BIO 189 Exam 1: Fundamentals of Biology V3 - Arizona
College Updated and Latest Questions and Correct
Answers with Rationale
1. Which of the following properties of water allows it to move upward through the xylem of plants against
the force of gravity?
A. High specific heat capacity
B. Solvent versatility
C. Density as a solid
D. Cohesion and adhesion
Ans: D
Explanation: Cohesion occurs when water molecules stick to each other through hydrogen bonding.
Adhesion involves water molecules sticking to other surfaces such as the walls of plant vessels. These two
forces work together to create capillary action in the narrow tubes of the xylem. This process is essential
for transporting nutrients and water from roots to leaves. Without these specific intermolecular
attractions, tall vascular plants could not survive.
2. In the process of dehydration synthesis, which of the following is true regarding the formation of a
polymer?
A. A water molecule is removed as a new covalent bond forms
B. Energy is released as a byproduct
C. A water molecule is added to break a bond
D. The reaction is exclusively catabolic
Ans: A
,Explanation: Dehydration synthesis is a chemical reaction where two monomers are joined to form a
larger molecule. During this reaction, a hydroxyl group from one monomer and a hydrogen atom from
another combine. This results in the release of a water molecule while a covalent bond is established.
This process is the primary way biological macromolecules like proteins and carbohydrates are built. It is
an anabolic process that requires an input of energy to proceed.
3. An unknown cell is observed under a microscope and is found to have a plasma membrane, ribosomes,
and a nucleoid region but no membrane-bound organelles. What type of cell is this?
A. Animal cell
B. Prokaryotic cell
C. Plant cell
D. Eukaryotic cell
Ans: B
Explanation: Prokaryotic cells are characterized by the absence of a membrane-bound nucleus and other
organelles. Instead, their genetic material is located in a concentrated area called the nucleoid. They do
possess a plasma membrane and ribosomes which are necessary for basic life functions. Animal and plant
cells are eukaryotic and contain complex internal compartments like mitochondria. Therefore, the
presence of a nucleoid specifically identifies the specimen as a prokaryote.
4. What is the primary function of the smooth endoplasmic reticulum in eukaryotic cells?
A. Protein synthesis
B. Lipid synthesis and detoxification
C. Genetic information storage
D. ATP production
, Ans: B
Explanation: The smooth endoplasmic reticulum is a network of membranes involved in several
metabolic processes. It plays a critical role in the synthesis of lipids, including phospholipids and steroids.
Additionally, it is responsible for the detoxification of drugs and poisons in the liver. Unlike the rough ER,
it lacks ribosomes on its surface and does not synthesize proteins. This organelle is essential for
maintaining the chemical balance within the cell.
5. A solution with a pH of 3 is how many times more acidic than a solution with a pH of 6?
A. 2 times
B. 30 times
C. 100 times
D. 1000 times
Ans: D
Explanation: The pH scale is logarithmic, meaning each unit represents a tenfold difference in hydrogen
ion concentration. A jump from pH 6 to pH 5 is a 10-fold increase in acidity. Moving from pH 6 to pH 4
represents a 100-fold increase. Finally, a change from pH 6 to pH 3 results in a 1,000-fold difference (10
to the power of 3). Therefore, the solution with pH 3 has significantly higher acidity than the one at pH 6.
6. Which level of protein structure is characterized by alpha-helices and beta-pleated sheets formed by
hydrogen bonding between backbone atoms?
A. Primary structure
B. Secondary structure
C. Tertiary structure
D. Quaternary structure
College Updated and Latest Questions and Correct
Answers with Rationale
1. Which of the following properties of water allows it to move upward through the xylem of plants against
the force of gravity?
A. High specific heat capacity
B. Solvent versatility
C. Density as a solid
D. Cohesion and adhesion
Ans: D
Explanation: Cohesion occurs when water molecules stick to each other through hydrogen bonding.
Adhesion involves water molecules sticking to other surfaces such as the walls of plant vessels. These two
forces work together to create capillary action in the narrow tubes of the xylem. This process is essential
for transporting nutrients and water from roots to leaves. Without these specific intermolecular
attractions, tall vascular plants could not survive.
2. In the process of dehydration synthesis, which of the following is true regarding the formation of a
polymer?
A. A water molecule is removed as a new covalent bond forms
B. Energy is released as a byproduct
C. A water molecule is added to break a bond
D. The reaction is exclusively catabolic
Ans: A
,Explanation: Dehydration synthesis is a chemical reaction where two monomers are joined to form a
larger molecule. During this reaction, a hydroxyl group from one monomer and a hydrogen atom from
another combine. This results in the release of a water molecule while a covalent bond is established.
This process is the primary way biological macromolecules like proteins and carbohydrates are built. It is
an anabolic process that requires an input of energy to proceed.
3. An unknown cell is observed under a microscope and is found to have a plasma membrane, ribosomes,
and a nucleoid region but no membrane-bound organelles. What type of cell is this?
A. Animal cell
B. Prokaryotic cell
C. Plant cell
D. Eukaryotic cell
Ans: B
Explanation: Prokaryotic cells are characterized by the absence of a membrane-bound nucleus and other
organelles. Instead, their genetic material is located in a concentrated area called the nucleoid. They do
possess a plasma membrane and ribosomes which are necessary for basic life functions. Animal and plant
cells are eukaryotic and contain complex internal compartments like mitochondria. Therefore, the
presence of a nucleoid specifically identifies the specimen as a prokaryote.
4. What is the primary function of the smooth endoplasmic reticulum in eukaryotic cells?
A. Protein synthesis
B. Lipid synthesis and detoxification
C. Genetic information storage
D. ATP production
, Ans: B
Explanation: The smooth endoplasmic reticulum is a network of membranes involved in several
metabolic processes. It plays a critical role in the synthesis of lipids, including phospholipids and steroids.
Additionally, it is responsible for the detoxification of drugs and poisons in the liver. Unlike the rough ER,
it lacks ribosomes on its surface and does not synthesize proteins. This organelle is essential for
maintaining the chemical balance within the cell.
5. A solution with a pH of 3 is how many times more acidic than a solution with a pH of 6?
A. 2 times
B. 30 times
C. 100 times
D. 1000 times
Ans: D
Explanation: The pH scale is logarithmic, meaning each unit represents a tenfold difference in hydrogen
ion concentration. A jump from pH 6 to pH 5 is a 10-fold increase in acidity. Moving from pH 6 to pH 4
represents a 100-fold increase. Finally, a change from pH 6 to pH 3 results in a 1,000-fold difference (10
to the power of 3). Therefore, the solution with pH 3 has significantly higher acidity than the one at pH 6.
6. Which level of protein structure is characterized by alpha-helices and beta-pleated sheets formed by
hydrogen bonding between backbone atoms?
A. Primary structure
B. Secondary structure
C. Tertiary structure
D. Quaternary structure
