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A temperate phage can persist in its bacterial host or undergo productive infection. Which event identifies the lysogenic state in a lambda-like phage? A. Translation without host ribosomes B. Complete destruction of the viral genome on entry C. Immediate…
The diagram represents a chloroplast. Which labelled location contains the enzymes of the Calvin cycle? A. Location C B. Location D C. Location B D. Location A
A cell maintains the ion concentrations shown. Which mechanism can sustain these opposing gradients? Ion | Cytosol / mmol L⁻¹ | External fluid / mmol L⁻¹ Potassium | 142 | 4.5 Sodium | 12 | 138 A. Passive movement of both ions through permanently open channels…
Identify the labelled components of this membrane model. A. P: glycoprotein; Q: integral protein B. P: phospholipid; Q: free ribosome C. P: peripheral protein; Q: cholesterol D. P: nucleic acid; Q: carbohydrate chain
Type I and type II epithelial cells perform different roles in an alveolus. Which combination of structural adaptations supports these roles? A. Type I: a thick keratin layer; type II: no secretory organelles B. Type I: many motile cilia; type II: elongated…
Clathrin assembles on the cytoplasmic surface of a patch of membrane. What does this coat contribute to vesicle formation? A. It forms a scaffold that helps curve the membrane into a bud B. It breaks all phospholipid tails into amino acids C. It pumps water…
Which pair of structures occurs in both mammalian cardiac muscle cells and skeletal muscle fibres? A. Chloroplasts and mitochondria B. Central vacuoles and cilia C. Cellulose walls and sarcomeres D. Sarcomeres and mitochondria
An individual cell separated from a two-cell mammalian embryo can still generate both the embryonic body and the supporting extraembryonic tissues. How is its developmental potential classified? A. Multipotent B. Totipotent C. Unipotent D. Pluripotent
Early embryonic cells receive different concentrations of signalling molecules according to their positions. Which outcome can these gradients direct? A. Immediate loss of all chromosomes B. Replication of only the mitochondrial genome C. Development of…
Which statement accurately describes stem-cell potential? A. An adult blood-forming stem cell is multipotent B. A two-cell-stage blastomere is restricted to blood cells C. Every adult skin stem cell is totipotent D. A pluripotent cell can form only one mature…