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What conclusion about sodium transport follows from this membrane model? A. Sodium leaves through the ATP-powered transporter and can return through a channel B. Sodium leaves by simple diffusion through lipid and returns by protein synthesis C. Every sodium…
A cultured embryonic stem-cell line can form cell types from all three germ layers but cannot by itself form an entire organism with extra-embryonic tissues. How is its developmental potential described? A. Terminally differentiated B. Multipotent within one…
Which description is supported by the membrane drawing? A. A peripheral protein found only on the cytoplasmic surface B. A soluble carbohydrate floating freely inside the cell C. A membrane-spanning glycoprotein that may participate in recognition D. A channel…
Which signal commonly activates a membrane receptor possessing tyrosine kinase activity? A. Insulin released after a carbohydrate-containing meal B. Adrenaline acting through its usual G-protein-coupled pathway C. A steroid entering a cell and binding an…
In a model cell population, expression of gene K helps suppress uncontrolled division. The graph compares two promoter conditions. Which interpretation is best supported? A. Methylation increases DNA replication and therefore prevents tumours B. Methylation…
What role do histone proteins play in a eukaryotic chromosome? A. They supply the catalytic centre of a ribosome B. They join amino acids during translation C. They form the spindle fibres that pull chromosomes apart D. They help package DNA into chromatin
A young shoot bends towards a light source on its left. Which auxin distribution contributes to that response? A. More auxin on the illuminated left side, producing faster growth there B. Equal auxin on both sides, with identical elongation C. More auxin on…
A climacteric fruit begins ripening and releases a gaseous signal that stimulates further release of the same signal. Which description fits this process? A. Ethylene-mediated positive feedback B. Auxin-mediated negative feedback that stops ripening C.…
Which statement follows from the branching pattern? A. M is necessarily morphologically identical to the ancestral organism B. Exactly one nucleotide differs between P and Q C. Q and R share a more recent common ancestor than N and P D. The horizontal…
Water evaporates from mesophyll cell walls while roots have an adequate water supply. Which process helps replace the lost water? A. Upward bulk flow through xylem driven by transpiration pull B. Permanent closure of every stoma before any water is lost C.…