Practicles

Question 1

Investigate photosynthesis, light

Answer 1

Place a boiling tube 10cm away from a light source (LED) (measure with ruler). Fill the boiling tube with 0.2% sodium hydrogen carbonate solution. Place cut pondweed into boiling tube. Leave the tube to rest for 5 mins to acclimatise. Start stopwatch and count amount of bubbles produced in 1 min. Repeat each distance 3 times (10cm, 20cm, 30cm, 40cm & 50cm) and take an average. Record in table and plot a graph with rate of photosynthesis against light intensity.

Question 2

Investigate photosynthesis, carbon dioxide

Answer 2

Place a boiling tube 10cm away from a light source (LED) (measure with ruler). Fill the boiling tube with 0.2% sodium hydrogen carbonate solution. Place cut pondweed into boiling tube. Leave the tube to rest for 5 mins to acclimatise. Start stopwatch and count amount of bubbles produced in 1 min. Repeat 3 more concentrations and take an average. Record in table and plot a graph with rate of photosynthesis against sodium hydrogen carbonate solution.

Question 3

Investigate photosynthesis, chlorophyll

Answer 3

Use a variegated leaf (with green and white parts), immerse leaf in bio lounge water for 30 seconds. Place on white tile to see colour change. Add iodine solution using pipette. Green parts should turn black to blue as starch is present.

Question 4

Investigate the rate of transpiration from a leafy shoot

Answer 4

Cut leafy shoot underwater to prevent air getting into xylem and place in position. Fill potometer with water and use vaseline to seal apparatus and make sure it’s airtight. Trap an air bubble in capillary tube. Measure the starting distance of air bubble, then start timer for 10 mins. Measure end distance and plot in table. Repeat process for both fan and no fan, repeat each experiment 3 times and take an average.

Question 5

Investigate the effect of exercise has on breathing rate (CORMS)

Answer 5

C- Amount of star jumps performed (consistently)
O- Human
R- Repeat each recording 3 times and take average
M- Measure number of breaths per min)
S- Same person, same exercise, time of recovery (20s between), consistent jumps

Question 6

Investigate the effect of exercise has on breathing rate (IV, DV, CV)

Answer 6

IV- Amount of star jumps
DV- Number of breaths standing
CV- person, exercise, time, time between

Question 7

Investigate diffusion in non-living systems.1

Answer 7

• Place crystals potassium permanganate in water
• Overtime the molecules will diffuse from high to low concentration
• Colour will get weaker due to diffusion

Question 8

Investigate diffusion in non-living systems.2

Answer 8

Agar cubes of different sizes (relationship between diffusion and surface area)

• Cubes contagion alkali and an indicator, they are placed in acid
• Colour change from pink to colourless as acid neutralises it

Question 9

Investigate osmosis in living systems.1

Answer 9

Potato chips placed in sucrose or salt solutions or different concentrations

If solution has a high water concentration, water will move in and increase mass

If solution has a low water concentration, water will move out and decrease mass

If there is no change in mass, the conc is same and you can find the potato’s water potential

Question 10

Investigate osmosis in non-living systems

Answer 10

Use visking tubing as it only allows small soluble molecules to pass through, therefore osmosis will occur

Place coaling tubing with sucrose solution in water, water will rise out visking tubing

Change conc of sucrose of temp

Question 11

Investigate osmosis in living systems.2

Answer 11

Use thin section of onion cells
Cells in water become turgid
Cells in solution become plasmolysed

Question 12

Investigate the conditions needed for photosynthesis

Answer 12

C- Change the abiotic conditions in which the seeds germinate
O- Cress seeds are all taken from same parent plant
R- Repeat the investigation 3 times and take an average
M- Measure how meant seeds in each test tube germinate after a set period of time
S- Control type of water used, Control temp for tubes A, B and C

Question 13

Investigate the amount of plants in a given area

Answer 13

• Use random sampling
• Divisde up a grid and split it into 10 x 10 metre
• Use a random numbers generator to get a coordinate
• place quadrant on grid
• count number of species in the quadrat
• repeat until you have at least 10 counts and take an average

Question 14

Belt transect

Answer 14

• use measuring tape
• place quadrat on 0m
• count species
• record result in table
• measure 2m across and repeat until you have 10 point and plot on graph and take average