This question was a popular question and a lot of candidates answered it but their performance was not too encouraging .
The question required candidates to name two types of moveable joints e.g ball and socket joint and hinge joint. , but some candidates went ahead to name locations of the joints e.g. elbow, shoulder and knee joints and so lost the marks, others lost marks due to wrong spellings In stating how the features of the joint serve to protect the joint, many candidates could not state the functions of the parts of the joints but merely stated their features and so lost marks.
Some students could correctly define translocation and so scored full marks. in describing the experiment to indicate translocation many candidates could not properly describe the right experiment and a few candidates amongst the candidates who got the experiment right could not sequentially outline the steps for the experiment.
Expected answers include:
Types of immovable Joints
Hinge joint; ball and socket joints;
Pivot; gliding/sliding.
Features of moveable joints
- Capsular ligament; hold the bones at the joint together ( to prevent dislocation of the
bones)
- Synovial membranes; lines the inside of the ligament/secrete synovial fluid;
- Synovial fluid; lubricates the joint/ reduces friction between the bones;
- (Articular) Cartilage; lines the ends of the bones/reduces friction at the joint/; prevents
wearing, acts as shock absorbers/prevent breaking of the bones
Translocation
This is the movement of manufactured food substances; from the site of photosynthesis;
to the growing tips/storage organs; through the phloem vessels.
Experiment to demonstrate translocation of food in plants
Remove a ring of bark containing the phloem; from a photosynthesing plant; and leave
for a few weeks; the part above the ring will swell; indicating accumulation of food;
while the part below the ring remains the same but eventually shrivels; leading to the
death of the plant;
Test the sap above and below the ring; with fehiling solutions A and B; turns the sap
above the ring to brick red; indicating the presence of sucrose; while no such colour
change occurs from sap below the ring; showing that sucrose is absent; this experiment
shows that manufactured food substance in plants is translocated in the phloem
