CH 11.2: Features of Meiosis

Question 1

What does Meiosis consist of in a diploid organism?

Answer 1

• 2 rounds of division= Meiosis I & Meiosis II

- Each of these divisions also go through prophase, metaphase, anaphase & telophase

Question 2

What happens during early Prophase I of meiosis?

Answer 2

-Homologous chomosomes find each other & pair up

Question 3

What is Synapsis?

Answer 3

• The pairing of homologous chromosomes that happens before the 1st cell division
• Crossing over also takes place here

Question 4

What holds the homologous chromosome pairs together during before cell division?

Answer 4

-The Synaptonemal Complex protein

Question 5

What is the role of the Synaptonemal Complex?

Answer 5

-It holds the chromosomes together so that base-pairs can form between non-sister chromatids for crossing over

Question 6

What is the structure of the 2 homologous chromosome pairs held together by the Synaptonemal ComplexTcalled?

Answer 6

-Tetrad or Bivalent

Question 7

What is Crossing Over?

Answer 7

-It is the exchange of the corresponding chromatid fragments between homologous chromosmes

Question 8

What is the result of homologous chromosomes having sections of DNA that Cross Over?

Answer 8

-Genetic recombination

Question 9

What is Chiasmata?

Answer 9

• It is the site for crossing over

- They are also maintained until Anaphase I

Question 10

What happens during Metaphase I?

Answer 10

• The paired homologues move to the metaphase plate

- They also become oriented w/ homolouges of each pair attached at opposite poles of the spindle

Question 11

What makes the Homologues different in Mitosis vs. the homologues in Meiosis?

Answer 11

-The ones in mitosis don’t attach to eachother= they are more independent

Question 12

What happens during Anaphase I?

Answer 12

-Homologues are pulled to opposite poles for each pair chromosomes

Question 13

Why is the first meiotic cell division referred to as Reduction Division?

Answer 13

-Becuase it results in daughter cells that have one homologue from each chromosomes pair

Question 14

What happens in the 2nd meiotic cell division?

Answer 14

-The sister chromatids are separated from each homologue

Question 15

What is the major difference between Mitosis & Meiosis?

Answer 15

• Meiosis has 2 divisions w/ NO replication of genetic material between them
• The last division is like mitosis BUT w/ no chromosomes duplication