Practice Test 79 - High School Biology
20 questions. Answer them in any order, then submit to see your score and every explanation.
- In a lake ecosystem, a scientist tracks phosphorus (a nutrient) moving from algae to insects to fish. After organisms die, decomposers break them down and phosphorus returns to the water and sediments. Which statement best summarizes nutrient movement like phosphorus in ecosystems?
- A lake has declining native fish diversity after an invasive predatory fish was introduced. Managers consider three options: 1) Remove invasive fish using targeted netting each year. 2) Add more native fish from hatcheries without removing the invader. 3) Do nothing and let the ecosystem "rebalance." Which option is most likely to increase native fish biodiversity, and why?
- In a simplified model of transcription, a DNA gene is opened, RNA nucleotides pair to one DNA strand, RNA polymerase builds an mRNA strand, and the mRNA leaves the DNA. Which statement about the product of transcription is correct?
- A student claims: "Positive feedback is the main way the body maintains homeostasis." Which choice best corrects the student using the idea of response direction?
- In translation, the ribosome reads mRNA in units called codons. What is a codon?
- A student says, "Translation turns the message in mRNA into a protein." Which option correctly identifies where translation happens and what the ribosome does?
- A student gets a shallow cut on their finger. Over the next few days, the skin closes and the surface looks normal again. Which model best explains how the body repairs the damaged skin tissue at the cellular level?
- A gardener trims a plant, and over time the cut stem produces new tissue and continues growing. In a simple cell-based model, which pairing best explains how the plant both increases tissue and restores the cut area?
- A researcher recorded blood types in a sample of 60 people. Blood type | Count A | 20 B | 9 AB | 6 O | 25 Which statement best describes what the data show about variation in this population?
- In a plant population, a gene variant that helps conserve water (waxy leaf coating) is heritable. In wet years, plants with the waxy coating grow slightly slower than plants without it. In dry years, plants with the waxy coating survive drought better. Which statement best describes how natural selection on the waxy coating depends on the environment?
- Which option best matches the definition of an organ system?
- A tRNA has an anticodon that pairs with a codon on mRNA during translation. What is the main function of tRNA in protein synthesis?
- A flock of small birds forages on the ground. When one bird alarms, the whole flock quickly takes off. Compared with solitary birds, why can flocking reduce the chance of any one bird being eaten?
- A student says, "Alleles are the same thing as genes." Which response best corrects the student using an example such as eye color (B = brown, b = blue)?
- A chemical in the environment causes a substitution mutation in a skin cell's DNA (one base replaced). Which statement is most accurate about the possible effects of this mutation?
- Two mechanisms are described: Mechanism 1: A variable rises above normal, and the body's response causes the variable to decrease back toward normal. Mechanism 2: A process begins, and the response makes the process happen even more strongly until a clear endpoint is reached. Which option correctly classifies Mechanism 1 and Mechanism 2?
- A structure is described as a single nerve cell with long extensions that transmit electrical signals. What level of biological organization is this structure?
- Eye color is often used to illustrate basic dominance. Suppose allele B (brown eyes) is dominant over allele b (blue eyes). Which pair of genotypes could both produce the same phenotype of brown eyes?
- A teacher lists: (i) cardiac muscle cell, (ii) heart, (iii) cardiac muscle tissue, (iv) circulatory system. Which choice correctly matches each item to its level of organization?
- A lizard species has heritable variation in heat tolerance. Over several decades, average summer temperatures rise in the region. Which change is most likely to occur in the lizard population due to natural selection?