Ch.2 The Chemistry Of Life Verified Test Bank 4th Edition

Chapter 02

The Chemistry of Life

Multiple Choice Questions

Many traits of organisms, such as body form and color, are controlled by specific proteins, in turn controlled by the DNA genetic sequence of nucleotides. The genetic control of color, as in aphids, does not usually shift during the life of an organism. Researchers found that some specific aphid populations shift from an original red coloration to a green coloration.

Genetics could be a factor, if some programmed shift could be identified. Environmental conditions of the living and nonliving habitat could be a factor. Either way, the chemistry and observed changes of pigment molecules in the aphids can be studied with the scientific method.

1. What is the link between colored pigment molecules and other organic molecules?
2. All of the answer choices are correct.
3. In the case of the aphids, the pigment molecules of bacteria are genetically passed on to the DNA of infected aphids.
4. The DNA molecule genetic sequence regulates protein molecule function, which can change pigment structure that affects color.
5. Pigment molecules are made up of all four of the other organic molecule groups.
6. This one group of aphids can easily alter the pigment molecule structure by modifying its DNA nucleotide sequence and building new proteins.
7. The initial experiment of Koga and Fugatsu, in testing for any bacterial cause of aphid color change, involved all of these except
8. the specific amounts of red and green pigment molecules were initially measured as dependent variables.
9. a group of green aphids was grown, then killed in order to produce an extract to test on red aphids.
10. a group of red aphids was treated with the independent variable of Rickettsiella bacteria infection from green aphids.
11. a group of red aphids was grown as a control group.
12. a group of aphids infected with Rickettsiella bacteria was grown, then killed in order to produce an extract to test on red aphids.
13. The observations and research on aphid color changes can most directly be summarized in that
14. Koga and Fugatsu proved that the color change from red to green in aphids was ecologically favorable to survival.
15. the method of paper fiber separation of pigment molecules showed that Ricketsiella bacteria were the source of the green coloration of aphids.
16. species of organisms can be chemically diverse and affect each other, even among similar groups of aphids and bacteria.
17. it turned out that the green appearance of aphids was because of the large amount of green Ricketsiella bacteria coating their bodies.
18. All of the answer choices are correct.
19. Researchers noted that only a few aphids changed color to green from their original red. This is an unusual observation among any animals. What research question came out of the observations?
20. Is the color shift of certain aphids due to genetics within a select species?
21. Is the color shift of certain aphids due to changes in weather conditions?
22. Is the color shift of certain aphids due to genetics or some other factor?
23. Do other aphids change colors as they age?
24. Will green aphids change their color to red, or remain green as they age?
25. The four most abundant elements needed by the human body are carbon, hydrogen, oxygen, and nitrogen. Because these are needed in large amounts to support our cells, these are referred to as
26. buffers.
27. bulk elements.
28. essential elements.
29. trace elements.
30. isotopes.
31. In the 1700s, a French scientist, Antoine Lavoisier, gained new experimental information by reacting a metal and an acid. His observation of the results seemed to show

that much of the metal had been lost in the chemical reaction. Upon weighing the products, the total amounts of materials had not changed during the reaction.

This research resulted in the law of conservation of mass. This law also applies to biology, because the materials we are made of are that change forms, but aren't truly lost through biochemical reactions.

1. matter
2. isotopes
3. energy
4. metals
5. solutions
6. Water has unique properties which include its strength as a solvent; its three environmental stages of solid, liquid, and gas; and its temperature regulation. These properties are due to polar covalent bonds between oxygen and hydrogen. The polar covalent bonds are a result of
7. there being a greater number of electrons in oxygen outermost shell than in hydrogen.
8. oxygen being more electronegative and therefore attracting more electrons than hydrogen.
9. hydrogen being an electron donor and oxygen being an electron acceptor.
10. hydrogen and oxygen having equal electronegative strength and therefore have equal sharing of electrons.
11. hydrogen being more electronegative and therefore attracting more electrons than oxygen. Refer to this diagram with common examples of substances and their pH.

1. The correct functions of your lungs contribute to the normal pH level of between 7.35 and 7.45. If your lungs do not exchange and remove carbon dioxide from your blood, the blood pH will change. A pH 6.4 reading of your blood indicates
2. a health problem due to the pH value being 10X higher OH- concentrations than normal in your body.
3. a health problem due to the pH value being 2X higher OH- concentrations than normal in your body.
4. a health problem due to the pH value being 2X higher H+ concentrations than normal in your body.

D. no health risk, as part of normal pH changes in your body that in this case bring it closer to neutral pH.

E. a health problem due to the pH value being 10X higher H+ concentrations than normal in your body.

1. Our normal blood pH should be in a fairly narrow range. Imagine you sit down to eat a large meal with cola, tomato-based sauce, and a salad with many citrus fruit slices. Identify the one statement that does not apply as one of the likely outcomes of your meal.
2. Your blood and body fluids will likely become more basic, with a higher pH than the normal range.
3. The cola, tomato, and citrus fruits will add hydrogen (H+) to your blood and body fluids.
4. All of the answer choices are correct.
5. Your body will produce buffer molecules to help neutralize acids you ate, so your blood pH doesn't change much.
6. Your blood and body fluids will likely become more acidic, with a lower pH than the normal range. Examine this image of the glucose molecule.

10. Based on the 1:2:1 proportions of carbon, hydrogen, and oxygen, it can be determined that the glucose molecule is a(n)

1. triglyceride.
2. carbohydrate.
3. polymer.
4. amino acid.
5. disaccharide.
6. Starchy foods in our diets, such as rice and potatoes, consist of many glucose molecules covalently bonded together to form
7. a simple sugar.
8. a complex carbohydrate.
9. a fatty acid chain.
10. a triglyceride.
11. a protein.
12. This molecule of starch is different from a glucose molecule in that this molecule
13. is used by cells for long-term storage and release of energy for cell functions.
14. is a complex carbohydrate polymer.
15. has the same characteristics of glucose.
16. is used by cells for quick release of energy for cell functions.
17. can provide structure for cells that contain it.

True / False Questions

Examine these two sugars, as shown prior to the chemical reaction that would bond them.

1. These glucose and fructose molecules will bond to form a monosaccharide with the removal of water.

True False

Multiple Choice Questions

1. The diagram shows the monomers, glucose and fructose, before occurs, which builds a polymer via the removal of water.
2. reproduction
3. dehydration synthesis
4. oxidation
5. evaporation
6. hydrolysis
7. The ring structure of glucose indicates that it is a(n)
8. monosaccharide.
9. fatty acid.
10. disaccharide.
11. amino acid.
12. nucleotide.
13. The primary elements making up living organisms are
14. carbon, hydrogen, iron, sulfur, sodium, and calcium.
15. carbon, hydrogen, oxygen, sulfur, nitrogen, and phosphorus.
16. carbon, hydrogen, oxygen, calcium, iron, and iodine.
17. carbon, oxygen, iron, chlorine, sulfur, and phosphorus.
18. carbon, oxygen, sulfur, calcium, iron, and phosphorus.
19. The atomic number of an element is the number of
20. protons in the orbitals.
21. electrons in the nucleus.
22. neutrons in the orbitals.
23. protons in the nucleus.
24. neutrons in the nucleus.

18. Given this information from one element in the periodic table of elements, the number of neutrons and protons is

1. 7, which is also the atomic mass.
2. unable to be determined with the information provided.
3. 14, which is also the atomic mass.
4. 14, which is also the atomic number.
5. 7, which is also the atomic number.
6. The mass number is defined as the total number of of an atom.
7. protons
8. protons, neutrons, and electrons
9. neutrons and electrons
10. protons and electrons
11. protons and neutrons
12. An ion is an atom that has
13. a net negative charge.
14. a different number of neutrons from the number of protons.
15. a net negative or positive charge, with the number of electrons different from the number of protons.
16. the same number of electrons as it does protons.
17. a net positive charge.
18. The first energy shell of an atom has one orbital. Therefore, it can contain a maximum of electron(s).
19. one
20. sixteen
21. eight
22. four
23. two
24. In an oxygen element, each oxygen atom contains eight electrons in its valence shell. The atoms will be
25. highly reactive.
26. not chemically stable.
27. chemically stable.
28. highly likely to combine with other atoms.
29. not inert.
30. In a covalent bond, atoms
31. both become highly electronegative.
32. share protons.
33. share electrons.
34. of opposite charges attract each other.
35. lose electrons.
36. In an ionic bond,
37. two atoms are attracted by partial positive and negative charges.
38. two atoms are attracted by the same charges.
39. atoms attract each other by sharing electrons to fill their valence shells.
40. atoms, having gained or lost electrons, attract one another with opposite charges.
41. two atoms both become strongly electronegative and attract each other.

25. Carbon and hydrogen make up many biologically important molecules. Carbon has an electronegativity of 2.55, whereas hydrogen has an electronegativity of 2.2. Based on the electronegativity difference between the atoms, the carbon and hydrogens shown here have just formed

1. an ionic bond.
2. a hydrogen bond.
3. a polar covalent bond.
4. a nonpolar covalent bond.
5. an element.

26. Which statement summarizes the distinction between nonpolar and polar covalent bonds?

1. The difference in electronegativity of the atoms in a nonpolar covalent bond is very large.
2. The electrons are more evenly and symmetrically distributed in orbit among atoms in a nonpolar covalent bond.
3. The electrons are more evenly and symmetrically distributed in orbit among atoms in a polar covalent bond.
4. Polar covalent bonds are formed when the atoms gain or lose electrons to bond and become oppositely charged ions.

27. Referring to the ionic bond formation between sodium and chlorine, which of the following is not a true statement?

1. Na is the chemical symbol for sodium.
2. Sodium donates an electron.
3. Chlorine donates an electron.
4. Sodium becomes positively charged.
5. The bond that is formed is stronger than a hydrogen bond.

28. Water molecules exhibit cohesive and adhesive properties. What is the chemical bond characteristic that contributes to these and other numerous important properties of water molecules?

A. The covalent bond strengths of water molecules change with pH, temperature, or solute conditions present.

B. The covalent bonds that form water molecules transform to ionic bonds in presence of other molecules, temperature changes, or pH.

C. Hydrogen bonds form between water molecules, not requiring gain, loss, or sharing of electrons.

1. Bonds that form water are of the nonpolar covalent form.
2. Ionic bonds between water molecules create increased surface tension.

True / False Questions

29. The property of water demonstrated by a water strider, as it remains on top of the water, is that water molecules are held together by ionic bonds.

True False

Multiple Choice Questions

1. You can painlessly wade into a pool, but doing a belly flop off of the high diving board hurts because of
2. cohesion in water.
3. water's high boiling point.
4. water's high density.
5. water's neutral pH.
6. adhesion in water.
7. Trees are able to transport water from the roots to the top branches because
8. cohesion bonds water molecules to each other strongly.
9. liquid water has a higher density than the air in the plant cells of the roots, trunk, and branches.
10. water acts as a solvent of the tree cells as it moves upwards to the branches.
11. adhesion bonds water molecules to the inside of the plant conducting tubes.
12. leaves are hydrophilic.
13. Within a single molecule of water, as shown, bonds are formed between oxygen and hydrogen.

1. nuclear
2. hydrophobic
3. hydrogen
4. covalent
5. ionic

True / False Questions

1. If a molecule is added to a glass of water, and is easily dissolved by the water, the added molecule is described as hydrophilic.

True False

Multiple Choice Questions

1. Evaporation of water is a phase of water from
2. a liquid into a vapor.
3. a solid into a vapor.
4. a vapor into a liquid.
5. a vapor into a solid.
6. All of the answer choices are correct.
7. You collect and measure samples of ice and surrounding ice water from a stream in the winter. You find that you collected the same number of water molecules in each form. The volume of the ice samples are larger than the ice water samples. This is a result of
8. the ionic bonds between the water molecules being unstable and constantly forming and breaking that increases the volume and decreases the density of the ice.
9. the covalent bonds between the water molecules being unstable and constantly forming and breaking that increases the volume and decreases the density of the ice.
10. the covalent bonds between the water molecules being in a fixed position that increases the volume and decreases the density of the ice.
11. the hydrogen bonds between the water molecules being unstable and constantly forming and breaking that increases the volume and decreases the density of the ice.
12. the hydrogen bonds between the water molecules being in a fixed position that increases the volume and decreases the density of the ice.
13. In a chemical equation, which components of a chemical reaction are found on the left side of the arrows?
14. solvents
15. reagents
16. reactants
17. products
18. buffers
19. An acid
20. has a value above 7 on the pH scale.
21. is a chemical that takes hydrogen ions from a solution.
22. has a value of 7 on the pH scale.
23. is a chemical that adds hydrogen ions to a solution.
24. All of the answer choices are correct.
25. A base
26. is a chemical that adds hydrogen ions to a solution.
27. has a value below 7 on the pH scale.
28. is a chemical that absorbs hydrogen ions from a solution.
29. has a value of 7 on the pH scale.
30. All the answer choices are correct.

39. Algal phytoplankton are single-celled water organisms that perform photosynthesis like plants. In a lake, summer growth of phytoplankton can change the water pH from pH 7.2 to 6.2. This change indicates all of the following except

A. the water at pH 6.2 has twice the hydrogen (H+) concentration than before the phytoplankton growth.

B. the water at pH 6.2 has 10 times the hydrogen (H+) concentration as before the phytoplankton growth.

1. the growth of phytoplankton changed the pH of the water.
2. the lake water solution changed from slightly basic to slightly acidic in pH.
3. the water at pH 6.2 is a stronger acid solution than before the phytoplankton growth.
4. Organic molecules are defined as chemical compounds that contain in distinct ratios and structures.
5. carbon and nitrogen
6. carbon and oxygen
7. carbon
8. carbon and hydrogen
9. carbon, hydrogen, and nitrogen
10. The four major groups of organic compounds are
11. carbohydrates, proteins, amino acids, and nucleic acids.
12. fats, waxes, carbohydrates, and amino acids.
13. carbohydrates, lipids, steroids, and monosaccharides.
14. carbohydrates, lipids, proteins, and nucleic acids.
15. lipids, fats, waxes, and steroids.
16. In living cells, a process by which cells break polymers down into monomers with the addition of water is
17. hydrolysis.
18. dehydration synthesis.
19. reproduction.
20. All of the answer choices are correct.
21. reduction.
22. Which of the following is not an example of a monosaccharide?
23. glucose
24. ribose
25. fructose
26. cellulose

E. All of the answer choices are correct.

1. Blood is closely maintained at a pH of 7.4. A patient whose blood pH drops below 7.35 is suffering from metabolic acidosis and can go into a coma. What happens to the concentration of H+ ions in a patient with a blood pH of 6.4?
2. H+ concentration is decreased 10-fold.
3. H+ concentration is decreased 2-fold.
4. H+ concentration is increased 10-fold.
5. H+ concentration is increased 2-fold.
6. H+ concentration is decreased 4-fold.
7. Which is not a lipid?
8. a sterol
9. a phospholipid
10. a triglyceride
11. a starch
12. a wax
13. The primary building block (monomer) of proteins is
14. an amino acid.
15. a nucleotide.
16. a fatty acid.
17. a glucose molecule.
18. a group of four interconnected rings.

47. An amino acid contains a structural "backbone" chain of

1. nitrogens.
2. phosphorus atoms.
3. carbons.
4. carbon and phosphorus atoms.
5. nitrogens and carbons.
6. The bond that builds amino acid monomers into protein polymers is
7. a covalent bond also known as a peptide bond.
8. a denatured hydrogen bond.
9. a covalent bond also know as a glycosidic bond.
10. an ionic bond also known as a peptide bond.
11. a primary structural bond.
12. Many diseases, cancers, and even normal human variations can be caused by mutations and variations in the DNA nucleotide sequence. The most likely immediate result of DNA having a different nucleotide sequence is that
13. the protein resulting from the DNA mutation would be denatured and nonfunctional.
14. the peptide bonds in the protein would by hydrolyzed and the protein would fall apart.
15. no direct result of change in the protein molecule would occur if DNA is mutated.
16. the polypeptide of a protein would be altered.
17. the ability for the cell to make proteins would fail.
18. The primary building block (monomer) of nucleic acids is
19. a group of four interconnected rings.
20. a nucleotide.
21. an amino acid.
22. a glucose molecule.
23. a fatty acid.
24. The three major components in a nucleotide are
25. a carboxyl group, an R group, and an amino group.
26. glucose, a nitrogen base, and a phosphate group.
27. a nitrogen base, a six-carbon sugar, and a phosphate group.
28. a nitrogen base, a five-carbon sugar, and a phosphate group.
29. glucose, a fatty acid, and glycerol.
30. Of the comparisons listed below, which is not true in distinguishing DNA from RNA?
31. DNA is a long double-strand molecule while RNA is a shorter single-strand molecule.
32. All of the answer choices are correct.
33. DNA and RNA are different in that RNA has uracil instead of thymine.
34. DNA has a main function of storing genetic information, while RNA is used to build specific proteins in a cell.
35. DNA is a molecule that stores and regulates our genetics, while RNA is used for cellular energy storage and release for biological functions.
36. The four nitrogen bases found in RNA are
37. adenine, thymine, guanine, and uracil.
38. adenine, cytosine, guanine, and uracil.
39. adenine, thymine, cytosine, and uracil.
40. thymine, cytosine, guanine, and uracil.
41. None of the answer choices is correct.
42. Sugar (CH2O)n, as a solute, dissolves well in water because sugar forms bonds with water.
43. hydrophobic
44. ionic
45. hydrogen
46. covalent
47. nonpolar
48. bonds are formed between monomers to form a polymer.
49. Hydrogen
50. Nuclear
51. Covalent
52. Hydrophobic
53. Ionic

56. Saturated fats have long, straight tails of fatty acids and can clump tightly together in cells and animal bodies. Unsaturated fats have kinks in their tails due to double bonds, which prevent them from packing together as tightly.

Animals that are ectotherms (their body temperature fluctuates with the environment) need to keep their membranes fluid at cooler temperature and thus use in their membranes.

1. mostly unsaturated fats
2. mostly saturated fats
3. equal amounts of saturated and unsaturated fats
4. carbohydrates
5. proteins
6. Saturated fats have long, straight tails of fatty acids, whereas unsaturated fats from vegetables have kinks in their tails due to double bonds. These kinks prevent the fats from packing together as tightly. Hydrogenated vegetable oils, or trans fats, have hydrogens added back to the double bonds and thus behave like
7. proteins.
8. saturated fats.
9. unsaturated fats.
10. carbohydrates.
11. waxes.
12. The group of organic molecule polymers with the most complex and diverse three-dimensional structure is
13. unsaturated fats.
14. proteins.
15. waxes.
16. carbohydrates.
17. saturated fats.

True / False Questions

1. Cohesion is a property of water in which water molecules tend to stick together.

True False

1. A peptide bond is a covalent bond formed between the amino group of one amino acid and the R group of another amino acid.

True False

1. A substance in which other substances dissolve is called a solute.

True False

1. Vegetable oil is an unsaturated fat from multiple plant sources. Because it is unsaturated, it is composed of at least one pair of double-bonded carbons.

True False

1. Of the 20 amino acids in all organisms, essential amino acids are obtained by food consumption.

True False

Multiple Choice Questions

1. Which of these pairs does not correctly match a carbohydrate with its function?
2. Chitin provides an exoskeleton for insects.
3. Glycogen is the storage form of energy in animals.
4. Starch provides long-term energy.
5. Cellulose provides structural support for human hair.
6. Starch is the storage form of energy in plants.

True / False Questions

1. If a protein is denatured, its structure has been changed enough to make the protein nonfunctional.

True False

1. Proteins store the genetic information of the cell and transmit it to the next generation.

True False

Multiple Choice Questions

1. If a carbohydrate polymer is limited to two monomer units, such as sucrose made from glucose and fructose, it is called
2. an oligosaccharide.
3. a complex carbohydrate.
4. a disaccharide.
5. a polysaccharide.
6. a monosaccharide.

68. Having the typical ratio of carbon, hydrogen, and oxygen of carbohydrates, the chemical formula for glucose is

A. C12H6O12.

B. C6H6O12.

C. C12H22O11.

1. C6H12O6.
2. C6H6O6.