THE CELLULAR BASIS OF INHERITANCE

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THE CELLULAR BASIS OF INHERITANCE

• CHAPTER 9

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Why Is Cell ReproductionEssential for Life?

• 1) Maintain/Heal the Body
• TO REPLACE LOST OR DAMAGED
• CELLS
• Example
• Every minute of the day we lose about 30,000 to
  40,000 dead skin cells off the surface of our
  skin.

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Why Is Cell Reproduction Essential for Life?

• 2) GROWTH
• - Increase body size by increasing the number
  of cells in the body

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Why Is Cell Reproduction Essential for Life?

• 3) REPRODUCTION TO CREATE
• A COMPLETE NEW ORGANISM.
• 2 TYPES OF REPRODUCTION
• a) ASEXUAL
• b) SEXUAL

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ASEXUAL REPRODUCTION
How Many Parents?

• SINGLE PARENT
• OFFSPRING ARE GENETICALLY IDENTICAL TO EACH OTHER
  AND TO PARENT.
• SEEN IN UNICELLULAR ORGANISMS AND SOME
  MULTICELLULAR ORGANISMS SUCH AS PLANTS,FUNGI, AND
  SOME ANIMALS LIKE SPONGES AND STARFISH.

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SEXUAL REPRODUCTION

• 2 PARENTS
• GENETIC MATERIAL (CARRIED IN EGG AND SPERM) FROM
  EACH PARENT COMBINES
• EACH OFFSPRING IS GENETICALLY DIFFERENT FROM
  PARENTS
• Egg and Sperm are produced through
• cell division

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REVIEWWHY DO CELLS DIVIDE AND PRODUCE NEW CELLS?
For Maintenance of the body (multicellular
organisms) For Growth (multicellular
organisms) For Reproduction (multi- and
unicellular organisms)
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TheCELL CYCLE

• STARTS WHEN A CELL IS BORN ENDS WHEN IT
  REPRODUCES.
• CELL CYCLE PRODUCES CELLS NEEDED FOR GROWTH
  MAINTENANCE OF THE BODY

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TheCELL CYCLE
Cell is not dividing (Most of the time)
Cell is dividing
Nucleus divides first
Cytoplasm divides last
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TheCELL CYCLE

• HAS 2 MAIN STAGES
• INTERPHASE
• cell isnt dividing
• MITOTIC PHASE
• cell is dividing

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INTERPHASE

• WHAT IS IT?
• WHAT HAPPENS DURING IT?

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INTERPHASE

• LONGEST STAGE (90 OF THE CELL CYCLE)
• THE CELL GROWS PERFORMS ITS JOB AS A CELL

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INTERPHASE

• IN THIS STAGE DNA EXISTS AS A MASS OF VERY LONG
  THIN FIBERS CALLED
• _________________.

CHROMATIN
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INTERPHASE

• CELL ALSO PREPARES TO REPRODUCE (CELL DIVISION)
  BY INCREASING ITS NUMBER OF ORGANELLES BY
  MAKING COPIES OF ALL ITS _____________.

DNA
muy importante!!!

• EACH DNA STRAND IS COPIED THE 2 COPIES ARE
• JOINED AT ONE SPOT CALLED THE
  __________________.

CENTROMERE
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DNA IN CHROMATIN FORM
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What Happens Next?!

• After the cell has made all its preparations,
  then it divides!
• On to the Mitotic Phase!!

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MITOTIC PHASE

• SHORTEST STAGE of the CELL CYCLE
• THIS IS WHERE 1 CELL DIVIDES INTO 2 CELLS
• OCCURS IN 2 STEPS
• 1) MITOSIS
• 2) CYTOKINESIS

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MITOSIS

• All about the Nucleus!
• In this stage the nucleus divides into 2 and the
  chromosomes are evenly divided up.

• Each daughter nucleus
• receives a complete
• set of chromosomes

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MITOSIS
SISTER CHROMATIDS

• ALL THE DUPLICATED CHROMATIN FIBERS NOW COIL UP
  (GET SHORTER THICKER) ARE CALLED
• ____________________.
• EACH CHROMOSOME IS MADE UP OF 2 IDENTICAL HALVES
  CALLED ______________
• .

CHROMOSOMES
SISTER CHROMATIDS
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MITOSIS

• The SISTER CHROMATIDS SEPARATE GO TO OPPOSITE
  ENDS OF THE CELL FORMING 2 NEW DAUGHTER NUCLEI

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CYTOKINESIS

• The CYTOPLASM DIVIDES BETWEEN THE 2 NEW
  DAUGHTER NUCLEI FORMING 2 NEW CELLS

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TheCELL CYCLE
Cell is not dividing (Most of the time)
Cell is dividing
MITOTIC PHASE
INTERPHASE
Nucleus divides first
Cytoplasm divides last
MITOSIS
CYTO- KINESIS
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Name the Structure!
Centromere
?
?
?
Centromere
?
?
?
Chromosomes
SISTER CHROMATIDS
?
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______________ series of events that cells go
through as they grow and develop
CELL CYCLE
cells alive cell cycle
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CELL CYCLE

• INTERPHASE non-dividing phase
• G1- Grow bigger Cell is doing its
  job DNA is spread out as chromatin
• S - Synthesis (copy DNA) chromosomal
  proteins
• G2- Grow bigger, make organelles
  molecules needed for cell division

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CELL DIVISION

• MITOSIS Nuclear division
• Prophase
• Metaphase
• Anaphase
• Telophase
• Cytokinesis Cytoplasm divides
• G0 cell stops dividing (Ex nerve cell)

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• INTERPHASE (G1 - S - G2)

In between divisionsCells are in this phase most
of the time Can see nucleus DNA spread out as
chromatin
Cant see chromosomes
DNA gets copied (S) Cell gets ready to
divide
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Pearson Education Inc publishing as Pearson
Prentice Hall

• PROPHASE
• 1st dividing phase

http//www.life.uiuc.edu/plantbio/102/lectures/08m
itveg102.html
DNA scrunches into chromosomes
Centrioles appear in centrosome region
move to poles
Nuclear membrane nucleolus disappear
Spindle fibers form attach to
chromosomes
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________ region organizes spindle
CENTROSOME

• Spindle MICROTUBULES are part of cytoskeleton

http//www.coleharbourhigh.ednet.ns.ca/library/org
anelle_worksheet.htm
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• METAPHASE

Chromosomes line up in ___________
middle
Images fromPearson Eduction Ince Publishing as
Pearson Prentice Hall http//www.science.siu.edu/
plant-biology/PLB117/JPEGs20CD/0247.JPG
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• ANAPHASE

Centromeres splitCentrioles pull
chromatids_______
apart
Images fromPearson Eduction Ince Publishing as
Pearson Prentice Hall http//www.science.siu.edu/
plant-biology/PLB117/JPEGs20CD/0247.JPG
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• TELOPHASE (reverse prophase steps)

two
See ______ nuclei
Nuclear membrane nucleolus return
Chromosomes spread out as chromatin
Centrioles disappear
Spindle fibers disappear
Images fromPearson Eduction Ince Publishing as
Pearson Prentice Hall http//www2.bc.cc.ca.us/cnew
ton/Biology2011/Mitosis.html
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CYTOKINESIS Cytoplasm splits into 2 cells

ANIMAL CELLS pinch cytoplasm in two with a
______________________
CLEAVAGE FURROW
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CYTOKINESIS Cytoplasm splits into 2 cells

PLANT CELLS cant pinch because they have a
sturdy ____________ Plant cells separate
cytoplasm by growing a _______________ down the
middle.
CELL WALL
CELL PLATE
http//www.eastcentral.edu/acad/depts/BI/plant_mit
osis_nolabels.html
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Section 10-2
Spindle forming
Centrioles
Centromere
Chromatin
Centriole
Nuclear envelope
Chromosomes (paired chromatids)
Interphase
Prophase
Spindle
Cytokinesis
Centriole
Metaphase
Individual chromosomes
Telophase
Anaphase
Nuclear envelope reforming
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Section 10-2
Spindle forming
Centrioles
Centromere
Chromatin
Centriole
Nuclear envelope
Chromosomes (paired chromatids)
Interphase
Prophase
Spindle
Cytokinesis
Centriole
Metaphase
Individual chromosomes
Telophase
Anaphase
Nuclear envelope reforming
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Section 10-2
Spindle forming
Centrioles
Centromere
Chromatin
Centriole
Nuclear envelope
Chromosomes (paired chromatids)
Interphase
Prophase
Spindle
Cytokinesis
Centriole
Metaphase
Individual chromosomes
Telophase
Anaphase
Nuclear envelope reforming
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Section 10-2
Spindle forming
Centrioles
Centromere
Chromatin
Centriole
Nuclear envelope
Chromosomes (paired chromatids)
Interphase
Prophase
Spindle
Cytokinesis
Centriole
Metaphase
Individual chromosomes
Telophase
Anaphase
Nuclear envelope reforming
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Section 10-2
Spindle forming
Centrioles
Centromere
Chromatin
Centriole
Nuclear envelope
Chromosomes (paired chromatids)
Interphase
Prophase
Spindle
Cytokinesis
Centriole
Metaphase
Individual chromosomes
Telophase
Anaphase
Nuclear envelope reforming
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Section 10-2
Spindle forming
Centrioles
Centromere
Chromatin
Centriole
Nuclear envelope
Chromosomes (paired chromatids)
Interphase
Prophase
Spindle
Cytokinesis
Centriole
Metaphase
Individual chromosomes
Telophase
Anaphase
Nuclear envelope reforming