BIO 156 EXAM 1 - COMPREHENSIVE PRACTICE TEST
COMPLETE QUESTIONS WITH VERIFIED ANSWERS AND
DETAILED RATIONALES
1. Which of the following represents the correct hierarchy of biological
organization from smallest to largest?
A) Organism, population, community, ecosystem, biosphere
B) Cell, tissue, organ, organ system, organism, population, community, ecosystem,
biosphere
C) Atoms, molecules, organelles, cells, tissues, organs, organ systems, organism,
population, community, ecosystem, biosphere
D) Molecules, cells, tissues, organs, organ systems, organism, ecosystem,
population, community, biosphere
Correct Answer: C - This represents the complete hierarchical organization from
atoms to biosphere. Option A is incomplete and starts too large. Option B omits
atoms and molecules. Option D has the order of
ecosystem/population/community incorrect.
2. Which characteristic of living things refers to the maintenance of a relatively
stable internal environment?
A) Reproduction and development
B) Response to stimuli
C) Homeostasis
D) Adaptation
Correct Answer: C - Homeostasis is specifically defined as the maintenance of
internal balance. While organisms do respond to stimuli, reproduce, and adapt,
these are different characteristics from homeostasis.
,3. The element CHNOPS stands for:
A) Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus, Sulfur
B) Calcium, Helium, Neon, Oxygen, Potassium, Sodium
C) Carbon, Helium, Nitrogen, Oxygen, Phosphorus, Sulfur
D) Calcium, Hydrogen, Nitrogen, Oxygen, Phosphorus, Silicon
Correct Answer: A - CHNOPS is the mnemonic for the six most abundant elements
in living organisms: Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus, and Sulfur.
4. The atomic number of an atom represents the number of:
A) Neutrons in the atom
B) Protons in the atom
C) Electrons in the atom
D) Neutrons plus protons
Correct Answer: B - Atomic number equals the number of protons. Atomic mass is
neutrons + protons. Electrons can vary in ions.
5. Isotopes are atoms of the same element that have:
A) Different numbers of protons
B) Different numbers of electrons
C) Different numbers of neutrons
D) Different atomic numbers
Correct Answer: C - Isotopes have the same number of protons but different
numbers of neutrons. This means they have the same atomic number but
different atomic masses.
6. According to the octet rule, the inner electron shell can hold how many
orbitals?
,A) 8
B) 2
C) 6
D) 4
Correct Answer: B - The innermost electron shell has 2 orbitals. All other shells
have 8 orbitals (or multiples of 8).
7. Which type of bond is formed by the attraction between ions of opposite
charge?
A) Covalent bond
B) Hydrogen bond
C) Ionic bond
D) Polar bond
Correct Answer: C - Ionic bonds form through electrostatic attraction between
positively and negatively charged ions. Covalent bonds share electrons, and
hydrogen bonds are weaker interactions.
8. Sodium chloride (NaCl) is an example of which type of chemical bond?
A) Covalent bond
B) Ionic bond
C) Hydrogen bond
D) Peptide bond
Correct Answer: B - Sodium chloride forms through ionic bonding where sodium
donates an electron to chlorine, forming Na+ and Cl- ions that attract each other.
9. Which of the following is the weakest type of chemical bond?
A) Ionic bond
B) Covalent bond
, C) Hydrogen bond
D) Double covalent bond
Correct Answer: C - Hydrogen bonds are the weakest of the listed bonds. They are
important in water properties and DNA structure but are much weaker than ionic
or covalent bonds.
10. Water has a high heat capacity. This means water:
A) Heats up quickly and cools down quickly
B) Can absorb or release large amounts of heat with little temperature change
C) Has a low boiling point
D) Is a poor solvent
Correct Answer: B - High heat capacity means water can absorb or release
significant heat energy while undergoing minimal temperature change, helping
moderate temperature in organisms and environments.
11. On the pH scale, acids have a value:
A) Above 7
B) Equal to 7
C) Below 7
D) Between 7 and 14
Correct Answer: C - Acids have pH values below 7. Values above 7 are bases, and 7
is neutral.
12. Acids typically taste:
A) Bitter
B) Sour
C) Sweet
D) Salty
COMPLETE QUESTIONS WITH VERIFIED ANSWERS AND
DETAILED RATIONALES
1. Which of the following represents the correct hierarchy of biological
organization from smallest to largest?
A) Organism, population, community, ecosystem, biosphere
B) Cell, tissue, organ, organ system, organism, population, community, ecosystem,
biosphere
C) Atoms, molecules, organelles, cells, tissues, organs, organ systems, organism,
population, community, ecosystem, biosphere
D) Molecules, cells, tissues, organs, organ systems, organism, ecosystem,
population, community, biosphere
Correct Answer: C - This represents the complete hierarchical organization from
atoms to biosphere. Option A is incomplete and starts too large. Option B omits
atoms and molecules. Option D has the order of
ecosystem/population/community incorrect.
2. Which characteristic of living things refers to the maintenance of a relatively
stable internal environment?
A) Reproduction and development
B) Response to stimuli
C) Homeostasis
D) Adaptation
Correct Answer: C - Homeostasis is specifically defined as the maintenance of
internal balance. While organisms do respond to stimuli, reproduce, and adapt,
these are different characteristics from homeostasis.
,3. The element CHNOPS stands for:
A) Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus, Sulfur
B) Calcium, Helium, Neon, Oxygen, Potassium, Sodium
C) Carbon, Helium, Nitrogen, Oxygen, Phosphorus, Sulfur
D) Calcium, Hydrogen, Nitrogen, Oxygen, Phosphorus, Silicon
Correct Answer: A - CHNOPS is the mnemonic for the six most abundant elements
in living organisms: Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus, and Sulfur.
4. The atomic number of an atom represents the number of:
A) Neutrons in the atom
B) Protons in the atom
C) Electrons in the atom
D) Neutrons plus protons
Correct Answer: B - Atomic number equals the number of protons. Atomic mass is
neutrons + protons. Electrons can vary in ions.
5. Isotopes are atoms of the same element that have:
A) Different numbers of protons
B) Different numbers of electrons
C) Different numbers of neutrons
D) Different atomic numbers
Correct Answer: C - Isotopes have the same number of protons but different
numbers of neutrons. This means they have the same atomic number but
different atomic masses.
6. According to the octet rule, the inner electron shell can hold how many
orbitals?
,A) 8
B) 2
C) 6
D) 4
Correct Answer: B - The innermost electron shell has 2 orbitals. All other shells
have 8 orbitals (or multiples of 8).
7. Which type of bond is formed by the attraction between ions of opposite
charge?
A) Covalent bond
B) Hydrogen bond
C) Ionic bond
D) Polar bond
Correct Answer: C - Ionic bonds form through electrostatic attraction between
positively and negatively charged ions. Covalent bonds share electrons, and
hydrogen bonds are weaker interactions.
8. Sodium chloride (NaCl) is an example of which type of chemical bond?
A) Covalent bond
B) Ionic bond
C) Hydrogen bond
D) Peptide bond
Correct Answer: B - Sodium chloride forms through ionic bonding where sodium
donates an electron to chlorine, forming Na+ and Cl- ions that attract each other.
9. Which of the following is the weakest type of chemical bond?
A) Ionic bond
B) Covalent bond
, C) Hydrogen bond
D) Double covalent bond
Correct Answer: C - Hydrogen bonds are the weakest of the listed bonds. They are
important in water properties and DNA structure but are much weaker than ionic
or covalent bonds.
10. Water has a high heat capacity. This means water:
A) Heats up quickly and cools down quickly
B) Can absorb or release large amounts of heat with little temperature change
C) Has a low boiling point
D) Is a poor solvent
Correct Answer: B - High heat capacity means water can absorb or release
significant heat energy while undergoing minimal temperature change, helping
moderate temperature in organisms and environments.
11. On the pH scale, acids have a value:
A) Above 7
B) Equal to 7
C) Below 7
D) Between 7 and 14
Correct Answer: C - Acids have pH values below 7. Values above 7 are bases, and 7
is neutral.
12. Acids typically taste:
A) Bitter
B) Sour
C) Sweet
D) Salty
