Cell Cycle Mitosis Cell Cycle Mitosis Cell

					Cell Cycle
     &
 Mitosis
        Cell Reproduction
• Cell Theory
  – Cells come from preexisting cells

• Cell division - process which ends with
  new cells formed from an old cell.

• All organisms grow and change; worn out
  tissues are repaired or replaced by new
  cells
CHROM…word
    s
• Chromatin – uncoiled
  DNA + proteins
• Chromosome – coiled
  DNA + proteins (Looks like
  an X)
• Chromatid – only half of
  a chromosome
• Sister chromatids –
  Two chromatids joined
  together, by a centromere,
  to form a chromosome
            Chromosomes
• Contain DNA

• Becomes dark when stained

• Carriers of genetic material that is copied
  and passed from generation to generation

• Identity of cell
              Chromatin
• Is the same as chromosomes

• Long strands of DNA wrapped around
  proteins

• Looks chaotic - like a mess of tangled
  spaghetti

• Needs to be unorganized for the protein to
  be copied

• Must recoil before a cell can divide.
Chromatin
              Cell Cycle
• The sequence of
  growth and division
  of the cell
• Two general periods
   – Growth
     (interphase)
   – Division (mitosis)
• Majority of time is
  spent in the growth
  period known as
  Interphase
                Cell Cycle
• Four stages to the cell
  cycle
  – Growth period -
    Interphase includes:
    • G1
    • S Stage
    • G2
  – Division period -
    Includes:
    • Mitosis
              Interphase:
• Known as the
  growth period
• Majority of cells
  life
• Three stages
  within Interphase
  – G1
  – S Stage
  – G2
                  G1
               Stage #1
• Chromosomes are not
  visible under a
  microscope - because
  they are uncoiled,
  therefore called
  chromatin

• Proteins are quickly
  made
              S Stage
              Stage #2
• Chromatin is
  replicated in the
  nucleus

• Chromatin divides to
  form sister
  chromatids which
  are connected by
  centromeres
                      G2
                   Stage #3
• Chromatin shortens and coils

• Organelles are made

• Most proteins made are for
  mitosis

• Animals - centriole pair
  replicates and prepares to
  form spindle fibers.
       Interphase Information
• Busiest phase of cell cycle
• What are the three parts?
• When are the chromosomes
  replicated?
• When is the most protein
  production?
• When are organelles made?
• When are cell parts made?
• Which is the longest stage of
  interphase?
• Which is the shortest stage
  of interphase?
                   Mitosis
• Four Phases of
  mitosis
  – Prophase
  – Metaphase
  – Anaphase
  – Telophase
             Prophase
      first phase of mitosis

• Longest Phase
• Chromatin coils up into
  visible chromosomes
• Chromosomes look
  hairy
• Each chromosome now
  has two halves
                Prophase
         first phase of mitosis
• Chromosomes
 – are also called sister
   chromatids
 – Two sister chromatids can be
   called a diploid chromosome
 – One sister chromatid can also
   be called a haploid
   chromosome
 – DNA in sister chromatids are
   alike
 – Sister chromatids are held
   together by a centromere
                Prophase
         first phase of mitosis
• Nucleus disappears

• Nuclear envelope
  disintigrates

• Nucleolus disintigrates

• Completely absent by the
  end of prophase
                Prophase
         first phase of mitosis
• ANIMAL CELLS
  – Centrioles begin to go to
    opposite ends of the cell
  – Centrioles are small dark and
    cylinder like
  – Centrioles help to separate
    sister chromatids
• ANIMAL AND PLANT CELLS
  – Spindles begin to appear -
    look like footballs
  – Spindles have fibers in them
    which help to separate sister
    chromatids
     Metaphase
   second stage of
       mitosis
• Short stage
• Sister chromatids
  line up at the
  equator
• Sister chromatids
  are attached by their
  centromeres to the
  spindle fibers
               Anaphase
         third stage of mitosis
• SC are pulled apart at
  the centromere to
  opposite ends of the
  cell

• This ensures that each
  new cell gets one set of
  the information needed

• SC are pulled apart
  because the spindle
  fiber shortens
            Telophase
      fourth stage of mitosis
• Chromatids reach opposite poles
  of cell
• Chromosomes unwind
• Spindle breaks down
• Nucleolus reappears
• New nuclear envelope forms
  around each set of
  chromosomes
• New double membrane begins to
  form between the two new
  nuclei.
            Cytokinesis
          end of telophase
• The dividing of the
  cytoplasm

• ANIMALS
  – Plasma membrane
    pinches along the
    equator
  – Two new cells are
    separated
          Cytokinesis
        end of telophase
• PLANTS
 – B/c rigid cell wall:
    • Cell plate is laid across the equator
    • Cell membrane forms around each cell
    • New cell walls fom on each side of the cell
      plate until separation is complete
           Prophase




                      Metaphase




Anaphase
              Mitosis
• Guarantees genetic continuity

• Results in two new cells, daughter
  cells

• Daughter cells carry out same
  function and cellular process as the
  parent cell
         Cell Organization
• Cells work together to make up tissue

• Tissues work together to make organs

• Organs work together to make organ
  systems
                    Cells
• Cells can function on their own or together
  as a group.

• One-celled organisms remain one-celled

• Multicellular organisms use mitosis to
  replace and replenish their existing cells

				
DOCUMENT INFO
Shared By:
Categories:
Tags:
Stats:
views:6
posted:2/22/2012
language:English
pages:28