O-LevelBiologyTransport in Humans5090/22 · Oct/Nov 2023 · Q312 Marks

Fig. 3.1 shows diagrams that represent the blood flow into and out of three major organs through blood vessels P to U. P lungs Q R kidneys S T liver U [Figure 3.1]

(a)Identify each of the following blood vessels. Q R U[3]
(b)Compare the structures of blood vessels Q and R.[3]
(c)(i)Explain each of the following. Blood in vessel S has a lower concentration of urea than blood in vessel R.[3]
(c)(ii)Explain each of the following. Blood in vessel U sometimes has a higher concentration of glucose than blood in vessel T.[3]

This question uses a diagram from the original paper, which isn't shown here. Open the full paper from the past papers archive to see it.

Mark scheme

Marking points from the official mark scheme (Oct/Nov 2023). The mark or mark type is shown in brackets.

[3] (Q) pulmonary vein ; (R) renal artery ; (U) hepatic vein ;
[3] Q – (pulmonary) vein R – (renal) artery thin + wall + thick + wall ; thin muscle / thin elastic + thick muscle / thick elastic ; wide + lumen AW + narrow + lumen AW ; valves + no valves ;
[3] 1 urea + into kidney OR kidney removes + urea ; 2 filtration / filtering ; 3 nephron / Bowman’s capsule / glomerulus ; 4 urea + excreted / in urine ;
[3] 1 (blood) glucose decreased / sugar low / body needs more sugar ; 2 glycogen ; 3 breakdown / hydrolysis + to glucose ; 4 glucose + passed out of liver / goes into U / hepatic vein / blood ; 5 (stimulated by) glucagon ;

On Oracle Prep you can write or photograph your own answer and have it marked by AI against this mark scheme, with feedback on what you missed.