required practical 5

Question 1

what is required practical 5

Answer 1

Dissection of animal or plant gas exchange system or mass transport system
or of organ within such a system.

Question 2

Describe precautions that should be followed when performing a dissection

Answer 2

● Cover any cuts with a waterproof dressing
● When using a scalpel, cut away from body onto a hard surface
● When using a scalpel, use a sharp blade
● When using a scalpel, carry with blade protected / pointing down
● Wear disposable gloves and disinfect hands / wash with soap
● Disinfect surfaces / equipment
● Safe disposal - put gloves / paper towels / organ in a separate bag / bin to dispose
● If poisonous chemicals / toxins involved, work in a well ventilated environment

Question 3

Suggest an ethical consideration when dissecting animals

Answer 3

● Morally wrong to kill animals just for dissection
● So use animals for dissection that have already been killed (humanely) for meat

Question 4

Describe how you could prepare a temporary mount of a piece of plant
tissue for observation with an optical microscope

Answer 4

1. Add a drop of water to glass slide
2. Obtain a thin section of specimen and place on slide
3. Stain (eg. with iodine / potassium iodide to view starch)
4. Lower coverslip at angle using mounted needle without trapping air bubbles

Question 5

What are the rules of scientific drawing?

Answer 5

✓ Look similar to specimen / image - draw parts to the same scale / relative size
✓ No sketching - only clear, continuous lines
✓ No shading / hatching
✓ Include a magnification scale (eg. x 400)
✓ Label with straight, uncrossed lines