Mastering Microbiology Chapter 12 HW

The Major Groups of Eukaryotic PathogensPart complete In this activity, you will select eukaryotic organisms from a list including both prokaryotic and eukaryotic organisms.

-alga-arthropod-fungus-helminth-protozoan

For this section, you will identify statements that accurately describe medically important protozoa.

1. As a group, protozoa exhibit both asexual and sexual reproduction.2. While living in the gut of their host, intestinal protozoan parasites are usually in the trophozoite form.3. Protozoan cysts enable protozoan parasites to survive during passage from one host to the next.4. Most protozoa are motile via pseudopods, flagella, cilia, or undulating membranes.

Characteristics of Parasitic HelminthsPart complete In this activity, you will identify statements that accurately describe parasitic helminths.

1. Either eggs or larval stages of helminths may be infectious, depending on the species. 2. Some helminth infections involve more than one intermediate host. 3. Humans can serve as either definitive or intermediate hosts of flatworms. 4. Parasitic helminths lack a complete digestive system and they absorb nutrients directly through their cuticles. 5. The major organ system apparent in tapeworm proglottids is the reproductive system.

This section asks you to identify statements that accurately describe algae.

1. Some marine algae produce neurotoxins that can be concentrated in shellfish and pose a risk of paralytic shellfish poisoning to humans who consume the shellfish. 2. Algae lack roots, stems, leaves, and vascular tissues that are found in terrestrial plants. 3. Algae may be green, red, or brown. 4. Both asexual and sexual reproduction occurs among the diversity of algal species. 5. Most algae have a plantlike cell wall composed of cellulose.

Observational Clues—EukaryotesPart complete Now that we have reviewed the basic groups of pathogenic eukaryotes, let's see if you can identify which group each of the following eukaryotes belongs to.

Algae: - this was recovered from a sample of pond water Fungi:-These were recovered from a vaginal swab from a woman complaining of a vaginal discharge accompanied by intense vaginal itching. Protozoa:-These were observed in a duodenal specimen from a patient with diarrhea. They moved actively by using flagella. Helminths:-These were passed in a stool specimen from a patient who had no obvious intestinal symptoms.- This was observed in the stool (fecal) specimen of a patient had complained of a mild intestinal discomfort and was slightly anemic.

In this activity, you will identify whether the statements describe arthropods, helminths, fungi, algae, or protozoa.For each of the following statements, indicate whether it is most appropriately applied to arthropods, helminths, fungi, algae, or protozoa.

Algae: -Members of this group are found predominantly in aquatic environments.-Members of this group generally don't cause infections, but some produce neurotoxins that cause intoxications in animals that consume them. Protozoa: -Members of this group cause malaria and diarrheal illnesses such as amebiasis and giardiasis.-Many members of this group are motile by means of cilia, flagella, or pseudopods. Fungi: -Members of this group produce a variety of different reproductive spores and filaments referred to as hyphae.-This group includes unicellular as well as filamentous forms, a number of which cause infections. Helminths: -Members of this group come in flat or round forms, and although many parasitize animals, there are also free-living forms.-Parasitic members of this group often have complex life cycles involving one or more intermediate hosts in which larvae develop. Arthropods: -Members of this group serve as vectors, transmitting several different viruses, bacteria, and protozoan parasites between hosts.-Members of this group have hard exoskeletons and jointed appendages.

Which phylum of protozoa contains organisms that are non-motile, obligate intracellular parasites?

ApicomplexaCiliatesEuglenozoa Apicomplexa contains many species that cause disease, including the Plasmodium species that cause malaria.

Asexual and Sexual Reproductive Spores of Fungi

Asexual spores that form as buds coming off the parent cell are known as " blastoconidia" and are produced by yeasts such as Candida albicans and Cryptococcus neoformans. 2. Sexual spores known as " basidiospores" are located on a base pedestal and are found in mushrooms. 3. Candida albicans, a species of pathogenic yeast, is often recognized by its chlamydoconidia, which are large, thick-walled asexual spores within a hyphal segment. 4. Coccidioides immitis is a pathogenic fungus that forms asexual spores called arthroconidia, which result from fragmentation of hyphae. Some fungi reproduce sexually by forming ascospores, which are sexual spores contained within a sac structure 6. Rhizopus stolonifer, the common black bread mold, forms asexual spores called sporangiospores, which are contained in a sac at the end of aerial hyphae.

Which of the following is NOT a characteristic of parasitic helminths?

Extensive mechanisms for strong locomotion

Which statement regarding helminths is true?

Helminths usually possess specialized organ systems, including circulatory, nervous, and reproductive systems.

Which of the following is the correct life cycle of Ascaris lumbricoides?

Human ingests egg; egg hatches in intestine; larva crosses intestinal wall and travels to lung; larva is swallowed and matures in intestine; adult females lay eggs; eggs exit host in stool.

Trichomonas vaginalis can be distinguished from other parasitic protozoa by which of the characteristics listed below?

It has an undulating membrane, infects the vagina, and is frequently transmitted by sexual contact.

Which of the following statements best characterizes the signs and symptoms of an Ascaris lumbricoides infection?

It is rarely fatal, with exiting adult worms being the major sign and symptom.

Which of the following organisms requires an additional non-human host to complete its life cycle?

Plasmodium species The life cycle of Plasmodium species requires two hosts, one of which is a mosquito.

The helminths that parasitize humans belong to which two of the following phyla? Select all that apply.

Platyhelminthes Nematoda Parasitic helminths are members of the phyla Platyhelminthes (flatworms) and Nematoda (roundworms)

Before exploring some of the features of the different types of eukaryotes, we should first review some of the fundamental differences between eukaryotes and prokaryotes. The two groups of organisms differ fundamentally in the structure of their individual cells. For each of the following statements, identify whether it refers to prokaryotes, eukaryotes, or both groups.

Prokaryotes only:-cell wall contains peptidoglycan or pseudomurein-binary fission-70S ribosomes-singular circular chromosome Eukaryotes only:-membranous organelles, including mitochondria, lysosomes, endoplasmic reticulum-80S ribosomes- nuclear envelope compartmentalizes the chromosomes Both prokaryotes and eukaryotes:-plasma membrane encloses the cytoplasm-has both DNA and RNA-includes unicellular cells

Humans are the definitive host for __________, which is a type of __________.

Taenia saginata; tapeworm

Which of the following statements about protozoa is true?

When conditions become harsh, some protozoa can form a protective capsule, which is called a cyst.

Dinoflagellates are a type of unicellular __________. One genus of dinoflagellates is responsible for a foodborne disease called _______

algae; paralytic shellfish poisoning (PSP)

Mebendazole acts against Ascaris lumbricoides by __________.

inhibiting the formation of microtubules, which prevents the worms from absorbing nutrients

Dengue fever and Zika virus are transmitted by which of the following?

mosquitoes