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Exam 1 September 9, 2021 Dr. A. Pimentel

Each question has a value of 4 points and there are a total of 108 points in the exam. However, the maximum score of this exam will be capped at 100 points. Instructions: Select the BEST answer for each question

Scientific Method The following passage applies to Questions 1 through 3. Gregor Mendel was an Austrian monk that lived in the 19th century. He became interested in studying the mechanism by which parents pass on physical traits to their offspring. He reviewed the available information about this and found that previous scientists proposed two competing explanations for this topic. These explanations were: 1) the “Blending Hypothesis” that proposed, “fluids from all over the body migrate to the gonads and once they were seeded in the female womb, they create offspring”; 2) the “Preformist hypothesis” which proposed, “each sperm carries a tiny human being and once seeded in the womb, this allowed for the growth of this preformed human”. He decided to carry out experiments with pea plants to test which one of these hypotheses was correct. However, the results of his experiments found that inheritance is produced by the contribution of discrete units (AKA, chromosomes) from both parents. Fifty years after his publication in the early 20th century this theory was rediscovered and tested hundreds of thousands of times, always confirming Mendel’s results. 1. Select the statement that correctly states Mendel’s initial observation in

the second sentence of the passage.

A. The offspring look very similar to both parents. B. A tiny human can be seen in the sperm. C. Movement of fluids could be seen concentrating in the gonads. D. Discrete units could be seen coming together. E. No answer is correct.

Name: ___________________________ NetID: ____________________________ Version 2

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2. Which statement is correct about the description in the paragraph describing Mendel’s work?

A. Mendel’s work validated the preformation hypothesis. B. Mendel’s work is currently known as the chromosome theory of

inheritance. C. Mendel’s work is currently known as the chromosome hypothesis of

inheritance. D. Mende’s work is currently known as the preformation theory. E. Mendel’s work is currently known as the blending theory.

3. Mendel’s work was rediscovered in the early 20th century when it was possible to observe chromosomes under the microscope. If a 20th-century biologist decided to test Mendel’s theory by observing the chromosomes under a microscope, what would you predict the biologist would see if Mendel’s theory was correct?

A. That the chromosomes would be formed after fertilization. B. That the chromosomes would dissolve after fertilization. C. That the chromosomes from male gametes merge. D. That the chromosomes from female gametes merge. E. That the chromosomes from both parents contribute to the offspring.

4. Select the answer that lists the steps of the scientific method in their correct order.

A. Observations ->Questions -> Propose Hypothesis -> Perform Experiments -> Analyze Experimental data -> Make Conclusions -> Publish in Peer Review Papers

B. Questions -> Propose Hypothesis -> Perform Experiments -> Analyze Experimental data -> Observation -> Make Conclusions -> Publish in Peer Review Papers

C. Observations ->Questions -> Propose Hypothesis -> Perform Experiments ->Make Conclusions -> Analyze Experimental data -> Publish in Peer Review Papers

D. Propose Hypothesis -> Observations ->Questions -> Perform Experiments -> Analyze Experimental data -> Make Conclusions -> Publish in Peer Review Papers

E. Questions -> Observations -> Propose Hypothesis -> Perform Experiments -> Analyze Experimental data -> Make Conclusions -> Publish in Peer Review Papers

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Atoms and Molecules 5- In an ionic bond, the atom that donates one or more electrons becomes a:

A. Positive ion B. Negative ion C. Anion D. Cation E. A and D are correct

6- Which of the following atoms can form a maximum of three covalent bonds?

A. Nitrogen B. Hydrogen C. Carbon D. Calcium E. Neon

7. The atomic particles that would engage in chemical interactions with other atoms are:

A. Valence Neutrons B. Non-valence electrons C. Nuclear protons D. Valence electrons E. Protons

8. A solution with a pH of 4 will contain ________ more __________ than a solution of pH 7

A. 1000 times, hydronium ions B. 100 times, hydronium ions C. 10 times, hydronium ions D. 1000 times, Hydroxide ions E. 100 times, hydroxide ions

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9. Select the molecule from below that would not dissolve in water.

10. Select the answer that correctly identifies the flow of information under the Central Dogma of Molecular Biology. Transcription Translation A. DNA-------------------> RNA ------------------> Proteins Translation Transcription B. DNA-------------------> RNA ------------------> Proteins Transcription Translation C. DNA-------------------> Proteins ------------------> RNA Replication Translation D. DNA-------------------> RNA ------------------> Proteins Replication Translation E. Proteins -------------------> RNA ------------------> DNA

A

C

B

D

E

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11- In the molecules shown below, which molecule is held together by polar covalent bonds?

A. 1 B. 2 C. 3 D. 4

Cell theory 12. Select the incorrect statement regarding the cell theory

A. All organisms on earth are made out of cells B. With a few exceptions, the overwhelming majority of cells use DNA as

their genetic material. C. Organisms from the same species will have the same chemical

composition. D. Plants transfer the energy stored in sugars into the ATP molecule. E. All cells transfer copies of their genetic material to their offspring.

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13. The Theory of Evolution proposes that all organisms came from a common ancestor. Which of the following statements of the cell theory support the Theory of Evolution?

A. The activity of an organism depends on the total activity of independent cells.

B. All cells arise from pre-existing cells by division. C. All cells are basically the same in chemical composition in organisms

of similar species. D. All known living things are made up of one or more cells. E. Energy flow (metabolism and biochemistry) occurs within cells.

Organic Molecules 14. Which of the following characteristics is incorrect regarding the role of carbon molecules in organic molecules?

A. The carbon atom can form a maximum of 4 covalent bonds B. The carbon atom can form double covalent bonds C. The carbon atom can form an almost limitless number of structures D. The carbon atom provides polarity to organic molecules E. The carbon atom forms non-polar covalent bonds with hydrogen.

15. All monomers join together to form polymers by a ______________ reaction.

A. Dehydration reaction B. Hydrolysis reaction C. Ionic reaction D. Hydrogen bond reaction E. Van der Waals reaction.

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16. Select the correct answer regarding carbohydrate molecules.

A. A single change in the position of the functional group will make carbohydrates unique from another

B. When a double covalent bond is formed at the end of the monosaccharide between carbon and oxygen atoms, this functional group is known as an aldose

C. When a double covalent bond is formed at the center of the monosaccharide between carbon and oxygen atoms, this functional group is known as a ketose

D. Monosaccharides are polar molecules E. All the answers are correct

Proteins 17. What is the factor that ultimately determines the three-dimensional shape of a protein?

A. The Primary structure B. The Secondary structure C. The Tertiary structure D. The Quaternary structure E. The information in the DNA molecule

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18. Which of the following amino acids is hydrophobic?

19. The amino acids found in a region of a protein that contains a high concentration of hydrophobic amino acids will exhibit what type of chemical interactions?

A. Hydrogen bonds B. Ionic interactions C. Disulfide bonds D. Van der Waals' Interactions E. Non-polar covalent bond.

20. The primary structure of proteins are held together with:

A. Covalent bonds B. Hydrogen bonds C. Van der Waals’ Interactions D. Ionic bonds E. Disulfide bonds

A C B

E D

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21. Which of the following interactions will be affected if the pH of a cell is increased from 7.4 to 9?

A. Covalent bonds B. Hydrogen bonds C. Van der Waals’ Interactions D. Ionic bonds E. Disulfide bonds

22. If two Cysteine residues are in close proximity to each other in a polypeptide chain, they will most likely form a ______________ in the _____________ of the protein.

A. Disulfide bond, tertiary structure B. Disulfide bond, secondary structure C. Van der Waals’ interaction, tertiary structure D. Van der Waals’ interaction, secondary structure E. Hydrogen bonds, tertiary structure

23- The difference between the hydrogen bonds in the secondary and the tertiary structure of the protein is:

A. In the secondary structure, the hydrogen bonds form from backbone to backbone, in the tertiary structure the hydrogen bonds form from R-group to R-group or R-group to backbone.

B. In the secondary structure, the hydrogen bonds form from backbone to

backbone, in the tertiary structure the hydrogen bonds form from R-group or R-group only.

C. In the secondary structure, the hydrogen bonds form from backbone to

backbone, in the tertiary structure, the hydrogen bonds are formed from R-group to backbone only.

D. In the secondary structure, the hydrogen bonds form R-group to

backbone in the tertiary structure the hydrogen bonds form from R-group to R-group.

E. No answer is correct.

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24- The figure below displays a tertiary structure of a protein. Select the answer that correctly matches the interaction (numerically labeled) in the protein with the structural figures of the interactions (alphabetically labeled) on the right.

A. C, A, D, B B. D, A, C, B C. A, B, C, D D. B, C, D, A E. C, B, D, A

25- An excessive increase in temperature will affect the ____________ in the ___________ structure(s) of proteins.

A. Ionic bonding, secondary and tertiary B. Ionic bonding, secondary C. Ionic bonding, tertiary D. Hydrogen bonding, secondary E. Hydrogen bonding, secondary and tertiary

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Bonus: 26. Assertion Reason

Silicon could make a maximum of 4 single covalent bonds, as well as double and triple covalent bonds like carbon, does

Because Silicon has all the same properties as carbon does and therefore, on earth, some organisms use silicon instead of carbon to create organic molecules.

A. Assertion is true; Reason is true; Reason is the correct explanation B. Assertion is true; Reason true; Reason is NOT the correct explanation C. Assertion is true; Reason is false D. Assertion is false; Reason is true E. Assertion is false; Reason is false 27. Assertion Reason

The disulfide bond is the stronger chemical bond in the tertiary structure of a protein

Because Whether or not a disulfide bond occurs between two particular amino acids will depend on the primary structure of the protein

A. Assertion is true; Reason is true; Reason is the correct explanation B. Assertion is true; Reason true; Reason is NOT the correct explanation C. Assertion is true; Reason is false D. Assertion is false; Reason is true E. Assertion is false; Reason is false

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Appendix

Periodic Table with Electronegativity Values

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