1.2 Elements Of Life
Which set of elements is common to all four classes of biological macromolecules?
A researcher cultures bacteria in a medium that contains carbon, hydrogen, oxygen, nitrogen, and sulfur but completely lacks phosphorus. Which macromolecules would the bacteria be unable to synthesise in normal quantities?
Sulfur is an essential element for which of the following macromolecules?
A marine ecologist observes that algae in a nitrogen-depleted lake show reduced growth and reproductive failure. Which explanation best accounts for both of these effects?
A student claims that phosphorus is required for the synthesis of all lipids. Which statement correctly evaluates this claim?
Which element is required for both protein and nucleic acid synthesis but is NOT needed for carbohydrate synthesis?
An agricultural scientist adds a fertiliser containing only nitrogen and sulfur to crops that are showing signs of nutrient deficiency. Which macromolecule's synthesis would this fertiliser most directly support?
A cell is synthesising a molecule that contains carbon, hydrogen, oxygen, nitrogen, and phosphorus but does NOT contain sulfur. Which type of macromolecule is the cell most likely producing?
Why must living organisms obtain elements from their environment rather than creating them internally?
A farmer notices that a phosphorus-deficient crop develops weak cell membranes and fails to produce viable seeds. Which explanation correctly links phosphorus to both of these symptoms?
A student is given an unknown biological molecule and told it contains only carbon, hydrogen, and oxygen. Which macromolecule class can be definitively ruled out?
During a prolonged drought, a desert plant has access to water (H₂O) and atmospheric CO₂ but receives almost no mineral nutrients from the soil. Which macromolecule could the plant continue to synthesise most effectively under these conditions?