Choose Correct Answer For Compounds Chemistry Quiz

1. Which of the following would be regarded as compounds?

A) O2 and CH4

E

B)H2O, O2, and CH4

C) CH4 and O2, but not H2O

Compounds are substances composed of two or more elements chemically bonded together. In this case, H2O and CH4 are compounds as they consist of multiple elements bonded together, while O2 is a diatomic molecule composed of two oxygen atoms and not a compound.

Explanation

Compounds are substances composed of two or more elements chemically bonded together. In this case, H2O and CH4 are compounds as they consist of multiple elements bonded together, while O2 is a diatomic molecule composed of two oxygen atoms and not a compound.

2. If a salamander relied on hydrogen bonds to cling to surfaces, what type of surface would cause the most problems for the animal?

B

C. a surface made with silicon and oxygen atoms covalently bonded together

A. A surface made with carbon, hydrogen, nitrogen, and oxygen atoms covalently bonded together

D. a surface made with carbon, hydrogen, and oxygen atoms covalently bonded together

Hydrogen bonding relies on intermolecular forces between hydrogen and either nitrogen, oxygen, or fluorine. A surface made with carbon and hydrogen atoms covalently bonded together would not provide the necessary hydrogen bond interaction for the salamander to cling effectively.

Explanation

Hydrogen bonding relies on intermolecular forces between hydrogen and either nitrogen, oxygen, or fluorine. A surface made with carbon and hydrogen atoms covalently bonded together would not provide the necessary hydrogen bond interaction for the salamander to cling effectively.

3. A pH of 7 is neutral due to the dissociation of water molecules in pure water. How many molecules of water have broken down into a hydroxide ion and a hydronium ion at pH 7?

B

C) 1 in 100 Million

D) 1 in 1 Billion

A) 1 in a Million

At a pH of 7, which is considered neutral, the concentration of hydronium ions (H3O+) is equal to the concentration of hydroxide ions (OH-), which is 1x10^-7 M. This means that for every 1 molecule of water that dissociates, the concentration of H3O+ and OH- ions would be 1x10^-7 M each.

Explanation

At a pH of 7, which is considered neutral, the concentration of hydronium ions (H3O+) is equal to the concentration of hydroxide ions (OH-), which is 1x10^-7 M. This means that for every 1 molecule of water that dissociates, the concentration of H3O+ and OH- ions would be 1x10^-7 M each.

4. Why are 'carbs' advertised by manufacturers of candy bars and sports drinks as quick energy boost?

A) The energy in them can be stored as fat, which has high energy per unit weight

D

C) The carbons in carbs are rich in energy because they are highly oxidized

B) This is an advertising gimmick that has no scientific evidence to support it

Manufacturers advertise 'carbs' as a quick energy boost because they are reduced molecules that have high-energy electrons, allowing for a rapid release of energy when consumed.

Explanation

Manufacturers advertise 'carbs' as a quick energy boost because they are reduced molecules that have high-energy electrons, allowing for a rapid release of energy when consumed.

5. Changing a single amino acid in a protein consisting of 325 amino acids would

D) cause the tertiary structure of the protein to unfold

A) alter the primary structure of the protein but not its tertiary structure or function

E

B) Always alter the biological activity or function of the protein

C) alwys alter the primary structure of the protein and disrupt its biological activity

Changing a single amino acid in a protein can alter its primary structure, sometimes affect the tertiary structure, and potentially affect its biological activity. This is due to the intricate relationships between amino acids in determining the overall structure and function of a protein.

Explanation

Changing a single amino acid in a protein can alter its primary structure, sometimes affect the tertiary structure, and potentially affect its biological activity. This is due to the intricate relationships between amino acids in determining the overall structure and function of a protein.

6. Where would you expect to find the amino acids serine and leucine in a globular protein in aqueous solution?

D. Both serine and leucine would be on the exterior of the globular protein.

B. Both serine and leucine would be in the interior and on the exterior of the globular protein.

C. Both serine and leucine would be in the interior of the globular protein.

A

In a globular protein, hydrophobic amino acids like leucine are typically found in the interior for stability, while hydrophilic amino acids like serine are located on the exterior for interactions with the surrounding aqueous environment.

Explanation

In a globular protein, hydrophobic amino acids like leucine are typically found in the interior for stability, while hydrophilic amino acids like serine are located on the exterior for interactions with the surrounding aqueous environment.

7. A double-stranded DNA molecule contains a total of 120 purines and 120 pyrimidines. This DNA molecule could be composed of

A) 120 guanine and 120 thymine molecules

C

D) 120 cytosine and 120 thymine molecules

B) 120 adenine and 120 cytosine molecules

In DNA, adenine pairs with thymine and cytosine pairs with guanine. Since there are equal numbers of purines (adenine and guanine) and pyrimidines (cytosine and thymine) in the DNA molecule, the correct pairing would be 120 thymine and 120 adenine molecules.

Explanation

In DNA, adenine pairs with thymine and cytosine pairs with guanine. Since there are equal numbers of purines (adenine and guanine) and pyrimidines (cytosine and thymine) in the DNA molecule, the correct pairing would be 120 thymine and 120 adenine molecules.

8. If cells are grown in a medium containing radioactive 15 N, which of these molecules will be labeled?

C) amylase only

B) nucleic acids only

E

A) fatty acids only

Radioactive 15 N is incorporated into nitrogenous bases of nucleic acids during cell growth. Proteins and nucleic acids both contain nitrogenous bases, leading to labeling of both molecules. Fatty acids and amylase do not contain nitrogenous bases and therefore would not be labeled in this scenario.

Explanation

Radioactive 15 N is incorporated into nitrogenous bases of nucleic acids during cell growth. Proteins and nucleic acids both contain nitrogenous bases, leading to labeling of both molecules. Fatty acids and amylase do not contain nitrogenous bases and therefore would not be labeled in this scenario.

9. Why can a modern electron microscope resolve biological images to the subnanometer level, as opposed to tens of nanometers achievable for the best super-resolution light microscope?

D

B

C

A

Electron beams have much shorter wavelengths than visible light, allowing for higher resolution images in electron microscopes compared to light microscopes.

Explanation

Electron beams have much shorter wavelengths than visible light, allowing for higher resolution images in electron microscopes compared to light microscopes.

10. In a plant cell, DNA may be found

A) only in the nucleus

D

B) Only in the nucleus and mitochondria

C) only in the nucleus and chloroplasts

In plant cells, DNA is present not only in the nucleus, but also in mitochondria and chloroplasts. This is due to the endosymbiotic theory which suggests that mitochondria and chloroplasts were once independent prokaryotic organisms that were engulfed by ancestral eukaryotic cells, leading to their presence of DNA.

Explanation

In plant cells, DNA is present not only in the nucleus, but also in mitochondria and chloroplasts. This is due to the endosymbiotic theory which suggests that mitochondria and chloroplasts were once independent prokaryotic organisms that were engulfed by ancestral eukaryotic cells, leading to their presence of DNA.

11. Where is most ATP synthesis likely to occur in prokaryotic cells according to the endosymbiont theory for the evolutionary origin of mitochondria?

E

C

A

B

In prokaryotic cells, ATP synthesis is likely to occur on the plasma membrane based on the endosymbiont theory for the evolutionary origin of mitochondria.

Explanation

In prokaryotic cells, ATP synthesis is likely to occur on the plasma membrane based on the endosymbiont theory for the evolutionary origin of mitochondria.

12. The differences among the three categories of cytoskeletal elements outlined in the table above would suggest that each of the following has specialized roles. Which of the following is a correct match?

B) microfilaments and the nuclear lamina

C

E) microfilaments and ciliary motion

A) intermediate filaments and cytoplasmic streaming

D) microtubules and cleavage furrow formation

The correct match is C, microtubules and chromosome movement. Microtubules play a crucial role in chromosome movement during cell division, specifically in helping to separate the chromosomes into daughter cells during mitosis or meiosis.

Explanation

The correct match is C, microtubules and chromosome movement. Microtubules play a crucial role in chromosome movement during cell division, specifically in helping to separate the chromosomes into daughter cells during mitosis or meiosis.

13. Which of the following is a reasonable explanation for why unsaturated fatty acids help keep any membrane more fluid at lower temperatures?

B. unsaturated fatty acids are more polar that saturated fatty acids

A. the double bonds block interaction among the hydrophilic head groups of the lipids

C. the double bonds result in shorter fatty acid tails and thinner membranes

D

Unsaturated fatty acids have double bonds that create kinks in the fatty acid tails, preventing adjacent lipids from packing tightly together. This results in a more fluid membrane at lower temperatures.

Explanation

Unsaturated fatty acids have double bonds that create kinks in the fatty acid tails, preventing adjacent lipids from packing tightly together. This results in a more fluid membrane at lower temperatures.

14. Mammalian blood is hypotonic to seawater. What will happen if red blood cells are transferred to seawater?

A

The blood cells will expend ATP for active transport of NaCl into the cytoplasm

NaCl will be exported from the red blood cells by facilitated diffusion

NaCl will passively diffuse into the red blood cells

When red blood cells are transferred to seawater, which is hypertonic to mammalian blood, water will leave the cells in an attempt to equalize the concentrations. This results in the cells shrinking and collapsing.

Explanation

When red blood cells are transferred to seawater, which is hypertonic to mammalian blood, water will leave the cells in an attempt to equalize the concentrations. This results in the cells shrinking and collapsing.

15. For living organisms, which of the following is an important consequence of the first law of thermodynamics?

B

C

D

A

The first law of thermodynamics states that energy cannot be created or destroyed, only transformed or transferred. This means that living organisms must obtain all necessary energy for life from their environment in order to maintain their energy content. This is why option C is the correct choice.

Explanation

The first law of thermodynamics states that energy cannot be created or destroyed, only transformed or transferred. This means that living organisms must obtain all necessary energy for life from their environment in order to maintain their energy content. This is why option C is the correct choice.

16. When glucose monomers are joined together by covalent bonds to form a cellulose polymer, the changes in free energy, total energy, and entropy are as follows:

C

B

D

A

When glucose monomers are joined to form a cellulose polymer, the process requires an input of energy (+ΔG), the total energy increases (+ΔH), but the disorder in the system decreases as the monomers are organized into a polymer, leading to a decrease in entropy (-ΔS). This is consistent with option B.

Explanation

When glucose monomers are joined to form a cellulose polymer, the process requires an input of energy (+ΔG), the total energy increases (+ΔH), but the disorder in the system decreases as the monomers are organized into a polymer, leading to a decrease in entropy (-ΔS). This is consistent with option B.

17. A solution of starch at room temperature does not readily decompose to form a solution of simple sugars because

D

A

B

C

The activation energy barrier for this reaction cannot be surmounted. Starch molecules are large and complex, requiring an input of energy to break down into simpler sugars. This energy barrier prevents the spontaneous decomposition of starch into sugars.

Explanation

The activation energy barrier for this reaction cannot be surmounted. Starch molecules are large and complex, requiring an input of energy to break down into simpler sugars. This energy barrier prevents the spontaneous decomposition of starch into sugars.

18. During glycolysis, when each molecule of glucose is catabolized to two molecules of pyruvate, most of the potential energy contained in glucose is

B

D

C

A

During glycolysis, most of the potential energy contained in glucose is retained in the two pyruvates produced at the end of the pathway.

Explanation

During glycolysis, most of the potential energy contained in glucose is retained in the two pyruvates produced at the end of the pathway.

19. Which of the following represents the activation energy needed for the enzyme-catalyzed reverse reaction C+D->A+B?

C

D

A

B

Activation energy for a reaction is represented by the symbol 'A'. This is a common notation used in chemical kinetics to denote the energy barrier that must be overcome for the reaction to proceed.

Explanation

Activation energy for a reaction is represented by the symbol 'A'. This is a common notation used in chemical kinetics to denote the energy barrier that must be overcome for the reaction to proceed.

20. Why does the oxidation of organic compounds by molecular oxygen to produce CO2 and water release free energy?

A

E

B

D

The oxidation of organic compounds does not directly produce ATP.
The kinetic energy of covalent bonds does not determine the release of free energy.
The potential energy of electrons is not determined by their association with water and CO2.

Explanation

The oxidation of organic compounds does not directly produce ATP.
The kinetic energy of covalent bonds does not determine the release of free energy.
The potential energy of electrons is not determined by their association with water and CO2.

21. What is the primary role of oxygen in cellular respiration?

D

B. Yield energy in the form of ATP as it is passed down the respiratory chain

A. Combine with carbon, forming CO2

C. Combine with lactate, forming pyruvate

22. The synthesis of ATP by oxidative phosphorylation, using the energy released by movement of protons across the membrane down their electrochemical gradient, is an example of

B

C

A

D

In this process, the synthesis of ATP is coupled with the movement of protons down their electrochemical gradient, which releases energy. This coupling of an endergonic (ATP synthesis) and exergonic (proton movement) reaction is an example of energy coupling in biological systems.

Explanation

In this process, the synthesis of ATP is coupled with the movement of protons down their electrochemical gradient, which releases energy. This coupling of an endergonic (ATP synthesis) and exergonic (proton movement) reaction is an example of energy coupling in biological systems.

23. When oxygen is released as a result of photosynthesis, it is a direct by-product of

B) reducing NADP+

D

C) the electron transfer system of photosystem I

A) chemuiosmosis

24. In photosynthetic cells, synthesis of ATP by the chemiosmotic mechanism occurs during

B

C

A

E

The chemiosmotic mechanism for ATP synthesis occurs in both photosynthesis and respiration.

Explanation

The chemiosmotic mechanism for ATP synthesis occurs in both photosynthesis and respiration.

25. A gardener is concerned that her greenhouse is getting too hot from too much light, and seeks to shade her plants with colored translucent plastic sheets. What color should she use to reduce overall light energy, but still maximize plant growth?

E. orange

C

A. green

D. yellow

Blue colored translucent plastic sheets are known to filter out excess light energy while still allowing enough light for plant growth. Green, yellow, and orange colored sheets may not be as effective in achieving the desired balance of light reduction and plant growth stimulation.

Explanation

Blue colored translucent plastic sheets are known to filter out excess light energy while still allowing enough light for plant growth. Green, yellow, and orange colored sheets may not be as effective in achieving the desired balance of light reduction and plant growth stimulation.

26. If the power fails and the lights go dark, what will happen to CO2 levels?

C

E

A

B

When the power fails and lights go dark, plant respiration will continue to release CO2 into the atmosphere while the animals will also respire, leading to an overall increase in CO2 levels.

Explanation

When the power fails and lights go dark, plant respiration will continue to release CO2 into the atmosphere while the animals will also respire, leading to an overall increase in CO2 levels.

27. Which process is most directly driven by light energy?

D

C

B

A

The correct answer is D because the removal of electrons from chlorophyll molecules is the process most directly driven by light energy in photosynthesis. This is where light energy is absorbed by chlorophyll and used to initiate the conversion of light energy into chemical energy.

Explanation

The correct answer is D because the removal of electrons from chlorophyll molecules is the process most directly driven by light energy in photosynthesis. This is where light energy is absorbed by chlorophyll and used to initiate the conversion of light energy into chemical energy.

28. Which process contributes the most to the huge increase in biomass of a mature maple tree starting from a seed weighing less than 1 gram?

B. absorption of mineral substances from the soil via the roots

A. absorption of solar radiation into the leaf

C. incorporation of H2O from the soil into molecules by green leaves

D

During photosynthesis, green leaves use sunlight to convert CO2 from the atmosphere into sugar molecules, which are then transformed into various organic compounds to support the growth and increase in biomass of the tree. This process is the primary contributor to the significant biomass increase in mature trees.

Explanation

During photosynthesis, green leaves use sunlight to convert CO2 from the atmosphere into sugar molecules, which are then transformed into various organic compounds to support the growth and increase in biomass of the tree. This process is the primary contributor to the significant biomass increase in mature trees.