ISA

Question 1

Why did we stare at the after paper quickly?

Answer 1

So square didn’t disappear

Question 2

Why did we stare at the centre of the after paper?

Answer 2

The after image could move - don’t want it to move off page

Question 3

Why avoid blinking when staring at square/afterimage?

Answer 3

So couldn’t lose afterimage

Question 4

Why were we in a well lit room?

Answer 4

So that cone cells were stimulated

Question 5

Why did people have different results?

Answer 5

Differences in cone cells between individuals

Different eyesight - corrective vision

Reaction timer of partner on stopwatch

Personal judgement on when afterimage disappeared

Question 6

What nerve carries information from the eye to the brain?

Answer 6

The optic nerve

Question 7

What is an a,ternate be experiment that could have been done?

Answer 7

Look at two different coloured squares - see if colour affects duration of afterimage

Null hypothesis - ‘colour of square has no difference on duration of afterimage’

Repeat - work out mean - comparing two means - STANDARD ERROR

Question 8

What are the green types of cone cells?

Answer 8

Red, blue, green

Question 9

Why was the colour of the fther image yellow?

Answer 9

When staring at blue square - blue cone cells activated

So blue cone cells got tired/not working as effectively

Red and green were still working effectively (Red + Green = Yellow)

E.g. If original square was green, afterimage would be a mix of blue and red

Question 10

Describe rod cells

Answer 10

3 to 1 bipolar cell

Retinal convergence

Black and White image

Summation

Lower visual acuity

Question 11

Describe cone cells

Answer 11

1 to 1 bipolar cell

No retinal convergence

Colour image

Higher visual acuity

Question 12

Describe a trichromatic vision graph

Answer 12

Each peak represents a maximum wavelength

3 peaks - 3 types of wavelength - each peak represents a colour

Some cone cells detect a range of wavelengths

Question 13

If a trichromatic vision graph has 4 peaks, how do you compare it to a 3 peak one?

Answer 13

Which peaks are the same

Which peaks differ

Extra peaks

Question 14

How do you select at random?

Answer 14

Names out of hat

Random name generator

Number names then pick out of hat

Question 15

How would mutation cause a different protein?

Answer 15

Alter base sequence - substitution or deletion/addition (frameshift)

Changes amino acid sequence

Changes tertiary structure

Question 16

If there is 10,000 cone cells per mm2 in the fovea and the diameter of the fovea is 10mm. How many cone cells are there in total?

Answer 16

Pi x r2

Pi x 25 x 10,000 = ans

Question 17

Does the data in resource A/B support a conclusion?

Answer 17

Yes and no

Look for error bars - if they don’t overlap then the difference is significant/not due to chance

Sample size - is it large enough to be representative? Small sample size goes against conclusion.

Is it the environment the organism would normally be accustomed to? If it’s artificial it goes against conclusion

Question 18

How do you calculate percentage difference?

Answer 18

Difference/original x 100

Question 19

What did the experiment involve?

Answer 19

Varying the duration of staring at the blue square and then timing the duration of the afterimage