Biology 9 Lesson 6: Practice Calculating the probability of occurrence of faces of metallic copper
1. Theoretical Summary
1.1. Experiment purpose
– Know how to determine the probability of one and two events occurring simultaneously through the seeding of metals.
– Know how to use probability to understand the ratio of gametes and the ratio of genotypes in a pair of traits
1.2. Laboratory instruments
Have each student or group prepare two coins
2. Contents of progress
2.1. Sow a metal coin
Note: Metal copper has 2 faces (heads and tails), each side represents a type of gamete, for example, the tail shows type A gamete, the face up indicates gametophyte type a, proceed:
– Take 1 metal coin, hold it next to it and drop it freely from a specified height.
– Statistical results each time falling into table 6.1
Table 6.1: Statistics of the result of sowing a metal coin
2.2. Sow two metal coins
– Each group sows 25 times, there can be 3 cases: 2 heads (SS), 1 head, 1 head (SN), 2 heads (NN).
- Take 2 metal coins, hold them next to them and drop them freely from a specified height.
- Statistical results of each fall and compare the percentage of times of each possibility mentioned above in the sample table 6.2 and relate this result to the genotypic ratio F2 cross a pair of traits, explaining the similarity.
Table 6.2. Statistics of the results of sowing two metal coins
3. Practice report
3.1. Statistical results of groups
a. Sow a metal coin
– The odds of appearing heads: heads when rolling metal coins is approximately 1:1
– As the number of times to sow metallic copper increases, the ratio is closer to 1:1
– When an F hybrid has genotype Aa, meiosis gives two types of gametes carrying genes A and a with equal probability.
– Relate the above result to the ratio of gametes of F . hybrid organismfirst (Aa) Mendel’s experiment:
In the case of explaining Mendel’s one-pair crossbreeding experiment, we see that the hybrid Ffirst having KG Aa when meiosis will produce 2 types of gametes carrying A and a with equal probability, that is, in the process of crossing 1 pair of traits, in the F generationfirst the ratio of 2 traits can appear equally and when expressed together in phenotype, we can analyze the dominant recessive trait in Ffirst and F2
⇒ Excellent formula: P(A) = P(B) = 1/2 Or 1A:1a
b. Sow two metal coins
– The odds of spawning 2 coins are approximately 1:2:1
– As the number of times the metal is sown increases, the ratio is closer to 1:2:1 or 1/4: 1/2:1/4
– Explain according to the formula for calculating probability:
- P(AA)=1/2.1/2= 1/4
- P(Aa)= 1/2.1/2= 1/4
- P(Aa)= 1/2.1/2= 1/4
- P(aa)= 1/2.1/2= 1/4
– Therefore, we have the ratio: P(AA): P(Aa): P(aa) = 1/4AA: 1/2 Aa: 1/2aa
– Similarly, we have: the proportion of F1 gametes with genotype AaBb is:
- P(AB) = P(A). P(B) = 1/2. 1/2 =1/4
– The same, similar:
- P(aB) = P(a). P(B) = 1/4
- P(Ab) = P(A). P(b) = 1/4
- P(ab) = P(a). P(b) = 1/4
So the ratio at F2 is determined by the union of 4 types of male gametes with 4 types of female gametes in equal numbers:
(AB, Ab, aB, ab). (AB, Ab, aB, ab) is 9:3:3:1
This is because the pairs of genes segregate independently during gametogenesis and freely combine during fertilization.
After completing the knowledge of the lesson Calculating the probability of the occurrence of faces of this metal, you need to:
– Determine the probability of one and two events occurring simultaneously through the tossing of coins.
– Use probability to understand the ratio of gametes and the ratio of genotypes in a pair of traits.