Required Practical 4

Question 1

Why wash beetroot discs before the test?

Answer 1

To remove surface pigment (betalins).

Question 2

Why prove pigment release is due to alcohol?

Answer 2

Washing shows pigment isn’t pre-released, only from alcohol effect.

Question 3

What’s in the control group?

Answer 3

Distilled water + 2 beetroot discs.

Question 4

Why use distilled water control?

Answer 4

To compare pigment leakage caused by alcohol.

Question 5

Why spread beetroot discs in alcohol?

Answer 5

To maximize surface contact and prevent sticking.

Question 6

Why keep time constant for all discs in alcohol?

Answer 6

To ensure equal diffusion time for pigment release.

Question 7

What effect does heating have on beetroot membranes?

Answer 7

It damages plasma membranes.

Question 8

How does heat damage membranes?

Answer 8

It disrupts phospholipid bilayer or denatures membrane proteins.

Question 9

What happens to pigment during cooking?

Answer 9

Lots of pigment leaks out, less remains in tissue.

Question 10

Why does diffusion slow at lower temperatures?

Answer 10

Molecules have less kinetic energy.

Question 11

How does temperature affect molecule speed?

Answer 11

Molecules move slower when colder.

Question 12

How does temperature affect diffusion rate?

Answer 12

Lower temperature means lower diffusion rate.

Question 13

How does temperature affect membrane fluidity?

Answer 13

Membranes are less fluid when cold.

Question 14

What causes variation in results?

Answer 14

Differences in beetroot or subjective color judgment.

Question 15

Why shouldn’t the graph curve extend beyond data?

Answer 15

No control with water to validate those points.

Question 16

What do phospholipids do in membranes?

Answer 16

They maintain membrane structure and integrity.

Question 17

What happens to membranes at higher alcohol?

Answer 17

Membranes break down faster.

Question 18

How does high alcohol affect membrane permeability?

Answer 18

It increases permeability.

Question 19

What happens to betalins at high alcohol?

Answer 19

More betalins leak out.

Question 20

Why does pigment diffuse faster with more alcohol?

Answer 20

Membrane damage speeds diffusion.

Question 21

Why repeat experiment at 100% alcohol?

Answer 21

To check if results are consistent (concordant).

Question 22

What does pigment equilibrium mean?

Answer 22

Equal pigment concentration inside and outside cells.

Question 23

What does maximum membrane damage mean?

Answer 23

Maximum pigment release.

Question 24

How to monitor temperature accurately?

Answer 24

Measure with a thermometer during the test.

Question 25

What size factors must be measured?

Answer 25

Length, diameter, surface area, or mass.

Question 26

Why control time in solution?

Answer 26

To keep exposure consistent.

Question 27

How improve measurement precision?

Answer 27

Use finer scale instrument.

Question 28

What damage does 70°C cause?

Answer 28

Membrane damage (pigment release).

Question 29

How does heat affect membrane proteins?

Answer 29

Proteins denature.

Question 30

How does heat affect phospholipid bilayer?

Answer 30

Increases fluidity and damage.

Question 31

Effect of too much water on pigment solution?

Answer 31

Dilutes pigment; solution appears lighter.

Question 32

Effect of too little water on pigment solution?

Answer 32

Concentrates pigment; solution appears darker.

Question 33

Why control water amount?

Answer 33

To keep results comparable across tests.

Question 34

How measure temperature continuously?

Answer 34

Use digital thermometer or sensor.

Question 35

How to draw graph line?

Answer 35

Point-to-point or smooth s-curve.

Question 36

What to avoid in graphing?

Answer 36

No extrapolation beyond data range.

Question 37

What happens to membranes at high temp?

Answer 37

Membrane damage occurs.

Question 38

What happens to membrane proteins at high temp?

Answer 38

Proteins denature.

Question 39

What happens to bilayer at high temp?

Answer 39

Fluidity and damage increase.

Question 40

Name one soil factor to control.

Answer 40

Mineral ion concentration.

Question 41

Name another soil factor to control.

Answer 41

Soil pH.

Question 42

Name one environmental factor to control.

Answer 42

Temperature.

Question 43

How does 2,4-D affect wild oats?

Answer 43

Increases ion release from cells.

Question 44

Effect of 2,4-D on wheat ion release?

Answer 44

Little or no effect.

Question 45

Why is ion loss bad?

Answer 45

Leads to cell death or damage.

Question 46

Why maintain temperature during experiment?

Answer 46

Keeps diffusion rate constant.

Question 47

Why shake leaf discs in solution?

Answer 47

To expose all surfaces and maintain concentration gradient.