Home / IB DP Biology- B3.2 Transport- IB Style Questions For HL Paper 1A

IB DP Biology- B3.2 Transport- IB Style Questions For HL Paper 1A -New Syllabus

IBDP Biology HL Paper 1 - All Chapters

Question

The micrograph shows part of the stem of the common sunflower (Helianthus annuus) in cross section.

What is the name and function of the structure labelled Z?

 NameFunction
AXylemTransport water
BPhloemTransport water
CXylemTransport sugars
DPhloemTransport sugars
▶️ Answer/Explanation

Correct Answer: \( \boxed{\mathbf{A}} \)

The structure labelled Z is the xylem, identified by its large, thick-walled vessels. Xylem transports water and mineral ions from the roots to the rest of the plant and also provides mechanical support to the stem.

Question

The graph below shows how blood pressure varies during the cardiac cycle, recorded using a sphygmomanometer. A cuff is placed on the upper arm, inflated to temporarily block blood flow in the artery, and then gradually released.

From the graph, determine the approximate values of the diastolic and systolic pressures.

 Diastolic pressure / mmHgSystolic pressure / mmHg
A.12076
B.13066
C.76120
D.66130
▶️ Answer/Explanation
The systolic pressure is the highest pressure reached during ventricular contraction (the first pulse detected as the cuff deflates), while the diastolic pressure is the lowest pressure before the sound disappears.
From the graph, these correspond approximately to 120 mmHg and 76 mmHg respectively.
✅ Answer: (C) 76 mmHg diastolic and 120 mmHg systolic

Question

How is the phloem adapted for transport?

(A) Sieve tube elements have many mitochondria for active transport.
(B) Plasmodesmata between companion cells and sieve tube elements aid transport between them.
(C) Phloem tubes unload carbon compounds at sources by pressure flow.
(D) Companion cells have reduced cytoplasm to enhance loading of carbon compounds.
▶️ Answer/Explanation

Correct Answer: \( \boxed{\mathbf{B}} \)

Plasmodesmata form cytoplasmic connections between companion cells and sieve tube elements, allowing sugars and other substances to move efficiently between them. Companion cells provide the energy and metabolic support needed for phloem translocation.

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