CLEP-BIOLOGY CLEP Biology Practice Questions
Prepare for CLEP-BIOLOGY with more than an answer.
- 1
According to the cohesion-tension theory of sap ascent in vascular plants, what is the primary physical mechanism pulling water from root systems up to the highest foliage of tall trees?
flowchart TD A["Stomata: Transpiration of Water Vapor into Atmosphere"] -->|Generates Negative Tension| B["Mesophyll Cell Walls and Menisci"] B -->|Cohesion & Adhesion Pulls Column| C["Xylem Vessel Elements & Tracheids"] C -->|Draws Water Upward| D["Root Cortex and Soil Solution"]Show answer details
Correct answer: B
Evaporation of water from mesophyll cell walls generates negative tension, pulling continuous, cohesive water columns upward through xylem vessels without ATP.
- 2
In angiosperm leaves, which specialized epidermal structures regulate the exchange of carbon dioxide and oxygen while controlling transpirational water vapor loss?
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Correct answer: C
Guard cells regulate stomatal pore aperture to balance atmospheric CO2 assimilation for photosynthesis against transpirational water vapor loss.
- 3
True or False: In angiosperms, phloem translocation of organic photoassimilates occurs strictly in a downward direction, moving exclusively from mature source leaves down to underground root storage sinks.
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Correct answer: B
Phloem sap moves multidirectionally from sources (photosynthetic leaves or storage organs) to sinks (developing shoots, fruits, or roots) via hydrostatic pressure gradients.
- 4
A microbiologist isolates an uncharacterized unicellular microorganism from an alkaline hot spring. Which cellular feature definitively demonstrates that the organism is a eukaryote rather than a prokaryote?
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Correct answer: C
Eukaryotes uniquely compartmentalize genomic DNA within a membrane-bound nucleus, whereas prokaryotic genomes reside in an unbound nucleoid. All cells share ribosomes, membranes, and dsDNA.
- 5
Which eukaryotic organelle carries out the beta-oxidation of very long-chain fatty acids and contains catalase to decompose the resulting toxic hydrogen peroxide byproduct into water and oxygen?
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Correct answer: D
Peroxisomes perform fatty acid oxidation and neutralize toxic hydrogen peroxide into water and oxygen using catalase. Lysosomes degrade macromolecules via acidic hydrolases.
- 6
True or False: In biological plasma membranes, integral transmembrane proteins are anchored within the phospholipid bilayer primarily by covalent bonds formed between fatty acid tails and amino acid side chains.
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Correct answer: A
Integral membrane proteins are anchored primarily by noncovalent hydrophobic interactions between nonpolar amino acid residues and the fatty acid core, not by covalent bonds.
