difficult exam questions

Question 1

explain why glucose is required for the contraction of skeletal muscles (3)

Answer 1

• for respiration
• to produce ATP.
• ATP also used to break the cross bridges b/w actin + myosin to stop contraction.

Question 2

outline the importance of photosynthetic pigments in photosynthesis?

Answer 2

• absorbs photons of light
• electrons excited + move up an energy level.
• accessory pigments will pass energy to the reaction center
• the primary pigment will then pass the electron ETC for light dependant reaction

Question 3

outline the role of membranes within the cells?

Answer 3

• compartmentalisation

- act as a site of chemical reactions eg oxidative phosphorylation.

Question 4

give 3 properties that make cellulose suitable as the bases of plant cell walls?

Answer 4

• high tensile strength
• insoluble
• flexible

Question 5

what sort of things do a graph need to be correct?

Answer 5

• a title
• labelled axis and units
• if continuous data (ie polygen, numbers w/in range) —> line graph
• if discontinuous –> (ie monogen, x or y) -. bar graph

Question 6

what does taking repeats help with ? (2)

Answer 6

• use it to calculate a mean

- thus reduce impact of anomalous result + to alllow the anomaly to be identified.

Question 7

what would be the effect on activity on a neuron if something caused the Na+ channels to change 3 struc + thus Na+ channels closed? (4)

Answer 7

• Na+ would not be able to diffuse + enter via the channel into the neurone
• membrane will not be depolarised.
• action potential is not generated along the axon.
• thus NO release of a neurotransmitter.

Question 8

explain how paralysis of the diaphragm could lead to suffocation? (2)

Answer 8

• paralysis would cause little change in the volume of the thorax + pa in thorax(1)
• and thus little AIR would enter the lungs.

Question 9

what would be the effect on heart rate if speed of conduction in Purkinje Fibres of the heart ? (3)

Answer 9

• decreased heart rate
• the ventricular contraction would be slower
• diastole would take longer

Question 10

WHY is transmission of action potentials along the axon slower in the absence of saltatory conduction? (1)

Answer 10

• the depolarisation has to occur across the WHOLE axon.