FROM ATOMS TO ECOSYSTEMS: THE
ULTIMATE BIOD 101
COMPREHENSIVE REVIEW Subtitle: A
Complete Question Bank Covering
Chemistry of Life, Cell Biology,
Genetics, Metabolism, Immunology,
and Ecology with Evidence-Based
Explanations
Question 1
Which of the following elements is the primary component of organic
molecules, forming the backbone for carbohydrates, lipids, proteins,
and nucleic acids?
A) Oxygen (O)
B) Nitrogen (N)
C) Carbon (C)
D) Hydrogen (H)
Answer: C) Carbon (C)
,Rationale: Carbon is the foundational element of life due to its ability to
form four stable covalent bonds, allowing for the formation of complex,
diverse chains and rings. While hydrogen, oxygen, and nitrogen are also
essential in organic molecules, carbon provides the structural skeleton. This
versatility allows for the vast array of biological macromolecules found in
living organisms .
Question 2
Matter can exist in which of the following states?
A) Solid only
B) Liquid only
C) Gas only
D) Solid, liquid, and gas
Answer: D) Solid, liquid, and gas
Rationale: Matter is anything that occupies space and has mass. It can exist
in three physical states: solid (definite shape and volume), liquid (definite
volume but variable shape), and gas (variable shape and volume) .
Question 3
Water is essential for life due to its unique properties. Which property
of water allows it to act as an effective solvent for polar molecules like
salts and sugars?
,A) High specific heat
B) Cohesion and adhesion
C) Polarity
D) Lower density as a solid
Answer: C) Polarity
Rationale: Water is a polar molecule, meaning it has a partial positive
charge on one end and a partial negative charge on the other due to the
electronegativity of oxygen. This polarity allows water to form hydrogen
bonds with other polar substances, dissolving them effectively. Cohesion
relates to water sticking to itself, and high specific heat relates to
temperature resistance, not solvency .
Question 4
A solution with a pH of 3 is considered:
A) Neutral
B) Slightly basic
C) Strongly acidic
D) Weakly acidic
Answer: C) Strongly acidic
Rationale: The pH scale ranges from 0 to 14, with 7 being neutral. Values
below 7 are acidic; the lower the number, the higher the concentration of
hydrogen ions (H+) and the stronger the acid. A pH of 3 is significantly
below 7, classifying it as strongly acidic .
, Question 5
Which type of bond is responsible for holding two water molecules
together and contributes to surface tension?
A) Covalent bond
B) Ionic bond
C) Hydrogen bond
D) Peptide bond
Answer: C) Hydrogen bond
Rationale: Hydrogen bonds are weak attractions between a slightly
positive hydrogen atom in one molecule and a slightly negative atom (like
oxygen or nitrogen) in another. In water, these bonds form between the
hydrogen of one molecule and the oxygen of another, creating surface
tension and high cohesion. Covalent and ionic bonds are much stronger
intramolecular forces .
Question 6
Which of the following organic molecules is the primary source of
quick energy for the cell and is characterized by a 1:2:1 ratio of
Carbon, Hydrogen, and Oxygen?
A) Lipid
B) Protein
ULTIMATE BIOD 101
COMPREHENSIVE REVIEW Subtitle: A
Complete Question Bank Covering
Chemistry of Life, Cell Biology,
Genetics, Metabolism, Immunology,
and Ecology with Evidence-Based
Explanations
Question 1
Which of the following elements is the primary component of organic
molecules, forming the backbone for carbohydrates, lipids, proteins,
and nucleic acids?
A) Oxygen (O)
B) Nitrogen (N)
C) Carbon (C)
D) Hydrogen (H)
Answer: C) Carbon (C)
,Rationale: Carbon is the foundational element of life due to its ability to
form four stable covalent bonds, allowing for the formation of complex,
diverse chains and rings. While hydrogen, oxygen, and nitrogen are also
essential in organic molecules, carbon provides the structural skeleton. This
versatility allows for the vast array of biological macromolecules found in
living organisms .
Question 2
Matter can exist in which of the following states?
A) Solid only
B) Liquid only
C) Gas only
D) Solid, liquid, and gas
Answer: D) Solid, liquid, and gas
Rationale: Matter is anything that occupies space and has mass. It can exist
in three physical states: solid (definite shape and volume), liquid (definite
volume but variable shape), and gas (variable shape and volume) .
Question 3
Water is essential for life due to its unique properties. Which property
of water allows it to act as an effective solvent for polar molecules like
salts and sugars?
,A) High specific heat
B) Cohesion and adhesion
C) Polarity
D) Lower density as a solid
Answer: C) Polarity
Rationale: Water is a polar molecule, meaning it has a partial positive
charge on one end and a partial negative charge on the other due to the
electronegativity of oxygen. This polarity allows water to form hydrogen
bonds with other polar substances, dissolving them effectively. Cohesion
relates to water sticking to itself, and high specific heat relates to
temperature resistance, not solvency .
Question 4
A solution with a pH of 3 is considered:
A) Neutral
B) Slightly basic
C) Strongly acidic
D) Weakly acidic
Answer: C) Strongly acidic
Rationale: The pH scale ranges from 0 to 14, with 7 being neutral. Values
below 7 are acidic; the lower the number, the higher the concentration of
hydrogen ions (H+) and the stronger the acid. A pH of 3 is significantly
below 7, classifying it as strongly acidic .
, Question 5
Which type of bond is responsible for holding two water molecules
together and contributes to surface tension?
A) Covalent bond
B) Ionic bond
C) Hydrogen bond
D) Peptide bond
Answer: C) Hydrogen bond
Rationale: Hydrogen bonds are weak attractions between a slightly
positive hydrogen atom in one molecule and a slightly negative atom (like
oxygen or nitrogen) in another. In water, these bonds form between the
hydrogen of one molecule and the oxygen of another, creating surface
tension and high cohesion. Covalent and ionic bonds are much stronger
intramolecular forces .
Question 6
Which of the following organic molecules is the primary source of
quick energy for the cell and is characterized by a 1:2:1 ratio of
Carbon, Hydrogen, and Oxygen?
A) Lipid
B) Protein
