WGU C190 Objective Assessment (NEW 2025/ 2026 Update)
Introduction to Biology | 150 Questions & Answers WITH RATIONALES
| Grade A| 100% Correct (Verified Solutions)
1. Which organelle is responsible for producing ATP in a cell?
A. Nucleus
B. Ribosome
C. Mitochondrion
D. Golgi apparatus
Rationale: The mitochondrion is the “powerhouse” of the cell where cellular respiration occurs,
producing ATP from glucose.
2. What type of macromolecule are enzymes?
A. Lipids
B. Carbohydrates
C. Proteins
D. Nucleic acids
Rationale: Enzymes are proteins that catalyze biochemical reactions. Their function depends on
their 3D structure.
3. Which process produces gametes in humans?
A. Mitosis
B. Meiosis
C. Binary fission
D. Budding
Rationale: Meiosis reduces the chromosome number by half to produce haploid gametes
(sperm and eggs).
4. The sequence of DNA that codes for a protein is called a:
A. Chromosome
B. Gene
C. Allele
D. Genome
,Rationale: A gene is a segment of DNA that contains the instructions to make a specific protein.
5. Which level of organization comes after cells?
A. Organism
B. Tissue
C. Organ system
D. Population
Rationale: Cells with similar structure and function form tissues.
6. What type of bond holds the two strands of DNA together?
A. Ionic bond
B. Covalent bond
C. Hydrogen bond
D. Peptide bond
Rationale: Hydrogen bonds between complementary base pairs hold the two DNA strands
together.
7. Natural selection acts on:
A. Populations
B. Individuals
C. Molecules
D. Ecosystems
Rationale: Natural selection changes allele frequencies in populations over generations, though
individuals experience selection.
8. What is the main function of chloroplasts?
A. Cellular respiration
B. Protein synthesis
C. Photosynthesis
D. Waste removal
Rationale: Chloroplasts capture sunlight to produce glucose in plants via photosynthesis.
,9. Which molecule carries genetic information from the nucleus to the ribosome?
A. DNA
B. mRNA
C. tRNA
D. rRNA
Rationale: mRNA transcribes the DNA code in the nucleus and delivers it to ribosomes for
protein synthesis.
10. Which type of mutation changes a single nucleotide in a DNA sequence?
A. Frameshift
B. Point mutation
C. Deletion of a chromosome
D. Duplication
Rationale: A point mutation alters a single nucleotide, which can change a single amino acid in
a protein.
11. In ecology, what is a producer?
A. An organism that eats others
B. A photosynthetic organism
C. A decomposer
D. A scavenger
Rationale: Producers, like plants and algae, make their own food using sunlight.
12. Which part of the cell cycle involves DNA replication?
A. G1 phase
B. S phase
C. G2 phase
D. M phase
Rationale: During the S (synthesis) phase, DNA is replicated to prepare for cell division.
13. What type of symmetry does a starfish exhibit?
, A. Bilateral
B. Radial
C. Asymmetry
D. Spherical
Rationale: Starfish exhibit radial symmetry, meaning body parts radiate from a central point.
14. Which process breaks down glucose for energy in the absence of oxygen?
A. Aerobic respiration
B. Fermentation
C. Photosynthesis
D. Transcription
Rationale: Fermentation allows cells to produce ATP without oxygen, yielding less energy than
aerobic respiration.
15. In Mendelian genetics, what is the probability of a heterozygous cross (Aa x Aa) producing
a homozygous recessive offspring?
A. 25%
B. 50%
C. 75%
D. 100%
Rationale: A Punnett square shows one out of four combinations (aa) is homozygous recessive.
16. Which macromolecule stores genetic information?
A. Protein
B. DNA
C. Lipid
D. Carbohydrate
Rationale: DNA is the hereditary material that stores the instructions for an organism.
17. Which organ system is responsible for transporting oxygen and nutrients throughout the
body?
Introduction to Biology | 150 Questions & Answers WITH RATIONALES
| Grade A| 100% Correct (Verified Solutions)
1. Which organelle is responsible for producing ATP in a cell?
A. Nucleus
B. Ribosome
C. Mitochondrion
D. Golgi apparatus
Rationale: The mitochondrion is the “powerhouse” of the cell where cellular respiration occurs,
producing ATP from glucose.
2. What type of macromolecule are enzymes?
A. Lipids
B. Carbohydrates
C. Proteins
D. Nucleic acids
Rationale: Enzymes are proteins that catalyze biochemical reactions. Their function depends on
their 3D structure.
3. Which process produces gametes in humans?
A. Mitosis
B. Meiosis
C. Binary fission
D. Budding
Rationale: Meiosis reduces the chromosome number by half to produce haploid gametes
(sperm and eggs).
4. The sequence of DNA that codes for a protein is called a:
A. Chromosome
B. Gene
C. Allele
D. Genome
,Rationale: A gene is a segment of DNA that contains the instructions to make a specific protein.
5. Which level of organization comes after cells?
A. Organism
B. Tissue
C. Organ system
D. Population
Rationale: Cells with similar structure and function form tissues.
6. What type of bond holds the two strands of DNA together?
A. Ionic bond
B. Covalent bond
C. Hydrogen bond
D. Peptide bond
Rationale: Hydrogen bonds between complementary base pairs hold the two DNA strands
together.
7. Natural selection acts on:
A. Populations
B. Individuals
C. Molecules
D. Ecosystems
Rationale: Natural selection changes allele frequencies in populations over generations, though
individuals experience selection.
8. What is the main function of chloroplasts?
A. Cellular respiration
B. Protein synthesis
C. Photosynthesis
D. Waste removal
Rationale: Chloroplasts capture sunlight to produce glucose in plants via photosynthesis.
,9. Which molecule carries genetic information from the nucleus to the ribosome?
A. DNA
B. mRNA
C. tRNA
D. rRNA
Rationale: mRNA transcribes the DNA code in the nucleus and delivers it to ribosomes for
protein synthesis.
10. Which type of mutation changes a single nucleotide in a DNA sequence?
A. Frameshift
B. Point mutation
C. Deletion of a chromosome
D. Duplication
Rationale: A point mutation alters a single nucleotide, which can change a single amino acid in
a protein.
11. In ecology, what is a producer?
A. An organism that eats others
B. A photosynthetic organism
C. A decomposer
D. A scavenger
Rationale: Producers, like plants and algae, make their own food using sunlight.
12. Which part of the cell cycle involves DNA replication?
A. G1 phase
B. S phase
C. G2 phase
D. M phase
Rationale: During the S (synthesis) phase, DNA is replicated to prepare for cell division.
13. What type of symmetry does a starfish exhibit?
, A. Bilateral
B. Radial
C. Asymmetry
D. Spherical
Rationale: Starfish exhibit radial symmetry, meaning body parts radiate from a central point.
14. Which process breaks down glucose for energy in the absence of oxygen?
A. Aerobic respiration
B. Fermentation
C. Photosynthesis
D. Transcription
Rationale: Fermentation allows cells to produce ATP without oxygen, yielding less energy than
aerobic respiration.
15. In Mendelian genetics, what is the probability of a heterozygous cross (Aa x Aa) producing
a homozygous recessive offspring?
A. 25%
B. 50%
C. 75%
D. 100%
Rationale: A Punnett square shows one out of four combinations (aa) is homozygous recessive.
16. Which macromolecule stores genetic information?
A. Protein
B. DNA
C. Lipid
D. Carbohydrate
Rationale: DNA is the hereditary material that stores the instructions for an organism.
17. Which organ system is responsible for transporting oxygen and nutrients throughout the
body?
