Ureaseis an enzyme used by plants to break down (a nitrogen-containing compound) into carbon dioxide and...

    

Transcribed Image Text:

Ureaseis an enzyme used by plants to break down (a nitrogen-containing compound) into carbon dioxide and ammonia. Plants need nitrogen to grow and can obtain it from ammonia, but not from urea. In soybean plants there are 2 different kinds of urease, one produced in the seeds and the other produced in the leaves of the plant. Mutations in th chromosomes of the soybean can stop production of either enzyme. In the following experiments, 3 types of soybean plants were used: normal soybeans and 2 mutant strains, lacking the seed urease (Strain 1) and 1 lacking the leaf urease (Strain 2). Experiment 1 Separate areas in a field were planted with normal, Strain 1, and Strain 2 soybeans. All types of soybeans appeared to grow, flower, and produce seeds equally well. There were no externally detectable differences among the strains. Experiment 2 Small pieces of plant tissue of equal weight were obtained from each type of soybean plar and separately placed on media in culture dishes. Tissue growing in this way will become an unorganized clump of cells referred tass. To provide a controlled nitrogen source, half the tissue samples of each type were placed on media containing urea, and the other half the samples were placed on media containing ammonia. After 30 days, the weight gain for each of the callus samples was determined. Results are shown in the table below. Plant type Urea Normal 150 Strain 1 Weight gain (mg) Ammonia 180 155 160 Strain 2 50 170 Question are related to this Passage above 1. Which of the following not describes the role of urease in the plants grown in the field? A. Urease activity in leaves is not essential for soybean growth. B. Urease activity in seeds is not essential for soybean growth. C. Urease breaks down into carbon dioxide and ammonia. Ureaseis an enzyme used by plants to break down (a nitrogen-containing compound) into carbon dioxide and ammonia. Plants need nitrogen to grow and can obtain it from ammonia, but not from urea. In soybean plants there are 2 different kinds of urease, one produced in the seeds and the other produced in the leaves of the plant. Mutations in th chromosomes of the soybean can stop production of either enzyme. In the following experiments, 3 types of soybean plants were used: normal soybeans and 2 mutant strains, lacking the seed urease (Strain 1) and 1 lacking the leaf urease (Strain 2). Experiment 1 Separate areas in a field were planted with normal, Strain 1, and Strain 2 soybeans. All types of soybeans appeared to grow, flower, and produce seeds equally well. There were no externally detectable differences among the strains. Experiment 2 Small pieces of plant tissue of equal weight were obtained from each type of soybean plar and separately placed on media in culture dishes. Tissue growing in this way will become an unorganized clump of cells referred tass. To provide a controlled nitrogen source, half the tissue samples of each type were placed on media containing urea, and the other half the samples were placed on media containing ammonia. After 30 days, the weight gain for each of the callus samples was determined. Results are shown in the table below. Plant type Urea Normal 150 Strain 1 Weight gain (mg) Ammonia 180 155 160 Strain 2 50 170 Question are related to this Passage above 1. Which of the following not describes the role of urease in the plants grown in the field? A. Urease activity in leaves is not essential for soybean growth. B. Urease activity in seeds is not essential for soybean growth. C. Urease breaks down into carbon dioxide and ammonia.