Download Chromosome Lab Activity 2 Instructions

ETHC 210
CHROMOSOME LAB ACTIVITY 2 INSTRUCTIONS:
Constructing and Thinking about Chromosomes
Introduction:
In this lab, you will complete the mitosis and meiosis simulations. Both of these processes are
part of the stage of cell division called karyokinesis. Karyokinesis is just one phase of cell
division and is defined as the division (or reproduction) of the genetic material, or we could say
the division (reproduction) of the nucleus. The second phase of cell division is called cytokinesis
and involves the division of the cytoplasm.
In most multicellular organisms, mitosis dominates as the most abundant nuclear division
process. It is essentially part of a copying process whereby tissue cells are replaced or
regenerated, for instance, in the replacement or growth of cardiac muscle, neurons in the brain,
or skin cells.
Meiosis is the nuclear division (reproduction) process only found in gametes or the “sex cells,”
which are the egg and sperm cells of sexually reproducing organisms. It is also a reducing
process at the same time that it is a reproduction process. What does this mean? It’s a reducing
process since egg and sperm cells are created with half the number of chromosomes. Why does
this occur? This reduction occurs so that when the egg and sperm fuse to make the new
individual, the original number of chromosomes is restored.
Also during meiosis, two processes which lead to genetic variability occur: crossing over of
chromosomes (which we explored briefly in Chromosome Lab Activity 1) and separation of
homologous pairs of chromosomes. The overall process of meiosis begins with a single diploid
pre-gamete cell, which in humans contains 46 chromosomes, and the end result is four haploid
gamete cells, each containing 23 chromosomes.
To simulate meiosis in our lab, you will use 2 chromosomes (1 yellow and 1 red) to represent the
diploid condition and 1 chromosome to represent the haploid condition. At the end of meiosis,
the result will be 4 haploid cells containing only 1 chromosome. To help you visualize this, look
at the sketch below (also view Figure 3.3 in the Lewis text). You will see a single diploid cell
with 2 chromosomes. Crossing over will occur before the first division (meiosis I), and then
there is a second cell division (meiosis II) resulting in 4 haploid cells. In the third activity, you
will be looking at chromosome misregulation or nondisjunction. This occurs when chromosomes
fail to separate from one another. It will be helpful to look at Figure 13.12 in the Lewis text.
In this lab, you will be constructing chromosomes from a kit from Carolina Biologicals. Follow
the instructions as stated for construction of the chromosomes, then answer a series of short
answer questions and write a short essay (see assessment below).

Supplies needed
o Meiosis and Mitosis Chromosome Simulation Kit, Carolina Biological Supply
o String, short rope, or masking tape to make outline of nucleus
o Phone/tablet/computer camera, or digital camera
Page 1 of 3
ETHC 210
Reading:

Lewis text: chs. 2–3 (Sections 2.1, 2.3, 3.3 [especially Figure 3.3]), and ch. 13, pp. 245–
246 (especially Figure 13.12)

Carolina Distance Learning Investigation Manual: Mitosis and Meiosis: Chromosome
Simulation, pp. 11–24
Activity:
Construct and observe the chromosomes within the nucleus. To do this, follow the instructions in
the Carolina Distance Learning Investigation Manual Activities 1–3. Complete activities 1–3.
Assessment:
Take 2 photos, 1 of each of the end results of Activity 2 and Activity 3. Each of the following
questions involves a 1 or 2-word answer. Upload your answers as 1 or 2-word answers and
number them 1–10. Also, upload your photo with your answers. See instructions below for the
short essay.
Short Answer and Photos (10 pts for answers and 15 pts for photos =25 pts)
1. Aneuploidy is a condition whereby cells are missing a chromosome or have an extra
chromosome. This occurs because of the process of chromosomes NOT separating called
_____________________________.
2. The nuclear division process which contributes to the formation of two diploid cells is called
__________________.
3. The nuclear division process which contributes to the formation of four haploid gamete
daughter cells is called__________________.
4. Mitosis is a karyokinesis process which in humans occurs primarily in ________________
cells (biological term for non-gamete tissue cell).
5. During Interphase 1 of meiosis, similar chromosomes line up together. When they do this they
are called ______________________ pairs.
6. Gametes in humans contain half the number of cells compared to somatic cells and therefore
they are classified as being _______________ cells.
7. The sperm and the egg are haploid cells and in general they are called ___________________.
8. Trisomy 21 or Down’s syndrome occurs during a nondisjunction event which results in
gametes with _______________ copies of the same chromosome (answer is a number).
9. When homologous pairs of chromosomes exchange parts during meiosis this is called
_________________ __________________ (2 words).
10. The diploid pre-egg or pre-sperm cell which undergoes meiosis was originally created by the
karyokinesis process called________________________.
Page 2 of 3
ETHC 210
Short Essay (25 pts):
Investigate a nondisjunction-based human illness or genetic condition and describe the condition
and chromosomes affected if known. The short essay must be 100–140 words and demonstrate
course-related knowledge. The short essay must include 1 citation from the Bible and 1 outside
source other than your course textbook cited in current Turabian format. (References are not
included in the final word count.)
Submit this assignment by 11:59 p.m. (ET) on Monday of Module/Week 2.
MEIOSIS DIAGRAM
diploid condition = two chromosomes
Page 3 of 3