BY4-Jan2012

Question 1

Where in the spinal cord would you find the cell body of the nerve?

Answer 1

Grey matter.

Question 2

In which spinal cord root would you find the myelinated axon in?

Answer 2

Ventral root.

Question 3

What are the functions of the myelin sheath?

Answer 3

Electrical insulation.
Saltatory conduction.
Speed up nerve transmission.
Prevent movement of ions.
Protection of axon.

Question 4

Describe how energy is released from ATP.

Answer 4

Hydrolysis.
ATPase.
ATP to ADP and Pi.
30.6KJ.

Question 5

Give the name of two different types of effectors.

Answer 5

Muscles and glands.

Question 6

Explain the function of circular DNA.

Answer 6

Codes of primary structure of protein or enzyme. Allows mitochondria to self replicate.

Question 7

Explain how the inter membrane space of the mitochondria becomes more acidic?

Answer 7

Chemiosmosis.
Protons/hydrogen ions.
Pumped from matrix to inner membrane space.
Using energy from passage of electrons along the ETC.
Accumulation of hydrogen ions.

Question 8

Describe and explain the distribution of bacteria in an experiment using filamentous alga and oxygen seeking bacteria.

Answer 8

Photosynthesis produces oxygen.
Aerobic bacteria need oxygen for respiration.
Most bacteria move to blue and red regions.
Most photosynthesis occurs in blue and red regions.

Question 9

Describe the process by which alga produces oxygen.

Answer 9

Light dependent stage.
Absorbed energy passed to reaction centre/chlorophyll a.
Excites electron.
At PSII.
Photolysis.
Use of photolysis to replace lost electrons.
Oxygen released.

Question 10

Give the name of the pigment found at the reaction centre.

Answer 10

Chlorophyll a.

Question 11

Give the names of two other light absorbing pigments found in chloroplasts.

Answer 11

Carotenoids and xanthophylls.

Question 12

What is the advantage to a plant having several different light absorbing pigments?

Answer 12

Increases range of wavelengths/absorb different wavelengths of light.
More photosynthesis.
More glucose/carbohydrate made.

Question 13

Describe the process of ultrafiltration.

Answer 13

Afferent arteriole wider then efferent.
Gaps in endothelium wall.
Pass through pores in basement membrane. 
Acts as molecular sieve.
Eg water and salts.
Eg RBC and plasma proteins.
Filtration between feet of podocytes.

Question 14

Explain why there is a difference in population growth between the glucose and lactose.

Answer 14

Glucose is a monosaccharide.
So can be used instantly for respiration.
Glucose more easily absorbed.
Lactose is a disaccharide.
So need hydrolysis into monosaccharides.
Enzyme Lactase needs to be synthesised.

Question 15

Describe the function of enzymes and coenzymes (carriers) in the process of respiration.

Answer 15

Decarboxylase, which removes CO2, in link reaction and Krebs Cycle.
Dehydrogenase, which removes H, in glycolysis/link/Krebs.
ATP synthase, which produces ATP from ADP and Pi.
NAD acts as a H carrier/is reduced, in glycolysis/link/Krebs.
FAD acts as H carrier/is reduced, in Krebs.
Reduced NAD and FAD carry protons/electrons to ETC.
Coenzyme A, joins with acetyl, forms acetyl coenzyme A.

Question 16

Describe the roll of the cell membrane in the generation of a nerve impulse.

Answer 16

Sodium potassium pump.
3Na+ ions out, 2K+ ions in.
Creates potential difference across the membrane/inside more -ve than outside/membrane polarised.
Resting potential.
Threshold reached.
Sodium channels open.
Sodium floods in.
Depolarisation occurs.
Potassium channels open.
Sodium channels close. 
Sudden influx of K+ ions flooding out.
Repolarisation.

Question 17

Describe the role of the cell membrane in the passage of a nerve impulse between two neurones.

Answer 17

Presynaptic membrane and Ca++ ion channels open.
Synaptic vesicles fuse with presynaptic membrane.
Exocytosis/release of neurotransmitter.
Receptors on post synaptic membrane.