Q: A solution has a pH of 4. What is the concentration of hydrogen ions $$[H^+] in $$this solution?

$$[H^+] = 1 \times 10$$^{-4}$$ \ \mathrm{M}$$

Question 1

Which of the following best describes the concept of emergent properties in biological systems?

Accepted Answer

Emergent properties are characteristics that arise only when individual components interact at higher levels of organization.

Question 2

A scientist is studying the effect of a new fertilizer on plant growth. She sets up two groups: one receives the fertilizer, and the other does not. She measures plant height weekly. Which aspect of scientific inquiry is best demonstrated by this experiment?

Accepted Answer

Controlled experiment

Question 3

Which of the following correctly matches a macromolecule with its monomer?

Accepted Answer

Protein – amino acid

Question 4

Which of the following statements about water is correct and explains why ice floats on liquid water?

Accepted Answer

Hydrogen bonds in ice are more stable and keep water molecules farther apart, making ice less dense than liquid water.

Question 5

A molecule of glucose ($$C_6H_{12}O_6$) is formed by joining six molecules of carbon dioxide (CO_2$) and six molecules of water (H_2O$) during photosynthesis. What type of reaction is this?

Accepted Answer

Dehydration synthesis

Question 6

Which of the following best explains why water has a high specific heat?

Accepted Answer

Hydrogen bonding between water molecules requires more energy to change temperature.

Question 7

Which of the following is a correct statement about the structure of DNA?

Accepted Answer

DNA is a double helix with antiparallel strands held together by hydrogen bonds between complementary bases.

Question 8

A patient is diagnosed with a genetic disorder caused by a single amino acid substitution in a protein. Which level of protein structure is directly affected by this mutation?

Accepted Answer

Primary structure

Question 9

Which of the following best describes the difference between saturated and unsaturated fatty acids?

Accepted Answer

Saturated fatty acids have no double bonds between carbon atoms, while unsaturated fatty acids have one or more double bonds.

Question 10

Which of the following is an example of a hypothesis in scientific inquiry?

Accepted Answer

If fertilizer increases plant growth, then plants given fertilizer will be taller than those not given fertilizer.

Question 11

Which of the following best explains why carbon is able to form such a wide variety of molecules?

Accepted Answer

Carbon has four valence electrons, allowing it to form up to four covalent bonds with other atoms.

Question 12

A solution has a pH of 4. What is the concentration of hydrogen ions $$[H^+] in $$this solution?

Accepted Answer

$$[H^+] = 1 	imes 10$$^{-4}$$ \ \mathrm{M}$$

Question 13

Which of the following best describes the role of enzymes in biological systems?

Accepted Answer

Enzymes lower the activation energy of chemical reactions, increasing the reaction rate.

Question 14

Which of the following is a correct pairing of a functional group and its property?

Accepted Answer

Amino group ($$-NH_2$): acts as a base and can pick up a proton (H$$^+$$)

Question 15

Which of the following best explains the difference between DNA and RNA?

Accepted Answer

DNA contains deoxyribose sugar and thymine, while RNA contains ribose sugar and uracil.

Question 16

A protein is exposed to high heat and loses its three-dimensional structure but retains its primary sequence. What process has occurred?

Accepted Answer

Denaturation

Question 17

Which of the following is a correct statement about the secondary structure of proteins?

Accepted Answer

It is formed by hydrogen bonds between the backbone atoms of the polypeptide chain.

Question 18

Which of the following best describes the relationship between structure and function in biological molecules?

Accepted Answer

The specific shape of a molecule determines how it interacts with other molecules and its biological function.

Question 19

Which of the following is an example of a hydrolysis reaction in biological systems?

Accepted Answer

Breaking down a polysaccharide into monosaccharides by adding water.

Question 20

A researcher is comparing the properties of two solutions: Solution A has a pH of 7, and Solution B has a pH of 5. How many times greater is the hydrogen ion concentration in Solution B compared to Solution A?

Accepted Answer

$$100$$ times greater

General Biology: Themes, Chemistry of Life, and Biological Molecules

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