Name___________________ Class______________ Date________
Write true if the statement is true or false if the statement is false.
F 1. A homozygous individual could have a Bb genotype.
T 2. In Mendel's experiments, purple flowers are dominant over white flowers.
F 3. Heredity is the science of genetics.
T 4. In Mendel's initial experiments, white flowers disappeared after the first parental crosses.
F 5. It was his knowledge of genes that allowed Mendel to interpret his data correctly.
T 6. Having naturally light or dark skin is part of your phenotype.
T 7. Different alleles account for much of the variation in the characteristics of organisms.
T 8. Mendel showed that factors controlling different characteristics are inherited independently.
T 9. Mendel came up with the idea that two factors control a characteristic, such as pod color.
F 10. Mendel developed three laws of inheritance.
F 11. The expression of an organism’s phenotype produces its genotype.
F 12. After he published his work, Mendel achieved great fame among scientists.
F 13. Through his experiments, Mendel was able to prove some aspects of the blending theory of inheritance.
T 14. A Dd genotype has two different alleles.
T 15. Flowers are the reproductive organs of plants.
Lesson 6.1: Critical Reading
Name___________________ Class______________ Date________
Read these passages from the text and answer the questions that follow.
Mendel’s First Set of Experiments
At first, Mendel experimented with just one characteristic at a time. He began with flower color. As shown in the figure below, Mendel cross-pollinated purple- and white-flowered parent plants. The parent plants in the experiments are referred to as the P (for parent) generation.
This diagram shows Mendel’s first experiment with pea plants. The F1 generation results from cross-pollination of two parent (P) plants. The F2 generation results from self-pollination of F1 plants. (Image courtesy of CK-12 Foundation and under the Creative Commons license CC-BY-NC-SA 3.0.)
F1 and F2 Generations
The offspring of the P generation are called the F1 (for filial, or “offspring”) generation. As you can see from the figure above, all of the plants in the F1 generation had purple flowers. None of them had white flowers. Mendel wondered what had happened to the white-flower characteristic. He assumed some type of inherited factor produces white flowers and some other inherited factor produces purple flowers. Did the white-flower factor just disappear in the F1 generation? If so, then the offspring of the F1 generation — called the F2 generation — should all have purple flowers like their parents. To test this prediction, Mendel allowed the F1 generation plants to self-pollinate. He was surprised by the results. Some of the F2 generation plants had white flowers. He studied hundreds of F2 generation plants, and for every three purple-flowered plants, there was an average of one white-flowered plant.
Law of Segregation
Mendel did the same experiment for all seven characteristics. In each case, one value of the characteristic disappeared in the F1 plants and then showed up again in the F2 plants. And in each case, 75 percent of F2 plants had one value of the characteristic and 25 percent had the other value. Based on these observations, Mendel formulated his first law of inheritance. This law is called the law of segregation. It states that there are two factors controlling a given characteristic, one of which dominates the other, and these factors separate and go to different gametes when a parent reproduces.
Questions
1. What did Mendel do in his first experiment? Only test the one charasteric of plant which was color.
2. What was the outcome of the F1 generation in Mendel's first experiment? All were purple.
3. What was the outcome of the F2 generation in Mendel's first experiment? Foe every three purple flowers there was one white flower.
4. Did Mendel repeat his initial experiment with