Exam 1: Biology

Dutch elm disease is a fungal infection of elm trees that usually results in death.The disease has killed millions of NorthAmerican elm trees that were not resistant to the fungus. Scientists have bred resistant elms by crossing North American species with Asian species that show resistance.Which of the following best describes how natural selection would promote resistant elm populations once the resistance genes from the Asian species were successfully introduced?

Fatty acids are one of the products that result from the action of lipase in the digestive system. What is one way that atty acids are used in the body?

Hemoglobin is a protein that carries oxygen in red blood cells. The hemoglobin molecules produced by some people have one specific amino acid that is different from the amino acid at that position in normal hemoglobin.Which of the following is the most likely cause of this amino acid variation?

In sheep, the allele for white wool (W) is dominant, and the allele for black wool (w) is recessive. A farmer has mated two Suffolk sheep for a few years. These matings have resulted in six offspring, four with white wool and two ith black wool. One parent has white wool and the other has black wool.Which of the following could be the genotypes of the parent sheep?

The mold Aspergillus flavus grows on grain. A. flavus produces a toxin that binds to DNA in the bodies of animals that eat the grain. The binding of the toxin to DNA blocks transcription, so it directly interferes with the ability of an animal cell to do which of the following?

The Asian shore crab invaded parts of the eastern coast of the United States about 15 years ago. The Asian shore crab preys on blue mussels. In the time since the Asian shore crab arrived, the average shell thickness has increased in the blue mussel population.Which of the following is the most likely reason that this increase in shell thickness has occurred?

Some bacteria live in hot springs. Their cells contain enzymes that function best at temperatures of 70°C or higher.At a temperature of 50°C, how will the enzymes in these bacterial cells most likely be affected?

Which of the following statements gives the most likely explanation for the presence of two very similar species of squirrels living on opposite sides of the Grand Canyon?

In July, a student tested the soil in two plots and calculated the concentration of nitrogen compounds present in each plot. The student then planted 20 seedlings in the first plot and allowed them to grow. Nothing was planted in the second plot. The student tested the soil in both plots again after one month. The concentration of nitrogen compounds had decreased in the first plot but had remained the same in the second plot. Which of the following best explains the decrease in nitrogen compounds in the first plot?

Which of the following elements is most common in the tissues of plants?

All organisms classi?ed in kingdom Animalia must also be classi? ed as which of the following?

During the fall reproductive season, the belly of a male brook trout becomes bright orange. The orange belly provides some camou?age and helps attract females. This trait evolved in brook trout because, compared to males with pale bellies, males with bright orange bellies are more likely to

According to Mendel's law of segregation, which of the following statements describes what happens to the alleles of a gene pair?

Which of the following statements best describes the relationship of the kidneys and the liver to the circulatory system?

In the deserts of the southwestern United States, rock formations made from lava flows are found scattered across the sand. The rock pocket mouse, which has dark fur, lives on the black lava rocks. The Apache pocket mouse, which has light fur, lives on the tan sand.Which of the following statements best explains how these two types of mice could have evolved from a common ancestor?

Which of the following human activities reduces biodiversity?

In red blood cells, the compound carbonic anhydrase increases the rate at which carbon dioxide is converted to bicarbonate ions for transport in the blood. In red blood cells, carbonic anhydrase acts as which of the following?

Fertilizers can enable farmers to grow the same crop in a ?eld for several years in a row. Farmers who use less fertilizer often rotate their crops by planting the crop one year and legumes, such as beans and clover, the following year. Fertilizer use and crop rotation with legumes both increase the availability of which of the following nutrients in soil?

Populations of Caribbean coral have decreased significantly over the past 30 years due to disease. Which of the following is most likely a major factor leading to the increased amount of disease in the coral?

Starting in 1954, commercial fishers in the northwest Pacific were paid by weight, rather than by the individual fish, for pink salmon. The fishers increased the use of a type of net that selectively catches larger fish. Which of the following effects did this change in fishing techniques most likely have on the salmon population over the next 20 years?