substance	process that produces the substance	organ that excretes the substance
carbon dioxide	Table answer r1_process that produces the substance	Table answer r1_organ that excretes the substance
Table answer r2_substance	photosynthesis	Table answer r2_organ that excretes the substance

2(b)(i)Human Nutrition DigestionMedium4 marks

Figure 2.1 shows the movement of nitrogen-containing substances through the human body.

Figure 2.1, a flow diagram with a key (rectangle = substance, oval = organ, arrow = direction of movement): food passes by arrow F to the mouth and on to the small intestine, then by arrow G to amino acids in the blood; arrow H leads from amino acids in the blood to body cells; amino acids in the blood also pass to the liver, then by arrow J to substance K, then to the kidney and on to urine

Identify the processes occurring at F, G, H and J in Figure 2.1.

2(b)(ii)Excretion OsmoregulationEasy1 mark

State the name of substance K in Figure 2.1.

2(c)(i)Excretion OsmoregulationEasy2 marks

Figure 2.2 is a diagram of a nephron from a human kidney and its associated blood vessels. The arrows show the direction of blood flow.

Figure 2.2, a nephron from a human kidney with its associated blood vessels; at the top left, arrows show blood flowing in through vessel Q and out through vessel L, and the letters M, N, O and P label other parts of the nephron and its blood supply

State the letter in Figure 2.2 that identifies the glomerulus and describe its function. letter function

Answer

0 words

2(c)(ii)Excretion OsmoregulationHard4 marks

The oxygen concentrations of the blood in blood vessel Q and blood vessel L are different. State and explain the difference in oxygen concentration between blood vessel Q and blood vessel L.

Answer

0 words