Biology STAAR 2016

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.

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.

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

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.

In the early 1900's 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 1940's 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

During meiosis, homologous chromosomes exchange genetic material. This exchange of

genetic material —

• increases the genetic variation

• reduces the diploid number to the haploid number

• increases the haploid number to the diploid number

• reduces the probability of mutations

As a fertilized egg divides, the cells differentiate because they —

• contain a lipid bilayer

• can clump together

• metabolize sugars rapidly

• have specific genes activated

The photograph shows monarch butterflies landing on plants where there are thousands of other monarch butterflies. These butterflies feed on milkweed plants as they travel south for the winter, covering distances of 5,000 km or more each year. However, the population of these butterflies has been steadily declining over the last 20 years. What is the most likely reason the population of these butterflies has been declining?

• The number of bird species evolving to prey on butterflies has increased.

• The butterflies are evolving to tolerate cold weather in the northern United States and southern Canada.

• The increase in yearly temperatures has warmed the northern habitats.

• The number of milkweed plants along the butterflies’ migratory route has decreased. This is a form of habitat destruction.

Bactrian camels, dromedaries, llamas, and alpacas are all members of the same taxonomic family, Camelidae. Members of this family all have two toes, no hooves, true canine teeth, and a split upper lip. The family Camelidae originated in North America. The physical features

of animals in this family and the family’s geographical origin provide evidence that all these

animals —

• live in the same type of ecosystem

• have slowly evolved to become herbivores

• have a common ancestor

• exchanged DNA at some point in the past

Which statement best describes the relationship between the products of photosynthesis and the reactants in cellular respiration?

• The products of photosynthesis serve as the reactants in cellular respiration to provide chemical energy.

• The products of photosynthesis combine with the reactants in cellular respiration to remove ATP from cells.

• The products of photosynthesis inhibit the reactants in cellular respiration in the presence of light.

• The products of photosynthesis change the structure of the reactants in cellular respiration in the presence of light.