| A | B |
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| With what type of plants did Gregor Mendel conduct his experiments on inheritance? | He used pea plants that were true-breeding. |
| What is meant by "true-breeding"? | This refers to plants like peas tht if allowed to self-pollinate wil produce off-spring identical to themselves. |
| How did Mendel prevent self-pollination in the pea plants he used in his experiments? | He carefully cut away the pollen-bearing male parts. |
| What did Mendel do to cross-pollinate his pea plants? | After cutting away the pollen-bearing male parts of one plant, he dusted pollen from another plant onto the other flower. (this process = cross-pollination) |
| What were the 7 traits in pea plants studied by Mendel? | The shape [of: seed & pod (traits 1 &2)]; color [of the seed, seed coat, & pod (traits 3,4,5)]; flower position (6); plant height (7). Remember: shape, color, position, height. |
| Define "trait". | It's a specific characteristic that varies from one individual to another (for example, seed color or plant height). |
| What is meant by the "first filial"? | It refers to the first generation of offspring from a P (parental) generation. |
| To what does the word "hybrid" refer? | It refers to the offspring of crosses between parents with different traits. |
| In Mendel's experiments, what did he see (phenotype) in the first generation offspring? | The offspring had the character of only one of the parents. The character of the other parent did not appear! |
| What 2 conclusions did Mendel make after seeing the F1 generation? | 1) Biological inheritance is determined by factors passed from one generation to another to the next (genes) 2) Principle of dominance: some alleles (the different forms of a gene) are dominant and others are recessive. |
| Why did Mendel produce a second filial generation F2? | He wanted to see if the recessive alleles had disappeared completely, or whether the alleles were still present in the F1 generation. |
| How did Mendel answer his questions about recessive alleles in the first filial generation? What was the result? | He let all 7 kinds of F1 plants self-pollinate. He saw that the traits controlled by recessive alleles reappeared in about 1/4 of the F2 generation. |
| How did Mendel explain the phenotypes of the F2 generation? | When each F1 plant flowers & produces gametes, the 2 alleles (1 for tallness; 1 for shortness) segregate from each other so each gamete carries a single copy of each gene. So, each F1 plant produces 2 types of gametes (1 for tallness; 1 for shortness) resulting in an F2 generation with a new combination of alleles. |
| What is meant by probability? | It is the likelihood that a particular event will happen. |
| How do you calculate probability? | See the example of the coin toss on pg. 267. This is important because Mendel concluded that the principles of probability could be used to predict the results of genetic crosses. |
| What is a Punnett square? | It's a diagram showing the gene combinations that might result from a genetic cross. (see example pg. 268). They're used to predict and compare the genetic variations that will result from a cross. |
| What do the letters ina Punnett square represent? | They stand for alleles. |
| What is the difference between homozygous and heterozygous plants? | Homozygous plants have 2 identical alleles for a particular trait; heterozygous plants have 2 different alleles for the same trait. |
| Explain the difference between the phenotype and genotype of a plant. | Phenotype refers to the physical characteristics of a plant (what is seen); genotype refers to the genetic makeup of the plant. |
| What does the ration of 3:1 mean? | It means 3 dominant to 1 recessive alleles.ss |
| Fo probabilities predict exact ratios? | No; they predict averages. (see pg. 269) |
