirogyra is a type of freshwater alga that is filamentous in structure. It is characterized by its spiral-shaped chloroplasts, which contain chlorophyll. This enables Spirogyra to carry out photosynthesis and produce energy from sunlight. The description provided matches the characteristics of Spirogyra, making it the correct answer.

The cell wall of diatoms contains silica, which is a component of glass and does not decompose. Silica provides strength and rigidity to the cell wall, allowing diatoms to maintain their shape and structure. This unique characteristic of silica in the cell wall makes diatoms resistant to decomposition, enabling their preservation in the fossil record.

Dinoflagellates are single-celled organisms that have armored plates made of cellulose, which provide them with protection. They are motile, meaning they are capable of movement, and can be found in various aquatic environments. Some dinoflagellates are parasitic, meaning they obtain nutrients from other organisms, while others are photosynthetic producers, capable of converting sunlight into energy through photosynthesis. Overall, dinoflagellates exhibit a unique combination of characteristics that allow them to thrive in different ecological niches.

Pfiesteria piscicida is a type of Dinoflagellate that is commonly found in the Chesapeake Bay and its tributaries. It is typically found in the harmless cyst-stage in the sediment of these waters.

Pfiesteria piscicida appears in its parasitic stage when there is an increase in rainfall and when there is runoff of wastes. The increase in rainfall provides the necessary conditions for the growth and proliferation of Pfiesteria piscicida. Additionally, the runoff of wastes, such as agricultural or industrial runoff, can introduce nutrients into the water, creating an ideal environment for Pfiesteria piscicida to thrive and transition into its parasitic stage.

The correct answer is "neurological, tissue." The parasitic stage of Pfiesteria piscicida produces two toxins, one being a neurological toxin and the other being a tissue toxin. The neurological toxin affects the nervous system, while the tissue toxin causes lesions on fish.

Burkholder's research lab demonstrated the impact of aerosolized Pfiesteria neurotoxin on humans.

Euglenoids are motile organisms that resemble protozoa. They are commonly found in aquatic environments and are often used as indicators of water quality. Euglenoids are non-pathogenic, meaning they do not cause disease. The given information suggests that euglenoids are classified as algae, which is a group of photosynthetic organisms that can be found in various aquatic habitats. Therefore, the correct answer is euglenoid.

Protozoa are single-celled organisms that are classified as animal-like consumers. They can be both pathogenic, meaning they can cause diseases, and non-pathogenic, meaning they do not cause diseases. Protozoa have diverse characteristics and can be found in various environments, including freshwater, marine, and soil. They play important roles in ecosystems as predators and decomposers. Some well-known examples of protozoa include amoebas, paramecia, and trypanosomes.

Cilia are the hair-like structures found on the surface of ciliates, which are a type of protozoa. These cilia beat in a coordinated manner, creating a wave-like motion that allows the ciliates to move through their environment. The cilia also help in capturing food particles and in maintaining a steady flow of water around the ciliate. Therefore, cilia are the means of locomotion for ciliates.

Flagella are whip-like appendages that are used by protozoa called flagellates for locomotion. These long, hair-like structures help the flagellates move through their environment by propelling them forward in a whip-like motion. Flagella are found in various types of flagellates, such as Euglena and Trypanosoma, and play a crucial role in their survival and ability to find food and mates.

Cytoplasmic streaming refers to the movement of the cytoplasm within a cell. In amoeboids, which are a type of protozoa, cytoplasmic streaming plays a crucial role in their locomotion. The cytoplasmic streaming allows the amoeboids to extend and retract their pseudopodia, which are temporary projections of the cell membrane. This movement helps the amoeboids to crawl and change their position. Therefore, cytoplasmic streaming is the means of locomotion for the protozoa "amoeboids".

Paramecium is a type of ciliate that is commonly found in freshwater environments. It is non-pathogenic, meaning it does not cause disease in humans or other organisms. Paramecium is often used as an indicator species in aquatic ecosystems because its presence indicates good water quality. It is sensitive to changes in temperature, pH, and pollution levels, so its absence or decline in numbers can be a sign of environmental degradation. Therefore, Paramecium is considered a good indicator of the health and suitability of freshwater habitats.

The correct answer is "oral groove." The oral groove is a structure found in paramecium that opens in order for it to feed. This groove acts as a channel through which food particles can enter the cell. It is lined with cilia that create a current, allowing the paramecium to sweep food particles into its mouth and into its digestive system. The oral groove is an essential part of the feeding process for paramecium.

The contractile vacuole is responsible for regulating water pressure in Paramecium. This organelle collects excess water from the cytoplasm and expels it out of the cell through a pore. By controlling the amount of water in the cell, the contractile vacuole helps maintain osmotic balance and prevents the cell from bursting due to excessive water intake.

Balantidium coli is a ciliate that is a pathogen commonly found in pigs. It is transmitted through the fecal-oral route, meaning that it is spread through contaminated food or water. This parasite has a cyst stage that is able to survive the acidic environment of the stomach, allowing it to reach the intestine. In the intestine, the cyst stage transforms into a trophozoite stage, which is the active form of the parasite. Balantidium coli infection can cause dysentery, which is characterized by symptoms such as diarrhea, abdominal pain, and bloody stools.

Plasmodium is a flagellate that causes malaria in the equatorial belt. It is responsible for being the leading killer of humans throughout history. This parasite has evolved resistance to chloroquin and primaquin, which are commonly used antimalarial drugs.

The correct answer is "anopheles" because anopheles mosquitoes are the specific type of mosquitoes that transmit the Plasmodium parasite, which causes malaria. During the first stage of the Plasmodium life cycle, female anopheles mosquitoes deposit sporozoites (a form of the parasite) into the bloodstream when they bite a human. These sporozoites then circulate to the liver, where they multiply and continue the infection process.

Once the sporozoites infect the liver cells in the second stage of Plasmodium, they undergo asexual reproduction to make merozoites. These merozoites then rupture the liver cells and cause jaundice.

In the third stage of Plasmodium, the merozoites infect the red blood cells (RBCs) and transform into trophozoites. These trophozoites feed on the hemoglobin inside the RBCs and multiply. Eventually, some of the trophozoites differentiate into gametocytes, which are the sex cells of Plasmodium. The gametocytes are responsible for the sexual reproduction of the parasite within the mosquito vector, completing the life cycle of Plasmodium.

Toxoplasma gondii is a parasite that infects warm-blooded animals, including mice, rats, birds, grazing animals, and cats. These animals act as reservoirs for the parasite, picking up cysts from the soil. This explanation highlights the relationship between the parasite and the various warm-blooded animals that serve as hosts, emphasizing the role they play in the transmission and spread of Toxoplasma gondii.

Toxoplasmosis is caused by the infection of Toxoplasma gondii. It can manifest with symptoms of mononucleosis in healthy individuals, including fatigue, fever, and swollen lymph nodes. In immunosuppressed individuals, such as those with HIV/AIDS, it can lead to more severe symptoms like seizures and coma. Additionally, Toxoplasma gondii can cross the placenta in pregnant women, resulting in birth defects or miscarriage.

Giardia lamblia is a protozoan parasite that uses beavers, bunnies, and raccoons as its reservoir. It is transmitted through a fecal-oral route, typically from contaminated water.

Trypanosoma brucei is a parasitic protozoan that causes African trypanosomiasis, also known as sleeping sickness. It is characterized by having two flagella, which are whip-like structures used for movement. The presence of an undulating membrane further distinguishes this species. The tsetse fly serves as the vector for Trypanosoma brucei, allowing the parasite to be transmitted to humans and other animals.

The correct answer is Trypanosoma cruzi. This is because the given information mentions that the organism resembles Trypanosoma brucei, but to differentiate between the two, it is important to check the infected person's travel history. Additionally, Trypanosoma cruzi is found in Central and South America and is transmitted by the Reduviid bug, which supports the identification of the organism as Trypanosoma cruzi.

This question is asking for the name of the infection caused by Trypanosoma cruzi, and the correct answer is Chagas disease. Chagas disease is a parasitic infection that is primarily found in Latin America. It is transmitted to humans through the bite of infected triatomine bugs, also known as "kissing bugs." The infection can also be spread through blood transfusions, organ transplants, and from mother to baby during pregnancy. Chagas disease can cause a range of symptoms, including fever, fatigue, body aches, and swollen lymph nodes. If left untreated, it can lead to serious complications, such as heart and digestive system damage.

Amoeboids are single-celled organisms that have the ability to change their shape and move by extending their pseudopodia. Pseudopodia are temporary projections of the cell membrane that allow amoeboids to crawl and engulf food particles. These extensions are formed by the cytoplasm flowing into the protrusion, providing support and allowing movement. Therefore, pseudopodia are essential for the locomotion and feeding of amoeboids.

Amoeba proteus is a non-pathogenic amoeboid that serves as a good indicator of freshwater environmental conditions. It is commonly found in freshwater habitats and its presence indicates a healthy ecosystem. Amoeba proteus is known for its ability to adapt to various environmental conditions and is often used in laboratory studies to understand cellular processes and behavior. Its presence in freshwater environments suggests that the water is clean and suitable for other organisms to thrive.

Entamoeba histolytica is a pathogenic amoeboid that is transmitted through the fecal-oral route. It is commonly found in countries with poor sanitation. Once it enters the body, it takes up residence in the small and large intestines. The infection caused by Entamoeba histolytica can result in mild diarrhea, as well as ulceration and perforation of the intestines.

Fungi are a group of organisms that include single-celled yeasts and multicellular molds. They obtain their nutrients by decomposing organic matter, making them consumers in the ecosystem. Additionally, fungi can be either pathogenic, causing diseases in plants and animals, or non-pathogenic, having no harmful effects.

Mold is a type of fungi that requires a moist, terrestrial environment to thrive. To differentiate between different types of molds, one needs to examine the sporulating structure under a microscope. This microscopic examination helps in identifying and distinguishing one type of mold from another.

A single filament of mold is called a hypha. Hyphae are long, thread-like structures that make up the body of a fungus. They are responsible for absorbing nutrients from the environment and play a crucial role in the growth and spread of mold. By intertwining and branching out, hyphae form a network called mycelium, which is the main body of the fungus. Therefore, the correct answer is hypha.

The given correct answer, Rhizopus stolonifer, is a zygomycete fungus commonly known as black bread mold. This fungus is characterized by its black color and its ability to grow on bread, fruits, and other organic materials. Rhizopus stolonifer reproduces through the formation of specialized structures called sporangia, which release spores that can spread and colonize new substrates. It is a common contaminant in food and can cause food spoilage and infections in immunocompromised individuals.

Rhizopus stolonifer is a type of bread mold that produces rhizoids. Rhizoids are root-like structures that anchor the mold to the bread and absorb nutrients. These structures also secrete enzymes that break down the complex carbohydrates present in bread into simpler forms that the mold can absorb and use as a food source. Therefore, it is correct to say that rhizoids produce enzymes to break down bread.

Aspergillus is a genus of fungi that belongs to the deuteromycete group. It is known for its ability to decompose damp grains and peanuts, making it a common cause of food spoilage. Aspergillus species can produce toxins that are harmful to humans and animals if consumed, and they can also cause respiratory infections in individuals with weakened immune systems. Therefore, the presence of Aspergillus in damp grains and peanuts is a concern for food safety and storage.

Aspergillosis is a term used to describe the infection caused by the fungus Aspergillus. It is also known as farmer's lung, as it is commonly found in individuals who work with moldy hay or other agricultural materials. The fungus can enter the lungs and cause inflammation, leading to symptoms such as coughing, wheezing, and difficulty breathing. Treatment typically involves antifungal medication to eliminate the infection and manage symptoms.

The correct answer lists three examples of sporulating structures: Rhizopus, Aspergillus, and Penicillum. These are all types of fungi that produce spores as part of their reproductive process. Rhizopus is a common bread mold that forms black sporangia, which contain spores. Aspergillus is a genus of fungi that produces conidiophores, which bear conidia (asexual spores). Penicillum is another genus of fungi that produces conidiophores and conidia. These three examples demonstrate different types of sporulating structures found in different types of fungi.

Histoplasma capsulatum is a fungus that causes a respiratory infection called histoplasmosis. It is commonly found in soil contaminated with bird or bat droppings. The name "Spelunkers' disease" refers to the fact that spelunkers, or cave explorers, are at a higher risk of contracting histoplasmosis due to the fungus being present in caves. This term is used colloquially to describe the disease, highlighting the specific group of people who are more susceptible to it.

Yeast is a single-celled fungi that belongs to the kingdom Fungi. It is commonly used in baking and brewing due to its ability to ferment sugars, producing carbon dioxide and alcohol. Yeast cells are oval or spherical in shape and reproduce through a process called budding, where a smaller cell grows out from the parent cell. They can be found in various environments, including soil, plants, and the skin of fruits. Yeast is also known for its nutritional value and is a rich source of B vitamins and minerals.

Candidiasis is the correct answer because it is the name of the infection caused by Candida albicans when its numbers become too high. In the oral cavity, this infection is known as thrush. It is commonly seen in immunosuppressed adults and can be transmitted from mother to baby since babies are not born with normal flora.

Cryptococcus neoformans is a fungal pathogen that commonly affects individuals with weakened immune systems, such as those who are immunosuppressed. The infection caused by this fungus is known as cryptococcosis. It primarily affects the lungs, but can also spread to other organs, including the brain and central nervous system. Symptoms may include cough, shortness of breath, headache, fever, and altered mental status. Prompt diagnosis and treatment with antifungal medications are crucial in managing this potentially life-threatening infection.

Cryptococcosis is a fungal infection caused by the yeast Cryptococcus. When the macrophages, which are immune cells responsible for engulfing and destroying pathogens, are suppressed, the yeast is able to enter the cerebrospinal fluid (CSF), leading to meningitis. Meningitis is diagnosed through a spinal tap, where a sample of the CSF is collected and tested for the presence of the fungus. Treatment of cryptococcal meningitis can be challenging due to the blood-brain barrier, which limits the penetration of antifungal drugs into the brain. Therefore, it may require prolonged and aggressive therapy to effectively treat the infection.

Helminths are multicellular consumers that are always pathogenic in humans. They are classified according to their shape. Helminths include various types of parasitic worms such as roundworms, tapeworms, and flukes. These organisms invade the human body and cause diseases by feeding on host tissues or by releasing toxins. They can infect various organs and systems, leading to a wide range of symptoms and health issues. Due to their pathogenic nature and ability to cause harm to humans, helminths are considered significant pathogens and are a focus of medical research and treatment.