BIO 189 Exam 1: Fundamentals of Biology V1 - Arizona
College Updated and Latest Questions and Correct
Answers with Rationale
1. Which of the following is considered the smallest basic unit of life?
A. Cell
B. Organelle
C. Atom
D. Molecule
Ans: A
Explanation: The cell is the fundamental structural and functional unit of all living organisms. While
atoms and molecules are smaller, they are not considered living entities on their own. Organelles perform
specific tasks within a cell but cannot survive independently. Biology defines life starting at the cellular
level of organization. Understanding this hierarchy is essential for studying complex biological systems.
2. In the scientific method, what is a tentative explanation that can be tested?
A. Theory
B. Conclusion
C. Hypothesis
D. Law
Ans: C
Explanation: A hypothesis is a proposed explanation for a set of observations that can be investigated. It
must be testable and falsifiable to be valid in a scientific context. A theory is much broader and supported
,by a larger body of evidence. A conclusion is the result of the experiment after data analysis. Scientists
use hypotheses to guide their experimental design and data collection.
3. Which property of life involves the maintenance of a stable internal environment?
A. Homeostasis
B. Metabolism
C. Evolution
D. Reproduction
Ans: A
Explanation: Homeostasis is the process by which organisms keep their internal conditions relatively
constant. This balance is necessary for biochemical processes to function correctly despite external
changes. Metabolism refers to the chemical reactions that provide energy for the body. Evolution involves
changes in populations over many generations rather than individual stability. Constant internal
monitoring is a hallmark of all living things.
4. What subatomic particle carries a negative charge and orbits the nucleus?
A. Proton
B. Neutron
C. Isotope
D. Electron
Ans: D
Explanation: Electrons are negatively charged particles that move in shells around the central nucleus.
Protons and neutrons are found inside the nucleus and provide most of the atom’s mass. The number of
, electrons determines the chemical reactivity and bonding behavior of the atom. Isotopes are variations of
elements with different numbers of neutrons. Mastering atomic structure is key to understanding
molecular biology.
5. Which type of bond is formed when two atoms share electrons?
A. Covalent bond
B. Hydrogen bond
C. Ionic bond
D. Metallic bond
Ans: A
Explanation: Covalent bonds involve the sharing of electron pairs between atoms to achieve stability.
This type of bonding is very common in organic molecules like water and glucose. Ionic bonds occur
when electrons are transferred from one atom to another, creating ions. Hydrogen bonds are weak
attractions between polar molecules rather than sharing electrons. These strong bonds hold the
backbone of DNA and proteins together.
6. Water molecules stick to each other due to which property?
A. Cohesion
B. Adhesion
C. Solubility
D. Density
Ans: A
College Updated and Latest Questions and Correct
Answers with Rationale
1. Which of the following is considered the smallest basic unit of life?
A. Cell
B. Organelle
C. Atom
D. Molecule
Ans: A
Explanation: The cell is the fundamental structural and functional unit of all living organisms. While
atoms and molecules are smaller, they are not considered living entities on their own. Organelles perform
specific tasks within a cell but cannot survive independently. Biology defines life starting at the cellular
level of organization. Understanding this hierarchy is essential for studying complex biological systems.
2. In the scientific method, what is a tentative explanation that can be tested?
A. Theory
B. Conclusion
C. Hypothesis
D. Law
Ans: C
Explanation: A hypothesis is a proposed explanation for a set of observations that can be investigated. It
must be testable and falsifiable to be valid in a scientific context. A theory is much broader and supported
,by a larger body of evidence. A conclusion is the result of the experiment after data analysis. Scientists
use hypotheses to guide their experimental design and data collection.
3. Which property of life involves the maintenance of a stable internal environment?
A. Homeostasis
B. Metabolism
C. Evolution
D. Reproduction
Ans: A
Explanation: Homeostasis is the process by which organisms keep their internal conditions relatively
constant. This balance is necessary for biochemical processes to function correctly despite external
changes. Metabolism refers to the chemical reactions that provide energy for the body. Evolution involves
changes in populations over many generations rather than individual stability. Constant internal
monitoring is a hallmark of all living things.
4. What subatomic particle carries a negative charge and orbits the nucleus?
A. Proton
B. Neutron
C. Isotope
D. Electron
Ans: D
Explanation: Electrons are negatively charged particles that move in shells around the central nucleus.
Protons and neutrons are found inside the nucleus and provide most of the atom’s mass. The number of
, electrons determines the chemical reactivity and bonding behavior of the atom. Isotopes are variations of
elements with different numbers of neutrons. Mastering atomic structure is key to understanding
molecular biology.
5. Which type of bond is formed when two atoms share electrons?
A. Covalent bond
B. Hydrogen bond
C. Ionic bond
D. Metallic bond
Ans: A
Explanation: Covalent bonds involve the sharing of electron pairs between atoms to achieve stability.
This type of bonding is very common in organic molecules like water and glucose. Ionic bonds occur
when electrons are transferred from one atom to another, creating ions. Hydrogen bonds are weak
attractions between polar molecules rather than sharing electrons. These strong bonds hold the
backbone of DNA and proteins together.
6. Water molecules stick to each other due to which property?
A. Cohesion
B. Adhesion
C. Solubility
D. Density
Ans: A
