BIO MIDTERM

Select the smallest and most basic unit of life. cell genome DNA nucleotide

cell

The fact that the onset of autism symptoms typically occurs at about the same age children receive many of their vaccinations, including the MMR, is an example of an observed correlation but not necessarily evidence of a cause-effect relationship. correlation and strong evidence of a cause-effect relationship. cause-effect relationship supported by empirical evidence. cause-effect relationship but not necessarily a correlation.

correlation but not necessarily evidence of a cause-effect relationship.

Therapeutic touch (TT) is a type of "energy" medicine that involves the practitioner moving his or her hands over the energy field of the patient, without actually touching the patient, to redirect the energy field and heal the patient. Which of the following would be the first concept to investigate to help evaluate the claims of TT practitioners? documentable and repeatable evidence that an external energy field actually exists for humans documentable and repeatable evidence that any existing energy field can be manipulated by merely passing hands over it documentable and repeatable evidence that TT practitioners can, without seeing or touching their subjects, actually feel the energy field of a patient documentable claims by TT practitioners and their patients that the patients thought they felt better after being treated by the TT practitioner even though there was no change in their diseases

documentable and repeatable evidence that an external energy field actually exists for humans

Neurotransmitters are chemicals that are released by nerve endings. These chemicals are often large and unable to pass through the membrane, so the nerve cell packages them in a vesicle that can fuse with the plasma membrane. The inside of the vesicle opens to the outside of the cell, releasing the neurotransmitters. This type of transport of cellular products is called pinocytosis. receptor-mediated endocytosis. exocytosis. phagocytosis.

exocytosis.

Recently, beekeepers have noticed an alarming and sudden disappearance of honeybees from their hives. Some beekeepers and environmentalists worry that crops genetically engineered to produce Bt insecticidal toxin may be killing the bees. Select the controlled experiment that tests the hypothesis that Bt toxin is killing the bees. spraying Bt toxin on a field and counting the number of bees present after spraying exposing 100 bees to plants that express the gene for Bt toxin, while another 100 bees of the same species are exposed to normal plants; the survival rate for both sets of bees would be calculated and compared collecting hundreds of bees and spraying half of them with Bt toxin and the other half with DDT, another insecticide; the survival rate for both sets of bees would be calculated and compared introducing two different species of bees to a field that was sprayed with the Bt toxin; the number of dead bees from each species would be calculated and compared

exposing 100 bees to plants that express the gene for Bt toxin, while another 100 bees of the same species are exposed to normal plants; the survival rate for both sets of bees would be calculated and compared

Ionic bonds __________, whereas covalent bonds __________. form between the same two elements; form between different elements hold together compounds that do not dissolve in water; hold together molecules that dissolve in water hold together oppositely charged atoms; hold together atoms that share electrons consist of atoms with partial charges; consist of atoms with full positive and negative charges

hold together oppositely charged atoms; hold together atoms that share electrons

Phospholipids are large organic molecules with a hydrophilic, polar phosphate head connected to hydrophobic, nonpolar fatty acid tails. These molecules arrange themselves to form a mostly impermeable barrier between the fluid inside a liposome and its external environment by lining up hydrophilic head to hydrophilic head, with the tails all facing outward from the center line of the membrane. hydrophobic tails facing each other at the center line of the membrane, with the hydrophilic heads facing outward, away from the center line of the membrane. hydrophobic tails facing hydrophilic heads. hydrophilic tails facing hydrophobic heads, with every other tail facing outward from the center line of the membrane.

hydrophobic tails facing each other at the center line of the membrane, with the hydrophilic heads facing outward, away from the center line of the membrane.

The following figure shows a beaker divided into two compartments by a semipermeable membrane that allows the passage of water molecules, but prevents the passage of sugar molecules. Assume that each sugar molecule represents a percentage point of sugar dissolved in the solution. Over time, the solution volume on the left side of the figure would __________. This is because the solution on the left side of the figure is __________ relative to the solution on the right. increase; hypertonic decrease; hypertonic decrease; hypotonic increase; hypotonic

increase; hypertonic

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

independent variable

When calcium (Ca2+) and chloride (Cl-) interact with one another, they bond using __________ bonds. hydrogen peptide covalent ionic

ionic

Sodium chloride (table salt) is formed when positively charged sodium ions and negatively charged chloride ions are chemically attracted to each other. This attraction is best described as a(n) hydrogen bond. ionic bond. covalent bond. solution.

ionic bond.

Laura's supervisor provides her with lipids, carbohydrates, proteins, and nucleic acids and asks her to determine their chemical components. Which of the following elements would she NOT expect to find in these items? carbon iron hydrogen nitrogen

iron

A solid waste (garbage) transfer facility that sorts and breaks down garbage into recyclables and waste to be thrown away in the landfill would be a suitable analogy for which cellular organelle? smooth ER rough ER lysosome nucleus

lysosome

Scientists analyzed 62 studies and determined that a strong physician recommendation for the HPV vaccine was a positive determining factor in whether or not parents chose to vaccinate their children. This analysis of various studies is referred to as meta-analysis. beta-analysis. secondary study. secondary analysis.

meta-analysis

Carbon, hydrogen, and oxygen atoms are held together by chemical bonds to form __________ of sugar. organ systems molecules cells atoms

molecules

If the concentration of sugar molecules in water on side A of a selectively permeable membrane is 5 percent, and the concentration of sugar molecules in water on side B of a selectively permeable membrane is 15 percent, the water molecules will mostly move from side B to side A because the water concentration is higher on side "B." mostly move from side A to side B because the water concentration is higher on side "A." mostly move from side A to side B because the water concentration is higher on side "B." not move at all because the water concentrations are isotonic.

mostly move from side A to side B because the water concentration is higher on side "A.

Announcing "scientific" findings in a press conference before they have been published in an established scientific journal is an example of primary literature. secondary literature. neither primary nor secondary literature because it has not yet undergone peer review to be primary literature, and secondary literature follows primary literature. both primary and secondary literature because it does not need to undergo peer review to be either primary or secondary literature.

neither primary nor secondary literature because it has not yet undergone peer review to be primary literature, and secondary literature follows primary literature.

Liposomes form spontaneously from __________ and are important because __________. DNA; they provide a rigid structure to support the cell phospholipid monolayers; these phospholipid monolayers provide a stable barrier between the internal and external environments rigid cell walls; they provide support for the living cell and a barrier between the external and internal environments phospholipids and water; they provide a barrier between an external environment and an internal environment

phospholipids and water; they provide a barrier between an external environment and an internal environment

The bonds connecting the atoms in the following molecule are __________ bonds. polar, hydrogen polar, covalent nonpolar, ionic nonpolar, covalent

polar, covalent

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

polypeptide—amino acid

You are reading an article written by Neil Shubin et al. regarding the pectoral fin of Tiktaalikroseae in the peer-reviewed journal Nature. Dr. Shubin is a member of the National Academy of Sciences and is employed by The University of Chicago. This article represents a __________ literature presentation of __________ research. primary; basic primary; applied secondary; basic secondary; applied

primary; basic

Of the following values, which indicates the most basic pH? 5 7 8 10

10

Which one of the following images illustrates both hydrogen bonds and covalent bonds?

A

If iodide ions (I-) were dissolved in water (as pictured here), they would be attracted to A only B only C only A and C

A and C

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

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

As shown in the following figure, the highest concentration of free hydrogen ions is found in household ammonia. lemons. human blood. stomach acid.

stomach acid

Rick has high blood pressure and decides to try an herbal supplement recommended by his friend. Which of the following questions should Rick ask first to scientifically evaluate his friend's recommendation before he begins taking the herbal supplement? Has this herbal supplement been studied in a clinical trial by trained medical professionals? If this supplement was studied, who paid for the study? If this supplement was studied, how many people were included as patients in the study? What are the credentials of the team investigating the supplement?

Has this herbal supplement been studied in a clinical trial by trained medical professionals?

Which of the following statements about the process of science is accurate? Science is a systematic method designed to answer questions by evaluating evidence. Science attempts to solve a problem by evaluating the plausibility of only one solution without considering other possible explanations. Science does not use evidence and data collected to advance our understanding of natural and supernatural phenomena. Science can answer all questions regarding the human experience and personal values.

Science is a systematic method designed to answer questions by evaluating evidence.

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

Specific pathogens are directly responsible for specific diseases and conditions.

Based on the scientific evidence presented in more than 100 peer-reviewed, published research articles that evaluated millions of children, which of the following is NOT the reason for the observed increase of autism in the United States and other countries since the 1970s? There is a heightened awareness of autism in society. More schools are screening more students for autism. People are generally more willing to label a broader range of conditions within the spectrum of autism disorders. The MMR vaccine is being more broadly administered, so more children are getting autism.

The MMR vaccine is being more broadly administered, so more children are getting autism.

The graph below shows which of the following? There is a strong correlation between the sale/consumption of organic food and the number of individuals diagnosed with autism between 1998 and 2007. The increased consumption of organic food has led to an increase in the rate of autism between 1998 and 2007. Consuming organic food causes autism. There is strong evidence that a cause-effect relationship exists between the consumption of organic food and the development of autism.

There is a strong correlation between the sale/consumption of organic food and the number of individuals diagnosed with autism between 1998 and 2007.

Thomas's foot began to swell after he was stung by a scorpion. Thomas's friend said his mom had an old, trusted herbal poultice remedy that would absorb the venom from the foot, reduce the swelling, and heal the foot. Thomas allowed his friend to place the herbal poultice on his foot before going to bed that night, and the swelling was gone in the morning. Which of the following can be concluded about the herbal poultice remedy? The poultice definitely worked because the swelling went down. The poultice definitely did not cause the swelling to go down. It is very likely that the poultice caused the swelling to go down. There is not anything that can be concluded about the effectiveness of the poultice remedy.

There is not anything that can be concluded about the effectiveness of the poultice remedy.

Why would hydrophilic substances such as sodium ions (Na+), hydrogen ions (H+), sugars, and amino acids be unable to simply diffuse across a plasma membrane? They readily mix with the hydrophobic tails that form the core of the phospholipid bilayer. They are repelled by the hydrophilic heads of the phospholipids that form the phospholipid bilayer. They do not readily mix with the hydrophobic tails forming the core of the phospholipid bilayer; therefore, they must move across by facilitated diffusion. They do not readily mix with the hydrophobic tails forming the core of the phospholipid bilayer; therefore, the only way they can move into the cell is by endocytosis.

They do not readily mix with the hydrophobic tails forming the core of the phospholipid bilayer; therefore, they must move across by facilitated diffusion.

The following image diagrams the action of an enzyme. Notice that the enzyme is depicted as being more tightly wrapped around the substrates in step 2 than it is in step 1. Why is this? When a substrate locks into the active site of an enzyme, the enzyme changes shape to mold itself around it. Generally, the size of a substrate is larger than the size of the active site into which it must fit. When the substrate enters the active site, the active site must stretch to fit. Before catalysis can occur, a substrate must change its shape so that it fits into the active site of the enzyme more precisely. Most active sites are only designed to hold one substrate. In this image, two substrates enter the active site, creating a tighter fit.

When a substrate locks into the active site of an enzyme, the enzyme changes shape to mold itself around it.

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

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

A group of researchers conducted an experiment and collected the data that is presented in the following graph. The hypothesis that the fungus is sufficient to cause death is __________ by the data because all members of the control group __________ while most of the members of both treatment groups __________ by the end of the study. proven beyond a doubt; survived; died proven; survived; died not supported; died; survived supported; survived; died

supported; survived; died

Is it important for scientists to communicate their results to fellow scientists? Yes. The scientific method generates data, but only other scientists can determine the morally correct way to act on that information. No. There is no reason for scientists to communicate their results to fellow scientists. Yes. The quality and accuracy of the scientific work can be enhanced by input, further review, and even repetition by other scientists working in the same field. No. Communication between scientists is discouraged because it can confuse the details of the experiments.

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

A scientific hypothesis must be __________; if not, science cannot evaluate it. provable testable accepted rejected

testable

Ice floats on water because the crystal structure of ice is more regular than that seen in liquid water. the distance between water molecules in ice is greater than in liquid water. the cool temperature of ice reduces the extent of molecular motion relative to liquid water. when ice forms, the hydrogen bond in the water molecule becomes nonpolar; ice behaves like oil.

the distance between water molecules in ice is greater than in liquid water.

When sodium chloride (Na+Cl-) is dissolved in water, the sodium ion is attracted to the hydrogen atoms of water molecules. repelled by the oxygen atoms of water molecules. attracted to other sodium ions that are being dissolved. attracted to the oxygen atoms of water molecules.

attracted to the oxygen atoms of water molecules.

Carbon's prominence in living systems can be explained by the fact that it forms weak reversible bonds. it bonds with up to three other atoms. carbon-based molecules can form long chains and rings. it does not form small molecules.

carbon-based molecules can form long chains and rings.

Chemical reactions that break down lipids are catabolic. anabolic. metabolic. respiration.

catabolic

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

concentration of hydrogen ions in a solution.

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 determine whether the compound is held together by hydrogen bonds. determine the number of electrons in the compound's outer shell. mix the compound with an ionic substance to see whether its bonds can withstand the pressure. determine whether the compound dissolves in water.

determine whether the compound dissolves in water.

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

donates hydrogen ions to the solution.

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

electrons.

Enzymes can catalyze a reaction only if they encounter a molecule of ATP. have a phosphate bound to their active site. have both products in their active site at the same time. encounter a substrate that fits their active site.

encounter a substrate that fits their active site.

When ATP breaks down into ADP and a phosphate group, energy is absorbed by ADP and transferred to enzymes. energy is released and can power cellular activities. ADP becomes the active site in an enzyme. the energy in the broken bond is transferred to the phosphate group.

energy is released and can power cellular activities.

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 the fungus Geomyces destructans. Group 2 was housed in an area that shared the same air as bats infected with white-nose syndrome (WNS), but these bats did not have direct contact with the infected bats. Group 3 was housed in direct contact with other bats infected with WNS. Bats in group 4 were 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? group 1 group 2 group 3 group 4

group 1

CDC's HPV Vaccine Impact Monitoring Project evaluated data from over 10,000 biopsy specimens collected between 2008 and 2014. The proportion of cervical precancers due to HPV types 16 and 18 decreased from 55 percent to 33 percent in women ages 18-39 who had been vaccinated with the HPV vaccine. Additionally, precancers among unvaccinated women declined due to HPV-16/18. This decline is likely due to __________ immunity, which occurs when a significant proportion of a population has developed immunity to a disease. individual herd natural vaccination

herd

In making her morning tea, Dorothy drops a sugar cube into some hot water. She stirs the mixture but no longer sees the sugar cube at the bottom of her mug. Based on her observation of sugar dissolving in hot water, she can properly conclude that the sugar is hydrophobic. nonpolar. hydrophilic. inert.

hydrophilic.

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

hypothesis.

Hypotheses can be tested through observational studies or experimental studies. Which of the following represents an experimental approach to testing a hypothesis? injecting trees with insecticide to determine whether it protects against a certain insect pest measuring crop yields to better document the impacts of a severe drought searching for fossils in a recently exposed outcropping of rock predicting migration routes for monarch butterflies in light of anticipated future climate change

injecting trees with insecticide to determine whether it protects against a certain insect pest

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. carbohydrate nucleotide protein lipid

nucleotide

Prokaryotes and eukaryotes are primarily distinguished by the absence or presence of ribosomes. plasma membranes. organelles. cell walls.

organelles.

During the process of __________, water diffuses across a semipermeable membrane from an area where water is more concentrated to an area where water is less concentrated (it moves along the water concentration gradient). osmosis active transport endocytosis pinocytosis

osmosis

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

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

Scientists are human beings and, like all human beings, are 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 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 hypothesis rejection. fact checking. peer-reviewed publications. controlled experiments.

peer-reviewed publications

Which of the following is LEAST likely to include unchecked bias when making scientific statements? political groups religious groups marketing groups peer-reviewed scientific journals

peer-reviewed scientific journals

A white blood cell (WBC) encounters bacteria in a scrape on the knee of a child who has fallen off a bicycle. The WBC's job is to take the bacteria inside itself and destroy it. If the bacteria are too large to be transported via transported proteins, how will the WBC most likely take them in? exocytosis pinocytosis facilitated diffusion phagocytosis

phagocytosis

Living cells have an intact phospholipid bilayer that separates the cell from its external environment; this structure is commonly referred to as the nuclear envelope. protein coat. cell wall. plasma membrane.

plasma membrane.

Hydrogen and oxygen atoms are held together within an individual water molecule by __________ bonds. hydrogen peptide polar covalent ionic

polar covalent

Which of the following is the largest in size? glucose protein carbon atom nucleotide

protein

A protein molecule, transferrin, that is embedded in the plasma membrane recognizes iron molecules and causes the plasma membrane to fold in around the iron and take it into the cell. This is an example of exocytosis. diffusion. receptor-mediated endocytosis. pinocytosis.

receptor-mediated endocytosis.

In science, when a hypothesis or group of hypotheses supported by repeated experimental evidence holds true through time, it can be developed into a scientific fact. proven explanation. peer-reviewed prediction. scientific theory.

scientific theoryscientific theory

You are reading an article in National Geographic regarding the evolution of humans. This would be an example of __________ literature. primary secondary peer-reviewed scientific journal meta-analysis

secondary

O2, also referred to as atmospheric oxygen, is formed by a covalent bond between two oxygen atoms. This type of bond involves oxygen atoms releasing protons. releasing electrons. sharing protons. sharing electrons.

sharing electrons

Which of the following could be built solely from glucose molecules? fatty acids DNA oils starch

starch

Once it has been supported by a predictable experimental outcome, a scientific hypothesis is never reexamined. still cannot be considered to have been proven true. cannot be refuted by future experiments. is elevated to the status of theory.

still cannot be considered to have been proven true.

A disaccharide consists of two sugars. hydrocarbons. fatty acids. amino acids.

sugars.

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 white-nose syndrome (WNS), but these bats did not have direct contact with the infected bats. Group 3 was housed in direct contact with other bats infected with WNS. Bats in group 4 were directly exposed to Geomyces destructans when it was applied to their wings. During the study period the bats were monitored for signs of WNS. In this experiment, the independent variable was __________ and the dependent variable was __________. the type of exposure to Geomyces destructans; whether the bats became sick with WNS whether the bats became sick with WNS; the type of exposure to Geomyces destructans whether the bats became sick with WNS; the number of bats included in the study the number of bats included in the study; the type of exposure to Geomyces destructans

the type of exposure to Geomyces destructans; whether the bats became sick with WNS

Which of the following would be likely to move through a plasma membrane by simple diffusion? water (H2O), carbon dioxide (CO2), and oxygen (O2) polysaccharides, large protein molecules, and low-density lipoprotein particles bacteria and yeast sodium ions (Na+), hydrogen ions (H+), sugars, and amino acids

water (H2O), carbon dioxide (CO2), and oxygen (O2)

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

water is polar and oil is nonpolar

Which of the following examples indicates a situation where the researcher is MOST likely to have a possible bias regarding his or her work? A researcher, funded by a pharmaceutical company, is testing the clinical effectiveness and safety of a new vaccine. A researcher, funded by a public grant, is testing the clinical effectiveness and safety of a new vaccine. A federally funded researcher is working on developing a genetically engineered microbe to quickly digest oil spills. A privately funded researcher is working on developing a genetically engineered and patented microbe to quickly digest oil spills. If successful, the microbe would be marketed worldwide.

A privately funded researcher is working on developing a genetically engineered and patented microbe to quickly digest oil spills. If successful, the microbe would be marketed worldwide.

A scientist publishes a paper in a peer-reviewed journal; this paper is later retracted. Which of the following (if found to be true) is NOT a legitimate reason for the retraction? The study involved only 12 participants, but sweeping conclusions were made by the author. These participants were not randomly sampled; they were picked specifically for their symptoms. Furthermore, there was no control group. The findings could not be replicated, and there were many peer-reviewed studies, including millions of participants that found no evidence for the claims of the original paper. The primary author of the paper received large amounts of money as a paid expert for lawyers who were suing companies based on the author's claim. The author would also benefit financially in other ways, such as patents on alternative products. Although the findings were not replicated by other researchers, some studies indicated that the original paper might suggest a valid line of reasoning and warrants further investigation.

Although the findings were not replicated by other researchers, some studies indicated that the original paper might suggest a valid line of reasoning and warrants further investigation.

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? Antibiotics cannot kill a virus because viruses are not living cells with cell walls to puncture, nor do they have the structures necessary for autonomous reproduction. Viruses are too virulent to be killed by those antibiotics. Viruses are too quick for the antibiotics to work. Viruses mutate at a rate faster than the rate at which antibiotics can kill them.

Antibiotics cannot kill a virus because viruses are not living cells with cell walls to puncture, nor do they have the structures necessary for autonomous reproduction.

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

Bats with white noses have been observed in the wild.

Which of the following statements most accurately describes a selectively permeable membrane? Solutes always move across a selectively permeable membrane from a region of higher concentration to a region of lower concentration. Charged molecules are always excluded from crossing the membrane. All substances require specific transport proteins to pass through the membrane. Certain solutes move freely across the membrane by simple diffusion, while others require transport proteins; some substances are completely excluded from crossing the membrane.

Certain solutes move freely across the membrane by simple diffusion, while others require transport proteins; some substances are completely excluded from crossing the membrane.

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

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

Recently, beekeepers have noticed an alarming and sudden disappearance of honeybees from their hives. Some beekeepers and environmentalists worry that crops that are genetically engineered to produce 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? Yes, because it is obviously the Bt crops that are killing the bees. Yes, because there cannot possibly be any other explanation for the loss of the honeybees. No, because there is no reason to suspect that an insecticide would kill honeybees. No, because there could be some other unknown or unmentioned factor affecting the survival of honeybees.

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

When Lori was diagnosed with breast cancer, the doctor recommended a lumpectomy followed by radiation therapy. Lori underwent the prescribed treatment recommended by the doctor. However, she also continued to eat lots of fruits and vegetables, walk three miles every day, and practice daily yoga. Within about three months, Lori was cancer-free. Afterward, Lori told everyone that her healthy lifestyle had helped to cure her. Is this conclusion reasonable given the circumstances? No, a healthy diet and exercise regimen can never help cure cancer. No, there are too many confounding factors to know exactly what happened. Yes, the healthy diet and exercise regimen definitely helped to cure her. Yes, this evidence very strongly supports the hypothesis that a healthy diet and exercise regimen probably helped to cure her.

No, there are too many confounding factors to know exactly what happened.

What is the importance of photosynthesis to organisms other than plants? All other organisms require carbon dioxide for life processes. The sugars made during photosynthesis are the direct building blocks of DNA. All cells must contain chloroplasts in order to survive. Photosynthesis captures energy that other organisms access when they ingest or absorb nutrients from photosynthetic organisms.

Photosynthesis captures energy that other organisms access when they ingest or absorb nutrients from photosynthetic organisms.

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. 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? Scientific knowledge is absolute knowledge. Scientific knowledge is based on current knowledge. Scientific knowledge is a static and unchanging collection of facts. Scientific knowledge is a rigid collection of invariable facts.

Scientific knowledge is based on current knowledge

Based on these macromolecule images, what is a shared feature? They are all polar compounds. They are all organic compounds. They are all nonpolar compounds. They are all acidic compounds.

They are all organic compounds.

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

They can evolve as groups.

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

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

Which of the following accurately describes viruses? 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. Each is typically a piece of genetic material encased in proteins, and they can reproduce on their own. They can attack plants and animals, and each is typically a piece of self-replicating genetic material encased in a protein envelope. Typically a piece of genetic material encased in proteins; they are small, noncellular infectious agents that are only capable of reproducing when inside a living cell such as those of plants, animals, or bacteria.

Typically a piece of genetic material encased in proteins; they are small, noncellular infectious agents that are only capable of reproducing when inside a living cell such as those of plants, animals, or bacteria.

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

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

In making her morning tea, Dorothy drops a sugar cube into the hot water. She stirs the mixture but no longer sees the sugar cube at the bottom of her mug. In this scenario, the sugar is nonpolar. the solvent. an acid. a solute.

a solute

Which of the following would be the best analogy for the function of the Golgi apparatus? the machine that assembles a product a worker in a factory who places labels on products and then packs them into a shipping box the garbage truck that hauls away the wastes produced as a product is made the blueprints for making the product

a worker in a factory who places labels on products and then packs them into a shipping box

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? monosaccharides phospholipids amino acids nitrogenous bases

amino acids

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 salt. a base. water only. an acid.

an acid

According to the following figure, which of the following has a lower concentration of hydrogen ions? milk. oranges. antacids. baking soda.

antacids

Scientists working for a major cosmetics company want to determine if a new face cream can reduce the number of fine lines and wrinkles on a person's face. This is an example of applied research. basic research. meta-analysis. a cohort study.

applied research

A pharmaceutical company conducts trials on animals and cell lines to determine the safety of a new vaccine before performing clinical trials on adult human volunteers. This is an example of basic research. applied research. a case-control study. a cohort study.

applied research.

The federally funded Centers for Disease Control routinely collect and evaluate data regarding communicable diseases. This information helps researchers make recommendations regarding vaccination schedules for children and adults. This is an example of basic research. applied research. a case-control study. a cohort study.

applied research.

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

are the building blocks of nucleic acids

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

base.

Scientists at a major university are attempting to isolate a gene that slows the degeneration of collagen in skin. This is an example of applied research. basic research. meta-analysis. a case-control study.

basic research

A plant cell is mutated so that ATP synthase no longer functions. Which process will be affected? photosynthesis only respiration only both photosynthesis and respiration neither photosynthesis nor respiration

both photosynthesis and respiration