Question 1

Which subatomic particle determines the atomic number of an element, and where is it located within the atom?

Accepted Answer

Proton; located in the nucleus

Question 2

A radioactive isotope of carbon, $$^{14}C$$, is commonly used in biological research. What property makes $$^{14}C$$ useful for dating ancient biological samples?

Accepted Answer

It decays at a predictable rate, allowing measurement of elapsed time

Question 3

Which of the following best explains why elements in the same group of the periodic table have similar chemical properties?

Accepted Answer

They have the same number of valence electrons

Question 4

Which of the following is a compound?

Accepted Answer

Sodium chloride ($$NaCl)$$

Question 5

Which statement correctly describes the difference between ionic and covalent bonds?

Accepted Answer

Ionic bonds involve transferring electrons; covalent bonds involve sharing electrons

Question 6

Water has a high heat capacity. Which property of water molecules is primarily responsible for this?

Accepted Answer

The hydrogen bonds between water molecules

Question 7

Which property of water allows it to move upward through the stem of a plant against gravity?

Accepted Answer

Cohesion and adhesion (capillary action)

Question 8

Why are hydrogen bonds important for biological molecules such as DNA?

Accepted Answer

They allow DNA strands to separate and rejoin during replication

Question 9

How does molecular polarity influence the solubility of a substance in water?

Accepted Answer

Polar molecules dissolve easily in water because water is also polar

Question 10

Which of the following best describes the function of a buffer in biological systems?

Accepted Answer

Buffers prevent drastic changes in pH by neutralizing acids and bases

Question 11

The bicarbonate buffer system in blood helps maintain homeostasis. Which equation represents the equilibrium involved in this buffer system?

Accepted Answer

$$CO_2 + H_2O$$ \leftrightarrow H_2CO_3 \leftrightarrow H^+ + $$HCO_3$$^-$$

Question 12

Which of the following is NOT a unique property of water that supports life?

Accepted Answer

Low surface tension

Question 13

Which scenario best illustrates the concept of capillary action in nature?

Accepted Answer

Water rising in a thin glass tube due to adhesion and cohesion

Question 14

Which of the following statements about isotopes is correct?

Accepted Answer

Isotopes have the same number of protons but different numbers of neutrons

Question 15

Which of the following best explains why salt ($$NaCl) $$dissolves easily in water?

Accepted Answer

Water molecules are polar and surround $$Na^+$$ and $$Cl^-$$ ions, separating them

Question 16

Which property of water allows aquatic organisms to survive in lakes during winter?

Accepted Answer

Water's density decreases as it freezes, causing ice to float

Question 17

Which of the following is an example of a molecule formed by covalent bonding?

Accepted Answer

Water ($$H_2O)$$

Question 18

Which of the following best describes the role of hydrogen bonds in water's solvent abilities?

Accepted Answer

Hydrogen bonds enable water molecules to surround and separate polar solutes

Question 19

Which of the following is a real-world example of a buffer system maintaining pH in a biological context?

Accepted Answer

The bicarbonate buffer system in human blood

Question 20

Which of the following equations correctly represents the formation of an ionic bond between sodium and chlorine?

Accepted Answer

$$Na + Cl \rightarrow NaCl$$

Fundamental Concepts in General Biology: Atomic Structure, Chemical Bonds, and Water Properties

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