Biology STAAR 2016

1 The four butterflies in the illustrations represent the offspring in the F 1 generation. Which statement is best supported by the phenotypes of these offspring?

• The F1 generation is composed only of males.

• Two of the offspring in the F1 generation will not be able to reproduce.

• The F1 generation is the result of a dihybrid cross.

• Two of the offspring in the F1 generation will experience a spontaneous mutation.

2 The 1918 influenza epidemic killed between 50 million and 100 million people worldwide. This epidemic happened near the end of World War I. More people died from the influenza epidemic than were killed in the war. Which of the following explains why this virus was so deadly worldwide?

• Infected soldiers returning from the war spread the virus when they coughed.

• Food was scarce because of the war, so people were undernourished, and their immune systems were weakened.

• Medical personnel often became ill as a result of exposure to airborne virus particles.

• All of the above

3 The amount of energy the producers in this energy pyramid provide the primary consumers is 54,000 joules. From this amount, 540 joules are provided to the tertiary consumers.

Based on this model, how much of the energy was provided to secondary consumers?

• 53,460 J

• 5,400 J

• 540 J

• 54 J

4 The survival of a species depends on its ability to adapt to changes in the environment. A species must be capable of surviving and reproducing despite changes to food sources, climate, or threats from predators. Which statement correctly describes a way that mutations increase the likelihood that a species will survive in a changing environment?

• Mutations are a source of variation in the species.

• Mutations are the cause of disease in the species.

• Mutations are not harmful when they occur in somatic cells of the species.

• Mutations are always passed on to subsequent generations of the species.

5 The diagram represents one way an enzyme can be inhibited.

Which statement explains the effect of an inhibitor on an enzyme?

• A substrate will be able to bond with the enzyme.

• The enzyme will likely be attacked by immune cells.

• The enzyme will be unable to produce more enzymes.

• A substrate will be unable to attach to the enzyme.

6 Four different nucleotides are used as building blocks of DNA. Which of the following can be used to distinguish one nucleotide from another?

• The nitrogenous base

• The shape of the deoxyribose sugar

• The length of the phosphate group

• The type of fatty acid

7 The green frog (Lithobates clamitans clamitans) is found in many parts of the United States. The table contains some information about this frog.

Why does the ability to lay 1,000 to 5,000 eggs increase the fitness of the species L. clamitans clamitans?

• It increases opportunities for offspring to compete for limited resources.

• It increases the probability that some offspring will survive long enough to reproduce.

• It increases the probability that moving water will promote gene flow from one population to another.

• It increases the chance of the recombination of alleles, leading to genetic drift in the population.

8 Food webs such as the one shown were first used in 1927 by the animal ecologist Charles Elton. The food web below represents the feeding relationships among organisms in an Alaskan ecosystem.

An environmental change that removed which of these organisms from the ecosystem would cause the most instability in the ecosystem?

• Auklets

• Foxes

• Salmon

• Zooplankton

9 During the final stages of human gestation, receptors for the hormone oxytocin increase on the smooth muscle cells of the uterus. The release of oxytocin during labor stimulates the smooth muscle tissue in the wall of the uterus. The vigorous contraction of the uterine smooth muscle helps push the baby through the birth canal so that delivery can occur. This process involves the interaction of which organ systems?

• Endocrine and muscular only

• Endocrine and reproductive only

• Endocrine, muscular, and reproductive

• Endocrine, reproductive, and excretory

10 In the early 1900s a scientist hypothesized a link between DNA and the production of proteins in the cytoplasm. However, the fact that DNA could not be found outside the nucleus led scientists to believe that another substance was also involved in the synthesis of protein in the cytoplasm. In the 1940s scientists performed an experiment that ultimately identified the site of protein synthesis. They also identified the molecule responsible for transporting information from the nucleus to the site of protein synthesis. What was this newly identified molecule?

• A gene

• mRNA

• ATP

• Thymine