Download Mitosis/Meiosis Exam Review

Mitosis/Meiosis Exam Review KEY
Ramshaw – Biology
Name ______________________
Hour ________ Date __________
Cell Cycle:
1. Complete the 4 missing labels for the cell cycle diagram. Shade in the parts that include interphase.
G1 phase
Cytokinesis!
Mitosis
S Phase
G2 phase
2. What major events occur in each stage? (Include which stage most cells are in for about 90% of the time.)
Interphase: G1 – organelles double, S – DNA doubles, G2 – DNA is checked for errors and cell grows. Cell
spends about 90% of time in this phase.
Mitosis – cell division
CYTOKINESIS: cell splits into 2 new daughter cells
3. Does this cell cycle happen in prokaryotic or eukaryotic cells?
Both
4. What happens if a cell enters the G0 phase? Give an example.
It gets stuck in interphase and will never go through mitosis. Brain cells, heart cells, etc.
Mitosis:
5. Define these vocabulary words:
(you can find these in the glossary)
Sister chromatid
Centromere
Spindle apparatus or spindle fibers
Mitosis
Chromatid
Chromatin
Cell plate
Cleavage Furrow
6. Draw a picture of DNA as it is seen in each of the following stages:
Chromatin
(can’t draw this on the computer but it is loosely packed DNA, looks like a string that has been wadded up)
Chromatid
One straight line
Chromosome (unreplicated)
One straight line
Sister Chromatids
Looks like an X
7. Write a summary of what happens in each of these stages of mitosis. Include a simple picture.
Prophase: nucleus disappears, chromosomes become visible, centrioles and spindle fibers spread apart
Metaphase: Chromosomes line up down the equator
Anaphase: sister chromatids pull apart
Telophase: 2 new cells start to form
(see your notes for pictures)
8. What is the result of mitosis?
2 new genetically identical cells.
9. Why do we need mitosis?
To replace old or worn out cells, cells that have become sick, to grow (from childhood to adulthood)
Cancer:
10. What is cancer?
Uncontrolled mitosis (uncontrolled growth and division of cells)
11. What is the term used for substances that can cause cancer to happen?
Carcinogens
12. What is cancer caused by? (2 answers)
Unrepaired genetic changes or exposure to carcinogens
13. How is cancer often prevented? Explain.
Cell cycle checkpoints, that monitor for DNA damage or spindle fiber failure and stop the cell cycle before
cytokinesis
14. How does apoptosis help to prevent cancer?
It kills cancerous cells before the divide and make more cancer cells
15. How does cancerous cell growth differ from normal cell growth?
Cells that are growing normally respond to cell cycle control mechanisms. Cancer is uncontrolled mitosis that
results when cells do not respond to cell cycle control mechanisms. Cancer cells can crowd out normal cells,
causing loss of tissue function.
Stem Cells:
16. Write a general description of each of the following:
Embryonic Stem Cells – Cells taken from a blastocyst between days 6 and 12. They are not federally
funded and there have been no cures from them yet. They are pluripotent (can become any type of cell). These
are also very controversial because the inner cell mass that is taken out is what the baby would have been if it
would have been implanted into a woman. Some people believe this is “killing a life”.
Adult Stem Cells – Cells that have differentiated and are taken from a fully formed human and also
from umbilical cords. These are federally funded and have cured people of diseases.
iPs Cells – the newest kind of stem cell. They are pluripotent adult stem cells. They work backwards
and turn adult somatic cells into “embryonic like” cells and then can be turned into the type of cell the patient
needs. These are federally funded.
17. How would Somatic Cell Nuclear Transfer help someone cure themselves of a spinal cord injury?
They would grow their own identical twin to the blastocyst stage, harvest the inner cell mass, create spinal cord
cells from those embryonic stem cells and cure themselves.
18. Define the following terms: (you can find these on the back of you stem cell web that we did in class)
Teratoma
Pluripotent
Blastocyst
Inner cell mass
Cloning
Differentiated
Undifferentiated
19. Briefly discuss the ethical arguments against some of these types of stem cells. Identify which ones are
involved in the ethical arguments and are not federally funded.
(see my answer for number 16)
Meiosis:
20. Define these terms: (you can find these in the glossary)
Homologous Chromosomes (or homologues)
Synapsis
Tetrad
Crossing Over
Independent Assortment
Diploid
Haploid
Gametes
Oogenesis
Polar bodies
Spermatogenesis
Somatic cell
21. Meiosis is a special kind of cell division. It consists of _1__ replication of the DNA followed by __2__ cell
divisions.
22. Why does meiosis reduce the chromosome number in gametes?
So the egg has half the chromosomes and the sperm has half, when they come together the zygote has the
correct number of chromosomes (is diploid).
23. Are any of the final cells created in meiosis the same? Why or why not?
No, the chromosomes have gone through crossing over and independent assortment.
24. Using the knowledge you have gained about meiosis to explain why people look different from their
brothers and sisters.
Each egg and each sperm are unique. When each life is created, it is a different combination of DNA from your
mom and dad.
25. Draw out the process of meiosis, starting with Prophase I and ending with Telophase II.
Use your Trogdor Meiosis to do this one!
26. Compare and contrast mitosis and meiosis: Answer each of the following 5 questions for mitosis & meiosis.
1.
2.
3.
4.
5.
The type of cell (somatic or gamete) that undergoes this process
If the daughter cells are genetically identical the parent or not
If the resulting daughter cells are diploid or haploid
The purpose of the process (replace old/sick cells or to make reproductive cells)
The names of all the stages they go through in the process
Mitosis
1.
2.
3.
4.
5.
somatic cells
genetically identical
diploid
replace old/sick cells
interphase, prophase,
metaphase, anaphase,
telophase, cytokinesis!
Meiosis
1.
2.
3.
4.
5.
gametes
not genetically identical
haploid
make reproductive cells
interphase, prophase I,
metaphaseI, anaphaseI,
telophaseI, prophaseII,
metaphaseII,
anaphaseII, telophaseII
AND CYTOKINESIS!