Chapter 7 Practice Paper: Transport Systems — mark scheme (print)

Back to Chapter 7

Question paper PDF

QuizQuipPractice Series

QQ/S2SCI/CH7

Secondary 2 · Lower Secondary Science (G2 / G3)

Mark scheme

Transport Systems

Chapter 7 Practice Paper · Maximum mark: 30

Notes for markers

Award one mark for each point marked [1], up to the marks shown for the part.
Accept answers worded differently that show the same understanding.
Units are required where the answer line shows one. ecf: allow an error carried forward.

Section A: Multiple-choice questions[10 marks]

Question	Answer
1	AArteries carry blood away from the heart. Veins carry it back.	1
2	CVeins return blood to the heart.	1
3	BCapillaries are the exchange vessels.	1
4	DXylem carries water and mineral salts. Phloem carries food such as sugars.	1
5	APhloem carries sugars and other food around the plant.	1
6	COsmosis is the net movement of water molecules from a dilute solution to a more concentrated solution through a partially permeable membrane.	1
7	DRed blood cells carry oxygen. Plasma carries dissolved food. Platelets help clotting.	1
8	BPlatelets help the blood to clot. They do not carry oxygen.	1
9	APlasma is the liquid part of blood. It carries dissolved food, carbon dioxide and the cells.	1
10	CDiffusion is the net movement of particles from higher concentration to lower concentration. Osmosis is the net movement of water molecules from a dilute solution to a more concentrated solution through a partially permeable membrane.	1

Section B: Structured questions[20 marks]

Question	Answer and marking points	Marks
1(a)	Plasma carries dissolved food. Red blood cells carry oxygen. White blood cells defend the body against disease. Plasma carries dissolved food [1] Red blood cells carry oxygen [1] White blood cells defend against disease [1]	3
1(b)	They help the blood to clot at a cut. Help clotting [1]	1
1(c)	Diffusion alone is too slow to supply cells that are far from the outside. Diffusion is too slow over long distances [1]	1
	Total for Question 1	5
2(a)	An artery carries blood away from the heart. A vein carries blood towards the heart. A capillary is where substances are exchanged with cells. Artery: away from the heart [1] Vein: towards the heart [1] Capillary: exchange [1]	3
2(b)	Oxygen diffuses from a higher concentration in the blood to a lower concentration in the cell. Diffusion [1] From higher concentration to lower concentration [1]	2
	Total for Question 2	5
3(a)	Water molecules move by osmosis from the more dilute soil solution to the more concentrated solution in the cell, through a partially permeable membrane. From dilute to more concentrated [1] Water molecules [1] Through a partially permeable membrane [1]	3
3(b)	Xylem [1]	1
3(c)	Phloem [1]	1
	Total for Question 3	5
4(a)	The leaf is thin, so the cell is close to the air. Carbon dioxide can diffuse that short distance without blood. The distance is short / the leaf is thin [1] Diffusion is fast enough over that distance [1]	2
4(b)	In the blood. In the blood / plasma [1]	1
4(c)	Any two: did the donor consent; is the risk acceptable; is the chance of a transplant shared fairly. One ethical question, such as consent [1] A second ethical question, such as fairness or risk [1]	2
	Total for Question 4	5

— End of mark scheme —