Mitosis and Meiosis

Question 1

What is the Cell Theory?

Answer 1

Cells are the fundamental units of all living organisms

Question 2

What is mitosis?

Answer 2

division of a parent somatic cell into 2 genetically identical daughter cells/ progeny. (asexual reproduction)

(more complex in eukaryotic than prokaryotic cells- binary fission)

Question 3

What are 2 stages of mitosis?

Answer 3

1. Interphase
   
   • Cell growth and development (G1/G0)
   • the cell is preparing for division (S/G2)
   • period between cell divisions
2. M-phase (Mitotic phase)
   -period of active cell division
   
   • firstly nuclear division or mitosis occurs
   • followed by cytokinesis or cytoplasmic division

Question 4

What are the phases of mitosis?

Answer 4

PMAT =>
Prophase
Metaphase
Anaphase
Telophase and Cytokinesis

Question 5

What is meiosis?

Answer 5

division of parent germ cell into four genetically variable daughter cells/ progeny

Question 6

What are the phases of meiosis?

Answer 6

Meiosis I
*Prophase I (Leptotene- this threads, Zygotene- homologous chromosomes, Pachytene- thick threads/ crossing over at synapse, Diplotene- two threads still attached at chiasmata, Diakinesis- break down of membrane and spindle fibres form)
*Metaphase I (Homologous Chromosomes align- random assortment)
*Anaphase I
*Telophase I (and Cytokinesis)

Meiosis II
*Prophase II
*Metaphase II
*Anaphase II
*Telophase II (and Cytokinesis)

Question 7

What accounts for genetic variation?

Answer 7

1. Mutation (both mitosis and meiosis)
   
   • Creates novel alleles (point mutation)
   • Polyploids (chromosomal aberrations)
2. Recombination (only in meiosis)
   
   • Shuffles existing alleles to create novel allelic combos