Module 3 Practical

Question 1

3.1
Explain how to carry out a fish gill dissection

Answer 1

Using a sharp scalpel, remove the operculum flap
Use the scalpel to remove the gill arch
Put gill arch in water, observe the splaying out of gills

Question 2

3.1.2
Explain the differences between a vein and an artery

Answer 2

Artery has a much more circular shape
Arteries have thicker walls
Veins have larger Lumen
Veins collapse when not full

Question 3

3.1.2
Explain how to do a mammalian heart dissection

Answer 3

Identify coronary artery and locate where it comes from aorta
Examine external surface of heart, identify the four chambers
Identify left and right side
Use the scissors to cut through the wall of the left atrium, cut down to apex
Open up left atrium and ventricle
Examine tendinous cords and atrioventricular valve, and semilunar valve
Make a similar cut on the right side
Measure the thickness of the walls of the left and right atria and ventricles

Question 4

2.1.3
Drawing of a plant tissue to show xylem and phloem

Answer 4

Cut the celery into thin slices using a microtome and a scalpel
Stain
Observe under microscope

Question 5

3.1.3
Using a potometer to investigate transpiration

Answer 5

Immerse potometer underwater
Put cut end of stalk under water and cut off end diagnoally
Push the stalk into the underwater potometer
Remove from water
Apply vaseline to the joints to prevent air entering
Dab leaves with a paper towel
Clamp potometer upright, with capillary tube under the water in the beaker
Remove capillary tube and let one air bubble enter, put tube back into water
Record how fast the air bubble travels in a known time
Repeat
Calculate rate, using volume (pixr2xh) mm2 per minute