BSC Final Exam 2027 | 200+ Questions &
Correct Answers | Detailed Rationales |
Complete Biology Study Guide & Exam Prep
1. The _____ is the basic unit of structure and function in an organism.
A) Atom
B) Molecule
C) Cell
D) Organ
Answer C: Cell
Rationale: The cell is the smallest unit of life that can perform all life processes.
2. Central dogma: DNA is transcribed into _____ then translated into a _____.
A) Protein; RNA
B) RNA; protein
C) RNA; DNA
D) Protein; DNA
Answer B: RNA; protein
Rationale: DNA → RNA (transcription) → protein (translation) is the central dogma.
3. A _____ cell has membrane-enclosed organelles while a _____ cell is simpler, usually smaller, and
does not contain any membrane-enclosed organelles.
A) Prokaryotic; eukaryotic
B) Eukaryotic; prokaryotic
C) Plant; animal
D) Animal; plant
Answer B: Eukaryotic; prokaryotic
Rationale: Eukaryotic cells have membrane-bound organelles; prokaryotic cells do not.
4. Anything that takes up space and has mass is _____.
A) Energy
B) Matter
,C) Weight
D) Volume
Answer B: Matter
Rationale: Matter is anything that has mass and occupies space.
5. An _____ is a substance that cannot be broken down to other substances by chemical reactions.
A) Compound
B) Mixture
C) Element
D) Molecule
Answer C: Element
Rationale: An element is a pure substance that cannot be broken down chemically.
6. _____ are two atoms of an element that differ in the number of neutrons.
A) Ions
B) Isotopes
C) Molecules
D) Compounds
Answer B: Isotopes
Rationale: Isotopes have the same protons but different neutrons.
7. _____ electrons are those in the outermost shell and are responsible for the chemical behavior of
the atom.
A) Core
B) Inner
C) Valence
D) Orbital
Answer C: Valence
Rationale: Valence electrons determine how an atom bonds.
8. The bond angle of a water molecule is _____ degrees.
A) 90
B) *105*
C) 109.5
D) 120
,Answer B: 105
Rationale: Water has a bent shape with a bond angle of about 105 degrees.
9. Hydrogen bonds hold water molecules together in a phenomenon called _____, which is
responsible for the transport of water against gravity in plants.
A) Adhesion
B) Cohesion
C) Surface tension
D) Capillary action
Answer B: Cohesion
Rationale: Cohesion is the attraction between water molecules due to hydrogen bonding.
10. _____ is an attraction between different substances, for example, between water and plant cell
walls.
A) Cohesion
B) Adhesion
C) Surface tension
D) Osmosis
Answer B: Adhesion
Rationale: Adhesion is the attraction between water and other molecules.
11. In a _____ covalent bond, the atoms share electrons equally, while in a _____ covalent bond, the
atoms do not share electrons equally.
A) Polar; nonpolar
B) Nonpolar; polar
C) Ionic; covalent
D) Covalent; ionic
Answer B: Nonpolar; polar
Rationale: Nonpolar bonds share electrons equally; polar bonds have unequal sharing.
12. In any aqueous solution at 25°C, the product of [H+][OH-] = _____.
A) 10^-7
B) *10^-14*
C) 10^-10
D) 10^0
, Answer B: 10^-14
Rationale: The ion product constant of water (Kw) is 10^-14 at 25°C.
13. A _____ substance has an affinity for water while a _____ substance does not have an affinity for
water.
A) Hydrophobic; hydrophilic
B) Hydrophilic; hydrophobic
C) Polar; nonpolar
D) Acidic; basic
Answer B: Hydrophilic; hydrophobic
Rationale: Hydrophilic substances interact with water; hydrophobic substances repel water.
14. All carbon enters the biosphere as _____ gas, which is converted to sugar and biological
macromolecules.
A) O2
B) CO2
C) N2
D) CH4
Answer B: CO2
Rationale: Carbon dioxide is fixed into organic molecules during photosynthesis.
15. When carbon bonds with four molecules of hydrogen, the resulting molecule has a _____
geometry and bond angles of _____ degrees.
A) Linear; 180
B) Tetrahedral; 109.5
C) Trigonal planar; 120
D) Bent; 105
Answer B: Tetrahedral; 109.5
Rationale: Methane (CH4) has a tetrahedral shape with 109.5-degree bond angles.
16. A _____ occurs when two monomers bond together through the loss of a water molecule.
A) Hydrolysis
B) Dehydration synthesis
C) Oxidation
D) Reduction
Correct Answers | Detailed Rationales |
Complete Biology Study Guide & Exam Prep
1. The _____ is the basic unit of structure and function in an organism.
A) Atom
B) Molecule
C) Cell
D) Organ
Answer C: Cell
Rationale: The cell is the smallest unit of life that can perform all life processes.
2. Central dogma: DNA is transcribed into _____ then translated into a _____.
A) Protein; RNA
B) RNA; protein
C) RNA; DNA
D) Protein; DNA
Answer B: RNA; protein
Rationale: DNA → RNA (transcription) → protein (translation) is the central dogma.
3. A _____ cell has membrane-enclosed organelles while a _____ cell is simpler, usually smaller, and
does not contain any membrane-enclosed organelles.
A) Prokaryotic; eukaryotic
B) Eukaryotic; prokaryotic
C) Plant; animal
D) Animal; plant
Answer B: Eukaryotic; prokaryotic
Rationale: Eukaryotic cells have membrane-bound organelles; prokaryotic cells do not.
4. Anything that takes up space and has mass is _____.
A) Energy
B) Matter
,C) Weight
D) Volume
Answer B: Matter
Rationale: Matter is anything that has mass and occupies space.
5. An _____ is a substance that cannot be broken down to other substances by chemical reactions.
A) Compound
B) Mixture
C) Element
D) Molecule
Answer C: Element
Rationale: An element is a pure substance that cannot be broken down chemically.
6. _____ are two atoms of an element that differ in the number of neutrons.
A) Ions
B) Isotopes
C) Molecules
D) Compounds
Answer B: Isotopes
Rationale: Isotopes have the same protons but different neutrons.
7. _____ electrons are those in the outermost shell and are responsible for the chemical behavior of
the atom.
A) Core
B) Inner
C) Valence
D) Orbital
Answer C: Valence
Rationale: Valence electrons determine how an atom bonds.
8. The bond angle of a water molecule is _____ degrees.
A) 90
B) *105*
C) 109.5
D) 120
,Answer B: 105
Rationale: Water has a bent shape with a bond angle of about 105 degrees.
9. Hydrogen bonds hold water molecules together in a phenomenon called _____, which is
responsible for the transport of water against gravity in plants.
A) Adhesion
B) Cohesion
C) Surface tension
D) Capillary action
Answer B: Cohesion
Rationale: Cohesion is the attraction between water molecules due to hydrogen bonding.
10. _____ is an attraction between different substances, for example, between water and plant cell
walls.
A) Cohesion
B) Adhesion
C) Surface tension
D) Osmosis
Answer B: Adhesion
Rationale: Adhesion is the attraction between water and other molecules.
11. In a _____ covalent bond, the atoms share electrons equally, while in a _____ covalent bond, the
atoms do not share electrons equally.
A) Polar; nonpolar
B) Nonpolar; polar
C) Ionic; covalent
D) Covalent; ionic
Answer B: Nonpolar; polar
Rationale: Nonpolar bonds share electrons equally; polar bonds have unequal sharing.
12. In any aqueous solution at 25°C, the product of [H+][OH-] = _____.
A) 10^-7
B) *10^-14*
C) 10^-10
D) 10^0
, Answer B: 10^-14
Rationale: The ion product constant of water (Kw) is 10^-14 at 25°C.
13. A _____ substance has an affinity for water while a _____ substance does not have an affinity for
water.
A) Hydrophobic; hydrophilic
B) Hydrophilic; hydrophobic
C) Polar; nonpolar
D) Acidic; basic
Answer B: Hydrophilic; hydrophobic
Rationale: Hydrophilic substances interact with water; hydrophobic substances repel water.
14. All carbon enters the biosphere as _____ gas, which is converted to sugar and biological
macromolecules.
A) O2
B) CO2
C) N2
D) CH4
Answer B: CO2
Rationale: Carbon dioxide is fixed into organic molecules during photosynthesis.
15. When carbon bonds with four molecules of hydrogen, the resulting molecule has a _____
geometry and bond angles of _____ degrees.
A) Linear; 180
B) Tetrahedral; 109.5
C) Trigonal planar; 120
D) Bent; 105
Answer B: Tetrahedral; 109.5
Rationale: Methane (CH4) has a tetrahedral shape with 109.5-degree bond angles.
16. A _____ occurs when two monomers bond together through the loss of a water molecule.
A) Hydrolysis
B) Dehydration synthesis
C) Oxidation
D) Reduction
