Test 1 study guide Flashcards
1
Q
describe the distinguishing characteristics of Kingdom Fungi (where they grow, what they eat, etc.)
A
- Fungi lack chlorophyll. Fungi are heterotrophic; they feed on other organisms via absorption by secreting digestive enzymes as their hyphae grow.
- Some are single celled (called yeasts) most are multicellulara. Bulk of multicellularstructure is found deeper in the ground because their filaments require moisture for growth. Fruiting bodies (mushroom) is what is seen above ground.
- Fungi have cell walls at some time in their life.a. The cell wall is composed of chitin.
- Chitin is very resistant to breakdown by microorganisms.It is a nitrogen containing polysaccharide that is strong and flexible.
- Fungi grow best in moist environments.
- Fungi require water as they grow.
- When the environment gets dry fungi survive by going into aresting stage or by producing sporesthat are resistant to desiccation.
2
Q
describe the body plan of a fungus (keywords: hyphae, mycelium, coenocytic, septa, monokaryotic, dikaryotic, yeasts)
A
- the vegetative (non-reproductive) body plan of most fungi consists oflong, branched, threadlikefilaments called hyphae.
- Hyphae form atangled mass or tissue-like aggregation known as mycelium.a. Some fungi are not divided into individual cells but are elongated, multinucleatedgiant cells called coenocytic fungi.
- Other hyphae are divided by cross walls calledsepta.
- The septa are perforated by a pore that may be large enough for organelles to pass through
3
Q
describe sexual & asexual reproduction. Example…trace the fate of a fungal spore that lands in a favorable location, such as an overripe peach, and describe conditions that permit fungal growth. What is the basis for sexual reproduction?
A
- Spores are usually produced by special aerial hyphae or in fruiting structures for easier dispersal.
- Fruiting body
- Spores may be produced sexually or asexually.
- Meiospore
- Mitospores
- Fungi usually contain HAPLOID nuclei.
- In sexualreproductiontwo geneticallycompatible mating types come together, and their cytoplasm(plasmogamy)and nuclei fuse(karyogamy)forming a diploid zygote.
- The mating types are designated + and -
- In sexual reproduction use pheromones, sexual signaling molecules, to test if mycelia are of different mating types.
- In manyfungi the hyphae cytoplasms fuse, plasmogamy,but the nuclei do not fuse immediately. Parts of the fused hyphae contain coexisting, genetically different nuclei, forming a heterokaryon.
- Heterokaryon
- In some fungi, the haploid nuclei pair off two to a cell; such a mycelium is said to be dikaryotic. The cells are n + n. The twonuclei in each cell divide in tandem without fusing.
- If nuclei fuse the cells are diploid (2n) and in a zygote stage.
- General sequence of sexual reproduction.
- Hyphae that are designated +and -unite in plasmogamy.
- The fusion of + and -produce an n + n mycelium (heterokaryotic stage).
- Eventually the haploid nuclei fuse in karyogamy and produce a 2n nucleus.
- The 2n nucleus goes through meiosis to produce 4 haploid genetically unique meiospores.
- Meiosporesgrow into haploid mycelia via mitosis starting the life cycle again.
- General sequence of asexualreproduction.
- Haploid mycelium produce haploid spores by mitosis (these species are known as molds)
- Mitospores germinate growing into haploid mycelia starting the life cycle again.
4
Q
Identify distinguishing characteristics of the phyla: Chytridiomycetes (general!), Zygomycetes, ascomycetes, Basidiomycetes, Glomeromycetes (general defining feature). Make sure you know all of your phylum names!
A
- Chytridiomycota
- Classified by molecular data
- Some are decomposers, parasites of protists, plants, or animals, others are mutualistsa. anaerobic chytrids live in digestive tract of sheep and cattle to help break down plant matter contributing to the animal’s growth
- Unique in having flagellated spores called zoospores
- Result from asexual and sexual reproduction.
- Zygomycetes
- The zygomycetes produce zygosporangium.a. Include fast growing molds responsible for causing strawberries, bread, peaches, etc to rot. Some live as parasites and others commensalists of animals.
- The hyphae are aseptate (coenocytic) however,septa do form to separate the hyphae fromthe reproductive structures called gametangia.
- A common life cycle example is Rhizopus stolonifer, black bread mold.
- ascomycetes
- Sometimes called sac fungibecause their sexual spores are produced in microscopic sacs call asci.
- Their hyphae usually have septa with pores.
- This taxa includes yeasts, powdery mildews, most blue-green, pink and brown molds that spoil food, cup fungi, and edible morels and truffles.
- Ascomycetes cause serious plant diseases such as Dutch elm disease, ergot disease of rye powdery mildew on fruits and chestnut blight.
- Ergots contain alkaloids including lysergic acid.
- May be the culprit in the hallucinations in SalemWitch Trials (Massachusetts)
- Asexual reproduction.
- Conidia
- Conidiophore
- Conidia formation is a faster process than the process used by sporangium.
- As soon as food comes in contact with the hyphae,conidophores are produced.
- Conidia are released and fall on a suitable substrate.
- Conidia go through mitosis to produce hyphae.
- Hyphae grow and produce more conidiophore.
- Conidia vary in color, shape, and size in different species.
- The yeastsmainly use buddingas a form of asexual reproduction. Some yeast may use fission.
- Budding
- Binary fission
- Sexual reproduction.
- Begins when haploid mycelia make specialized hyphaeand conidia of the opposite mating type, join by plasmogamy to make a fusion cell with nuclei from bothparent strains.
- Dikaryotic hyphae begin to grow from fused structure. Haploid hyphae from the parent also continue to grow.
- The twotypes of hyphae cooperate to make an ascocarp.
- ascocarp
- The tip of the dikaryotic hyphae develop into asci where two of the dikaryotic nuclei fuse, (karyogamy)to form a zygote.e. The zygote nucleus goes through meiosis, yielding four haploid nuclei.
- The haploid nuclei divide by mitosis to form eight nuclei.
- Walls form around the nuclei, making ascosporesthat are released to formnew mycelium.
- Basidiomycetes
- mainly reproduce sexuallyby forming basidiospores.
- Taxa include familiar fungi: the mushrooms, bracket (shelf) fungi, and puffballs.
- Includes plant parasites such as wheat rust and corn smut.
- Basidiomycetes are sometimes called the club fungibecause of the shape of theirclub shaped basidia.
- Basidia form n + n nuclei that may live for a long time.
- Sexual reproduction intypical basidiomycetes.
- Two haploid spores grow into mycelia.
- The tips of the hyphae fuse, plasmogamy, to make a dikaryotic mycelium.
- The dikaryotic hyphae grow together to form the reproductive body thebasidiocarp.
- The tips of the hyphae in the gills of the basidiocarp develop into basidia, the dikaryoticsporeproducing structures.
- The nuclei in the hyphae tip fuse (karyogamy)to form a diploid zygote.
- The zygote goes through meiosis creating four haploid nuclei. The nuclei and cytoplasm are forced through sterigmata(extension of the basidium) making basidiospores.
- Note the spores are on the outsideof a basidium, whereas ascospores develop within an ascus.
- Glomeromycetes
- Identified by molecular data
- Reproduction is similar to zygomycetes, where glomeromycetes were formerly grouped
- Nearly all glomeromycetes form arbuscular mycorrhizae.
- The tips ofthe hyphae push into plant root cells and branch into tiny treelike arbuscules.
- Mycorrhizal fungi can improve delivery of phosphate ions and other minerals to plantsbecause the vast mycelia networks of the fungi are more efficient than theplants’ roots at acquiring these minerals from the soil.
- The plants supply the fungi with organic nutrients such as carbohydrates.
- About 90% of all plant species have this mutualistic relationship with glomeromycetes
- The tips ofthe hyphae push into plant root cells and branch into tiny treelike arbuscules.
5
Q
describe the lifecycles of Zygomycota (Rhizopus stolonifer), Ascomycota (both muticellular and unicellular (yeasts), Basidiomycota
A
- Asexual Reproduction:
- Bread becomes moldy when haploid sporesfall on it and grow into mycelium.
- Eventually certain hyphaecalled sporangiophoregrow upward and develop spore sacs called sporangia.
- Asexual spores, mitospores, are released from each sporangium and give rise to morehyphae.
- Sexual reproduction:
- Occurswhen a +and -hyphae grow into contact with one another.
- Hormones produced cause the tips of the hyphae to cometogether and form specialized sexual structures knownasgametangia.
- Gametangia unite and form an immature zygosporangiumthat may lie dormant for a long time.
- The zygosporangium represents the zygote (2n) stage in the life cycle, but it is not a cell with one diploid nucleus. It is a multinucleate structure, first heterokaryotic with many haploid nuclei from the two parents, then with many diploid nuclei after karyogamy.
- Before karyogamy occurs the zygosporangium develops a rough, thick walled coating that can resist harsh conditions for months.
- In favorable conditions karyogamy occurs and the zygosporangium nuclei go through meiosis.
- The zygosporangium germinates into a sporangium dispersing many genetically diverse haploidspores.
- The spores germinate and grow into new mycelia starting the process over again
6
Q
describe how each phyla reproduces (sexual, asexual reproduction, etc…) Make sure to know all of the terms and vocabulary associated with Zygomycota, Ascomycota, and Basidiomycota life cycles~ you will see questions on all of these!!!!
A
- Zygomycota
- asexual
- sporangiophore
- sexual
- zygosporangium
- asexual
- Ascomycota
- Asexual
- Conidia
- Conidiophore
- sexual
- ascocarp
- asci
- ascospores
- Asexual
- Basidiomycota
- sexual
- basidiocarp
- basidia
- sexual
7
Q
characterize the unique nature of a lichen, including the 3 major body forms (identify!)
A
- Lichens are “Dual Organisms”
- photosynthetic organism is either greenalgae or cyanobacteria
- The phototrobe suppliesfood for both itself and the fungus. algae provide carbon compounds. cyanobacteria provide organic nitrogen compounds
- The fungal portion is usually ascomycetes
- Three different groups(types)of lichens.
- Crustose(encrusting)lichens. Flat and grow tightly against the substrate they grow on.
- Foliose(leaflike)lichens. Flat with leaf likelobes and are not so tightly pressed to the substrate.
- Fruticose(shrublike)lichens. An erect growing lichen that has many branches.
8
Q
describe the special ecological role of mycorrhizae
A
- mutualisticrelationship between fungi and roots of some plants.
- Relationship occurs in more than90% of all plant families.
- The mycorrhizal fungus breaks down organic material in the soil sowater andminerals are available for absorption by the plant roots.
- The roots provide sugars and nutrients for the fungus
- Mycorrhizae are vital to healthy plant growth.
- Ectomycorrhizal fungi form sheaths of hyphae over a root and also grow into the extracellular spaces of the root cortex
- Arbuscular mycorrhizal fungi extend hyphae through the cell walls of root cells and into tubes formed by invagination of the root cell membrane
9
Q
how might fungi play a symbiotic role with organisms such as ants?
A
- the fungi breaks down the nutrients in the substance and the organism can eat it to get the nutrients from it.
- gut of cattle and sheep
- leaf-cutter ants
- All plant species harbor symbiotic endophytes, most are ascomycetes
10
Q
summarize some of the ways humans use fungi (economic/ecological)
A
- food (truffels, morrels, mushrooms)
- help plant growth
- medicine (penicillium, choresterol meds)
- Fungi provide beverages and food. (yeast) (cheese)
- Fungi cause many important plant diseases.
- Fungi cause certain animal diseases (ring worm, athletes foot, thrush)
11
Q
Discuss some environmental challenges of living on land, and describe how several adaptations meet these challenges.
A
- plants needed systemto absorb nutrients ( roots and rhizoids)
- Needed system for gas exchange (stomata)
- Needed a conducting system for products of photosynthesis (vascular tissue - xylem and phloem)
- Prevent desiccation (Spores)
- Wall is composed of polymer sporopolleninwhich enables spores to be dispersed through dry air without harm.
- Above ground structures needed protection from drying out
- Plants have a thin waxy cuticlethat prevents desiccation via evaporation.
- System of support to compete for sunlight
- vascular tissue and woody structures allow plants to grow taller (lignin)
- Plants have apical meristems
- Method of gamete transportation that doesn’t rely on water
- Pollen (Uses wind, water, or biotic vectors)
- Other Plant Structures leading to their success on land
- Secondary compoundsthat help defend a plant against herbivores and parasites
- Plants have sex organs called gametangia that are surrounded and protected by a layer of sterile cells. After fertilization the embryo is protected and nourished via embryophytes
12
Q
Describe the reproductive strategies of plants (alternation of generations/ sporophyte & gametophyte)
A
- Gametophyte Generation
- The gametophyteproduces reproductive structures called gametangiawhich produce gametes (Antheridia and Archegonium)
- A sperm cell fertilizes an egg cell and a diploid zygote is formed.
- The zygote is the beginning of the sporophyte and the start of the sporophyte generation.
- The zygote cell undergoes mitosisand the embryo forms insidethe archegonium for protection.
- Sporophyte Generation
- The embryo will eventually develop into mature sporophyte
- The sporophytes produce specialized cells(spore mother cellsor sporocytes)that divide by meiosisto form haploid spores.
- The spores are the beginning of the gametophyte generation
- spores will be released and divided by mitosisto form a multicellular gametophyte.
- The cycle will continue in this fashion as long as the plants live.
13
Q
Describe the characteristics that unite nonvascular seedless plants, and the characteristics that unite seedless vascular plants
A
- Nonvascular plantsand seedless vascular plants (ferns and related plants) use spores as their primary method of reproduction and dispersal.
- need water for reproduction.
14
Q
Name and briefly describe the three phyla of the nonvascular plants (Know phylum names and general characteristics of each!)
A
- PhylumBryophyta: Mosses
- Agametophyte with rhizoids and leaf like blades. Blades are usually one cell thick and are never lobed or divided.
- The mosses are not considered vascular plants because their vascular tissue is so limited the mosses cannot control their internal environment
- PhylumHepatophyta: The Liverworts(“liver plant”)
- Small and green usually with fattened shape gametophyte.
- PhylumAnthocerophyta: Hornworts
- The mature sporophyte looks like miniature,greenish cattle horns.
- Consists of foot and capsule (sporangium), NO stalk
- Gametophytes are a flat green thallus similar to those of liverworts.
- Rhizoids anchor the plants to their substrate.
15
Q
Describe the life cycle of mosses, and compare their gametophyte and sporophyte generations.(which is dominant? what is antheridia and archegonia?)
A
- Asexual Reproduction
- Form brood bodies, small plantlets that detach from the parent plant and grow into new, genetically identical copies of their parent.
- Rhizoids can produce new ‘buds’.
- Sexual Reproduction.
- Some mosses are monoecious and some are dioecious.
- The antheridia are elongated structures that contain sperm.
- Archegonia are clustered and form at the tips of certain stem like structures. Each archegonium has a singleegg and a long stalk.
- The sperm are released and swim to the archegonium tofertilize the egg to create a diploid zygote.
- The zygote develops into an embryo that differentiates into a foot, seta (stalk), and sporangia.
- The mature sporophyte sporangium contains spore mother cells (sporocytes) that go through meiosis to create haploid spores.
- As the sporophyte matures the peristome teeth when the air is dry bend outward to drop off the operculum and release the spores.
- The spores land on the ground and filaments germinate from the spore to create the protonema.
- If the conditions are favorable tiny buds may appear at intervals along the protonemal filaments. The buds develop rhizoids and grow into a new gametophyte completing the cycle.
25
Q
Trace the steps in the life cycle of a pine, and compare its sporophyte and gametophyte generations.
A
26
Q
Summarize the features that distinguish flowering plants from other plants. Be able to label Floral Structure
A
- The production of seeds aids in the dispersal of the plant.
- Double fertilization creates endosperm for nutrition which increasesthe chance of reproductive success.
- Flowering plants have a highly developed vascular system.
- Leafs are broad to absorb light for photosynthesis and are shed, abscission, in harsh periods to reduce water loss.
- Variation of roots, stems, and leaves and theadaptability of the sporophyte to so many different regions
27
Q
Contrast dicots and monocots,
A
28
Q
Briefly explain the life cycle of a flowering plant, and describe double fertilization.
A
