Transcript Asexual Reproduction & Mitosis Notes

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 buds
ex – yeast & hydra
2. Binary Fission
Most simple form of asexual reproduction; Parent divides
equally and results in two separate individuals
Ex.-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 differentiate
to produce the same organism
Ex.- strawberry plant, pick-a-back plant
Period of time from one division to the next
Cell Cycle
Unicellular division results in formation
of new individuals of the species
Multicellular division results in replacement
of old or damaged cells
Mitosis
Process by which the nucleus divides while
maintaining number of chromosomes
Cytokinesis Division of the cytoplasm
Asexual
Reproduction
Reproduction that only involves one parent
so therefore no special reproductive organs
are needed
Chromatin
Nuclear DNA wound around proteins known
as histones
Chromosomes
Condensed rolls of chromatin that are able
to be seen during mitosis (rod-like structures)
There are 5 phases in MITOSIS
Interphase
Prophase
Metaphase
Anaphase
Telophase
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
Mitosis Begins
• Mitosis is the division of the nuclei
• Happens in somatic/ body cells
Prophase
•Double chromosomes become visible - Chromatid
•Chromosomes are 2 sister chromatids connected by a centromere
Sister
Chromatids
Centromere
•At the beginning, centrioles move to opposite poles
•Spindle fibers attach
•By the end, the nuclear envelope and nucleus have
disappeared
DON’T DRAW
EARLY
LATE
Metaphase= “Middle”
•Centromeres line up on the middle
Anaphase= “Away”
•Daughter chromosomes move to opposite sides of cell
(poles)
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
Cytokinesis
• Two identical daughter cells are formed.
• Each cell has the diploid (2n) number of chromosomes.
• In humans this is 46 chromosomes.
Same as mitosis in animals except:
• Plants have no centrioles – spindle fibers take their place
• Asters do not form
• Cell wall does not pinch because it is too rigid
• Cell plate divides the cell into two