BIO 189 Exam 1: Fundamentals of Biology V2 - Arizona
College Updated and Latest Questions and Correct
Answers with Rationale
1. Which component of the scientific method is a tentative explanation for an observation?
A. Theory
B. Law
C. Hypothesis
D. Conclusion
Ans: C
Explanation: A hypothesis is a testable and tentative explanation for a specific phenomenon observed in
nature. It serves as the starting point for further investigation and experimentation. A theory is much
broader and is supported by a large body of evidence over time. A conclusion is the final statement based
on the results of an experiment. Understanding the distinction between a hypothesis and a theory is
fundamental to the process of scientific inquiry.
2. What is the smallest unit of life that can perform all required activities?
A. Atom
B. Cell
C. Organelle
D. Molecule
Ans: B
Explanation: The cell is considered the basic structural and functional unit of all living organisms. Every
living thing is composed of one or more cells that carry out vital processes. Atoms and molecules are
,smaller, but they are not considered alive on their own. Organelles are specialized structures within cells,
yet they cannot survive independently of the cell. This concept is a core principle of the Cell Theory in
modern biology.
3. In a controlled experiment, which variable is the one that is being manipulated by the researcher?
A. Independent variable
B. Dependent variable
C. Control variable
D. Standardized variable
Ans: A
Explanation: The independent variable is the factor that the scientist intentionally changes to observe its
effects. By manipulating this variable, researchers can determine if it causes a change in the experimental
outcome. The dependent variable is what the researcher measures or observes in response to those
changes. Control variables are kept constant to ensure that only the independent variable affects the
results. Mastering these definitions is essential for designing valid and reliable scientific experiments.
4. Maintaining a stable internal environment despite external changes is known as:
A. Evolution
B. Homeostasis
C. Metabolism
D. Photosynthesis
Ans: B
, Explanation: Homeostasis refers to the regulatory processes that keep an organism’s internal conditions
within a narrow range. This includes the regulation of temperature, blood sugar, and pH levels to ensure
survival. Evolution involves genetic changes in a population over long periods rather than individual
regulation. Metabolism consists of all the chemical reactions occurring within a cell to maintain life.
Without homeostasis, biological systems would fail to function correctly under fluctuating environmental
conditions.
5. Which of the following is a subatomic particle found in the nucleus with a positive charge?
A. Electron
B. Neutron
C. Proton
D. Ion
Ans: C
Explanation: Protons are positively charged particles located in the central nucleus of an atom. The
number of protons determines the specific identity of an element on the periodic table. Electrons carry a
negative charge and orbit the nucleus in various energy shells. Neutrons are also in the nucleus but
possess no electrical charge, contributing only to atomic mass. Understanding atomic structure is the
foundation for learning how chemical bonds form between elements.
6. An atom that has gained or lost an electron and now carries an electrical charge is called a(n):
A. Isotope
B. Molecule
C. Element
D. Ion
College Updated and Latest Questions and Correct
Answers with Rationale
1. Which component of the scientific method is a tentative explanation for an observation?
A. Theory
B. Law
C. Hypothesis
D. Conclusion
Ans: C
Explanation: A hypothesis is a testable and tentative explanation for a specific phenomenon observed in
nature. It serves as the starting point for further investigation and experimentation. A theory is much
broader and is supported by a large body of evidence over time. A conclusion is the final statement based
on the results of an experiment. Understanding the distinction between a hypothesis and a theory is
fundamental to the process of scientific inquiry.
2. What is the smallest unit of life that can perform all required activities?
A. Atom
B. Cell
C. Organelle
D. Molecule
Ans: B
Explanation: The cell is considered the basic structural and functional unit of all living organisms. Every
living thing is composed of one or more cells that carry out vital processes. Atoms and molecules are
,smaller, but they are not considered alive on their own. Organelles are specialized structures within cells,
yet they cannot survive independently of the cell. This concept is a core principle of the Cell Theory in
modern biology.
3. In a controlled experiment, which variable is the one that is being manipulated by the researcher?
A. Independent variable
B. Dependent variable
C. Control variable
D. Standardized variable
Ans: A
Explanation: The independent variable is the factor that the scientist intentionally changes to observe its
effects. By manipulating this variable, researchers can determine if it causes a change in the experimental
outcome. The dependent variable is what the researcher measures or observes in response to those
changes. Control variables are kept constant to ensure that only the independent variable affects the
results. Mastering these definitions is essential for designing valid and reliable scientific experiments.
4. Maintaining a stable internal environment despite external changes is known as:
A. Evolution
B. Homeostasis
C. Metabolism
D. Photosynthesis
Ans: B
, Explanation: Homeostasis refers to the regulatory processes that keep an organism’s internal conditions
within a narrow range. This includes the regulation of temperature, blood sugar, and pH levels to ensure
survival. Evolution involves genetic changes in a population over long periods rather than individual
regulation. Metabolism consists of all the chemical reactions occurring within a cell to maintain life.
Without homeostasis, biological systems would fail to function correctly under fluctuating environmental
conditions.
5. Which of the following is a subatomic particle found in the nucleus with a positive charge?
A. Electron
B. Neutron
C. Proton
D. Ion
Ans: C
Explanation: Protons are positively charged particles located in the central nucleus of an atom. The
number of protons determines the specific identity of an element on the periodic table. Electrons carry a
negative charge and orbit the nucleus in various energy shells. Neutrons are also in the nucleus but
possess no electrical charge, contributing only to atomic mass. Understanding atomic structure is the
foundation for learning how chemical bonds form between elements.
6. An atom that has gained or lost an electron and now carries an electrical charge is called a(n):
A. Isotope
B. Molecule
C. Element
D. Ion
