Mitosis and Development

Mitosis and Development

Mitosis and Development

NOTE: Please use Basic English language/ Common language just like last time.

NOTE: Try to make your answers short and neat “no long answers because the professor will not approve”

Refer to the laboratory models and charts, your slides, or your textbook’s diagrams of the mitotic phases in plants. In the spaces below, make realistic rough sketches (not cartoons) of each stage of the cell cycle (including interphase) as one onion root tip cell divides into two daughter cells.

Make diagrams here: List the main actions that happen during this phase here. Use arrows and words to label important parts:






Table 1. Number tally of onion root tip cells

in different phases of the cell cycle

  Group Tally Other Group Counts Class Total Percent of Time Class Avg.
Interphase X x x
Prophase X X X
Metaphase x x X
Anaphase X X X
Telophase x x X
Total Cells X X X




  1. Calculate the percent of the cells’ total cycle time spent in each phase using the following formula:

percent of time spent in phase =


  1. Record the values in Table 1 and in the class data table on the board.



Question 1. Based on your calculations which phase plant cells spend the most time. Be able to explain why.

Question 2. Why is a class average more likely (than your group’s data alone) to reflect the truepercentage of time spent in each phase?

Question 3. Using the class averages for each phase (Table 1, previous page), draw a “pie chart” to graphically demonstrate the relative amount of time an average onion root tip cell spends in each phase of mitosis:

Using the whole “pie” below to represent 100% of the cell cycle time, sketch in “wedges” which reflect the portion of the pie (relative percent of time) spent in the different phases by the cells in your onion root tips.



Figure 3. Pie Chart: Relative Amounts of Time

Spent in the Various Phases of Plant Mitosis


Question 4. Compare your chart with a general pie chart for plant mitosis found in your textbook or some other reference. Describe the similarities and differences.


Question 5. Speculate on why our class’ pie chart percentages may not agree exactly with those seen in your reference.



Question 6. Are the aboral (top side) and oral (under side) surfaces similar? If not, how do they differ?

Question 7. Closely observe the flat oral surface. Locate the main opening in the center, surrounded by the five-pointed star-like structure. The star-like structure is often difficult to see in a sand dollar as it covered by many of the moveable spines. However, this structure is much more easily seen in a relative of the sand dollar, an urchin. View the following video to observe this structure. What is this structure’s function?

Question 8. Observe the following short video: Video”A Sea Biscuit’s Life) 3:36 minutes

Use the above Video to answer questions 8, 9, 10, and 12.

Above is a Sand Dollar Egg, notice the difference between it and the Sea Biscuit egg (35 seconds into the video). What do you see as the major differences between the two species?

Question 9. Describe the sperm movement (31 to 33 seconds in video). Does it appear to be directed or random?



Question 10. In the spaces below, briefly describe the form (shape) of an egg and a sperm. Then describe the mobility(movement), if any, of the two kinds of cells. Now compare the gametes’ sizes(make sure you are viewing them both at the same magnification).

  Sperm Egg

Suggest a possible explanation for the observed differences.









Question 11. Surrounding the egg cells, you will notice a protective gelatinous material containing colored granules. This material is outside the cell membrane of the egg. (Label this material in the image labeled Unfertilized Egg in Figure 4.)

  1. Fertilization

Question 12. It is usually not possible to observe fertilization (nuclear union) but you can tell when it has occurred, for a fertilization membrane (40seconds) will develop around each fertilized egg, inside the egg’s gelatinous cover. (Label this on the image of the Fertilized Egg in Figure 4.) This halo-appearing membrane emerges from the surface of the cell and signals the formation of the zygote. Draw a fertilized egg showing the fertilization membrane. What might be its function?


Question 13. Draw arrows between each of the stages in Figures 4 and 5. Then on the top of the arrow, label what process is happening (formation of fertilization membrane, first cleavage, etc.) based on what is listed in Table 2 below. On the bottom of the arrow, label how long the process takes (e.g. 2-5 minutes, etc.). See the example on Figure 4.

Question 14. On entering the egg, the sperm nucleus carrying the male chromosomes unites with the nucleus of the egg to produce a zygote with the chromosomes of both egg and sperm. What is the relative chromosome number of the zygote compared to the gametes? THINK!



Question 15. Were the photographs of all the stages up to gastrulation pictured in the video of the Sea Biscuit seen earlier taken at the same power magnification?

  1. Within individual stages in the early cleavage stages, how do the individual cell sizes compare?
  1. How does the size of the entire cell mass compare at these different stages?

Question 16. Find the mass of cells called a morula (1:22 in the Video) and on figure 5 Draw the morula. Be sure to label it as a solid sphere of cells. Mitosis and Development

Question 17. Draw a blastula (only seen in Figure 5). Be sure to label it as a hollow, fluid-filled sphere.

Question 18. Compare the size of a blastula to that of an unfertilized egg. Has the embryo actually grown? Estimate the number of cells the blastula contains:

Question 19. Describe how you tell if an embryo is a simple mass of cells (“morula“) or actually a blastula (fluid-filled sphere of cells). Mitosis and Development



Question 20. Draw a gastrula. Label the ectoderm and endoderm (using arrows to point to parts).

Question 20. A gastrula will develop into free-swimming “pluteus” larvae (1:34 minutes) in a day or two. In contrast a sea star forms a bipinnaria larva. What does gastro- (as in gastrointestinal tract) mean?

Questions 22. At what point in development would you logically expect the larvae to be capable of growth (growing in size)? Explain your answer. Mitosis and Development

  1. Review of Sand Dollar Development

Answer the following questions with reference to the letter designations in the chart below.

Processes Stages
a. fertilization f. larva
b. morphogenic migration g. gametes
c. hatching h. blastula
d. cleavage i. zygote
e. metamorphosis j. gastrula

Question 23. Which of the following represents the sequence of occurrence for the developmental processes?

  1. a, b, c, d, e
  2. a, d, b, c, e
  3. b, e, d, c, a
  4. e, d, b, a, c
  5. a, d, e, c, b

Question 24 . Which of the following represents the sequence of occurrence for the developmental stages?

  1. f, g, h, i, j
  2. j, h, i, f, g
  3. g, h, i, j, f
  4. g, i, h, j, f
  5. i, g, f, j, h


Instant Nursing Papers
Hire a Nursing Expert
Pages (550 words)
Approximate price: -

Why Choose Instant Nursing Papers?

Quality Nursing Papers

We assist students in achieving the best top-grade in their nursing papers, and in compliance with the provided instructions. Have your nursing paper written with a certified specialist Ph.D., Bachelor's, and Master's graduates with many years of experience in academic writing.

Experts with Ph.d., MDs and DNP Holders

Our writers have acquired Ph.D., MDs and DNP credentials from world class institutions. Our writers can handle papers from any discipline and can handle over 100+ subjects.

Nursing Papers Cheap

We provide a great deal of student-friendly prices and professionalism with all our nursing essay writing services. Our paper writing services have a user-friendly interface and professional nursing academic assistance. We are committed to assisting all students with their nursing assignments and projects regardless of their academic level.

Fast Paper Delivery

Our writers follow a strict schedule to ensure papers are delivered before the deadline to enable our editors to proofread before the final delivery to our customers. We strictly observe the early delivery of assignments to meet our clients' deadlines.

Plagiarism-free Nursing Papers

Our expert nursing paper writers are dedicated to conducting thorough research and writing papers from scratch to deliver original papers. To avoid paper plagiarism, all orders go through steps of writing, editing, and proofreading.

24Hour Customer Help

Our customer support is available 24/7/365 to help clients and make their paper writing services easy to use. Our experienced support team is available to answer your queries any time, 24 hours a day.

Try it now!

Calculate the price of your order

We'll send you the first draft for approval by at
Total price:

How it works?

Follow these simple steps to get your paper done

Place your order

Fill in the order form and provide all details of your assignment.

Proceed with the payment

Choose the payment system that suits you most.

Receive the final file

Once your paper is ready, we will email it to you.

Our Nursing Papers Writing Service

We provide Nursing Assignment Services to Nursing students. Also, we are not limited to providing Nursing assignment help to students only. We also provide assignment help and solutions to community health nursing, Anatomy & Physiology, Microbiology, Biochemistry and Biophysics, and Nutrition & Dietetics.


Nursing Essays

Sit back, relax while our writers sort you out on your most daunting nursing essay queries on how to write a good nursing essay. We got you if you are looking for the best nursing essay services.


Nursing Projects

It is no doubt that qualifying for a nursing career is difficult and requires a series of tests. Most nursing students must put in a lot of work in their assignments and coursework. will help you answer queries such as “who can write my nursing research paper?”.


Nursing Dissertation Help will save you the hustle of undergoing pressure or even depression while doing your nursing dissertation paper. Save yourself from all the long sleepless nights and pressure by working with our best nursing dissertation writing professionals.


Nursing Coursework Help

If you happen to hop into our site in search of nursing coursework help, look no further. We are the number one solution for the best nursing coursework assignments. Therefore, to complete the best APA nursing coursework, seek help from professional nursing coursework experts at