Keystone Testing: Biology

In order for medicine X to produce the effects that the researchers observed, it must have entered into which part of the targeted cells? A . nucleus B . ribosomes C . Golgi apparatus D . rough endoplasmic reticulum

A . nucleus

Which condition would most likely result in an increase in the phenotypic variation within a population? A . The variety of food available in the habitat decreases . B . A mutation leads to individuals with genetic differences . C . Competition is reduced for all individuals during the winter . D . Climate remains unchanged in the population's ecosystem .

B . A mutation leads to individuals with genetic differences .

Which statement best explains how organisms accomplish passing on traits to their offspring? A. Traits are acquired when parents care for their offspring. B. Offspring inherit traits when DNA is replicated during mitosis. C. Traits are inherited by the transfer of genetic material from parent to offspring. D. Offspring acquire traits when cells become specialized for certain functions.

C. Traits are inherited by the transfer of genetic material from parent to offspring.

Which statement best describes the outcomes of both meiosis and mitosis? A . Cell division results in daughter cells that contain DNA . B . Each daughter cell has two complete sets of chromosomes . C . Within a cell, two chromosomes pair up and exchange segments of genetic material . D . Genetically identical daughter cells are produced that can function as body cells or sex cells

A . Cell division results in daughter cells that contain DNA .

At a point in the cell cycle, chromosomes have aligned near the middle of a cell . Which sequence of events will the cell need to complete to produce two identical daughter cells? A . anaphase -> telophase -> cytokinesis B . anaphase II -> telophase II -> cytokinesis II C . prophase -> metaphase -> anaphase D . metaphase II -> anaphase II -> telophase II

A . anaphase -> telophase -> cytokinesis

Cell Observations • chromatin has condensed into visible chromosomes • nuclear envelope has disappeared • nucleolus is no longer visible A student looking through a microscope records observations about a cell. Which stage of the cell cycle has the student described? A. prophase B. anaphase C. interphase D. telophase

A. prophase

Which cell process is best modeled by the diagram? A . osmosis B . exocytosis C . passive transport D . facilitated diffusion

B . exocytosis

Original RNA Sequence of Organism AUG-GCU-UGU Which mutation would most likely affect the organism's phenotype? A. AUG-GCC-UGU B. AUG-GCG-UGU C. AUG-GCU-UGA D. AUG-GCU-UGC

C. AUG-GCU-UGA

Which statement best describes how channel and carrier proteins in the plasma membrane are similar? A . Both allow for the flow of molecules into and out of a cell . B . Both directly connect the membrane to the nucleus of a cell . C . Both use energy to continuously move water molecules out of a cell . D . Both cause the phospholipid bilayer to form a rigid membrane for a cell

A . Both allow for the flow of molecules into and out of a cell .

Some pistol shrimp within a population do not have eye tissue pockets . What role will natural selection most likely have in the frequency of the alleles responsible for the presence of tissue pockets in the shrimp population over time? A . Natural selection will increase the allele frequency for tissue pockets because they are beneficial to the shrimp . B . Natural selection will decrease the allele frequency for tissue pockets because they are beneficial to the shrimp . C . Natural selection will not affect the allele frequency for tissue pockets because the trait is only in a few organisms . D . Natural selection will lead to the extinction of the shrimp species over time because the tissue pockets could cause poor vision

A . Natural selection will increase the allele frequency for tissue pockets because they are beneficial to the shrimp .

Ash from a volcanic eruption decreases the amount of available solar energy for a region . Which statement describes how a decrease in available sunlight will most likely affect ecosystems of this region? A . Producer populations will decrease, causing a decrease in consumer populations . B . Producer populations will decrease, causing an increase in consumer populations . C . Decomposer populations will increase, causing a decrease in consumer populations . D . Decomposer populations will increase, causing an increase in consumer populations

A . Producer populations will decrease, causing a decrease in consumer populations .

Which set of ecological organization levels is most likely to contain the largest variety of species? A . multiple biomes in a biosphere B . multiple ecosystems in a biome C . multiple individuals in a population D . multiple populations in a community

A . multiple biomes in a biosphere

Which statement best describes a direct role of ATP in a paramecium? A. ATP provides the energy to move cilia. B. ATP stores the genetic code for replication. C. ATP signals the presence of other nearby organisms. D. ATP senses changes in the surrounding aquatic environment.

A. ATP provides the energy to move cilia.

Which statement best describes how organisms use DNA and amino acids to synthesize a protein? A. DNA is transcribed into mRNA, which is translated by the ribosome to produce an amino acid chain. B. DNA is translated into mRNA, which is transcribed by the ribosome to produce an amino acid chain. C. Amino acids are transcribed into mRNA, which is translated in the nucleus to produce a molecule of DNA. D. Amino acids are translated into mRNA, which is transcribed in the nucleus to produce a molecule of DNA.

A. DNA is transcribed into mRNA, which is translated by the ribosome to produce an amino acid chain.

How does a mitochondrion facilitate the movement of some materials between cells? A. It supplies the energy needed for moving molecules through membranes. B. It manufactures the proteins needed to form channels in cell membranes. C. It supplies digestive substances that break large molecules into smaller units. D. It produces fibers that attach to molecules and move them through the cytoplasm.

A. It supplies the energy needed for moving molecules through membranes.

Plants are dependent on water. In most plants, water is absorbed by the roots and then moves up the stem of the plant and into the leaves by capillary action. Which properties of water are most responsible for the capillary action in plants? A. adhesion and cohesion B. low density and adhesion C. polarity and high specific heat D. high specific heat and cohesion

A. adhesion and cohesion

HGT can occur naturally in the wild but can also be accomplished in a laboratory setting. Which laboratory procedure most closely resembles the process of HGT? A. inserting DNA from a bacterium into a corn plant B. selectively breeding corn plants for desired traits C. using radiation to induce genetic mutations in bacteria D. cloning a bacterium to produce an identical strain of cells

A. inserting DNA from a bacterium into a corn plant

Two closely related shrimp species have habitats and niches that partially overlap. Which factor most likely caused the divergence of the shrimp into separate species? A. reproductive isolation B. reduction of food supply C. a series of rapid mutations D. large initial population size

A. reproductive isolation

Which property of water is most responsible for plants being able to transport water from their roots to their leaves? A. the attraction between molecules B. a capacity to dissolve many substances C. the ability to form a low-density crystalline structure when frozen D. a capacity to absorb large amounts of energy as temperature increases

A. the attraction between molecules

Which action must occur for an enzyme to catalyze a chemical reaction? A . A competitive inhibitor must first bind to an active site . B . A substrate must bind to an active site of the enzyme . C . A substrate must bind to an allosteric site of the enzyme . D . A noncompetitive inhibitor must first bind to an active site

B . A substrate must bind to an active site of the enzyme .

Which statement correctly describes how a protein is formed? A . A monosaccharide bonded to a side chain is broken apart . B . Amino acids are bonded together in a long chain to form a new molecule . C . A molecule containing glycerol bonded to three fatty acids is broken apart D . A nitrogenous base, a sugar, and a phosphate group combine to form a new molecule

B . Amino acids are bonded together in a long chain to form a new molecule .

Lipase is an enzyme that breaks down lipids in the digestive system of humans. It functions best at a pH range of 4 .0 to 5 .0 . When a person takes an antacid tablet to relieve heartburn, the antacid increases the pH to around 7 in certain areas of the digestive system . Which initial effect would most likely be caused by a change in pH? A . More lipids would be digested . B . Fewer lipids would be digested . C . The production of lipase molecules would increase . D . The production of lipase molecules would decrease

B . Fewer lipids would be digested .

Which statement best describes how geographic isolation can contribute to land animal speciation? A . Geographic isolation physically separates populations but allows them to interact . B . Geographic isolation physically separates populations and prevents them from interacting . C . Geographic isolation causes genetic changes in individual organisms but allows them to interact . D . Geographic isolation causes genetic changes in individual organisms and prevents them from interacting

B . Geographic isolation physically separates populations and prevents them from interacting .

A male pistol shrimp with protective eye tissue pockets mates with a female shrimp without protective eye tissue pockets . All of the offspring have eye tissue pockets . Which statement is the most likely conclusion that can be made about the eye tissue pocket trait in pistol shrimp? A . It is a recessive, autosomal trait . B . It is a dominant, autosomal trait . C . It is a trait that results from multiple alleles . D . It is a trait that results from incomplete dominance

B . It is a dominant, autosomal trait .

An inversion occurs along part of a chromosome . How does the inversion most likely affect the region in which it occurs? A . Recessive alleles in the region become dominant alleles . B . The information in the region is read differently during transcription . C . The coding sequence in the region disappears entirely from the cell . D . Multiple frameshift errors in the region are triggered after translation

B . The information in the region is read differently during transcription .

Which process best describes the assembly of proteins from amino acids? A. Atoms are linked to form a compound. B. Monomers are linked to form a polymer. C. Atoms are added to a monomer until it becomes a polymer. D. Molecules are added to a compound until it becomes a monomer.

B. Monomers are linked to form a polymer.

Which statement best explains why the carotenoid gene has been present in pea aphids for millions of years? A. Environmental selection pressures prevented the carotenoid gene from mutating in the pea aphids. B. The HGT process introduced a benefit for survival and led to greater reproductive success in pea aphids with the carotenoid gene. C. Because genes acquired by HGT are less susceptible to selection pressures, the carotenoid gene remained in the pea aphid genome. D. The carotenoid gene had a long time to evolve before being introduced into the pea aphids, which led to a stable gene that can be successfully inherited.

B. The HGT process introduced a benefit for survival and led to greater reproductive success

Each cell in the human body contains thousands of different enzymes responsible for regulating reactions within the cell. Which statement explains why a single enzyme is unable to regulate a variety of reactions? A. The binding of a product and an enzyme is specific. B. The binding of a substrate and an enzyme is specific. C. The enzyme is consumed by the products of the reactions. D. The enzyme is consumed by the substrates of the reactions.

B. The binding of a substrate and an enzyme is specific.

Which statement best compares a carbohydrate and a nucleic acid? A. The sequence of monomers in a carbohydrate stores genetic information, and the bonds in a nucleic acid store energy. B. The bonds in a carbohydrate store energy, and the sequence of nucleotides in a nucleic acid stores genetic information. C. A carbohydrate has a unique structure to assist diffusion across a plasma membrane, and a nucleic acid has a unique structure to assist chemical reactions. D. A carbohydrate has a unique structure to assist chemical reactions, and a nucleic acid has a unique structure to assist diffusion across a plasma membrane.

B. The bonds in a carbohydrate store energy, and the sequence of nucleotides in a nucleic

Which statement best describes a function of the proteins embedded in the plasma membrane of cells? A. They provide instructions for the processes in the cell. B. They selectively allow certain particles into and out of the cell. C. They attract charges in the cell's environment to give the cell a net charge. D. They store the energy required by the rest of the membrane to perform its functions.

B. They selectively allow certain particles into and out of the cell.

Lungs and capillaries both have porous linings that allow certain substances to move into or out of the structures. Which function do these porous linings most likely serve in living organisms? A. heat release B. gas exchange C. carbohydrate absorption D. osmotic pressure regulation

B. gas exchange

Which sequence best orders ecological categories from the one with the fewest number of individuals to the one with the greatest number of individuals? A. ecosystem, population, community, biome B. population, community, ecosystem, biome C. biome, population, community, ecosystem D. community, biome, population, ecosystem

B. population, community, ecosystem, biome

Carbon can combine with many different elements but frequently combines with oxygen, hydrogen, and nitrogen to form organic molecules . Which statement best explains why carbon is able to form a large number of different molecules? A . Carbon forms only ionic bonds . B . Carbon can form only ring structures . C . Carbon can form four covalent bonds . D . Carbon forms small, simple structures

C . Carbon can form four covalent bonds .

A cell in the leaf of a green plant performs both photosynthesis and cellular respiration, often at the same time . Which statement best describes how these processes are related to each other? A . Both processes produce carbon dioxide . B . Both processes require energy directly from the Sun . C . Products of one process are used as some of the reactants for the other process . D . Thermal energy from one process is used as the energy source for the other process

C . Products of one process are used as some of the reactants for the other process .

Given the properties of the medicine Y molecule, which mechanism is most likely responsible for medicine Y's entry into cells? A . osmosis B . exocytosis C . active transport D . simple diffusion

C . active transport

Many scientists have concluded that whales and dolphins have a more recent common ancestor than do whales and sharks . Which characteristic most likely allowed scientists to make this conclusion? A . species niche B . predation behavior C . anatomical structure D . geographical distribution

C . anatomical structure

Tadpoles grown in ponds with high densities of tadpoles have lower survival and growth rates than tadpoles grown in ponds with lower densities of tadpoles . Which interaction between tadpoles grown in high-tadpole-density ponds would most likely cause the decreased survival and growth rates? A . symbiosis B . mutualism C . competition D . commensalism

C . competition

Which characteristic is shared by both prokaryotes and eukaryotes? A . have organ systems B . make their own food C . contain genetic material D . need oxygen gas to breathe

C . contain genetic material

Which of the following is essential to proper functioning of all prokaryotic and eukaryotic organisms? A. O2 B. CO2 C. ATP D. NaCl

C. ATP

Energy pyramids describe food and energy relationships within an ecosystem. Which factor most likely limits the number of levels an energy pyramid can have? A. biomass of the top-level organisms B. predation by the top-level organisms C. energy loss between each level of organisms D. chemical energy being decomposed at each level of organisms

C. energy loss between each level of organisms

A scientist observed that during the course of a chemical reaction the number of ATP molecules was reduced . What did the scientist most likely learn from the observation? A . The reaction produced water . B . The reaction consumed water . C . The reaction caused an output of energy . D . The reaction required an input of energy

D . The reaction required an input of energy

In order to study genetic mutations, scientists must study genetic material . Which statement describes the genetic material scientists are most likely studying? A . They study alleles that contain chromosomes, which are RNA . B . They study alleles that contain genes, which are chromosomes . C . They study chromosomes that contain DNA segments, which are RNA . D . They study chromosomes that contain genes, which are DNA segments

D . They study chromosomes that contain genes, which are DNA segments

During a cell division cycle, chromosome segments from two homologous chromosomes exchange places. Which result is most likely to occur following this cycle? A. Genetic material will be lost. B. The number of chromosomes will increase. C. The total number of genes in the cell will decrease. D. A change in gene location will occur on both chromosomes.

D. A change in gene location will occur on both chromosomes.

The element carbon has multiple bonding patterns. Which bonding pattern cannot be formed by carbon? A. C—C B. C—C—C C. C∙C∙C D. C≡C≡C

D. C≡C≡C

Before cellular division, the cell must duplicate its DNA so that daughter cells will contain complete copies of the DNA. Which characteristic of DNA makes it most suitable as a molecule for this role? A. DNA is located in the nucleus. B. DNA is a large macromolecule. C. DNA is made of repeating sugar-phosphate subunits. D. DNA is made of two strands of complementary nucleotides.

D. DNA is made of two strands of complementary nucleotides.

Which statement best compares eukaryotic cells and prokaryotic cells? A. Eukaryotic cells are smaller than prokaryotic cells. B. Prokaryotic cells are more complex than eukaryotic cells. C. Prokaryotic cells contain a distinct central organelle, and eukaryotic cells do not. D. Eukaryotic cells contain membrane-bound organelles, and prokaryotic cells do not.

D. Eukaryotic cells contain membrane-bound organelles, and prokaryotic cells do not.

Orchids living in tropical rainforests often grow on the branches of trees to access sunlight. The trees are not affected by the orchids. Which term best classifies the relationship between the orchids and the trees? A. predation B. parasitism C. competition D. commensalism

D. commensalism

What is the main purpose for initiating the production of folding helpers in a cell? A. DNA replication B. forming gametes C. passive transport D. maintaining homeostasis

D. maintaining homeostasis