IB Questionbank

9.2 Transport in the phloem of plants

Description

Nature of science:
Developments in scientific research follow improvements in apparatus—experimental methods for measuring phloem transport rates using aphid stylets and radioactively-labelled carbon dioxide were only possible when radioisotopes became available. (1.8)

Understandings:

Plants transport organic compounds from sources to sinks.
Incompressibility of water allows transport along hydrostatic pressure gradients.
Active transport is used to load organic compounds into phloem sieve tubes at the source.
High concentrations of solutes in the phloem at the source lead to water uptake by osmosis.
Raised hydrostatic pressure causes the contents of the phloem to flow towards sinks.

Applications and skills:

Application: Structure–function relationships of phloem sieve tubes.
Skill: Identification of xylem and phloem in microscope images of stem and root.
Skill: Analysis of data from experiments measuring phloem transport rates using aphid stylets and radioactively-labelled carbon dioxide.

Utilization:
Syllabus and cross-curricular links:
Biology
Topic 1.4 Membrane transport

Sub sections and their related questions

DP Biology Questionbank

9.2 Transport in the phloem of plants

Description

Directly related questions

Sub sections and their related questions