Cvd & Plant Fibres Test

Question 1

compare and contrast the structure of cellulose and amylopectin (3)

Answer 1

similarities:
- both are polymers of glucose
- both contain 1,4 glycosidic bonds

differences:
- cellulose = ß glucose,
amylopectin = alpha
- cellulose not branched, amylopectin branched

Question 2

compare and contrast the heart and circulatory system of a snake with that of a human (4)

Answer 2

• both have a double circulatory system
• both have a closed circulatory system
• both have valves to prevent backflow of blood
• snake heart has 3 chambers, human heart has 4 chambers

Question 3

Explain why a snake needs a heart (2)

Answer 3

• to supply oxygen to body cells
• by mass transport

Question 4

magnification formula

Answer 4

AIM:

Magnification = image/actual

Question 5

Explain why small animals, such as Daphnia, have a heart. (4)

Answer 5

• mass transport system is used to transport oxygen to body cells
• with a heart, blood can flow faster and has improved gaseous exchange
• diffusion alone would be too slow as they have a high metabolic rate

Question 6

what is the structure and function of veins?

Answer 6

• muscle and elastic layers are thin as blood returning to heart is at low pressure, vein doesn’t need thick muscle to withstand high b.p
• valves: since pressure is low, need to prevent back-flow of blood
• wide lumen: to maximise volume of blood carried to heart