Transcript S7 - 6 - Cell Division Mitosis

You started as a cell smaller
than a period at the end of a
sentence…
.
 Cell’s divide through a process called mitosis.
 Mitosis takes the nucleus of the cell and divides
it into two. These two nuclei are identical.
Why do the nuclei
need to be
identical?
 In the nucleus is the cell’s DNA.
 DNA gives you your specific traits! It is the code
that makes you who you are!
 Hair color
 Eye color
 Height
 The DNA is wound up into a chromosome.
chromatin
chromosome
 Unwound DNA is called chromatin.
Think of a ball of yarn…
 Most human cells have 23 pairs of chromosomes. This
includes a pair of chromosomes determine our gender.
 XY chromosome means your are a male
 XX chromosome means you are a female.
 Cell division increases the number of cells and causes
many-celled organisms to grow.
 Cells have life cycles.
 Occurs in a series of phases, or steps.
 Interphase
 Prophase
 Metaphase
 Anaphase
 Telophase
 Period of growth and development in a cell’s
life cycle.
 During interphase, a cell duplicates its chromosomes
and prepares for cell division
 Cell’s are in interphase the longest time
TIME
 After interphase, the nucleus divides, and then the
cytoplasm separates to form two new identical
cells.
 This process is called mitosis. There are 4 steps in
mitosis.
 Animal cells have centrioles which help them
divide.
 Chromosomes becomes visible
 The nuclear membrane dissolves
 Centrioles move to opposite ends of the cell
 Chromosomes line up
 Spindle fibers form
 Chromosomes separate
 The spindle fibers pull the chromosomes apart
 Cytoplasm Divides
 A new nucleus forms
 Spindle fibers disappear
 TADA! You have two new cells! These cells are
identical. This is because they reproduced
asexually.
 In asexual reproduction, a new organism
is produced from one organism. The new
organism will have heredity (DNA) material
identical to the heredity material of the
parent organism.
 MITOSIS!!!!!! HELLO!!!!!!
 Regeneration - a whole new organism grows
from each piece of the parent.
 For example – sponges, planaria, and sea
stars
 Budding – a small, exact copy of the adult
grows from the body of the parent.
 For example – Hydra
 Fission - an organism with no nucleus that
divides into two identical organisms.
 For example – Bacteria