Biology Lab Shahimermaid

We have discussed and worked with cells and their functions at some length. Now we should have a look at how cells reproduce themselves by cellular division. There are two kinds of cell divisions: Mitosis, which happens in somatic cells, and meiosis, which takes place in gametes, the sex cells. There are number of differences between these two types of cell division, because we need to have different outcomes.

Meiosis requires two divisions to happen; after the first division, the two daughter cells are haploid. I have posted a special descriptive comparison between these two processes into the Summaries of Special Topics section under Conferences – PLEASE read it carefully!

Lab 6 – Meiosis

Before you begin your work, please read very carefully the Introduction in the Lab Manual and study Figure 1 carefully. You will then simulate four chromosomes by using snap beads (they are in your kit). You also need red and blue markers (not in your kit).

Then read carefully Meiosis I and build your four chromosomes. Take it step by step, and please review the importance of crossing-over during the tetrad formation. Then do Meiosis II , and then do the drawings of chromosomes during the four phases of Meiosis I and Meiosis II. Please be sure to write down the number of chromosomes and chromatids you are working with, and also provide a brief description at each step. Following that, you will answer nine questions about meiosis. Please read them very carefully, and do not make any assumptions! You should remember that each and every species has different numbers of chromosomes. For example, humans have 23 pairs, that is, 46 total number of chromosomes. Mice have 40 chromosomes, dogs have 76, giraffes have 30, and some plants have over 200 chromosomes. The number of chromosomes found in the cells of individual species, are the result of their individual evolutionary history. In our lab exercise, you are working with an imaginary species that has four chromosomes.

This is a fun exercise, and you may want to involve your children or other interested family members or friends.