Lecture 8: The Cell Cycle and Reproduction Flashcards
When cells need to divide, ___ cells undergo mitosis while ___ cells undergo meiosis.
Somatic / Germ
What advantage does mitosis have over meiosis?
It allows somatic cells to divide, producing two daugter cells that are genetically identical (genetic uniformity).
What advantage does meiosis have over mitosis?
It provides distinct cells, offering genetic diversity.
What happens in G1 of interphase?
The cell grows, develops and lives its life
What happens in the “S phase” of interphase?
The cell needs to divide, so it makes a copy of its DNA
When does DNA replication take place?
The “S” phase of interphase
The two halves of this chromosome are attached at the ____.
Centromere
How many chromatids do cells have after the “S-phase” of interphase?
92
Mitosis is ___ reproduction, and results in ____.
Asexual / two genetically identical cells
The nucleus needs to break apart into pieces, and the centrioles spread spindle fibers across the cell. The chromosomes also become visible, because they “wind” together tightly. This occurs in ___ of mitosis.
Prophase
In order to split the chromosomes in mitosis, the copies must be pulled apart by centrioles “tugging” on the spindle fibers. This occurs during ___ of mitosis.
Anaphase
In order to complete the division of the cell, the membrane begins to pinch off, and the the nucleus of each new cell forms. This occurs in ___ of mitosis.
Telophase
In order to split the chromosomes, the spindle fibers arrange the chromosomes and chromatids along the ___ plate.
Metaphase
Mitosis (the splitting of cells) is part of interphase in the life cycle of the cell. True or False.
False
After mitosis, each of your cells will have ___ chromosomes.
46
Where are your germ cells located?
In the ovaries or testes
Meiosis I splits ___ apart, resulting in two haploid cells.
Tetrads
Meiosis II splits ___ apart, resulting in four haploid cells.
Chromatids
Meiosis results in genetic diversity in several ways:
In Prophase I, crossing over can occur.
In Metaphase I, a random arrangement of tetrads occurs.
There is a third way in which sexual reproduction results in genetic diversity. What is it?
Gametes can combine to form zygotes, which is totally random
When does crossing over occur?
Prophase 1
It is possible for genes to go from one chromosome to another during crossing over. True or False.
True
In Meiosis I, tetrads line up along the metaphase plate. There is nothing random about this - they are genetically pre-determined which way they are lined up, on purpose. True or False
False
