Unit 2 - Meiotic Division - Mar 17

Question 1

Ploidy, examples

Answer 1

refers to the # of each chromosome that an organism carries. One set is designated “n”
Haploid: 1n
Diploid: 2n
Triploid: 3n

Question 2

Mitosis vs Meiosis production

Answer 2

Mitosis: 2 identical daughter cells

Meiosis: 4 daughter cells, with half the genetic content of parent cell (2n parent->1n haploid daughter)

Question 3

Zygote

Answer 3

a fertilized egg - a diploid cell that gives rise to all the cells of an organism

Question 4

Reductive Division

Answer 4

When cells go from diploid to haploid in Meiosis 1. Meiosis occurs in 2 divisions called Meiosis 1 and 2.

Question 5

Crossing Over

Answer 5

homologous recombination, each chromosome is joined at the exact same spot to the paired homolog, mixes up maternal and paternal alleles during Meiosis 1

Question 6

Steps of Meiosis I

Answer 6

Interphase
Early Prophase 1 - chromosomes pair, spindle activates
Late Prophase 1 - nuclear envelope gone, spindle reach more, crossing over
Metaphase 1-crossed over pairs line up in middle
Anaphase 1-pairs pulled towards spindle (poles)
Telophase 1 + Cytokinesis-cell divides as haploid

Question 7

Bivalents

Answer 7

homologous pair of chromosomes which form during early prophase 1

Question 8

Meiosis II Steps

Answer 8

Prophase II-2 haploid cells duplicate chromosomes to sister chromatids
Metaphase II-sister chromatids line up in middle
Anaphase II-pulled apart
Telophase II + Cytokinesis-4 haploid cells

Question 9

Somatic Cells

Answer 9

cell that only do mitosis, vast majority of human body

Question 10

The Key to remembering the difference between meiosis and mitosis

Answer 10

homologous chromosomes only pair in meiosis,
homologous chromosomes ignore each other in mitosis

Question 11

Nondisjunction

Answer 11

chromosome segregation errors, either homologous chromosomes or sister chromatids can fail to separate

Question 12

Aneuploid

Answer 12

a cell with abnormal chromosome number