KEY CONCEPT Many organisms reproduce by cell division.

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5.4 Asexual Reproduction
KEY CONCEPTMany organisms reproduce by cell
division.
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Binary fission is similar in function to mitosis.
5.4 Asexual Reproduction
5.4

• Asexual reproduction is the creation of offspring
  from a single parent.
• Binary fission produces two daughter cells
  genetically identical to the parent cell.
• Binary fission occurs inprokaryotes.

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5.4 Asexual Reproduction
5.4

• Environment determines what form of reproduction
  is most advantageous.

• Asexual reproduction is an advantage in
  consistently favorable conditions.
• Sexual reproduction is an advantage in changing
  conditions.

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Some eukaryotes reproduce through mitosis.
5.4 Asexual Reproduction
5.4

• Budding forms a new organism from a small
  projection growing on the surface of the parent.

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5.4 Asexual Reproduction
5.4

• Fragmentation is the splitting of the parent into
  pieces that each grow into a new organism.

• Vegetative reproduction forms a new plant from
  the modification of a stem or underground
  structure on the parent plant.

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5.4 Asexual Reproduction
KEY CONCEPT Gametes have half the number of
chromosomes that body cells have.
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KEY CONCEPT Cells divide during mitosis and
cytokinesis.
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Chromosomes condense at the start of mitosis.

• DNA wraps around proteins (histones) that
  condense it.

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• DNA plus proteins is called chromatin.

• One half of a duplicated chromosome is a
  chromatid.
• Sister chromatids are held together at the
  centromere.
• Telomeres protect DNA and do not include genes.

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Mitosis and cytokinesis produce two genetically
identical daughter cells.

• Interphase prepares the cell to divide.
• During interphase, the DNA is duplicated.

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• Mitosis divides the cells nucleus in four phases.

• During prophase, chromosomes condense and spindle
  fibers form.

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• Mitosis divides the cells nucleus in four phases.

• During metaphase, chromosomes line up in the
  middle of the cell.

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• Mitosis divides the cells nucleus in four phases.

• During anaphase, sister chromatids separate to
  opposite sides of the cell.

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• Mitosis divides the cells nucleus in four phases.

• During telophase, the new nuclei form and
  chromosomes begin to uncoil.

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• Cytokinesis differs in animal and plant cells.

• In animal cells, the membrane pinches closed.
• In plant cells, a cell plate forms.

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You have body cells and gametes.
6.1 Chromosomes and Meiosis

• Body cells are also called somatic cells.
• Germ cells develop into gametes.
• Germ cells are located in the ovaries and testes.
• Gametes are sex cells egg and sperm.
• Gametes have DNA that can be passed to offspring.

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Your cells have autosomes and sex chromosomes.
6.1 Chromosomes and Meiosis

• Your body cells have 23 pairs of chromosomes.
• Homologous pairs of chromosomes have the same
  structure.
• For each homologous pair, one chromosome comes
  from each parent.
• Chromosome pairs 1-22 are autosomes.
• Sex chromosomes, X and Y, determine gender in
  mammals.

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Body cells are diploid gametes are haploid.
6.1 Chromosomes and Meiosis

• Fertilization between egg and sperm occurs in
  sexual reproduction.
• Diploid (2n) cells have two copies of every
  chromosome.
• Body cells are diploid.
• Half the chromosomes come from each parent.

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6.1 Chromosomes and Meiosis

• Haploid (n) cells have one copy of every
  chromosome.

• Gametes are haploid.
• Gametes have 22 autosomes and 1 sex chromosome.

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6.1 Chromosomes and Meiosis

• Chromosome number must be maintained in animals.

• Many plants have more than two copies of each
  chromosome.
• Mitosis and meiosis are types of nuclear division
  that make different types of cells.
• Mitosis makesmore diploid cells.

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6.1 Chromosomes and Meiosis

• Meiosis makes haploid cells from diploid cells.

• Meiosis occurs in sex cells.
• Meiosis produces gametes.