1.1 Reproduction in Prokaryotes, Protists, and Fungi

• Binary fission


  An asexual mode of reproduction where the offspring is the exact replica of the parent organism. They share the same set of genetic material, phenotypes, and traits.
• Processes Involved in Binary Fission

  1. Replication of the circular prokaryotic chromosome begins at the origin of replication and continues in both directions at once

  2. The cell begins to elongate. The FtsZ migrates towards the midpoint of cell

  3. The duplicated chromosomes go to separate ways while the proteins will form a ring around the periphery (midpoint)

  4. The FtsZ ring directs the formation of a septum that divides the cell. The cell wall material and plasma membrane will begin to cling to it

  5. After septum is complete, the cell becomes two. FtsZ is dispersed throughout the cytoplasm of the new cells
• FtsZ (filamentous temperature-sensitive mutant Z)


  Proteins that direct the division of the nucleoid or genetic material
• Conjugation


  A process where prokaryotes are able to achieve genetic variation among the succeeding generations. Exchange of genetic material can cause their genetic make-up and manifestations to be altered.
• Unusual Modes of Reproduction Among Prokaryotes

  • Staniera sp reproduces by making numerous baeocytes through a series of cytoplasmic fissions that emerge from one singular baeocyte
  • Budding - develops a bud and then the bud develops and separates
  • Cell Division - an individual cell becomes a mother cell with two small offspring cells and they are engulfed by the mother cell, develop, and emerge at both ends. The mother cell then dies
• Baeocyte


  A small cell, it grows up to eventually form a vegetative cell
• Binary fission occurs primarily in prokaryotes while mitosis only occurs in eukaryotes
• Sexual reproduction


  Evolved because of the eukaryotes' need for better chances of survival
• Essential Features Necessary for Sexual Reproduction

  • Gametes - opposing mating types in haploid forms, which are formed through meiosis
  • Fertilization - the fusing of these gametes, called fertilization, forms a diploid zygote, which has a genetic make-up of two individual organisms
• Haploid


  Describes a cell that contains a single set of chromosomes. This also refers to the number of chromosomes in egg or sperm cells (gametes). Has 23 chromosomes.
• Meiosis


  Process where a single cell divides twice to produce four cells. These daughter cells only have half the number of chromosomes of the parent cell, therefore they are haploid. Has 23 chromosomes.
• Diploid Zygote


  A zygote that is endowed with genes from two parents and therefore it is a diploid (cell). Has 46 chromosomes.
• Other Asexual Modes of Reproduction Among Protists

  1. Binary Fission - parent organism equally divides into 2 new daughter cells. Involved mitosis since protists have true nuclei

  2. Multiple Fission - parent organism divides into several daughter cells

  3. Plasmotomy - a multinucleate cell divides into multinucleated daughter cells through cytoplasmic division, not nuclear division. Meaning, there is no mitosis

  4. Spore Formation - happens in unfavorable conditions where some protists form spores with protective capsules. Each spore will eventually germinate and develop to a new individual

  5. Budding - small outgrowth develops and detaches from parent
• Mitosis


  Describes the duplication and distribution of chromosomes.
• Cytoplasmic Division


  Process where in the cytoplasm of a cell divides the cell.
• Other Sexual Modes of Reproduction Among Protists

  1. Syngamy - involves the complete fusion of gametes that results to a diploid zygote

  2. Isogamy - fusing of 2 similar gametes

  3. Anisogamy - fusing o 2 dissimilar gametes

  4. Oogamy - large non-motile gametes is fertilized by smaller motile ones

  5. Conjugation - the temporary union of 2 individuals, to exchange haploid pronuclear materials (genetic material), to form a zygote nucleus
• Hyphae


  Hypha in singular form, it is each of the branching filaments that make up the mycelium of a fungus
• Mycelium


  The root like structure of a fungus but consisting of branching hyphae
• Spores


  The type of cells that certain fungi produce and are the main reproductive units for them
• Cap


  The top like part of the fungi that supports the pore bearing surface (hymenium)
• Hymenium


  The spore bearing surface, something like inside the cap of the fungi
• Stipe


  The stem like structure supporting the cap of the mushroom
• Fruiting Bodies


  The ones that contain spores which are dispersed for reproduction
• Asexual Reproduction Among Fungi

  1. Mitosis and Cytokinesis - this is done by unicellular fungi

  2. Fragmentation - (multicellular) section o f the hyphae can grow into new individuals

  3. Mitotic Spores - (multicellular) are released for propagations
• Conidiospores


  An asexually produced fungal spore formed on a conidiophore. They are not produced in a sac but do develop at a hyphal tip or sidewall
• Conidiophore


  An aerial hyphae
• Sporangiospores


  Spores that develop within a sac (sporangium)
• Sporangiophore


  Another aerial hyphae
• Homothallic


  When they are present in the same mycelium
• Heterothallic


  When they are from different yet compatible mycelia
• Three Processes Involved in the Reproductive Process

  1. Plasmogamy - haploid cells from two different mycelia fuse to form a heterokaryotic cell with two or more nuclei

  2. Karyogamy - the nuclear fusion of the different nuclei which forms a diploid zygote nucleus

  3. Meiosis - the gametes of different mating types are produced in the gametangium/gametangia. These are then released as haploid spores ready to germinate in a new fungi
• Heterokaryotic Cell


  A multinucleate cell that contains genetically different nuclei
• The spores (final product) are then released for germination into a new mycelium