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 organic materials?

Accepted Answer

It decays at a predictable rate, allowing calculation of sample age

Question 3

Which statement 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 best describes the difference between a molecule and a compound?

Accepted Answer

A molecule is a group of atoms bonded together, while a compound is a molecule containing at least two different elements

Question 5

Which of the following is an example of an ionic bond in a biological system?

Accepted Answer

The bond between sodium and chloride in table salt ($$NaCl)$$

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

Hydrogen bonds form between water molecules due to water's polarity. Why are these hydrogen bonds biologically important?

Accepted Answer

They enable water to act as a good solvent for many biological molecules

Question 8

How does molecular polarity influence the solubility of substances in water?

Accepted Answer

Polar molecules dissolve easily in water because water is also polar

Question 9

Which of the following best describes the role of buffers in maintaining pH homeostasis in biological systems?

Accepted Answer

Buffers minimize changes in pH by accepting or donating $$H^+$$ ions

Question 10

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

Accepted Answer

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

Question 11

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 12

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

Accepted Answer

Inability to form hydrogen bonds

Question 13

A scientist adds acid to a solution containing a buffer. What will happen to the pH of the solution?

Accepted Answer

The pH will remain relatively stable

Question 14

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

Accepted Answer

Hydrogen bonds in ice create an open lattice structure, making it less dense

Question 15

Which scenario best illustrates capillary action in nature?

Accepted Answer

Water moving up a paper towel dipped in a spill

Question 16

Which of the following is a correct example of a covalent bond in a biological molecule?

Accepted Answer

The bond between two hydrogen atoms in $$H_2$$

Question 17

Which property of water is most important for temperature regulation in living organisms?

Accepted Answer

High heat capacity

Question 18

Which of the following best describes the process of hydrogen bonding between water molecules?

Accepted Answer

A hydrogen atom in one water molecule is attracted to the oxygen atom in another water molecule

Question 19

Which of the following best explains why polar molecules are soluble in water?

Accepted Answer

Water's polarity allows it to interact with and stabilize other polar molecules

Atomic Structure, Chemical Bonds, and Water Properties: Study Notes for Anatomy & Physiology

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