Meiosis Flashcards
A human cell that is N has how many chromosomes?
23
What are the two types of tumors?
Malignant and Benign
In women, meiosis produces what?
1 egg and 3 polar bodies
The act of chromosomes sharing parts is called
Crossing over
Prophase I of meiosis is different than Prophase of mitosis because it includes the formation of _____
Homologous Pairs (tetrads)
(homologous pairs - chromosomes with the same gene sequence as another)
Compare and contrast mitosis and meiosis.
Mitosis: one cell divides into 2 identical cells with the normal amount of chromosomes (46 chromosomes); mitosis includes only one division; mitosis doesn’t include crossing over; asexual reproduction; produces somatic cells
Meiosis: one cell divides into 4 different cells with 1/2 the chromosome count of normal cells (23 chromosomes); includes two divisions; sexual reproduction; produces sex cells
The spindle fibers role in meiosis is to
Separate the homologous pairs to opposite ends of the cell during Anaphase I
Separate the sister chromatids to opposite ends of the cell during Anaphase II
In humans, the diploid number is ____ and the haploid number is ____
Diploid = 46 Haploid = 23
What are the products of Cytokinesis II?
4 totally different cells, each with 23 chromosomes
(1/2 the normal count)
When does crossing over occur?
During Prophase I of meiosis
A human cell that is 2N has how many chromosomes?
46
How are cancer cells able to reproduce uncontrollably?
They do not respond to internal regulators (cyclins)
They do not respond to external regulators (touch)
When do the centrioles move to opposite ends of the cell?
During Prophase I and Prophase II
What are the products of Cytokinesis I?
2 cells are formed, each with 46 chromosomes
While the purpose of mitosis is to create new somatic (body) cells, the purose of meiosis is to create _______.
Gametes (sex cells)
(Ex. Sperm and egg cells)
The term haploid refers to
- Gametes
- Cells contain 1/2 the normal amount of chromosomes (N)
During which phase(s) do the chromosomes separate?
The homologous pairs separate during Anaphase I
The sister chromatids separate during Anaphase II
(Anaphase - away, apart)
During which phase(s) does the nucleus dissolve and the chromosomes thicken?
Prophase I and Prophase II
Mutated cells that reproduce quickly and are malformed are
Cancer
How does Metaphase I differ from Metaphase II?
During Metaphase I, the homologous pairs line up in the middle of the cell forming two lines
During Metaphase II, the sister chromatids line up down the middle of the cell forming one line
The term diploid refers to
- Somatic (body) cells
- Cells that contain the normal amount of chromosomes (2N)
A mass of cancerous cells is a
Tumor
Why are benign tumors still dangerous, even though they don’t metastisize?
The tumor can still grow larger
What makes benign tumors different from malignant?
Benign tumors are not as bad, but it depends on where in the body the tumor is
Benign tumors do not spread to other areas of the body
If a cell normally has 4 chromosomes, after going through meiosis, each of the new cells will have ___ chromosomes
Each of the new cells would have 2 chromosomes
If a cell normally has 8 chromosomes, what are its diploid and haploid numbers?
Diploid = 8
Haploid = 4
Meiosis produces __ sperm cells in men.
4
During which phase(s) do the chromosomes thin and become less visible?
Telophase I and Telophase II
Which type of tumor is the worst? Why?
Malignant.
Malignant tumors are able to metastisize (spread throughout the body)
How many divisions occur during meiosis?
Two
