Cellular Reproduction

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Cellular Reproduction

• Chapter 6
• pp. 116-137

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Definitions Related to Cell Division

• Gene-a segment of DNA that codes for a protein or
  RNA molecule
• Chromatid- one pair of strands of DNA that make
  up a chromosome
• Centromere-

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Chromosomes- DNA tightly coiled around
proteins Humans have 46
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Chromosomes affect Development

• Homologous Chromosomes-
• Similar in shape size and genetic content
• Diploid
• 2 sets of chromosomes
• Haploid
• One set of chromosomes
• Zygote
• Fertilized egg cell, the first cell

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Chromosomes affect Development

• Autosomes
• Chromosomes that do not determine sex
• Sex Chromosomes
• Contain genes that determine male or female
• Karyotype
• A picture of the chromosomes in a dividing cell
  that shows the chromosomes arranged by size.

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The Cell Cycle (Fig 6-6)
In your book

• Interphase
• 90 of time
• First Growth (G1)
• Cell grows rapidly
• Synthesis Phase (S)
• Cells DNA copied
• Second Growth (G2)
• Prepare for Mitosis

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Cell Division- 3 types

• 1. Binary Fission- asexual reproduction that
  produces identical offspring

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Cell Division

• 2. Mitosis (Fig 6-9)
• Nucleus of cell divides

In your book
Cells must divide because Surface Area to Volume
ratios get too small
Skin Cells
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Cellular Reproduction
Link!Mitosis animation
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Prophase

• Chromosomes coil up and become visible.
• The nuclear envelope dissolves and a spindle
  forms.

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Metaphase

• Chromosomes move to the middle of the cell and
  line up along the equator.
• Spindle fibers link the chromatids of each
  chromosome to opposite poles.

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Anaphase

• Centromeres divide
• Chromatids (now called chromosomes) move toward
  opposite poles

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Telophase

• A nuclear envelope forms around the chromosomes
  at each pole
• Chromosomes uncoil
• LAST step in mitosis

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Cytokinesis (Fig 6-10)
In your book

• Cytoplasm is divided in half.
• Cell membrane encloses each cell