Fungi II: Reproduction

Asexual process for Yeast

"Budding" 1) diploid parent cell produces a small protuberance that grows to a bud 2) mitosis occurs, duplicating the parental nucleas, one nucleaus migrates into developing bud 3) The bud continues to grow until it separates from the mother, forming a new cell.

nuclie of fungal hyphae are haploid

(N)

Asexual reproduction cycle of filamenous fungi

1) Haploid mycelium form special spore-forming structures 2) Mitosis occurs leading to the creation of mitospores

Sexual Reproduction Cycle for filamentous fungi

1) Pheromones secreted by two different mating types cause hyphae to grow close 2) Plasmogamy occurs, producing heterkaryotic cells (typically diplokaryotic) 3) Karyogamy occurs, producing a temporary zygote (diploid) 4) Meiosis occurs creating four haploid nuclie from the diploid zygote 5) spores are created when hard walls form aroud each haploid nuclieus; the durable meiospores are then realsed upon maturity and dispersed by the wind 6. Germination occurs when the spores land in a hospitable environment resulting in new haploid hyphae that grow.

Sexual process for Yeast

1) diploid cell can undergo meiosis to create Mat a and Mat alpha haploid cells 2) Two haploid cells of different mating types secretie pheromones 3) reception of the opposite pheromone cause cell to change shape and enter the Schmoo Stage. 4)Cells come together; cytoplasms fuse and then nuclei fuse to form a diploid zygote. 5) the cell then renters the cell division cycle and gives rise to its first diploid bud 6) the bud matures into fully formed daugther cell and seperates from the mother diploid zygote can undergo sporulation, only under high-stress conditions. (nutrient starvation)

Zygote

A diploid cell resulting from the fusion of two haploid nuclie

What is a hypha?

A single fungal filament

Hypha (plural= hyphae)

An interwoven mass of hyphae. each of fungal filaments that makes up the body of a fungus consist of tubular cell walls surrounding the plasma membrane and cytoplasm of the fungal cells

What is the above ground, spore-bearing fruiting body of a fungus called?

Basidiocarp

Which of the following might be the fruiting body of a fungus?

Basidiocarp

How is the asexual process of budding similar to binary fission?

Both produce clones of parent

How is the asexual process of budding different from binary fission?

Budding produces different sized (unequal) cells

Which of the following would have no septa?

Coenocytic cells

All fungi produce hyphae.

False

Most fungal hyphae are diploid.

False

Spores are only produced through sexual reproduction.

False

Which fungi can participate in plasmogamy?

Fungal hypha from different mating types of the same species

Karyogamy

Fusing of the two nuclei in a heterokaryotic cell may occur hours, days or centuries after plasmogamy produces a temporarily diploid cell (zygote)

What is the product of plasmogamy?

Heterokaryote

What is a single filament of a fungus called?

Hypha

Mycelium (plural=mycelia)

Interwoven mass of hyphae Infiltrates the material the fungus needs maximizes surface-to-volume ratio to make feeding very efficient 1cm3 may contain as much as 1 km of hyphae with total of 300 cm2 in contact with the soil

Of the following, which produces a zygote?

Karyogamy

Which of the following is uniquely involved in sexual reproduction?

Meiosis

What is the body of a fungus called?

Mycelium

What is the product of germination?

Mycelium

Of the following, which occurs first in sexual reproduction?

Plasmogamy

Spore

Reproductive structure adapted for dispersal and survival generated asexually or sexually germinate in moist, nutrient-rich places, to produce a new mycelium.

Which of the following is specifically formed for fungal reproduction?

Spore

What is a mycelium?

The body of a fungus

What is a filamentous fungus?

The multicellular form of a fungus

Which of the following best describes plasmogamy?

The process by which fungal cells fuse together

Which of the following best describes karyogamy?

The process by which nuclei fuse together

What is a yeast?

The single celled form of a fungus

Sexual reproduction produces greater genetic diversity

True

What is the product of karyogamy?

Zygote

Basidiocarp

above ground spore-bearing fruiting body of a fungus ("fungus") muschroom and suberranean mycelium are a continous network of hyphae

Septum (plural: septa)

cross-walls that divide hyphae into cells typical septa have pores large enough to allow ribsomes, mitochondria and nuclei to flow from cell to cell

Coenocytic fungi

fungi that lack septa consist of continous cytoplasmic mass of hundreds/thousands of nuclei result from the repeat division of nuclei without cytokinesis

What does Filamentoes mean?

multicellular fungal form most prevalent form typicallyl form network of tiny filaments

Pheromones

sexual signaling molecules bind to cellular receptors trigger the growth of hyphae toward the source result in cellular fusion between two compatible partners

What is yeast?

single celled fungal form require moist enviornments with a ready supply of soluble nutrients (sugars and amino acids)

Plasmogamy

the sexual union (fusing) of two haploid (n) parent mycelia produce heterokaryotic cells: genetically different nuclei co-existing in the same cell not diploid (2n) because the gnetic material from each parent is maintained separate nuclei Described (n+n)

many fungi can reproduce either sexually or asexually, but some only reproduce asexually

whether by sexual or asxual means, most filamentous fungi propagate by producing spores

diploid (2n)

zygote, only formed temporarily