quiz 2 Flashcards
What is mitosis?
The method by which most eukaryotic cells reproduce. A.K.A cell division.
What are the roles of cell division? (3)
R.G.T
1. Reproduction (division of unicellular organism reproduces an entire organism, increasing population)
- Growth and development
- Tissue renewal (repair and renew cells)
What are the two main stages in the cell cycle?
Interphase (most of cell’s life span) and mitotic phase (shortest stage and cell division).
What are the 4 subphases of interphase?
There is a checkpoint during G1 and a checkpoint at the end of G2
- G1 (gap) - vigorous growth and metabolism
- G0 - gap phase in cells that permanently cease dividing
- S (synthetic) - DNA replication
- G2 - preparation for division
This consists of 90% of cell’s life cycle
What happens during the G1 phase?
Synthesis of new organelles. Non-dividing cells are in this state.
What happens during the G0 phase (Quiescence)?
The G0 phase is the state of the cell that is not dividing (left the cell cycle)
What happens during the S phase?
DNA is replicated, and the chromosomes makes two copies of itself, called chromatids, which remain attached at the centromere. The sister chromatids are exact copies of one another and contain the same genetic information.
A cell in G2 (after S phase) a cell will have 46 chromosomes, 46 pairs of sister chromatids, and thus, 92 chromatids.
What happens during the G2 phase?
- The cell checks the duplicated chromosomes for error, and makes any needed repairs.
- Preparation for mitotic phase begins
What are the 2 subphases of the mitotic phase?
1) Mitosis
a. prophase
b. metaphase
c. anaphase
d. telophase
2) Cytokinesis (begins while in telophase)
What is early and late prophase?
In early Prophase, there is chromosome compaction. The nucleus remains intact but the nucleolus disintegrates. More than 90% of mitosis is in this stage.
In the late prophase, the nuclear membrane disappears, proteins bind on centromeres to form the kinetochore.
What is a karyotype?
It is an organized profile of a person’s chromosomes. They are arranged and numbered by size, from largest to smallest.
Why is the karyotype useful?
The karyotype arrangement can help scientists quickly identify genetic disorders, that are due to chromosomal alterations.
What is the metaphase?
Metaphase occurs when all chromatids have aligned along the cell midline. This plane in the middle of the cell (between the poles) is called the metaphase plate.
What is the anaphase?
The centromeres of the chromosomes split. The sister chromatids separate and move towards opposite ends of the cell.
What is the telophase?
Microtubules elongate the cell (looks like two buns squished together). The nuclear membrane forms around the chromosomes and the nucleolus reappears.
