5. 5
Procedure and Observations:
1. On a piece of paper, make a chart similar
to the one given below.
Head (H) Tail (h)
Total
Percentage
Ratio of the combinations
6. 6
Procedure and Observations:
2. Toss a coin. If a head comes up, mark
column 1; if a tail, then mark column 2.
Make 50 tosses of the coin.
3. Get the total number of times each face
of the coin appears. Calculate the percent-
tage of the appearance of each face. To
compute the percentage:
(total / 50) x 100 %
7. 7
Procedure and Observations:
Question 1.
What is the ratio of heads to tails?
4. Let us assume that the coin represents the
genotype of a parent, and each face is an
allele, with the head as the dominant
allele (H) and the tail as the recessive
allele (h).
Question 2.
What is the ratio of the gametes of this
parent with heterozygous genotype?
8. 8
Procedure and Observations:
5. On the same piece of paper, make a chart
similar to the one given below.
Head-Head
(HH)
Head-Tail
(Hh)
Tail-Tail
(hh)
Total
Percentage
Ratio of the
combinations
9. 9
Procedure and Observations:
6. Toss the two coins together. If a head-
head combination appears, mark column
1; if head-tail, mark column 2; and if tail-
tail, mark column 3. Make 50 tosses of
the coins.
7. Get the total number of times each com-
bination appears. Calculate the percent-
tage of the appearance of each combina-
tion. To compute the percentage:
(total / 50) x 100 %
10. 10
Procedure and Observations:
Question 3.
What is the ratio of a head-head, head-tail,
and tail-tail combination when you make 50
tosses?
Question 4.
If you toss the same coins in 100,000 times,
would you approximately get the same
ratio?
11. 11
Procedure and Observations:
Question 5.
Let the head (H) represent a dominant gene
and the tail (h), a recessive gene. Compare
the ratio you obtained in this activity with
the one obtained by Mendel in his mono-
hybrid F2 generation peas (see Table 3).
Are they approximately similar?
12. 12
Procedure and Observations:
Table 3. Results of Mendel’s crosses between hybrid plants
Characters
Studied
Hybrid
F2 Generation Produced
by Self-Pollinating F1
Hybrids
Observe
d Ratio
Seed shape Round Round Wrinkled 2.96:1
Seed color Yellow Green Yellow 3.01:1
Seed coat
color
Colored Colored White 3.15:1
Pod shape Inflated Inflated Constricted 2.95:1
Pod color Green Green Yellow 2.82:1
Flower
position
Axial Axial Terminal 3.14:1
Stem length Long Long Short 2.84:1
13. 13
Answer to the guide questions:
In the first part of the activity involving
a single coin toss, the students should
discover that because a coin has two sides
(Head and Tail), each side would have an
equal probability of coming up. Therefore, a
single coin tossed 50 times should have a
ratio of approximately 25 H: 25 T or 1:1. A
small deviation might be expected if the
result is not exactly 25:25 due to chance.
1. What is the ratio of heads to tails?
Answer:
14. 14
Answer to the guide questions:
Answer:
2. What is the ratio of the gametes of this pa-
rent with heterozygous genotype?
As with the coin toss exercise, this
parent would be able to produce two types
of gametes, one with H and the other with h,
each with equal probability of occurring.
15. 15
Answer to the guide questions:
Answer:
Assume that by tossing two coins, you
are crossing two heterozygote parents, and
each time the two coins face up, the
combination represents the genotype of the
offspring. Therefore, the expected ratio
should be ¼ HH, ½ HT and ¼ TT.
3. What is the ratio of a head-head, head-tail, and
tail-tail combination when you make 50 toss-
es?
16. 16
Answer to the guide questions:
Answer:
The ratio should remain the same even
if the number of tosses increases. In fact, as
the number of tosses increases, the closer
the results should be in approximating the
expected ratio.
4. If you toss the same coins in 100,000 times,
would you approximately get the same ratio?
17. 17
Answer to the guide questions:
Answer:
The results should approximate the
expected ratio of Mendel’s experiments
involving a single hybrid cross.
5. Let the head (H) represent a dominant gene
and the tail (h), a recessive gene. Compare the
ratio you obtained in this activity with the one
obtained by Mendel in his monohybrid F2 ge-
neration peas (see Table 3). Are they approxi-
mately similar?
