Mass transport and blood vesselsEdexcel International A Level Biology: Flashcards

What these 14 flashcards ask

Why can an amoeba rely on diffusion?
Why can't large animals rely on diffusion alone?
What is mass transport?
What is a closed circulatory system?
Which way do arteries carry blood?
Why do arteries have elastic tissue?
Why do arteries have a thick wall?
What is the role of smooth muscle in an artery wall?
How is a capillary adapted for exchange?
Why is slow blood flow in capillaries useful?
Which way do veins carry blood?
What is the function of valves in veins?
Why do veins have a thin wall with little muscle?
What helps blood to return through leg veins?

Exam questions on Mass transport and blood vessels

An amoeba is a single-celled organism less than 1 mm across and it obtains oxygen by diffusion across its cell surface membrane. A horse is a large mammal with a high metabolic rate and cannot obtain oxygen for its cells in this way.
A flatworm is a thin, flat animal that has no circulatory system. Explain why it can survive without one.2 marks
Blood flows from the heart to the leg muscles of a runner through an artery, passes through capillaries in the muscle and returns to the heart through a vein.
Explain how the structure of a capillary makes it suitable for exchanging oxygen and glucose with the muscle cells.2 marks
A student examines cross-sections of an artery and a vein from the same mammal. The artery has a much thicker wall than the vein, and the vein has a wider lumen than the artery.
Explain how the structure of the vein is suited to carrying blood back to the heart.3 marks

Written by the Exaim team, led by Shaun Daswani (Head of Upper Secondary, Improve ME Institute; MSc Financial Mathematics, Imperial College London; BSc, UCL) and Jason Daswani (operational lead, Improve ME Institute; LSE).