Biology Lab Report

4. Watch this animation of mitosis and answer the questions.

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http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__mitosis_and_cytokinesis.html

a. How many copies of the cells DNA are there at the beginning of mitosis?

-Two identical copies of each double stranded DNA molecule. These copies double irrespective of the total number of cells that are undergoing mitosis. Since mitosis is a continuous process, the formation of the two identical cells depends on the nature and characteristics of the cell which is the subject of the mitosis.

b. What is the function of microtubules?

Conveyor role-They move vesicles, granules, and other organelles through a special attachment of proteins. As a conveyor belt, microtubules transfer the organelles from one part of the cell to the other.

Cytoskeletal role- they act as linear polymers of tubulin; a globular protein. Polymers are the combination of several monomers. This role increases the strength of the cells as well as its maturity.

c. What are the names of the two result cells at the end of cytokinesis?

-chromatids; these are the two daughter cells that are formed after the cell splits in the process of cytokinesis.

5. Why do cells go through the cell cycle?

-Single cell fertilized eggs are able to develop into mature organisms. This is important as it helps the cells to multiply and become strong enough to perform their functions. Additionally, they become stronger and resistant to any external invasion.

-Hair, skin, blood cells, and other internal organisms are renewed. The renewal of the cells is important in ensuring that there is continued supply of cells. As a result, there can exist no deficit in the number of cells that are required art any given time.

Lab Procedure:

1. ONION ROOT (plant): Provided below are pictures of onion root tip slides. Above each picture, identify the stage of CELL CYCLE and below, write a brief description explaining your observations.

STAGES IN ONION ROOT:

Description: telophase

Two nuclei are formed almost at the centre of the slide.

Chromosomes at either side of the cell are beginning to cluster.

A new membrane is formed.

After cytokinesis, two separate cells are formed.

A cell plate is formed. Description: anaphase

The cells are pulling apart from the centre of the main slide.

The centromeres split.

The two daughters (sister chromatids) begin to migrate towards the opposite poles of the cell. Description: prophase

The chromosomes are visible but sporadic (not organized).

There is the formation of chromosome supercoil and the fibers of spindle apparatus between the chromosomes. Disintegration of the nuclear membrane.

Chromosomes migrate to the surrounding cytoplasm. Description: interphase

There is a dark mass of substance.

The cells are alternating.

They also become bigger and mature.

Each phase of the interphase has its specialized biochemical properties different from the other. Description:

Metaphase

Most of the chromosomes are lining up along the centre of the cell (equator)

There is the Concentration of the cells at the centre plane of the cell.

Works Cited

Highered.mcgraw-hill.com,. "Animation: Mitosis And Cytokinesis". N.p., 2016. Web. 8 Jan. 2016.