2019 STAAR BIOLOGY EXAM- NO DIAGRAMS- Questions Only

In a study of physical endurance, researchers observed significant increases in the heart rates and breathing rates of participants immediately after they engaged in strenuous exercise. Which statement best explains the increase in the heart rate and the breathing rate during exercise? F The water concentration in the blood increases. G Body cells require increased oxygen as energy is expended. H Muscle cells increase in temperature and require fluid to reduce the temperature. J An increase in muscle activity causes increases in glucose levels in red blood cells.

G Body cells require increased oxygen as energy is expended.

A team of students encounters an unknown organism in a field while conducting a biodiversity study. Some students think the organism is a plant, while others think it is a fungus. Which question should the students investigate to classify the organism correctly? F Is there a cell wall around the cells of the organism? G Does the organism perform photosynthesis? H Is there nervous tissue present in the organism? J Does the organism reproduce sexually?

G Does the organism perform photosynthesis?

Gibberellins are hormones produced in the root tips of plants. The plant uses these hormones to stimulate the growth of shoots. How are gibberellins able to affect other parts of the plant? F Gibberellins are absorbed through the stomata and attach to chloroplasts. G Gibberellins are transported through vascular tissues to other parts of the plant. H Gibberellins become concentrated within the tissues of the plant during mitosis. J Gibberellins become modified once they infect healthy cells and are later released to infect other cells.

G Gibberellins are transported through vascular tissues to other parts of the plant.

Grassland ecosystems in Texas have evolved to depend on periodic fires to return nutrients to the soil and encourage plant reproduction. Humans have prevented fires in many of these grassland areas, resulting in plant and animal communities with little diversity. Wildlife biologists often recommend purposefully starting fires called prescribed burns, which are monitored and controlled, in grassland ecosystems every 3 to 4 years. These biologists observe greater diversity in plant and animal life in the years following a prescribed burn. What natural processes are the biologists attempting to imitate? F Biomagnification G Succession H Population bottleneck J Species extinction

G Succession

Which four body systems interact to allow a person to sneeze? A Muscular, immune, nervous, respiratory B Nervous, respiratory, circulatory, skeletal C Respiratory, endocrine, skeletal, circulatory D Lymphatic, skeletal, respiratory, muscular

A Muscular, immune, nervous, respiratory

When cells lose their ability to regulate the cell cycle, they can divide at an accelerated rate and form a mass of cells. This mass of cells is referred to as — A a tumor B an embryo C a gland D an organ

A a tumor

Eight components present in nucleic acids are listed. Components of Nucleic Acids: 1. Phosphate 2. Ribose sugar 3. Deoxyribose sugar 4. Uracil 5. Thymine 6. Adenine 7. Guanine 8. Cytosine Which components bond with adenine in a section of double-stranded DNA? A 1,3,5,and6only B 3and5only C 2and4only D 3,4,7,and8only

B 3and5only

Which of these components are found in the cells of all living organisms? A Estrogen and testosterone B Hemoglobin and lymphocytes C Cytosine and guanine D Cellulose and chlorophyll

C Cytosine and guanine

Which role of protists has the most positive effect on maintaining the plant population in an ecosystem? A Protists are a major food source for animals. B Protists produce approximately 75 percent of the oxygen on Earth. C Protists decompose dead materials, returning nutrients to the soil. D Protists found in the gut of animals assist in digestion.

C Protists decompose dead materials, returning nutrients to the soil.

A segment of a DNA strand is shown. 3' AGGTCAGGT 5' Which of these is the correct complementary DNA strand for the segment shown? A 5' AGGTCAGGT 3' B 5' ACCUGAGGU 3' C 5' TGGACTGGA 3' D 5' TCCAGTCCA 3'

D 5' TCCAGTCCA 3'

In 1898 Friedrich Loeffler and Paul Frosch found evidence that the cause of the highly contagious hoof-and-mouth disease in livestock was a microscopic infectious particle. It was discovered that this particle requires a host cell to reproduce. Which pathogen is most likely responsible for causing hoof-and-mouth disease in livestock? A A bacterium, because it is contagious B A fungus, because it infects livestock C A protist, because it is microscopic D A virus, because it requires a host cell to reproduce

D A virus, because it requires a host cell to reproduce

A new predator of rabbits has been introduced within an ecosystem. This new predator runs faster than the native predators of rabbits. Which statement describes what will most likely occur in the rabbit population due to the introduction of the predator? A The rabbits will mutate their genes and express genes that increase their speed. B Slower rabbits will develop stronger legs and pass this trait to their offspring. C Rabbits will mate and produce offspring with a different species that has faster runners. D Faster rabbits will survive and reproduce increasing the average speed of the rabbit population.

D Faster rabbits will survive and reproduce increasing the average speed of the rabbit population.

Which statement accurately describes the energy needs for photosynthesis and cellular respiration? A Solar energy is needed for cellular respiration but not for photosynthesis. B Chemical energy in the form of glucose is needed for both cellular respiration and photosynthesis. C Chemical energy in the form of glucose is needed for photosynthesis, and solar energy is needed for cellular respiration. D Solar energy is needed for photosynthesis, and chemical energy in the form of glucose is needed for cellular respiration.

D Solar energy is needed for photosynthesis, and chemical energy in the form of glucose is needed for cellular respiration.

Male guppies found in areas without predators are more colorful than the ones found in locations with large predator populations. A population of adult guppies originating from an area with a large number of predators is transferred to a nearby area with few predators. Which of these is most likely to happen over a few generations? A The mortality rate of the guppies will increase. B Offspring will stop competing for resources. C There will be an increase in mutations in the offspring. D There will be an increase in the number of colorful guppies.

D There will be an increase in the number of colorful guppies.

CRISPR-Cas9 is a genetic modification technique that edits parts of the genome of an organism. Using this technique scientists can add, remove, or modify sections of the DNA sequence. How can scientists use this technique to control gene expression? A By activating or deactivating specific genes B By calculating the number of genes different organisms produce C By identifying how closely related one individual is to another D By determining the number of chromosomes in an organism

A By activating or deactivating specific genes

The San Marcos salamander, Eurycea nana, is a light reddish-brown translucent salamander about 2-5 cm in length. E. nana is found only in Spring Lake and a portion of the San Marcos River. Which human activity would most likely decrease the ability of the salamanders to survive? A Increasing water consumption that decreases the flow of clean water from the springs that feed the river B Public transportation that reduces the number of automobiles that contribute to pollution runoff into the river C Tourism that helps fund the educational programs related to river ecosystem conservation D The addition of a new food source into the river that limits competition for resources

A Increasing water consumption that decreases the flow of clean water from the springs that feed the river

Enzymes are proteins that have a three-dimensional shape that is specific to a particular substrate. Environmental conditions can change the shape of the protein. What is the most likely result if the shape of the enzyme changes? F The substrate will change its shape to match the enzyme. G The enzyme will no longer be able to catalyze the reaction with the substrate. H The products made from the enzyme and the substrate will be changed. J The enzyme will be able to bind to more diverse substrates than before.

G The enzyme will no longer be able to catalyze the reaction with the substrate.

Many tree frog populations are threatened due to habitat loss. In an effort to promote conservation, tree frogs may be bred in captivity. A zoo acquired male and female tree frogs from two different populations. In the zoo, the tree frogs were able to successfully mate within their own population, but breeding attempts between the two populations were unsuccessful. Based on this information, which statement correctly describes the relationship between the two populations of tree frogs? A They are in the same species but different kingdoms. B They are in the same class but different phyla. C They are in the same family but different orders. D They are in the same genus but different species.

D They are in the same genus but different species.

Gametes produced by an organism contain a combination of genes from that organism. In every gamete, this combination is — A the same because it is created from the same DNA B the same because chromosomes are copied prior to meiosis C different due to DNA replication prior to mitosis D different due to independent assortment during meiosis

D different due to independent assortment during meiosis

Students are modeling mRNA during the process of protein synthesis. Which answer choice correctly describes the model of the mRNA strand being transcribed? F The mRNA strand is complementary to the DNA template strand; however, uracil instead of adenine is paired with thymine. G The mRNA strand is complementary to the DNA template strand; however, uracil instead of thymine is paired with adenine. H The mRNA strand is an exact copy of the DNA template strand; however, uracil instead of adenine is paired with thymine. J The mRNA strand is an exact copy of the DNA template strand; however, uracil instead of thymine is paired with adenine.

G The mRNA strand is complementary to the DNA template strand; however, uracil instead of thymine is paired with adenine.

Exposure to the building material asbestos has been linked to certain types of cancers. Asbestos causes mutations in the p53 gene, which controls tumor suppression. Which statement best explains why people with cancer due to asbestos exposure do not pass the mutation on to their offspring? F The mutation occurred in gametic cells. G The mutation occurred in somatic cells. H The mutation is recessive. J The mutation is sex-linked.

G The mutation occurred in somatic cells.

Some species of millipedes will roll into a ball when threatened, while other species of millipedes can secrete noxious chemicals from their bodies. These adaptations allow the millipedes to — F survive in different temperatures G avoid different types of predators H conserve different amounts of energy J blend into different types of environments

G avoid different types of predators

Which answer choice best describes a community? F Praying mantises caring for their young G Three-spined sticklebacks living in estuaries H Different species of lizards occupying the same niche in a desert J Roosting mother bats recognizing their offspring

H Different species of lizards occupying the same niche in a desert

What would be the most likely effect of a wildfire that burned a large area of a forest? F More sugars and starches would be available for animals in the area. G The availability of fossil fuels for use by industries in the area would be reduced. H Less carbon dioxide would be removed from the atmosphere in the area by plants. J An increase in animal respiration would increase the release of carbon dioxide in the area.

H Less carbon dioxide would be removed from the atmosphere in the area by plants.

Conservation biologists studying cheetah populations have determined that the lack of genetic diversity among the cheetahs is due to genetic drift. Which statement explains the most likely consequence of having a low genetic diversity on the cheetah population? F The chances of a mutation occurring in the cheetah population are decreased, increasing the cheetah survival rate. G The gene pool remains in equilibrium and future generations of cheetah offspring are stronger and better adapted to their environments. H The cheetah population becomes less likely to survive an outbreak of a disease or an environmental change, increasing the chance of species extinction. J Genetic variability is maintained from older cheetah populations that have survived and endured environmental stressors.

H The cheetah population becomes less likely to survive an outbreak of a disease or an environmental change, increasing the chance of species extinction.

During secondary succession, which of these best describes why decomposing pioneer plants give way to larger, more complex plants species, such as hardwood trees? F Increased amounts of sunlight are able to reach the ground while the pioneer species are decomposing. G Increased soil temperatures from decomposing pioneer species help tree seeds germinate more quickly. H Increased amounts of decomposing pioneer species remove nutrients that tree seedlings need to grow and mature. J Increased amounts of soil from decomposing pioneer species allow plants with more extensive root systems to become established.

J Increased amounts of soil from decomposing pioneer species allow plants with more extensive root systems to become established