Life Processes — Respiration, Transport and Excretion: Which Organ Does What

Life processes are the four jobs every living body must do to stay alive: take in food, release energy from it, move things around inside, and throw out what is left over. Exam papers love this chapter because it is full of pairs that sound alike and mean different things — breathing and respiration, artery and vein, xylem and phloem, nephron and neuron. Almost every mark lost here is lost to a mix-up, not to ignorance.

The way through it is to ask one question of every structure: what goes in, and what comes out? A nephron takes in blood and puts out urine. An alveolus takes in air and puts out carbon dioxide. Phloem takes in the sugar made in the leaf and delivers it wherever the plant is growing. Once each part has a clear input and a clear output, the pairs stop swapping places in your memory.

1. Which of the following is the basic structural and functional unit of the kidney?

2. The pulmonary artery carries:

3. Anaerobic respiration in human muscle cells produces:

4. Glycolysis, the first step of respiration, takes place in which part of the cell?

5. Which plant tissue transports food and can move it in both directions?

6. The main nitrogenous waste excreted by birds and reptiles is:

7. The trachea (windpipe) is prevented from collapsing by:

8. Approximately how many ATP molecules are produced by the complete aerobic respiration of one glucose molecule?