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Asexual Reproduction
and Mitosis
SB2 e: Compare the advantages of sexual reproduction and asexual
reproduction in different situations
Occurs only through the process of mitosis
Each offspring has the same genetic information
Where can asexual reproduction be found?
BACTERIA YEAST PLANTS
There are 5 different types of asexual reproduction.
1. Budding
Parent divides unequally; new individuals develop from budsex – yeast & hydra
2. Binary Fission
Most simple form of asexual reproduction; Parent divides equally and results in two separate individualsEx.-paramecium, bacteria
3. Spore Formation
Single specialized cells that germinate when released from parent. Usually covered by a protective coating for preservation.
4. Regeneration/fragmentation
Ability to regrow new body parts/ability to grow new Organism from parts.ex – hyrda, planaria, starfish, the bad guy from Terminator 2
5. Vegetative Reproduction/Propagation
Refers to roots, stems, and leaves. Cells divide then differentiateto produce the same organismEx.- strawberry plant, pick-a-back plant
Period of time from one division to the next
Unicellular division results in formation of new individuals of the species
Multicellular division results in replacement of old or damaged cells
Process by which the nucleus divides while maintaining number of chromosomes
Division of the cytoplasm
Asexual Reproduction
Reproduction that only involves one parentso therefore no special reproductive organsare needed
Cell Cycle
Mitosis
Cytokinesis
Nuclear DNA wound around proteins knownas histones
Condensed rolls of chromatin that are able to be seen during mitosis (rod-like structures)
There are 5 phases in MITOSIS
Interphase
MetaphaseProphase
AnaphaseTelophase
Chromatin
Chromosomes
Cytokinesis
Interphase Known as “resting phase”
•Cells grow in size by producing more nucleic acids, proteins,and cellular organelles
•Chromosomes make copies of themselves, but they can’t be •seen
•Nucleus of the cell is contained within the nuclear envelope
•Centrioles are present and duplicate themselves
Prophase
•Double chromosomes become visible - Chromatid
•Chromosomes are 2 sister chromatids connected by a centromere
Centromere
Sister Chromatids
•At the beginning, centrioles move to opposite poles
•Spindle fibers attach
•By the end, the nuclear envelope and nucleus have disappeared
EARLY LATE
DON’T DRAW
Telophase=“The End”
•Chromosomes uncoil and return to previous shape (threadlike)
•Nuclear membrane and nuclei reform
NOTE: Cytokinesis begins during late anaphase and finishes during telophase
• Two identical daughter cells are formed.• Each cell has the diploid (2n) number of chromosomes.• In humans this is 46 chromosomes.
Cytokinesis