The Nature of Science
What best describes a scientific theory?
a) An untested guess
b) A well‑supported explanation based on evidence
c) A law once it is proven
d) A personal opinion
b) A well‑supported explanation based on evidence
Which level of organization comes directly after cell?
a) Organ system
b) Tissue
c) Organism
d) Molecule
b) Tissue
Which phrase describes the cell membrane?
a) Rigid cellulose wall only in animal cells
b) Phospholipid bilayer with embedded proteins that is semipermeable
c) Solid layer of protein preventing any movement
d) Single‑layer membrane that dissolves in water
b) Phospholipid bilayer with embedded proteins that is semipermeable
Where do the light‑dependent reactions occur?
a) Mitochondrial matrix
b) Cytoplasm
c) Thylakoid membranes of chloroplasts
d) Nucleus
c) Thylakoid membranes of chloroplasts
During which phase does sister chromatid separation occur in mitosis?
a) Prophase
b) Metaphase
c) Anaphase
d) Telophase
c) Anaphase
Which practice most improves the credibility of a scientific claim?
a) Using colorful graphs
b) Checking for peer‑reviewed primary literature and replication
c) Quoting celebrity endorsements
d) Posting on social media
b) Checking for peer‑reviewed primary literature and replication
Which characteristic is NOT required for an entity to be considered alive?
a) Ability to reproduce
b) Ability to maintain homeostasis
c) Ability to use energy
d) Ability to perform photosynthesis
d) Ability to perform photosynthesis
If a cell is placed in a hypotonic solution, water will:
a) Move into the cell, causing it to swell
b) Move out of the cell, causing it to shrink
c) Remain unchanged because tonicity only affects solutes
d) Immediately stop all diffusion
a) Move into the cell, causing it to swell
Which molecules are produced directly by the light‑dependent reactions for use in the Calvin cycle?
a) Glucose and O2
b) ATP and NADPH
c) CO2 and H2O
d) DNA and RNA
b) ATP and NADPH
Meiosis differs from mitosis because meiosis:
a) Produces two identical diploid daughter cells
b) Involves one division only
c) Produces four genetically unique haploid gametes after two divisions
d) Does not include pairing of homologous chromosomes
c) Produces four genetically unique haploid gametes after two divisions
In the C‑E‑R framework, "Evidence" refers to:
a) The final conclusion
b) A list of materials used
c) Personal beliefs about the outcome
d) Data and observations collected during testing
d) Data and observations collected during testing
An autotroph obtains energy by:
a) Consuming other organisms only
b) Producing its own organic molecules from inorganic sources
c) Relying exclusively on fermentation
d) Absorbing ATP from the environment
b) Producing its own organic molecules from inorganic sources
Facilitated diffusion differs from active transport because facilitated diffusion:
a) Requires ATP and moves solutes against their gradient
b) Uses transport proteins and moves molecules down their concentration gradient without ATP
c) Only moves water across membranes
d) Occurs only in organelles, not cells
b) Uses transport proteins and moves molecules down their concentration gradient without ATP
Which factor will most likely increase the rate of photosynthesis up to a saturation point?
a) Increasing light intensity when CO2 and temperature are non‑limiting
b) Decreasing CO2 concentration while light is high
c) Lowering temperature to near freezing
d) Removing chlorophyll from leaves
a) Increasing light intensity when CO2 and temperature are non‑limiting
Crossing‑over occurs during which stage and why is it important?
a) Anaphase II; it separates sister chromatids
b) Prophase I; it exchanges genetic material between homologous chromosomes increasing variation
c) Cytokinesis; it physically divides cells
d) G1 phase; it replicates DNA
b) Prophase I; it exchanges genetic material between homologous chromosomes increasing variation
Which statement correctly distinguishes correlation and causation?
a) Correlation proves causation if sample size is large
b) Causation means two variables change together for unknown reasons
c) Correlation means two variables vary together; causation means one variable causes the other
d) They are interchangeable terms
c) Correlation means two variables vary together; causation means one variable causes the other
Which example best shows homeostasis in humans?
a) Plants growing toward light
b) Sweating to cool the body during exercise
c) Leaves changing color in fall
d) Bacteria reproducing rapidly in warm conditions
b) Sweating to cool the body during exercise
Which membrane transport process involves vesicles fusing with the plasma membrane to release substances outside the cell?
a) Endocytosis
b) Facilitated diffusion
c) Exocytosis
d) Passive diffusion
c) Exocytosis
Which pigment primarily absorbs blue and red wavelengths and reflects green?
a) Carotenoids
b) Chlorophyll
c) Hemoglobin
d) Anthocyanin
b) Chlorophyll
Which best describes a malignant tumor?
a) A non‑dividing cluster of normal cells with no health risk
b) A localized benign growth that cannot spread
c) A mass of cancerous cells that can invade nearby tissues and metastasize
d) A healing scar formed after injury
c) A mass of cancerous cells that can invade nearby tissues and metastasize
Which scenario is an example of pseudoscience?
a) A peer‑reviewed randomized trial of a new vaccine
b) A claim that a herbal remedy cures all diseases without reproducible studies or testable mechanisms
c) A replicated lab experiment published in a journal
d) A systematic review summarizing clinical trials
b) A claim that a herbal remedy cures all diseases without reproducible studies or testable mechanisms
Stem cells are important because they:
a) Always remain undifferentiated forever
b) Cannot divide
c) Are only found in adult organisms
d) Can differentiate into multiple specialized cell types
d) Can differentiate into multiple specialized cell types
Which statement about cystic fibrosis is accurate in relation to membrane transport?
a) It results from excessive passive diffusion of water across membranes
b) It involves defective ion channels affecting mucus transport and cellular ion balance
c) It is caused by lack of mitochondria in epithelial cells
d) It increases the rate of exocytosis in all cells
b) It involves defective ion channels affecting mucus transport and cellular ion balance
Priestley’s bell jar experiment demonstrated that plants:
a) Consume oxygen and produce carbon dioxide only
b) Produce oxygen that can restore a candle flame’s ability to burn in a closed jar
c) Do not interact with gases in the atmosphere
d) Can photosynthesize without light
b) Produce oxygen that can restore a candle flame’s ability to burn in a closed jar
Which pair correctly matches a treatment with its general mechanism?
a) Radiation — introduces targeted DNA damage to cancer cells; Chemotherapy — uses drugs to kill or inhibit rapidly dividing cells
b) Surgery — stimulates cell division; Radiation — supplies nutrients to tumor
c) Chemotherapy — only removes tumors physically; Immunotherapy — causes DNA mutations
d) Radiation — increases blood flow to tumor; Surgery — uses radiation beams
a) Radiation — introduces targeted DNA damage to cancer cells; Chemotherapy — uses drugs to kill or inhibit rapidly dividing cells