Download Bio Lab Rebop Genetics

Biology
Genetics Unit
Name _______________________________
Period _________ Date _________________
Rebop Genetics
Rebops are ferocious imaginary animals that feed on cute furry puppies. They are prolific and require minimal
care. In this activity, you and a partner will perform a genetic cross to make a baby Rebop. After carrying out
the genetic cross, you will construct your baby Rebop. In the process, you will model the process of meiosis
and fertilization, and demonstrate the relationship between genotype and phenotype. Lastly, after the Rebops
are born, the Rebop siblings will be assembled together in the nursery to be analyzed.
Objectives:



To understand the relationship between chromosomes, genes, and alleles
To use genotype to find phenotype
To understand how genetic information is passed from parent to offspring
Pre-Lab Questions:
1. What are chromosomes? _______________________________________________________________
2. What is a gene? ______________________________________________________________________
3. What is an allele? _____________________________________________________________________
4. What is the difference between genotype and phenotype? ____________________________________
___________________________________________________________________________________
5. Circle the genotype that represents a heterozygous genotype:
TT
Tt
tt
Procedure:
Getting Started!
1. Remove all of the chromosomes from the bag. One partner should take the blue chromosomes (this
partner will be the father) and the other partner take the pink chromosomes (this partner will be the
mother).
2. Place the chromosomes face down so the letters do not show and arrange them in pairs based on size
(there should be eight pairs of the same size chromosomes for both the male and female).
Time to Reproduce!
3. Without turning the chromosomes over, the “father” should pick one BLUE chromosome from each pair
and set them aside. The “mother” should pick one PINK chromosome from each pair and set them
aside. Place all chromosomes NOT picked back into the parent bag and set aside.
4. Combine the piles from the two parents. Form new pairs by matching the BLUE and PINK
chromosomes based on size. You and your partner should end up with eight pairs of chromosomes,
each pair should have one BLUE and one PINK chromosome.
What a Beautiful Baby!
5. Turn over the blue and pink pairs of chromosomes. These represent a new baby. Record the alleles
contributed by the father and the mother in the table under the results section. Also record the
genotype and phenotype (use the Key to Traits to help with this) and state whether the genotype is
homozygous or heterozygous.
6. After filling out the table, return all chromosomes to the bag.
7. Based on your phenotypes and the Key to Traits table below, construct your baby Rebop.
Analysis and Clean Up
8. Place your baby Rebop in the “nursery” with its siblings for analysis.
9. Answer the analysis questions on a separate sheet of paper in COMPLETE SENTENCES.
10. Deconstruct your baby Rebop and put away in the proper containers when instructed.
Key to Traits:
Antenna (toothpicks)
AA = 2 antenna
Aa = 1 antennae
aa = No antennae
Tail Style (Pipe Cleaner)
TT or Tt = Curly tail
tt = Straight tail
Gender (Yarn)
XX = Female (include hair)
XY = Male (no hair)
Humps (Green mini-mallows)
Nose Color (Mini-mallows)
MM = 1 green hump
QQ = Red nose
Mm = 1 green + 1 white hump
Qq = Orange nose
mm = 1 white humps
qq = Yellow nose
Eye Number (Clear Push Pins)
Leg Color (Push Pins)
EE or Ee = 2 eyes
LL or Ll = Blue legs
ee = 3 eyes
ll = Green legs
Body Segment Number (Big mallows)
DD or Dd = 2 body segments
dd = 3 body segments
Results:
Trait
Allele
from
Father
Allele
from
Mother
Genotype
Homozygous or
Heterozygous
Phenotype
Antenna (A, a)
Nose (Q, q)
Eyes (E, e)
Body Segment (D, d)
Humps (M, m)
Tail (T, t)
Legs (L, l)
Gender (X, Y)
Analysis:
1. At the beginning of the activity, you were given a set of chromosomes that belonged either to the
mother or to the father Rebop.
a. How many chromosomes are in the Rebop genome?
b. How many pairs of homologous chromosomes do Rebops have?
c. What does it mean for the chromosomes to be homologous?
d. Are Rebops diploid or haploid? Explain how you know.
2. In Step 3 you took one chromosome from each homologous pair and set them aside in a pile.
a. Which of Mendel’s laws is demonstrated in this step?
b. In the real world, what is this process, which reduces the chromosome number in half, called?
c. What type of cells result from this process?
d. How many chromosomes are in each cell resulting from this process (in Rebops)?
e. Are these gamete cells diploid or haploid? Explain how you know.
3. In Step 4 you combined the two piles together in order to produce an offspring.
a. In the real world, what is the name of the process where the male and female gametes
combine?
b. What is the name of the cell resulting from this combination?
c. How many chromosomes are in this cell (in Rebops)?
d. Is this cell diploid or haploid? Explain how you know.
4. Explain why the baby Rebop is similar to both parents, but not identical to either one.
5. The traits for tail style, eye number, leg color, and number of body segments demonstrate the
traditional or “simple” inheritance pattern identified by the scientist Mendel (highlight these on your
table above). Identify the traits that don’t follow this pattern and in your own words describe how the
phenotypes were affected by the combination of alleles.