Biology · May / June 2024 · Paper 42 · Question 2

1

(groups of) receptor (cells / tissues)

OR

group of tissues, working together / to perform specific function ;

2

detecting / sense / reacting / responding, (specific named) stimuli / (change in) surrounding

OR

transmits impulse to (sensory) neurone ;

label line and the letter X that touches the neurone coming from the brain to the eye ;

any three from:

1

correct ref to neurotransmitter (molecules) ;

2

(neurotransmitters) released from vesicles (from first or presynaptic neurone / into synaptic gap) ;

3

(neurotransmitters) diffuse across (gap / cleft) ; 4

(neurotransmitters) bind / fit / attach / receive to, receptor (proteins / molecules) / membrane proteins (on the next neurone) ;

total of four from:

1

identify E as ciliary muscle and K as suspensory ligaments and F as lens ;

max three from:

2

ciliary muscle / E, contracts;

3

suspensory ligaments / K, slacken / loosen / AW ; 4

lens / F, becomes more convex / AW ;

5

more refraction ;

6

light / image (of object), is focussed onto the, retina / fovea / A or B ;

any four from:

distribution:

1

both (rods and cones) found in, retina / A ;

2

(high concentration of / more) cones / no rods, are found in the fovea / B ;

3

no rods or cones, at blind spot / C ;

function:

4

(rods / cones) are light receptors OR

detect / respond / sensitive, to light OR convert light energy to, (nerve / electrical) impulse ;

5

rods sense / detect / respond to, low light intensity / dim light / AW / give night vision and give, greyscale / black and white, image ;

6

cones sense / detect / respond to, high light

intensity / bright light / AW and detect colour / give colour vision / (different cones) absorb different wavelengths (of light) ;

allele ;

XaY ;