Unit 2 Genetics and Adaptation

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Unit 2 Genetics and Adaptation

• Meiosis haploid gamete formation

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Meiosis haploid gamete formation

• By the end of this lesson you should be able to
  do the following
• State that meiosis is a type of cell division
  that produces gametes.
• Explain the meaning of the terms diploid and
  haploid in relation to gamete mother cells and
  gametes.
• State the location of gamete mother cells in
  mammals and flowering plants.
• Describe the two consecutive divisions of
  meiosis with the use of diagrams.

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Meiosis

• Meiosis is a type of cell division which produces
  gametes.
• Meiosis occurs only in gamete mother cells and it
  results in variation.

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Gamete mother cells

• Gamete mother cells are diploid. This means they
  contain two sets of chromosomes (2n).
• Gamete mother cells undergo meiosis to produce
  gametes.

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Gametes

• Gametes (sex cells) are haploid which means they
  contain one set of chromosomes (n).
• Gametes fuse together during fertilisation to
  form a zygote.

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Task

• Copy and complete the following table using p82
  of the Higher Biology text book.

Location of gamete mother cells Gametes
Mammals
Flowering plants
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Task

• Without using your notes, work in pairs to
  complete the haploid / diploid cell diagram
  from your pack.

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Process of meiosis

• Meiosis consists of two consecutive divisions.
• The first reduces the chromosome number by half.
• The second produces four genetically different
  gametes.

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First meiotic division
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Task

• Complete the meiosis- 1st division diagram from
  your pack.
• Use p 80 of the Higher Biology text book to help.

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Second meiotic division
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Task

• Complete the Meiosis- 2nd division diagram from
  your pack.
• Use p81 from the Higher Biology text book to help.

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Can you do the following?

• State that meiosis is a type of cell division
  that produces gametes.
• Explain the meaning of the terms diploid and
  haploid in relation to gamete mother cells and
  gametes.
• State the location of gamete mother cells in
  mammals and flowering plants.
• Describe the two consecutive divisions of
  meiosis with the use of diagrams.