Scientists investigate nitrate ion uptake by a freshwater alga.
The concentration of nitrate ions is higher inside the algal cells than in the surrounding water. Cells containing more mitochondria take up nitrate ions more quickly.
Which statement explains this?
Mitochondria release energy by respiration, which draws water into the cells by osmosis and carries the nitrate ions in with it.
Mitochondria release energy by respiration, which carrier proteins use to change shape and carry nitrate ions into the cells.
Mitochondria release energy by respiration, which gives nitrate ions more kinetic energy so that they diffuse into the cells faster.
Mitochondria release energy by respiration, which opens protein channels so nitrate ions diffuse in down their concentration gradient.
194 exam-style questions on OCR GCSE Biology 2.1 Supplying the cell, covering 2.1.1 Transport across cell membranes, 2.1.2 Mitosis and the cell cycle, 2.1.3 Importance of cell differentiation, and 2.1.4 Stem cells. Each one has a worked solution and a mark scheme showing where the marks go.