Q: A solution has a pH of 5. What is its $$[H^+]$$ concentration?

$$[H^+] = 1 \times 10$$^{-5}$$ \ M$$

Question 1

A researcher wants to test the effect of a new fertilizer on plant growth. She sets up two groups: one receives the fertilizer, and the other does not. The group that does not receive the fertilizer is best described as which of the following?

Accepted Answer

Control group

Question 2

Which of the following best explains why water is considered a polar molecule?

Accepted Answer

Oxygen is more electronegative than hydrogen, creating partial negative and positive charges.

Question 3

A scientist calculates the standard error of the mean (SEM) for a data set using the formula $$SEM = SD / \sqrt{n}. If $$the standard deviation (SD) is 10 and the sample size ($$n) is 25$$, what is the SEM?

Accepted Answer

$$SEM = 2$$

Question 4

Which property of water is primarily responsible for the ability of some insects to walk on its surface?

Accepted Answer

Cohesion due to hydrogen bonding

Question 5

Which of the following statements about Van der Waals interactions is correct?

Accepted Answer

They are weak attractions due to temporary dipoles.

Question 6

A solution has a pH of 5. What is its $$[H^+]$$ concentration?

Accepted Answer

$$[H^+] = 1 	imes 10$$^{-5}$$ \ M$$

Question 7

Which of the following best describes the difference between dehydration and hydrolysis reactions in biological polymers?

Accepted Answer

Dehydration removes water to build polymers; hydrolysis adds water to break polymers.

Question 8

Which of the following is NOT a correct pairing of macromolecule and its primary elements (CHNOPS)?

Accepted Answer

Nucleic acids: C, H, O, S

Question 9

Which of the following best explains why ice floats on liquid water?

Accepted Answer

Hydrogen bonds hold water molecules farther apart in ice, making it less dense.

Question 10

A molecule with four valence electrons that can form chains, rings, and branching structures is most likely:

Accepted Answer

Carbon

Question 11

Which of the following is an example of a structural isomer?

Accepted Answer

Two molecules with different covalent arrangements of their atoms

Question 12

Which of the following statements about proteins is correct?

Accepted Answer

Proteins are built from amino acids joined by peptide bonds.

Question 13

A sample of DNA is found to have 30% adenine. According to base pairing rules, what percentage of thymine would you expect to find?

Accepted Answer

30%

Question 14

Which of the following best describes the function of phosphate groups in biological molecules?

Accepted Answer

They are hydrophilic due to negative charges and interact with water.

Question 15

Which of the following correctly matches a macromolecule with its building blocks and bond type?

Accepted Answer

Carbohydrates: monosaccharides, glycosidic linkage

Question 16

Which of the following best explains why phospholipids form bilayers in water?

Accepted Answer

Their hydrophobic tails avoid water while hydrophilic heads interact with water.

Question 17

During the nitrogen cycle, which process returns nitrogen to the atmosphere?

Accepted Answer

Denitrification

Question 18

In an isopod lab, why is it important to use a control chamber with constant conditions?

Accepted Answer

To ensure that observed behaviors are due to the variable being tested, not random factors.

Question 19

Which of the following best describes the difference between taxis and kinesis in animal behavior?

Accepted Answer

Taxis is directed movement toward or away from a stimulus; kinesis is random movement with rate affected by stimulus intensity.

General Biology: Foundations, Chemistry, Macromolecules, and Experimental Design

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