DP Biology (last assessment 2024)
Question 17N.3.HL.TZ0.05b
| Date | November 2017 | Marks available | [Maximum mark: 2] | Reference code | 17N.3.HL.TZ0.05b |
| Level | HL | Paper | 3 | Time zone | TZ0 |
| Command term | Explain | Question number | b | Adapted from | N/A |
b.
[Maximum mark: 2]
17N.3.HL.TZ0.05b
A cataract is a clouding of the lens in the eye, resulting in blurred vision.
[Source: Cataract in Human Eye, Rakesh Ahuja, MD (https://en.wikipedia.org/wiki/Cataract#/media/File:Cataract_in_human_eye.png)]
(b)
Explain the use of a local anesthetic during surgery to remove the cataract.
[2]
Markscheme
a. reduction/elimination of pain
OR
to block sensory perception
b. blocks synaptic transmission between «sensory neurons and CNS»
OWTTE
c. allows patient to remain aware
d. prevent reflex causing blinking/eye movement
OWTTE
[Max 2 Marks]
