Meiosis and Mitosis Lab

Investigation 1 (part 1):
Hypothesis: If a model of mitosis is built out of Oreo cookies then the mitotic processes will be easier to see and understand.

Materials:

• original Oreo cookies
• sprinkles (assorted colors)
• paper towel
• camera (phone)
• tweezers (optional)
  

Protocols:

1. Take a total of 5 Oreo cookies. (5 are needed just in case a mistake is made)​
2. Open each cookie, making sure one side of the cookie has the whole circle of frosting on it.
3. Place unfrosted cookies on side. (They can be eaten or thrown away)
4. Take a small cup of sprinkles and determine what colors will be used for what. 
5. Take sprinkles of the same color and create and "X" on the cookie; this will be a chromosome. 
6. Repeat step 5. (You'll need at LEAST 2 chromosomes)
7. Take another frosted cookie and place the chromosomes down the middle. 
8. On the same cookie create centrioles and spindle fibers; fibers should be attached to center of chromatids.
9. On a third cookie place centrioles on both side as well as shorter fiber spindles. To the end of each half of a chromatids should be on each.
10. The fourth frosted cookie should just be separated frosting and smaller sprinkles on both sides. Each color should  be paired on either side.​

Explanation

(1) DNA condenses into chromosomes and then paired chromatids. Nuclear envelope disappears.​

(2) The centrioles form and the spindle fibers are made. The chromosomes line up in the middle of the cell where the spindle fibers then attach to the center of the chromatids.

(3) Once attached, the spindle fibers pull the chromatids apart and pull them to either side of the cell. ​

(4) Spindle fibers are completely gone. Two nuclei are formed. The cell gets ready to split. (cytokinesis)

Justification: The model portrayed below displays the steps of mitosis. It show a cells getting ready to divide but in a cookie form. 
Key:
Oreo cookie- cell
Oreo cream- nuclear envelope
Sprinkles- chromosomes and spindle fibers

 ​Analyse Questions:

1. Identify 1 step in your model where a mistake could occur.  Describe the consequences of that mistake on the cell and on the organism.

When placing the sprinkles (chromosomes) in the middle of the metaphase cookie, the chromosomes don't line up directly in the middle just like they're supposed to. This could mess up the chromosomes if this had been a real life cell. Also in other phases, if the chromosomes didn't condense right or split correctly this could cause a mutated cell that could potentially be a cancerous cell. 

1. Describe the limitations of your model versus observing this in the real world.

In this model we aren't able to see the nucleus disappearing, we didn't see cytokinesis, and we didn't see the before and growth phase. These things may or may not be apart of mitosis but they are important to the process.

Conclusion:
Although we are able to get the jist of what is going on in the model, mitosis isn't something that can be fully explained with cookies. In order to get the real experience looking at the process under the microscope would be best. 
Mitosis is a very delicate process and if the body has to do this over and over again it is prone to make mistakes but it does rarely. If a cell, during mitosis, makes a mistake at copying itself it can cause cancerous cells in the body. 

Investigation 1 (part 2):
​Hypothesis: If a model of meiosis is built out of Oreo cookies then the mitotic processes will be easier to see and understand.

Materials: 

• original Oreo cookies
• sprinkles (assorted colors)
• paper towel
• camera (phone)
• tweezers (optional)

Protocols: 

1. Take a total of 20 Oreo cookies. (20 are needed just in case a mistake is made)​
2. Open each cookie, making sure one side of the cookie has the whole circle of frosting on it.
3. Place unfrosted cookies on side. (They can be eaten or thrown away)
4. Take a small cup of sprinkles and determine what colors will be used for what. 
5. Take sprinkles of the same color and create and "X" on the cookie; this will be a chromosome. 
6. Repeat step 5. (You'll need at LEAST 2 chromosomes)
7. Take another frosted cookie and place the chromosomes side by side
8. Mix them up (cross over).
9. Create centrioles and spindle fibers; fibers should be attached to center of chromatids.
10. On a fourth cookie place centrioles on both side as well as shorter fiber spindles. To the end of each half of a chromatids should be on each.
11. The fifth frosted cookie should just be separated frosting and smaller sprinkles on both sides. Each color should  be paired on either side.​
12. Repeat these steps, reducing the amount of chromosomes each time.
13. You should end with a single chromosome piece on 4 cookies.​

Explanation

(1) The DNA condenses into chromosomes and they become visible as paired chromatids and the nuclear envelope disappears.

(2) The chromosomes cross over to insure genetic variation in future cells.

(3) The centrioles form and the spindle fibers are made. The chromosomes line up in the middle of the cell where the spindle fibers then attach to the center of the chromatids.

(4) Once attached, the spindle fibers pull the chromatids apart and pull them to either side of the cell. ​

(5) Spindle fibers are completely gone. Two nuclei are formed. The cell gets ready to split. (cytokinesis)

(6)Now we have 2 new cells with half the number of chromosomes.

(7)The centrioles form and the spindle fibers are made. The chromosomes line up in the middle of the cell where the spindle fibers then attach to the center of the chromatids.

(8) Once attached, the spindle fibers pull the chromatids apart and pull them to either side of the cell. ​

(9) Spindle fibers are completely gone. Two nuclei are formed. The cell gets ready to split.

(10) Four new cells haploid cells are produced with ¼ of the original genes.

 ​Analyse Questions:

1. Identify 1 step in your model where a mistake could occur.  Describe the consequences of that mistake on the cell and on the organism.

If the haploid cells aren't made correctly then mutations could be, or will be, present in the fetus formed if or when a zygote is formed. 

1. Describe the limitations of your model versus observing this in the real world.

In this model we aren't able to see the nucleus disappearing, we didn't see cytokinesis, and we didn't see the before and growth phase. In real life we are able to see cell tools forming and disappearing and that might make the process easier for us to understand.

Conclusion:
The model does show us the process of meiosis but it does have flaws since we don't have the first cytokinesis and we aren't able to see things that could happen in real life. The model could've been depicted better if we had more time but a 40 minutes time limit was present. 
If any chromosomes got messed up the process of meiosis the zygote produced from this haploid cell would either be naturally rejected by the body or the fetus produced would be mutated. Silent mutations may occur, not affecting the offspring at all but still being a mutation.
 
Investigation 2: 
Studying the Effects of Environment on Mitosis:
Hypothesis: If the temperature surrounding an organism fluctuates then it will become more difficult for mitosis to occur.
*original lab failed, had to use alternative link* (Time Spent in the Phases of Mitosis)

Protocols:

1. Click link on document above.
2. Sort the cells into the 5 categories.
3. When finished sorting, count up the cells in each category. (put data in table)
4. Find percent by dividing by total # of cells.
5. Multiple the percent by 1440 minutes to find the time they were in each stage. 
6. Fill in table.

Phase	# of cells	% of cells counted	Time in each stage
Interphase	20	55.55%	79992 minutes
Prophase	10	27.77%	39988.8 minutes
Metaphase	3	8.33%	11995.2 minutes
Anaphase	2	5.55%	7992 minutes
Telophase	1	2.77%	3988.8 minutes

Conclusion:
The environment affects mitosis because of our bodies being accustomed to a certain internal environment, any external environment that adversely affects our internal environment will disrupt our cells ability to replicate. Mitosis happens best when it is in its ideal environment, which is the normal temperature in which the organism is healthy. If the temperature drops the cell walls will become more rigid and it will become more difficult to perform mitosis. Juxtaposed to that, if the temperature becomes too warm, the cell wall may begin to break down and make mitosis impossible

Investigation 3:
Karyotypes: 
Regular chromosomes:

Not so regular chromosomes:

Patient #	# of chromosomes	Extra, Missing, or Normal	Name of Syndrome	Effects on the patient
1	47 chromosomes	Extra chromosome 21	Trisomy 21 Down syndrome	Unique phenotype, slow development as well as short lifespan. Abnormally large tongue, lazy eye, bent finger, hearing loss, immune deficiency, thyroid disease, vision disorder.
2	47 chromosomes	extra chromosome 18	Trisomy 18 Edwards’ Syndrome	Abnormally small head, organs outside of body, drooped upper eyelids/wide spaced eyes, and abnormal deviation of fingers. Fatal before birth or within the 1st year of life.
3	47 chromosomes	extra chromosome 13	Trisomy 13 ​Patau Syndrome	Abnormally small head, cleft lip and cleft palate, episodes on no breathing, extra fingers/toes, learning disabilities, low set ears, seizures, single line on palm.

Conclusion:
Whenever there is a mistake in the chromosome count for humans it messes us up, bad. We don't form normally, we don't live as long, we don't function properly. The bodies DNA is all funky since there's so much extra DNA. No matter what number, if we don't have 46 chromosomes then we have a hard time functioning.

Investigation 4:
Meiosis and Crossing Over in Sordaria:

• 4 dark/4 light=No crossing over
  
• ANY other combination= Crossing over​

Number of Asci not showing Crossover	Number of Asci showing Crossover	Total	% Asci Showing Crossover	Gene to Centromere Distance (map units)
17	33	50	66%	33 map units

conclusion:
This shows that 66% of the offspring will be genetically different from their parents. This also shows that crossing over is very common. Without crossing over our genes would not be mixed and without mixing you would either look exactly like your mom or exactly like your dad. 
Genetic diversity is caused by crossing-over. Without it natural selection wouldn't be able to take place due to the fact that a different combination of genes wouldn't be present.