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Name______________________________________________Period__________Date______________
The Chromosomes of a Frimpanzee Lab
Introduction
In the last unit you created your Frimpanzees. You showed how DNA coded for an amino acid chain or
protein and that this protein is seen as a trait.
DNA
mRNA
amino acids (protein)
trait
This unit is all about reproduction. Frimpanzees grow by making identical cells. Mitosis is a form of
asexual reproduction that allows organisms to grow and make identical cells. When frimpanzees are
grown they reproduce sexually. To do this they must create sex cells called gametes. Frimpanzees do
not give all of their chromosomes to their offspring. They only give half. During fertilization the baby gets
half of its chromosomes from its mom and the other half from its dad. The process of creating sex cells
with half the number of chromosomes is meiosis.
Recap:
 Mitosis – creates diploid body (somatic) cells – for growth. Cells are identical to parent
 Meiosis – creates haploid sex cells (gametes) – for reproduction. Cells have half the number of
chromosomes.
 Fertilization – two haploid sex cells (egg and sperm) join to form a diploid cell (start of a baby).
The purpose of this activity is to see how mitosis and meiosis occurs in Frimpanzees. To do this we will
use colored paper to make models of the chromosomes in a cell of your Frimpanzees. Frimpanzees have
a total of 6 chromosomes per cell.
Part 1 - Making your chromosome models
1. Your teacher will tell you if you have a boy or a girl frimpanzee. If you have a boy you will work
with blue chromosomes. If you have a girl you will work with pink chromosomes.
2. Each partner should fold the sheet of chromosomes in half lengthwise (along the solid line).
3. Keeping the sheet folded, cut on the dotted lines – Keep the three folded pieces of paper that have
a shape that looks like <.
You should end up with 6 pieces that have the < shape. For now keep them folded. These are the
chromosomes in a normal Frimpanzee cell.
1. What does the folded model represent ( < )?
__________________________________________
2. Draw in the centromeres on the folded models. How many chromosomes does the
Frimpanzee have? __________
For each trait below, circle the one that represents your Frimpanzee:
Straight Hair (Aa)
or
Curly hair (aa)
No Spots (Bb)
or
Spots (bb)
Long nose (Cc)
or
Short nose (cc)
No antennae (Dd)
or
2 antennae (dd)
Blue skin (Ee)
or
Yellow skin (ee)
Pointy Ears (Ff)
or
Floppy ears (ff)
Notice there are letters written next to each trait. These letters represent the genes on the chromosomes.
Now write the appropriate letters on one side only of your folded chromosome. Use the following example
to help you.
Let’s say your Frimpanzee has straight hair (Aa), spots its skin (bb), a short nose (cc), 2 antennae (dd),
blue skin (Ee) and pointy ears (Ff). You would write the following letters on your chromosomes:
A & B genes are
on the large
chromosomes.
C & D genes are
on the medium
chromosomes.
E & F genes are
on the small
chromosomes.
3. Notice for every trait there are two copies. One of the copies comes from _____________
and the other copy comes from __________________.
4. We are now going to complete Interphase. Unfold the chromosome so that it is in the shape
of an X. What is the name of the process that the unfolding would represent?
_________________________________
5. Extend the centromeres onto the other side of the unfolded models. How many
chromosomes does the frimpanzee have now? __________ How many sister chromatids?
_____________
6. Write in the same exact letters on the other half of the X. Remember when DNA copies it
makes an exact copy of itself.
7. Your Frimpanzee is young and needs to grow and mature. S/he has to make new cells that are
identical to the other cells. In order to make more cells mitosis must occur. Follow the mitosis
directions to fill in the chart below.
Part 2 – Mitosis
Mitosis
Interphase
Prophase
# of Chromosomes = 6
# of Chromosomes =
Metaphase
Anaphase
# of Chromosomes =
# of Chromosomes =
Telophase/Cytokinesis
# of Chromosomes per cell = ___________
Are the cells produced by mitosis identical to the original cell or different? _____________
Part 3: Modeling Meiosis – Follow the steps on the instruction sheet and draw the chromosomes in
below. YOU DO NOT HAVE TO WRITE THE LETTERS ON THE CHROMOSOMES FOR EACH PHASE.
JUST DRAW THE CHROMOSOMES OF DIFFERENT SIZES.
Meiosis I
Prophase I Telophase I/Cytokinesis
# of Chromosomes = ___________
# of Chromosomes = ___________
Meiosis II
Prophase II
# of Chromosomes per cell = ________
Telophase II/ Cytokinesis
# of Chromosomes per cell = ___________
1. Look at all 4 cells. Are the same exact letters written on all four cells?
2. Which process, mitosis or meiosis, allows for genetic diversity (differences)? _______________
3. In humans we have 46 chromosomes. 23 chromosomes come from mom and 23 come from
dad. Frimpanzees have 6 chromosomes. How many chromosomes will each Frimpanzee
parent give to its baby?____________
Part 4 – Fertlization
Now choose ONE of your four sex cells (gametes). You can put the other sex cells aside. Your teacher
will have two groups join sex cells. Place the chromosomes you received from the other group with the
chromosomes from your sex cell. This represents random fertilization. Random fertilization is another
thing that leads to genetic diversity.
4. What is the male sex cell (gamete) called? ______________ female sex cell ________________?
5. Fill in the chart below with the traits of your new offspring.
Trait
Type of hair (A)
Letters of the Baby
Trait Baby Received
Spots on skin or no spots (B)
Type of nose (C)
Antennae (D)
Color of Skin (E)
Type of Ear (F)
6. Who does the baby look more like, mom or dad, or is the baby a nice blend between the two
parents? _____________________________________________________________
7. Are there any traits that neither of the parents have but the baby has? (Ex: Baby has yellow
skin but both parents have blue skin) ___________. How is it possible for the
baby to show a trait that neither parents show? _____________________________________
Extension Activity
Using your baby Frimpanzee work backwards to determine the DNA sequence for each trait
Does your Frimpanzee have straight or curly hair?
GENE
A
Does your Frimpanzee have spots on its skin?
GENE
B
Trait
Trait
Amino Acids
Amino Acids
mRNA
mRNA
DNA
DNA
Does your Frimpanzee have a long or short nose?
GENE
C
Does your Frimpanzee have antennae or not?
GENE
D
Trait
Trait
Amino Acids
Amino Acids
mRNA
mRNA
DNA
DNA
Does your Frimpanzee have blue or yellow skin?
GENE
E
Does your Frimpanzee have pointy or floppy ears?
GENE
F
Trait
Trait
Amino Acids
Amino Acids
mRNA
mRNA
DNA
DNA
Part 3 Meiosis Instructions.
Prophase I – On your desk take a piece of yarn and form a circle. This circle represents the nucleus.
Place the chromosomes inside the yarn circle and arrange them by size by placing the same size
chromosomes next to each other.. Chromosomes that are the same size with the same type of genes are
called homologous chromosomes. These chromosomes are still inside the nucleus but the nucleus is
beginning to break down.
Metaphase I – Remove the yarn from the desk. Move the homologous chromosomes so they line up in
the middle of your desk. The same size chromosomes should be right next to each other forming a double
file line down the center of the desk.
Anaphase I – Move the homologous chromosomes apart to opposite sides of the desk. The entire X
moves to the other side of the desk.
Telophase I / Cytokinesis- Take two pieces of yarn and form two circles around the chromosomes on
opposite sides of the desk. Two new cells form.
MEIOSIS II - This will be a separate process in each of the two new cells. Place a piece of yarn down the
center of the desk to represent the separation of each of the cells. One partner will work with one set of
chromosomes on one side of the desk and the other partner works with the other set.
Prophase II – Create a yarn circle to represent the nucleus. Place the chromosomes you are working
with inside the yarn circle. The chromosomes are inside the nucleus.
Metaphase II – Remove the yarn circle. Line the chromosomes up single file in the middle portion of your
part of the desk. .
Anaphase II - Chromosomes split at centromere. Cut each one of your chromosomes in half through the
centromere. Now move the chromatids to opposite sides of your portion of the desk.
Telophase II - Create two yarn circles around the chromosomes on your part of the desk. Two new cells
form. However remember your partner is doing the same things so you should have total of 4 cells on
your desk. These cells are called gametes - they are the sex cells that will become either frimpanzee
sperm or egg cells.
Part 2 – Mitosis Instructions
Interphase – Create a yarn circle to represent the nucleus. A major step during this phase is DNA
replication. I have drawn the picture of interphase for you. Remember DNA appears as chromatin during
this phase.
Prophase –Place the chromosomes you are working with inside the yarn circle. The chromosomes are
inside the nucleus.
Metaphase – Remove the yarn circle. Line the chromosomes up single file in the middle portion of your
part of the desk. .
Anaphase - Chromosomes split at centromere. Cut each one of your chromosomes in half through the
centromere. Now move the chromatids to opposite sides of your portion of the desk.
Telophase - Create two yarn circles around the chromosomes on your part of the desk. Two new cells
form.
Before replacing your chromosomes back inside of the baggie, tape the chromosomes back together at
the centromere and fold them in half.