Cellular Division 2

Question 1

What is mitosis?

Answer 1

The process that produces two new nuclei with the same number and kinds of chromosomes as the original nucleus
ensures the inheritance of a complete set of the parent cell;s genetic information

Question 2

Why must the cell divide?

Answer 2

The surface area (doors) to volume (needs, nutrients, wastes) ratio of the cell decreases and it can no longer supply itself with nutriends and get rid of wastes

Question 3

Describe the phases of Interphase:

Answer 3

interphase:
process of cell activity between cell divisions
90% of cell cycle

G1 (gap 1): DNA transcription-translation, growth and replication of organelles

S (synthesis): DNA replication (new chromosomes)

G2 (gap 2): DNA transcription-translation, structures associated with mitosis are replicated (spindle proteins)

Question 4

Describe chromosome, chromatin, and chromatid:

Answer 4

chromosomes and chromatin are made of nucleic acids (DNA) and proteins

Chromatin: uncondensed, long, thin, bumpy strands that cannot be seen under a light microscope

Chromosome: condensed, bar-like bodies that can be seen under a light microscope

Chromatid: 1 or 2 copies of a replicated chromosome, joined together in the center by a centromere (double helix strand), replication of DNA results in each strand becoming a doubled molecules of DNA and protein held together by a centromere

Question 5

What are the phases in mitosis?

Answer 5

nuclear division characterized by the formation of two identical daughter nuclei

prophase, metaphase, anaphase, telophase, cytokinesis (division of cytoplasm)

Question 6

What happens in prophase

Answer 6

chromatin condenses to form visible chromosomes
spindle fibers form
nuclear membrane and nucleolus disappear

Question 7

What happens in metaphase?

Answer 7

chromatid pairs align on the mid-plane (equatorial plate) of the cell maneuvered by the spindle fibres
(called metaphase plates in plants)
chromatids can become intertwined

Question 8

What happens in anaphase?

Answer 8

Centromeres divide and sister chromatids separate to opposite poles of the cell
same # of single stranded chromosomes will be found at each pole

Question 9

What happens in telophase and cytokinesis?

Answer 9

Chromosomes uncondense to become chromatid, spindle fibers dissolve, nuclear membrane forms

in animal cells: a clevage furrow forms near the equator, eventually slitting the two daughter cells into two daughter cells

in plant cells: a cell plate forms near the equator and separates the two daughter cells, forms the middle lamella of the new cell walls