Micro exam 4

how do some fungi cause cancer

Some fungi will produce aflatoxins that result in rapid cell death that can eventually due to statistic result in a mutation forming that leads to cancer. Other will manipulate the cellular expression to produce more cells for them to feed on.

Basidiomycota

many mushrooms, have haploid bsidiospores used for reproduction, during fusion nuclei do not always fuse

what is an aseptate hyphae? what are the pros and cons?

no septate present allows for a continuous linkage of the cytoplasm making transport easier and cell signals easier to permeate the entire cell.

excavate

primitive eukaryotes -most have a cytostome •characterized by a suspension-feeding groove •plays role in capturing particles from a feeding current

how do protists produce energy

through mitochondria in aerobic chemoorganotrophic protists chloroplasts and mitochondria in photosynthetic protists and hydrogenosomes in anaerobic chemoorganotrophs.

1. How does the life cycle of basidiomycota compare to other fungi? Why is its life cycle used as point of validation for why it is included in the fungal kingdom? What about basidiomycota makes them different from the other fungi?

decomposers edible and non-edible (hallucinogenics) pathogens of humans plants and animals reproduces sexually diploid zygote, then undergoes meiosis to become haploid basidiospores on mating strains help fertilize, causing it to be dikarya, which forms muchroom shape, then cycle repeats

icosahedral capsid

•An icosahedron is a regular polyhedron with 20 equilateral faces and 12 vertices •Capsomers -ring or knob-shaped units made of 5 or 6 protomers -pentamers (pentons) - 5 subunit capsomers -hexamers (hexons) - 6 subunit capsomers

why is symmetry important for the capsid?

The symmetry allows for the different pieces of the capsid to self form without help from assistor proteins or the like.

how do viruses enter the cell?

viruses use specific receptor attachment. They have receptor that determine host preference. They can be specific tissue (tropism), may be more than one host, may be more than one receptor or may be in lipid rafts providing entry of virus. Entry can be ntire genome or nucleocapsid, and varies between naked or enveloped virus. They uset hree methods, that include fusion of the viral envelope with host membrane; nucleocapsid enters, endocytosis in vesicle; endosome aids in viral uncoating and injection of nucleic acid

ascomycota

.goes through meiosis, can survive as haploid spores. Very diverse group

Zygomycota

.usually filamentous and nonseptated. Sexual reproduction results in thick walled zygospore

Describe the different morphologies that you find members of the super group amoeboza. How do they move?

Amoeboid motility - use of pseudopodia for locomotion and feeding. Their shapes can be found in forms of pseudopods including lobopodia - rounded, filopodia - long and narrow, and reticulopodia - form a netlike mesh. Some are naked amoebae surrounded only by a plasma membrane others such as testate amoebae have plasma membrane covered by material made by amoeba or obtained from the environment. They all reproduce by binary or multiple fission

how would you prove that something is an animal virus

Animal virus envelopes (lipids and carbohydrates) usually arise from host cell plasma or nuclear membranes. see if it infects an animal cell.

what would you look for to determine if an organism is a fungi?

First DNA sequencing of rRNA genes and a few other choice genes are going to be your best bet. The presence of Chitin it a good indicator, can stain for it Unlike bacteria fungal cell wall composition is unique from species to species so you could look for that. You can look for the unique structures that form in a number of yeast and molds like sporangium, coniophores, blastospores, arthroconidia hyphal cells, and budding yeasts.

How do you classify a slime mold?

Have been classified as plants, animals, or fungi. They are monophyletic group that includes myxogastria (the acellular slime mold), and dictyostelia (the cellular slime mold)

functions of viral protein envelopes

Many viruses are bound by an outer, flexible, membranous layer called the envelope. In animal virus envelopes (lipids and carbohydrates) usually arise from host cell plasma or nuclear membranes, and they can be structural just reinforcing the virus outer portion to protect the DNA inside. Envelope proteins, which are viral encoded, may project from the envelope surface as spikes or peplomers. They can have functions involved in viral attachment to host cell, such as hemagglutinin of influenza virus. They will often allow for the identification of virus. Some have enzymatic or other activity such as neuraminidase of influenza virus, and finally they may play a role in nucleic acid replication

unique life cycle of chlamydomonas

Member of subgroup Chlorophyta with cells that have a haploid nucleus, large chloroplast, conspicuous pyrenoid, stigma (eyespot) which plays a role in phototaxis they use osmoregulation controlled by two contractile vacuoles at flagella base and reproduces by sexual and asexual reproduction. grow by repeated mitotic division mating between gametes of opposite types diploid dormant zygote forms, becomes haploid after meiosis

parabasilia trichomonadida

Most are flagellated endosymbionts of animals •Lack a distinct cytosome, use phagocytosis to engulf food do not required oxygen, possess hydrogenosomes •asexual reproduction only •symbionts of digestive, reproductive, and respiratory traits of many vertebrates, including humans •some strains are human pathogens

two ways viruses are released from an infected cell?

Nonenveloped viruses lyse the host cell with viral proteins may attack peptidoglycan or membrane, or enveloped viruses use budding where viral proteins are placed into host membrane, with the nucleocapsid may bind to viral proteins and the envelope derived from host cell membrane, but may be Golgi, ER, or other. Some virus may use host actin tails to propel through host membrane

helical capsid

Shaped like hollow tubes with protein walls Protomers self assemble Size of capsid is a function of nucleic acid

compare cellular and acellular slime molds

The acellular molds include Plasmodium lacks cell membrane, contain up to 10,000 diving nuclei and streaming masses of colorful protoplasm. They creep along in amoeboid fashion and degrade rotting organic matter and feed by endocytosis. They are able to form fruiting bodies and resistant stalks with spores germinate in good environments . They also release haploid amoebaflagellate which fuse to form zygotes. There life cycles vary greatly. Whereas the cellular slime molds are strictly amoeboid that use endocytosis to feed on bacteria and yeast. They have a multicellularity in life cycle and can be see as pseudoplasmodium that are individual cells retain cell membrane that move as mass starved cells release compounds detected by other cells which form aggregate around signaling cell. This results in cells pile on top, bottom cell forms stalk with the tip cells produce spores that germinate

Compare and contrast the life cycle of yeast vs filamentous ascomycetes

The yeast life cycle will alternate between haploid and diploid. In nutrient rich, mitosis and budding occurs at non-scarred regions and stops after entire mother cell is scarred . In nutrient poor, meiosis and haploid ascus containing ascospores formed haploid cells of opposite mating types fuse that are tightly regulated by pheromones For the filamentouts ascomycota we see that during asexual reproduction it produces conidia, and during sexual reproduction like yeast it forms an ascus formation with ascospores. Only opposite mating types form zygote and the ascospores can be forcefully released from ascocarp, resulting in germination. In the winter they will form a sclerotia that are masses of hyphae survive the winter then germinate

how do viruses assemble in the cell and why is this process beneficial?

They self assemble, Put them in the right place they come together. They do not require any helpers that can be blocked or mutated. Much of what we know if from bacteriophage with late proteins being of important in assembly. The assembly is complicated but varies, with bacteriophages in stages , some are assembled in nucleus, some are assembled in cytoplasm, and some may be seen as paracrystalline structures in cell

The trichomonads class is a group of pathogenic protist, what are the symptoms of infection?

Trichomonas foetus cause spontaneous abortion in cattle. Dientamoeba fragilis cause diarrhea in humans. Trichomonas vaginalis causes trichomoniasis sexually transmitted infection in humans.

differences between viruses, viroids, satellites, and prions

Viruses - protein and nucleic acid Viroids- only RNA Satellites - only nucleic acids Prions - proteins only

Why are prions so dangerous?

Well to properly answer this question we need to define or understand what a prion is and what it causes. It can cause a variety of degenerative diseases in humans and animals including scrapie in sheep, bovine spongiform encephalopathy (BSE) or mad cow disease (my favorite) Creutzfeldt-Jakob disease (CJD) and variant CJD (vCJD) in humans, or kuru in humans. It is problematic as it is a problem that builds on itself. A mutant converts the nonmutants to mutants or otherwise: PrPC (prion protein) is present in "normal" form (abnormal form of prion protein is PrPSc) with PrPSc causes PrPC protein to change its conformation to abnormal form. The newly produced PrPSc molecules convert more normal molecules to the abnormal form through unknown mechanism. Evidence suggests that PrPC must be present for neural degeneration to occur. The interaction of PrPSc with PrPC may cause PrPC to crosslink and trigger apoptosis and PrPC conversion causes neuron loss, PrPSc is the infectious agent. All prion caused diseases that have no effective treatment. It results in progressive degeneration of the brain and eventual death.

what are different ways viruses cause cancer

While it is complex, multistep process it often involves oncogenes or cancer causing genes. These genes may come from the virus OR may be transformed host proto-oncogenes (involved in normal regulation of cell growth/differentiation). The viral proteins bind host cell tumor suppressor proteins, be carry oncogene into cell and insert it into host genome, altered cell regulation or insertion of promoter or enhancer next to cellular oncogene

How are different fungi identified as separate species?

best way to identify is rRNA sequence analysis much diversity makes identification overwhelming They are differentiated also on what they grow on, the temperature that they grow at, their life cycles, haploid vs diploid or both, but mainly they share a common lifecycle that all at least share some part of.

what are the different ways that protists obtain nutrition

chemoheterotrophic protists such as saprophytes whose nutrients are obtained from dead organic matter through enzymatic degradation. some use osmotrophy or absorb soluble products. Then there is holozoic nutrition - solid nutrients acquired by phagocytosis. A second major nutrition group is photoautotrophic protists that are strict aerobes, use photosystems I and II for oxygenic photosynthesis. Finally we find mixotrophic protists that are fascinatedly able to use use organic and inorganic carbon compounds simultaneously.

How are viruses classified?

consisting of 1 or more molecule of DNA/RNA in protein coat, some with additional layers. In general they cannot reproduce independent of living cells nor carry out cell division, but can exist extracellularly. In bacterial viruses called bacteriophages (phages), whereas there are few archaea viruses and most are eukaryotic viruses They tend to be classified on families based on genome structure, life cycle, morphology, genetic relatedness, unlike other organisms where genome sequences can often tell most if not all of the data needed for identification.

what are the functions of vacuoles in protists

contractile vacuoles help maintain osmoregulation and phagocytic vacuoles allow some protists to ingest food

Rhizopus asexual life cycle

dikarya after fertilization, then become diploid meiosis occurs- becomes haploid spores in asexual reproduction- germination stage hyphae cover surface to absorb nutrients

what si the difference between encystment and excystment

encystment is when a protist simplifies in structure and become dormant (cyst) with a cell wall and very low metabolic activity. It helps to protects against environmental changes so it would be more resistant to different environments. It can assist in nuclear reorganization/reproduction and serve as a means of host to host transfer for parasitic species an excystment is when the encystment returns to in favorable conditions may stimulate a cyst form to return to its original state. In the parasitic protists, this may occur following ingestion of a cyst by a new host organism.

Glomeromycota

filamentous, lack cilia form asexual spores outside of plant host, lack cenrtioles conidia and aerial spores

Chytridiomycota

flagellated cells in at least one life cycle. Produce a zygote that is a resting spore or sporangium

Dinoflagellates

found in marine plankton, cause toxic blooms most are photosynthetic, nutritionally complex •Trichocysts are defensive proteins symbiotic forms (zooxanthellae) -live in association with reef building corals

what is the life cycle of many fungi?

fusion of compatible nuclei they can be homothallic or have sexually-compatible gametes are formed on the same mycelium (self-fertilizing. In addition heterothallic or require outcrossing between different, yet compatible mycelia are also observed. Finally a dikaryotic stage can exist temporarily prior to fusion of two haploid nuclei. In general you will find that they have an asexual stage where they make clones of themselves and a sexual stage where haploid gametes can mate and form diploid organisms.

how are glomeromycota mutualistic with plants

glomeromycotan are aseptate flat hyphae (appressoria) to penetrate host plants; produce large, multinucleate spores and only reproduce asexually. Arbuscular mycorrhizae that do penetrate root cell wall or have a sort of mutualistic relationship (both benefit). It is thought that the fungus helps protect host from stress, delivers soil nutrients to the plant and in return the plant provides carbohydrates to fungus

based on mode of infection how would you determine if a virus is an animal virus or something else?

how it is released in the environment

Microsporidia

intracellular parasite of animals, lack mitochondria, perioxiosomes kinetosomes, cilia and centrioles. Spores have inner chitin wall and outer wall of protein. Penetrate host with a tube-like structure

what is structurally unique about entamoebida?

lack mitochondria and hydrogenosomes may have 20 mitochondrial proteins The Entamoeba histolytica causes amoebic dysentery acquired by consuming E. histolytica cysts may migrate to lungs, brain, liver, or skin

Trypanosomes are a particular nasty protists that cause a number of different diseases. Compare and contrast the different species and what the symptoms are of infection.

leishmaniasis caused by members of genus Leishmania and includes systemic and skin/membrane damage. Trypanosoma cruzi causes Chagas' disease transmitted by "kissing bugs" causes damage to nervous system. T. gambiense and T. rhodesiense cause African sleeping sickness that use an antigenic variation thick glycoprotein layer coating cell wall surface which is changeable which enables the parasite's escape from the host immune system

how would you determine if an unknown organism is a protist?

most likely diploid not quite a plant animal or fungus Plasma membrane structure similar to multicellular plants/animals, a cytoplasm sometimes subdivided into outer gelatinous ectoplasm just underneath plasma membrane and an inner fluid region termed endoplasm, and also potentially a pellicle structure provides support. You would also expect to see vacuoles commonly present in protists, including contractile vacuoles and phagocytic vacuoles Energy production through mitochondria in aerobic chemoorganotrophic protists , chloroplasts and mitochondria in photosynthetic protists, and hydrogenosomes in anaerobic chemoorganotrophs. Finally you would expect to see cilia/flagella may be present for motility/feeding.

how do you determine reproductive stages of a protist

observe the organism When it divides you can look and see if it ever mates or if all of the protists in a given area are clonal or genetically identical. Protists have asexual and sexual reproduction with the asexual stage usually binary fission and the sexual stages use fusion of gametes in syngamy process. This can occur within a single individual (autogamy) or between individuals (conjugation)

in Zygomycota, when does sexual reproduction occur and what are the conditions?

occurs when environment is not favorable It requires compatible opposite mating types and the hormone production causes hyphae to produce gametes. gametes fuse, forming a zygote and zygote becomes zygospore.

what should you look for when trying to identify the supergroup archaeplastida?

organisms containing a photosynthetic plastid that arose through an ancient endosymbiosis with a cyanobacterium. All higher plants and many algal species are included

how are viruses an important tool of evolution

packaging only their own DNA in capsid heads it is easy to see how they can transport DNA all over the place. They also can integrate into the genome so that would be a great way to induce new dna and to also disrupt the existing DNA sequences. they can be a mechanism to transport DNA or genes between bacteria and other species.

what are the different ways that fungi get their metabolism?

saprophytes- absorb nutrients from dead organic material by releasing degrative enzymes by osmotrophy to absorb solutes chemoorganoheterotrophs w/ absorptive metabolism none are photosynthetic- lack chlorophyll, dense cell wall sexual and asexual reproduction, sometimes have relationships with other organisms

why do some viruses have a nucleocapsid?

the capsid helps primarly for the protection against the environment and/or the host defenses. •Protect viral genetic material and aids in its transfer between host cells •Made of protein subunits called protomers •Capsids are helical, icosahedral, or complex

viral multiplication

the mechanism used depends on viral structure and genome. The steps are similar and include attachment to host cell, entry and uncoating of genome synthesis, assembly and release

difference between viruses and other microorganisms

they are acellular. Acellular tend to be rudimentary when compared to other microorganism and are comprised of few compounds.

why do we need a new flu vaccine every year?

they are constantly changing their genome and outer structures to avoid the host defense.

how are microsporidia similar and different to other fungi?

they are obligate intracellular fungal parasites that infect insects, fish, and humans. It is thought that aquatic birds are common hosts and contribute to large numbers of spores in environment. Like many other fungi, transitional form is a spore structure capable of surviving outside the host. They are structurally similar to 'classic' fungi in that they contain chitin, trehalose, and mitosomes , but they differ in that they lack mitochondria, peroxisomes and centrioles. unique polar tube essential for host invasion. Like many other fungi they are opportunistic waiting the host to be immunocompromised before becoming an infectious agent.

how are fungi model organisms for geneticists?

they can be haploid or diploid, and have a dikarya state they are easy to grow have defined life cycles short generation times small genomes make them easy to sequence and work with

how can we quantify a virus

this can be done by direct counting of viral particles, or indirect counting by an observable effect of the virus. This includes the use of hemagglutination assay orplaque assays where dilutions of virus preparation made and plated on lawn of host cells, number of plaques counted with the results expressed as plaque-forming units (PFU) - plaque forming units (PFU) and PFU/ml = number of plaques/sample dilution.

what does it mean to be dikarya and what is the function?

two distinct nuclei present in one cell used to determine if the fungi is leaving a starvation or other stressful condition before commiting to being a unikaryon. It is also most likely the source of new species as it can cause a two cells to merge unequally.

how is a protists characterized

very hard group to define diverse assemblage of plant, animal and fungal-like groups mostly single-celled Eukaryotes, lack complexity

Different structures of a virus

virions size range is ~10-400 nm in diameter and most viruses must be viewed with an electron microscope. All virions contain a nucleocapsid which is composed of nucleic acid (DNA or RNA) and a protein coat (capsid). some viruses consist only of a nucleocapsid, others have additional components. All will have an envelope of some sort. They are can found in a diverse number of morphologies evolve different shapes for survival

Foraminifera

•Called forams •~20mm - several centimeter size range •Filopodia are arranged in branching network (reticulopodia) •May harbor endosymbiotic algae -contribute to foram nutrition •Have characteristics tests arranged in multiple chambers that are sequentially added as organism grows •Only eukaryote that can reduce nitrate to dinitrogen gas •Complex life cycle, sexual and asexual reproduction •Found in marine and estuarine habitats •make up most modern-day chalk, limestone, and marble

diatoms

•Chlorophylls and accessory pigments •frustule- two-piece cell wall of silica -unique, beautiful patterns -No other organism use this -A inorganic glass shell •Important in global carbon cycling -marine planktonic diatoms produce 40-50% of organic ocean carbon

Apicomplexans

•Distinguished by the unipolar apical complex •Parasitic with complex life cycles -life cycle has both sexual and asexual phases •clonal and sexual stages are haploid, except for zygotes •sporozoite is the motile, infective stage •Most important member is Plasmodium, the cause of malaria

fornicata

•Microaerophilic protist -epidemic diarrhea from contaminated water -members are flagellated and lack mitochondria -Giardia have mitosomes (mitochondria-like double-membrane bounded organelles) •Most are harmless symbionts with the exception of Giardia

parabasilia trichonymphida

•Most are flagellated endosymbionts of animals •Lack a distinct cytosome, use phagocytosis to engulf food •obligate mutuals of wood-eating insects such as termites •release cellulose for digesting may account for 1/3 biomass in termite •Ecdysone(a steroid hormone that controls molting in insects) hormone produced by host triggers sexual reproduction