Meiosis

Question 1

What is the function of the synaptonemal complex?

Answer 1

A ladder-like complex with transverse segments that hold paired homologous chromosomes together

Ensures crossing over happens between homologous chromosomes
(during meiosis chromosome pairing)

Question 2

What does cohesion do?

Answer 2

Unites sister chromatids along their entire lengths

Question 3

What are chiasmata? What does a defect in chiasmata lead to?

Answer 3

Chiasmata are the points of attachment of homologous chromosome pairs. Non-disjunction (abnormal separation of homologous chromosomes)

Question 4

What is the kinetochore?

Answer 4

Point of attachment of microtubules on chromosomes

Question 5

Synaptonemal complex vs
Cohesion vs
Chiasmata vs
Kinetochore

Answer 5

Synaptonemal complex: ladder-like complex that holds homologous pairs together and enables crossing-over

Cohesion: hold sister chromatids together

Chiasmata: junction points of homologous chromosome pairs

Kinetochore: attach spindle to chromosomes

Question 6

Name the 5 stages of prophase I of metaphase I

Answer 6

• Leptotene (L) - homologous chromosomes pair
• Zygotene (Z) - synaptonemal complex forms
• Pachytene (P) - fully formed synaptonemal complex, crossing over
• Diplotene (D) - prolonged period, chromosomes are DE-condensed and active in transcription
• Diakinesis (D) - transition to metaphase, chromosomes re-condensed, transcription stops