Bio Study Guide - Test 1

The hypothesis that a common ancestor gave rise to all living organisms is strengthened by what observation? a. Almost all cells in all living organisms use DNA to direct their structure, function, and behavior. b. All living organisms use energy acquired directly from the environment or from other organisms. c. All living organisms reproduce. d. Each type of living organism adheres to the general principles of the biological hierarchy.

A. Almost all cells in all living organisms use DNA to direct their structure, function, and behavior.

Is it possible for scientists to study events that happened or animals/plants that lived millions of years ago? a. Yes. Apply the laws of physics and nature that we know exist today to evaluate the evidence of past events. For example, observe modern animal behavior, structure, and function, and compare them to the structures of fossilized animals to deduce the function of the fossilized structures. b. No. The laws of physics that exist today are not the same laws of physics that existed in the past, so there is no way to compare plant or animal fossils to those of modern organisms and deduce the function of fossilized structures. c. Yes. Genetic manipulation of fossils allows scientists to directly test metabolic and behavioral characteristics of plants and animals from the past. d. No. There is no way to analyze plant or animal fossils that lived millions of years ago because the laws of nature that exist today have changed dramatically from the past.

A. Apply the laws of physics and nature that we know exist today to evaluate the evidence of past events. For example, observe modern animal behavior, structure, and function, and compare them to the structures of fossilized animals to deduce the function of the fossilized structures.

In the chemical reaction that forms hydrogen peroxide (H2O2), hydrogen and oxygen share electrons creating ________ bonds between the two atoms. a. covalent c. hydrogen b. peptide d. ionic

A. Covalent

Which of the following represents conducting an experiment? a. dialing a telephone number b. comparing prices of computers c. checking your midterm grades online d. predicting the outcome of a basketball game

A. Dialing a phone number.

David Blehert and his research team captured 117 healthy bats to study in the laboratory and divided them into four groups. Group 1 was housed in an area free from Geomyces destructans. Group 2 was housed in an area that shared the same air as bats infected with WNS, but they did not have direct contact with the infected bats. Group 3 was housed in direct contact with other bats infected with WNS. Group 4 was directly exposed to Geomyces destructans when it was applied to their wings. During the study period the bats were monitored for signs of WNS. Which group is the control group? a. group 1 c. group 3 b. group 2 d. group 4

A. Group 1

The chemical reaction that represents photosynthesis is 6 H2O 6 CO2 C6H12O6 6 O2. What are the reactants? a. H2O and CO2 c. H2O and O2 b. C6H12O6 and CO2 d. C6H12O6 and CO2

A. H2O and CO2

Living organisms maintain a constant internal environment by sensing and responding to their internal conditions. This stable maintenance of internal conditions is known as a. homeostasis. c. reproduction. b. evolution. d. sensation.

A. Homeostasis

When scientists generate a single informed, logical, and plausible explanation for a question and observations of the natural world, they are proposing a scientific a. hypothesis. c. theory. b. observation. d. correlation.

A. Hypothesis

Which of the following is likely to participate in ionic bonding? a. Li c. He b. H2O d. C6H12O6

A. Li

Which of the following would be a theory? a. Specific pathogens are directly responsible for specific diseases and conditions. b. A fungal infection is responsible for the spread of white noses and associated higher mortality across bat populations and species. c. Bats with white noses have been observed in the wild. d. A fungal infection causes bats to wake up repeatedly during the winter and use up their fat reserves.

A. Specific pathogens are directly responsible for specific diseases and conditions.

A disaccharide consists of two a. sugars. c. fatty acids. b. hydrocarbons. d. amino acids.

A. Sugars

David Blehert and his research team captured 117 healthy bats to study in the laboratory and divided them into 4 groups. Group 1 was housed in an area free from Geomyces destructans. Group 2 was housed in an area that shared the same air as bats infected with WNS, but they did not have direct contact with the infected bats. Group 3 was housed in direct contact with other bats infected with WNS. Group 4 was directly exposed to Geomyces destructans when it was applied to their wings. During the study period the bats were monitored for signs of WNS. What were the independent and dependent variables in this experiment? a. The independent variable was the type of exposure to Geomyces destructans. The dependent variable was whether or not the bats became sick with WNS. b. The independent variable was whether or not the bats became sick with WNS. The dependent variable was the type of exposure to Geomyces destructans. c. The independent variable was whether or not the bats became sick with WNS. The dependent variable was the number of bats included in the study. d. The independent variable was the number of bats included in the study. The dependent variable was the type of exposure to Geomyces destructans.

A. The independent variable was the type of exposure to Geomyces destructans. The dependent variable was whether or not the bats became sick with WNS.

A researcher wanted to determine if consuming diet sodas causes diabetes. He conducted a study in which subjects were asked to recall how many diet sodas they drank each day, on average; the subjects' blood sugar levels were then measured. The average blood sugar levels were determined in the test subjects. Each group included an equal number of male and female participants and the groups were standardized for average weight and age. Which of these statements most accurately describes what is seen in the graph? a. There appears to be a positive correlation between the number of diet sodas consumed each day and the average blood sugar levels measured in mmol/L. However, no definite cause-effect relationship has been established. b. There appears to be a negative correlation between the number of diet sodas consumed each day and the average blood sugar levels measure in mmol/L. However, no definite cause-effect relationship has been established. c. Drinking four or more diet sodas each day causes diabetes; a definite cause-effect relationship has been established. d. Drinking six or more diet sodas each day causes diabetes; a definite cause-effect relationship has been established.

A. There appears to be a positive correlation between the number of diet sodas consumed each day and the average blood sugar levels measured in mmol/L. However, no definite cause-effect relationship has been established.

What characteristic is NOT shared by all living organisms? a. They make their own energy. c. They evolve through time. b. They grow and develop. d. They are composed of one or more cells.

A. They make their own energy.

You are coughing and producing a wheezing sound as you breathe; you also have a fever. You go to the doctor who listens to your chest, takes X-rays of your chest, and determines that you probably have something called croup. Which of the following are the facts in this scenario? a. You are coughing, wheezing, and have a fever. b. You probably have croup. c. You probably have whooping cough. d. You probably need antibiotics.

A. You are coughing, wheezing, and have a fever.

A solution with a pH of 3 is a. acidic. c. nonpolar. b. basic. d. neutral.

A. acidic

The genetic material found in all living things is made of building blocks called a. nucleotides. c. phospholipids. b. monosaccharides. d. steroids.

A. nucleotides

How many different amino acids are used to build proteins? a. 90 c. 19 b. 20 d. 4

B. 20

Which of the following is a monomer that can be commonly made from components in Earth's atmosphere? a. nucleotides c. triglycerides b. amino acids d. monosaccharides

B. Amino Acids

Based on the water molecule pictured below, which of the labeled areas possesses a partial negative charge? a. A only c. C only b. B only d. A and C

B. B only

The central element found in organic molecules is a. calcium. c. silicon. b. carbon. d. sodium.

B. Carbon

Experimental studies are an effective way of establishing a ________ relationship between two or more aspects of the natural world because they provide a way of testing predicted interaction(s). a. controlled c. correlative b. cause-effect d. casual

B. Cause-effect

Observational studies typically point out correlations between aspects of the natural world, but they do not establish solid ________ relationships. a. controlled c. correlative b. cause-effect d. casual

B. Cause-effect

Recently, beekeepers have noticed an alarming and sudden disappearance of honeybees from their hives. Some beekeepers and environmentalists worry that crops genetically engineered to contain the gene for the Bt insecticidal toxin may be killing the bees. Which of these experiments tests the hypothesis that Bt is killing the bees? a. Spraying Bt toxin on a field and counting the number of bees present before and after spraying. b. Collecting hundreds of bees. Half of the bees would be kept in a facility with plants genetically engineered to contain the gene for Bt toxin while the other half would be kept in a facility with plants not genetically engineered to contain the gene for Bt toxin. The survival rate for both sets of bees would be calculated and compared. c. Collecting hundreds of bees and spraying half of them with Bt toxin while the other half is not sprayed with Bt toxin. The survival rate for both sets of bees would be calculated and compared. d. The number of bees in two adjacent fields would be counted before and after spraying one of the fields with Bt toxin. The survival rate of bees in both fields would be calculated and compared.

B. Collecting hundreds of bees. Half of the bees would be kept in a facility with plants genetically engineered to contain the gene for Bt toxin while the other half would be kept in a facility with plants not genetically engineered to contain the gene for Bt toxin. The survival rate for both sets of bees would be calculated and compared.

In 1890, Robert Koch developed a hypothesis regarding the cause of communicable diseases. He designed an experiment and collected data that supported his hypothesis. Later, his experiment was repeated by many other scientists who used other pathogens and documented similar results that not only supported their hypotheses but also supported Koch's original hypothesis. These many experiments that supported multiple hypotheses regarding the cause of communicable diseases contributed to the development of the a. theory of evolution. c. theory of relativity. b. germ theory of disease. d. law of gravity.

B. Germ theory of disease.

New medications undergo extensive human testing before receiving FDA approval. These tests represent an experiment and variations in the dosage given to participants represents the a. dependent variable. c. correlation coefficient. b. independent variable. d. invariable.

B. Independent Variable.

A scientific hypothesis must be constructed with which of the following characteristics? a. It is always provable and clearly states what is already known to be fact. b. It provides a reasonable explanation to a question and is consistent with current observations; it must also be testable and falsifiable. c. It provides an explanation consistent with accepted theological ideas and does not need to be tested. d. It does not require testing by experimentation or additional observations. It is not falsifiable.

B. It provides a reasonable explanation to a question and is consistent with current observations; it must also be testable and falsifiable.

Victoria, who is 10 years old, wants to be a zoologist when she grows up because she loves animals. So, she decided to begin her training by "doing something scientific." Specifically, she weighed and measured the lengths of all the earthworms she could find in her yard and recorded the data in a notebook. She then made a graph showing the maximum, minimum, and average weights and heights of the earthworms. Was she doing something scientific? a. No, because she is too young to think like a scientist. b. No, because she had no hypothesis to direct her data collection or interpretation. c. Yes, because scientists always make measurements. d. Yes, because scientists always construct graphs with the data they collect.

B. No, because she had no hypothesis to direct her data collection or interpretation.

Which of these characteristics of living organisms are present in viruses? a. composed of one or more cells; obtain energy from their environment; reproduce using DNA (or RNA) b. reproduce using DNA (or RNA); sense their environment and respond to it; can evolve as groups c. maintain a constant internal environment; obtain energy from their environment; composed of one or more cells d. obtain energy from their environment; composed of one or more cells; maintain a constant internal environment

B. Reproduce using DNA (or RNA); sense their environment and respond to it; can evolve as groups.

Scientific understanding can always be challenged, and even changed, with new ways of observing and with different interpretations. For example, new tools and techniques have resulted in new observations and the discovery of additional information. This has resulted in revised ways of understanding how molecules are moved across the plasma membrane of cells. Hence, there is no certainty in science, only degrees of probability (likelihood) and potential for change. In light of this understanding, which of the following statements is most meaningful? a. Scientific knowledge is absolute knowledge. b. Scientific knowledge is necessarily contingent knowledge. c. Scientific knowledge is a static and unchanging collection of facts. d. Scientific knowledge is rigid collection of invariable facts.

B. Scientific knowledge is necessarily contingent knowledge.

Once supported by a predictable experimental outcome, a scientific hypothesis a. is never reexamined. b. still cannot be considered to have been proven true. c. can be used to predict the outcome of all future similar events. d. is elevated to the status of theory.

B. Still cannot be considered to have been proven true.

A scientific hypothesis must be ________; if not, science cannot evaluate it. a. provable c. accepted b. testable d. rejected

B. Testable

Which of the following explains why ice floats on water? a. The crystal structure of ice is more regular than that seen in liquid water. b. The distance between water molecules in ice is greater than in liquid water. c. The cool temperature of ice reduces the extent of molecular motion relative to liquid water. d. When ice forms, the hydrogen bond in the water molecule becomes nonpolar; ice behaves like oil.

B. The distance between water molecules in ice is greater than in liquid water.

Some questions fall outside the realm of science. Which of the following questions could NOT be answered using the scientific method? a. What is the function of the appendix in human beings? b. Why is it unethical to test newly developed drugs in animals? c. Why do smokers develop lung cancer more frequently than nonsmokers? d. Why is it so difficult to quit smoking?

B. Why is it unethical to test newly developed drugs in animals?

Nitrogen has seven protons, seven neutrons, and seven electrons. What is the atomic mass of nitrogen? a. 0 c. 14 b. 7 d. 21

C. 14

Antibodies are an important class of human proteins that function in immune defense. If scientists fragmented antibodies under laboratory conditions, what chemical building blocks would they recover? a. monosaccharides c. amino acids b. phospholipids d. nitrogenous bases

C. Amino acids.

Which of the following would be a fact? a. Specific pathogens are directly responsible for specific diseases and conditions. b. A fungal infection is solely responsible for the spread of white noses and associated higher mortality across bat populations and species. c. Bats with white noses have been observed in the wild. d. A fungal infection causes bats to wake up repeatedly during the winter and use up their fat reserves.

C. Bats with white noses have been observed in the wild.

The human heart pumps blood throughout the blood vessels in the body. This is a scientific a. theory. c. fact. b. hypothesis. d. experiment.

C. Fact

David Blehert and his research team captured 117 healthy bats to study in the laboratory and divided them into 4 groups. Group 1 was housed in an area free from Geomyces destructans. Group 2 was housed in an area that shared the same air as bats infected with WNS, but they did not have direct contact with the infected bats. Group 3 was housed in direct contact with other bats infected with WNS. Group 4 was directly exposed to Geomyces destructans when it was applied to their wings. During the study period the bats were monitored for signs of WNS. What is the specific hypothesis being tested by the inclusion of group 4 in this experiment? a. Geomyces destructans causes WNS, and it can be transmitted through the air. b. Geomyces destructans causes WNS, and it is only transmitted by direct contact with other infected bats. c. Geomyces destructans causes WNS, and it can be transmitted by direct contact with the fungus; no contact with infected bats is needed for transmission of the fungus. d. Group 4 is the control.

C. Geomyces destructans causes WNS, and it can be transmitted by direct contact with the fungus; no contact with infected bats is needed for transmission of the fungus.

Individual water molecules orient toward each other because of the ________ bonds that form between them. a. covalent c. hydrogen b. peptide d. ionic

C. Hydrogen

Which of the following distinguishes ionic bonds from covalent bonds? a. Ionic bonds form between the same two elements, whereas covalent bonds form between different elements. b. Ionic bonds hold together compounds that do not dissolve in water, whereas covalent bonds hold together molecules that dissolve in water. c. Ionic bonds hold together oppositely charged atoms, whereas covalent bonds hold together atoms that share electrons. d. Ionic bonds consist of atoms with partial charges, whereas covalent bonds consist of atoms with full positive and negative charges.

C. Ionic bonds hold together oppositely charged atoms, whereas covalent bonds hold together atoms that share electrons.

3. DNA is one of the features common to all known forms of life; a. it forms the protective outer membrane of cells. b. it is produced expressly for reproduction and is found only in egg and sperm. c. it is the blueprint that guides the growth, development, behavior, and reproduction of all organisms. d. its absence in viruses is the basis for classifying them as nonliving.

C. It is the blueprint that guides the growth, development, behavior, and reproduction of all organisms.

Recently, beekeepers have noticed an alarming and sudden disappearance of honeybees from their hives. Some beekeepers and environmentalists worry that crops genetically engineered to contain the gene for the Bt insecticidal toxin may be killing the bees. Without data from a scientific experiment, is it reasonable to state that Bt-containing crops are responsible for the loss of honeybees? a. Yes, because it is obviously the Bt crops killing the bees. b. Yes, because there cannot possibly be any other explanation for the loss of the honeybees. c. No, because there could be some other unknown or unmentioned factor affecting the survival of honeybees. d. No, because there is no reason to suspect that an insecticide would kill honeybees.

C. No, because there could be some other unknown or unmentioned factor affecting the survival of honeybees.

Experimentation is the primary, but not only, means used to verify or refute the ________ made by a hypothesis. a. variables c. predictions b. theories d. laws

C. Predictions

Which of the following questions could NOT be used to develop a testable hypothesis? a. Does exposure to secondhand smoke affect the probability of developing lung cancer? b. Do organic vegetables contain harmful substances? c. Should everyone drink bottled water only? d. Does a can of vegetable juice contain more salt than the same size can of iced tea?

C. Should everyone drink bottled water only?

Which of the following pieces of evidence would best demonstrate that a bacterium found on an asteroid originated in outer space? a. the presence of volcanic ash on the outside of the bacterial cell b. the absence of common gases found in Earth's atmosphere c. the presence of right-handed amino acids in the bacterium's proteins d. the absence of hydrogen bonds between water molecules in the bacterial cell

C. The presence of right-handed amino acids in the bacterium's proteins.

Which of the following statements is true? a. Once a hypothesis has been proposed, it can never be challenged. b. A valid scientific hypothesis is self-evident and does not need to be tested by experimentation. c. The scientific method or process can help people make informed medical and environmental decisions. d. If properly designed, experiments always prove hypotheses to be wrong.

C. The scientific method or process can help people make informed medical and environmental decisions.

A species of butterflies gradually becomes darker in color over many generations; this is an example of which characteristic of living organisms? a. They reproduce using DNA. b. They obtain energy from the environment to support metabolism. c. They can evolve as groups. d. They sense the environment and respond to it.

C. They can evolve as groups.

In living systems, a critical component of many reactions is a. carbon dioxide. c. water. b. calcium. d. hydrogen sulfide.

C. Water

Is it important for scientists to communicate their results to fellow scientists? a. Yes. Scientists want to receive recognition and monetary reward for their work. b. No. There is no reason for scientists to communicate their results to fellow scientists. c. Yes. The quality and accuracy of the scientific work can be enhanced by input, further review, and possibly even repetition by other scientists working in the same field. d. No. Communication between scientists is discouraged because it can confuse the details of the experiments.

C. Yes. The quality and accuracy of the scientific work can be enhanced by input, further review, and possibly even repetition by other scientists working in the same field.

The caves in upstate New York, where Alan Hicks' team first noticed the deaths of thousands of bats, represent the a. biosphere where the bats lived. c. ecosystem where the bats lived. b. biome where the bats lived. d. community where the bats lived.

C. ecosystem where the bats lived.

Chapter 2 1. Carbon, hydrogen, and nitrogen are all examples of a. compounds. c. elements. b. macromolecules. d. amino acids.

C. elements

In making your morning tea, you drop a sugar cube into some hot water. You stir the mixture but no longer see the sugar cube at the bottom of your mug. Based on your observation of sugar dissolving in hot water, you properly conclude that the sugar is a. hydrophobic. c. hydrophilic. b. nonpolar. d. inert.

C. hydrophilic

Scientists are human beings and are, like all human beings, susceptible to personal and group biases that may influence how they interpret evidence. Before original research work is accepted and added to a growing body of scientific understanding, perhaps even contributing to our understanding of an important scientific theory, it must be scrutinized by experts in the field who have no direct connection to the research under review. The main mechanism for doing this is a. popular magazines. c. peer-reviewed publications. b. the Discovery Channel. d. Wikipedia.

C. peer-reviewed publications.

Which of the following types of bonds hold hydrogen and oxygen atoms together within an individual water molecule? a. hydrogen bond c. polar covalent bond b. peptide bond d. ionic bond

C. polar covalent bond

Whenever we ________, we are proceeding scientifically. a. invoke a supernatural power as an explanation for how a natural phenomenon occurred b. stop questioning our observations c. try to solve a problem by systematically evaluating the plausibility of various solutions d. develop an unchangeable and definitive explanation

C. try to solve a problem by systematically evaluating the plausibility of various solutions

Of the following values, which indicates the most basic pH? a. 5 c. 8 b. 7 d. 10

D. 10

How many atoms are present in a single molecule of C8H10N4O2? a. 4 c. 12 b. 8 d. 24

D. 24

If iodide ions (I) were dissolved in water, they would be attracted to a. A only c. C only b. B only d. A and C

D. A and C

In making your morning tea, you drop a sugar cube into the hot water. You stir the mixture but no longer see the sugar cube at the bottom of your mug. In this scenario, the sugar is a. nonpolar. c. an acid. b. the solvent. d. a solute.

D. A solute.

After adding a small amount of Solution A to Solution B, the pH of Solution B declines from 8 to 3. Solution A must contain a. a salt. c. water only. b. a base. d. an acid.

D. An acid

Bats use echolocation to orient themselves and locate objects. Doing this requires special adaptations in their inner ear, midbrain, and auditory cortex of their cerebrum. The echolocation system of bats is an example of a. a cell. c. an organ. b. a tissue. d. an organ system.

D. An organ system.

O2, also termed atmospheric oxygen, is considered to be a molecule but not a compound. Why not? a. It contains no covalent bonds. b. It contains a double covalent bond but not a single covalent bond. c. To be considered a compound there must be a minimum of three atoms; atmospheric oxygen is too small. d. Compounds are defined as molecules constructed from two or more different elements.

D. Compounds are defined as molecules constructed from two or more different elements.

An acid is a polar substance that dissolves in water and a. becomes nonpolar. b. leaves behind an OH ion. c. accepts hydrogen ions from the solution. d. donates hydrogen ions to the solution.

D. Donates hydrogen ions to the solution.

2. The subatomic particles that possess a single negative charge and surround the nucleus are the a. isotopes. c. neutrons. b. protons. d. electrons.

D. Electrons

You often experience numbness and pain in the thumb and first two fingers on your right hand. You go to the doctor who suspects that carpal tunnel syndrome is the reason for the numbness and pain. The doctor then orders a simple test to see how fast nerve impulses are moving up and down your arm. The doctor's preliminary diagnosis of carpal tunnel syndrome is a(n) a. theory. c. experiment. b. fact. d. hypothesis.

D. Hypothesis

When calcium (Ca) and chloride (Cl) interact with one another they bond using ________ bonds. a. hydrogen c. covalent b. peptide d. ionic

D. Ionic

A carwash attendant offers to treat your windshield with a protective agent. This substance coats the glass, causing beads of water to easily roll off during a rain shower. Which of the following must be correct about the protective agent? a. It resists temperature changes well. c. It is a polar substance. b. It must be an acid. d. It must be hydrophobic.

D. It must be hydrophilic.

Which of the following could be built solely from glucose molecules? a. fatty acids c. oils b. DNA d. starch

D. Starch

A group of researchers conducted an experiment and collected the data presented in this graph. Which of the following statements are supported by the information in this graph? a. The hypothesis was proven beyond a doubt because all members of the control group survived while most of the members of both treatment groups died by the end of the study. b. The hypothesis was proven because all members of the control group survived while most of the members of both treatment groups died by the end of the study. c. The hypothesis was not supported because all members of the control group died while most of the members of both treatment groups survived through the end of the study. d. The hypothesis was supported because all members of the control group survived while most of the members of both treatment groups died by the end of the study.

D. The hypothesis was supported because all members of the control group survived while most of the members of both treatment groups died by the end of the study.

In science, when a hypothesis or group of hypotheses supported by repeated experimental evidence holds true through time, it can be developed into a ________. It is not a guess. It is not static. It is tentative and dynamic and can be adjusted when new, compelling evidence is discovered. It is typically an overarching explanation that best fits all of the available information or evidence. a. law c. hypothesis b. mathematical theorem d. theory

D. Theory

Which of the following is correct about hydrogen bonds? a. Individually, hydrogen bonds are very strong. b. They form between neighboring oxygen atoms. c. They do not involve binding with a hydrogen atom. d. They form due to partial positive and partial negative charges on atoms.

D. They form due to partial positive and partial negative charges on atoms.

The roots of a sunflower plant growing downwards while the shoot grows upwards and the flower turns towards the sun are examples of what characteristic of all living organisms? a. They reproduce using DNA. b. They evolve through time. c. They make their own energy. d. They sense the environment and respond to it.

D. They sense the environment and respond to it.

Nucleotides a. are the building blocks of proteins. b. are involved in every chemical reaction in the cell. c. form physical structures such as hair. d. are the building blocks of nucleic acids.

D. are the building blocks of nucleic acids.

Carbon atoms are bound to each other by a. ionic bonds. c. hydrogen bonds. b. polar bonds. d. covalent bonds.

D. covalent bonds

Living cells have an intact phospholipid bilayer that separates the cell from its external environment; this structure is commonly referred to as the a. nucleus. c. endoplasmic reticulum. b. mitochondria. d. plasma membrane.

D. plasma membrane.

Chemists often represent the structure of atoms using p, n, and e to indicate the number of protons, neutrons, and electrons. Which atom would have an atomic weight of 30? a. 15 p, 15 n, 15 e c. 15 p, 0 n, 15 e b. 10 p, 10 n, 10 e d. 0p, 15n, 15 e

a. 15 p, 15 n, 15 e

Some antibiotics used to treat bacterial infections kill the bacteria by chemically punching holes in the cell wall of the bacteria, by preventing the bacteria from replicating their DNA, or by many other actions that ultimately cause cell death. Why do these antibiotics not work to kill viruses and cure people of viral infections? a. Antibiotics cannot kill a virus because viruses are not living cells with cell walls to puncture, nor do they have their own organelles to replicate DNA. b. Viruses are just too virulent to be killed by those antibiotics. c. Viruses are too quick for the antibiotics to work. d. Viruses mutate at a rate faster than the rate at which antibiotics can work to kill them.

a. Antibiotics cannot kill a virus because viruses are not living cells with cell walls to puncture, nor do they have their own organelles to replicate DNA.

When ammonia (NH3) is dissolved in a solution, it accepts hydrogen ions from its surroundings. Ammonia is therefore a. a base. c. a salt. b. an isotope. d. an acid.

a. a base.

A tissue is defined as a. a group of cells that performs a unique set of tasks in the body. b. two or more atoms held together by strong chemical bonds. c. the basic unit of life. d. a network of organs which perform a wide range of functions.

a. a group of cells that performs a unique set of tasks in the body.

Which of the following types of organisms are commonly single-celled (unicellular)? a. bacteria, some fungi (yeast), and many protozoans b. many fungi, some protozoans, and plants c. plants and animals d. many fungi, plants, and animals

a. bacteria, some fungi (yeast), and many protozoans

Which of the following sequences correctly represents the biological hierarchy of a multicellular organism? a. cells tissues organs individual b. tissues organs cells individual c. individual cells organ systems tissues d. organ systems organs tissues individual

a. cells tissues organs individual

Which of the following amino acids begins the construction of all proteins in the human body? a. methionine c. proline b. leucine d. tryptophan

a. methionine

Which of the following solutions has the highest concentration of free H ions? a. pH 1 c. pH 7 b. pH 4 d. pH 14

a. pH 1

Neighboring water molecules are held together with hydrogen bonds because a. partially negatively charged oxygen atoms and partially positively charged hydrogen atoms on separate water molecules are attracted to one another. b. the hydrogen and oxygen atoms within a single water molecule share electrons equally. c. the oxygen and hydrogen atoms that participate in hydrogen bonding are sharing electons within a single valence shell. d. ionic interactions repel water molecules from hydrophobic oils that may be present in a solution.

a. partially negatively charged oxygen atoms and partially positively charged hydrogen atoms on separate water molecules are attracted to one another.

Macromolecules are typically formed by repetitively adding small monomers together. Which macromolecule is properly matched with the appropriate monomer? a. polypeptide—amino acid c. polysaccharide—nucleotide b. nucleic acid—amino acid d. triglyceride—cholesterol

a. polypeptide—amino acid

Oil and water do not mix together well because a. water is polar and oil is nonpolar. b. only identical molecules of the same chemical can easily mix together. c. water has hydrogen bonds and oil is polar. d. water and oil are covalently bonded together.

a. water is polar and oil is nonpolar.

Which of the following is an organic compound? a. water (H2O) c. ammonia (NH3) b. methane (CH4) d. carbon dioxide (CO2)

b. methane (CH4)

Adenine (A), thymine (T), guanine (G), and cytosine (C) are the ________ building blocks for DNA; they are organized in different combinations to code for all of the proteins needed to accomplish everything the cell does. a. carbohydrate c. protein b. nucleotide d. lipid

b. nucleotide

Which of the following factors explains carbon's prominence in living systems? a. Carbon forms weak reversible bonds. b. Carbon bonds with up to three other atoms. c. Carbon-based molecules can form long chains and rings. d. Carbon does not form small molecules.

c. Carbon-based molecules can form long chains and rings.

Which of the following statements is true of proteins, carbohydrates, and nucleic acids? a. All three are used to store genetic information. b. None of these macromolecules mixes well with water. c. Each of these molecules is built from a common set of monomers. d. All of these molecules are primarily used as energy-storage molecules.

c. Each of these molecules is built from a common set of monomers.

A group of astronauts returning from outer space studied samples taken from their lunar landing. They found that one of their samples was coated with organic compounds. Which of the following statements must be correct about their samples? a. The compounds must be covered with ammonia (NH3) and water vapor. b. The samples must lack water, but contain DNA. c. The samples must contain carbon atoms. d. The specimen must lack water, pesticides, and added hormones.

c. The samples must contain carbon atoms.

Why do scientists repeat their experiments over and over again? a. They never get it right the first time. b. They can never be sure what procedural steps they followed the first few times. c. They must make sure the results were not an accident and that they are repeatable. d. They simply have extra time and resources that must be used.

c. They must make sure the results were not an accident and that they are repeatable.

In the laboratory you identify protein in a food item that you've tested. Which of the following must the food item also contain? a. glucose c. amino acids b. lipids d. nucleotides

c. amino acids

The pH scale measures a. the amount of water in a solution. b. the likelihood that a solution will evaporate. c. the concentration of hydrogen ions in a solution. d. the number of atoms found within a molecule.

c. the concentration of hydrogen ions in a solution.

Chapter 3 Which of the following is/are part of accepted cell theory? a. Every living organism is composed of one or more cells, and all living cells have membrane-enclosed organelles. b. All living cells arise from preexisting cells, and all living cells have membrane-enclosed organelles. c. All living cells have membrane-enclosed organelles. d. Every living organism is composed of one or more cells, and all living cells arise from preexisting cells.

d. Every living organism is composed of one or more cells, and all living cells arise from preexisting cells.

From what substance do liposomes spontaneously form and why are they important? a. Liposomes spontaneously form from DNA and proteins and provide a rigid structure to support the cell. b. They are formed from phospholipid monolayers. These phospholipid monolayers provide a stable barrier between the internal and external environments. c. Liposomes were the first rigid cell walls providing support for the living cell and a barrier between the external and internal environments. d. Liposomes form from phospholipid bilayers and provide a barrier between an external environment and an internal environment; this creates an internal environment where specific chemical reactions needed to establish a living cell can occur separately from the external environment.

d. Liposomes form from phospholipid bilayers and provide a barrier between an external environment and an internal environment; this creates an internal environment where specific chemical reactions needed to establish a living cell can occur separately from the external environment.

Which of the following can be used to accurately describe viruses? a. They are small, cellular infectious agents that are only capable of reproducing when inside a living cell, and they can attack plants as well as animals. b. Each is typically a piece of genetic material encased in proteins, and they can reproduce on their own. c. They can attack plants, animals, and protozoans, and each is typically a piece of self-replicating genetic material encased in proteins. d. Typically just a piece of genetic material encased in proteins, viruses are small, non-cellular infectious agents that are only capable of reproducing when inside a living cell such as those of plants, animals, fungi, protozoans, or bacteria.

d. Typically just a piece of genetic material encased in proteins, viruses are small, non-cellular infectious agents that are only capable of reproducing when inside a living cell such as those of plants, animals, fungi, protozoans, or bacteria.

You are given an unknown substance and asked to determine whether it is polar or nonpolar. The easiest way to do this would be to a. determine whether the compound is held together by hydrogen bonds. b. determine the number of electrons in the compound's outer shell. c. mix the compound with an ionic substance to see whether its bonds can withstand the pressure. d. determine whether the compound dissolves in water.

d. determine whether the compound dissolves in water.

When sodium chloride (NaCl) is dissolved in water, the sodium ion a. is attracted to the hydrogen atoms of water molecules. b. is repelled by the oxygen atoms of water molecules. c. is attracted to other sodium ions that are being dissolved. d. is attracted to the oxygen atoms of water molecules.

d. is attracted to the oxygen atoms of water molecules.