| Date | November 2016 | Marks available | 1 | Reference code | 16N.3.SL.TZ0.5 |
| Level | Standard level | Paper | Paper 3 | Time zone | TZ0 |
| Command term | State | Question number | 5 | Adapted from | N/A |
Question
The diagram shows the early development of the nervous system in embryonic chordates.
Outline the process taking place in the diagram.
[2]
a.
State what occurs to structure X immediately following its formation.
[1]
b.
Outline how spina bifida could occur during embryonic development.
[1]
c.
Markscheme
a. infolding of the ectoderm /neural plate
“Ectoderm” is essential for the mark.
b. formation of the neural tube
OR
neurulation
“Neural tube” or “neurulation” is essential for the mark.
a.
elongation / forms a tube
b.
a. neural tube/structure X does not close properly
b. folic acid/folacin/folate/vitamin B9 deficiency
c. may be due to mutation / genetic condition
c.
Examiners report
[N/A]
a.
[N/A]
b.
[N/A]
c.
Syllabus sections
Option A: Neurobiology and behaviour » Option A: Neurobiology and behaviour (Core topics) » A.1 Neural development
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