GACE Biology 5 — Questions and Answers
Question 1: Which reproductive strategy describes organisms that produce many offspring with minimal parental investment, typical of r-selected species?
- K-selection
- r-selection (Correct answer)
- Sexual selection
- Kin selection
Correct answer: r-selection
r-selected species invest energy in producing large numbers of offspring with little parental care, maximizing reproductive output in unpredictable environments.
Question 2: A student notices that a plant kept in a dark room for several days has yellow leaves instead of green. This yellowing most likely results from:
- Increased chlorophyll synthesis
- Chlorophyll breakdown due to lack of light (etiolation) (Correct answer)
- Overproduction of carotenoids
- Increased photosynthetic rate
Correct answer: Chlorophyll breakdown due to lack of light (etiolation)
Without light, chlorophyll is not synthesized and existing chlorophyll degrades, causing leaves to yellow as carotenoids become more visible — a process called etiolation.
Question 3: Which of the following correctly describes the central dogma of molecular biology?
- Protein → RNA → DNA
- DNA → RNA → Protein (Correct answer)
- RNA → Protein → DNA
- Protein → DNA → RNA
Correct answer: DNA → RNA → Protein
The central dogma states that genetic information flows from DNA to RNA via transcription, and from RNA to protein via translation.
Question 4: Which ecological concept describes the total number of individuals of a species that an environment can sustainably support?
- Biotic potential
- Ecological footprint
- Carrying capacity (Correct answer)
- Population density
Correct answer: Carrying capacity
Carrying capacity (K) is the maximum population size an environment can support indefinitely given available resources such as food, water, and space.
Question 5: In an experiment, researchers find that a drug prevents the separation of sister chromatids during cell division. At which phase would cell division most likely be arrested?
- Metaphase
- Anaphase (Correct answer)
- Telophase
- Prophase
Correct answer: Anaphase
Sister chromatids separate during anaphase when cohesin proteins are cleaved; blocking this process would arrest the cell at anaphase.
Question 6: Which type of mutation involves the insertion or deletion of nucleotides that changes the reading frame of the entire downstream mRNA sequence?
- Nonsense mutation
- Missense mutation
- Frameshift mutation (Correct answer)
- Silent mutation
Correct answer: Frameshift mutation
Frameshift mutations result from insertions or deletions that alter the triplet codon reading frame, typically producing a nonfunctional protein.
Question 7: Which defense mechanism is part of the innate immune system and provides a nonspecific, immediate response to pathogens?
- Production of antigen-specific antibodies
- Memory B cell activation
- Phagocytosis by neutrophils and macrophages (Correct answer)
- T cell receptor-mediated killing
Correct answer: Phagocytosis by neutrophils and macrophages
Phagocytosis by neutrophils and macrophages is a rapid, nonspecific innate immune response that engulfs and destroys pathogens without prior exposure.
GACE Biology 5
Which reproductive strategy describes organisms that produce many offspring with minimal parental investment, typical of r-selected species?