VCE Biology Question Thread

[Billuminati]

Which process of respiration relies on partial pressure gradients?
A pulmonary ventilation only
B pulmonary gas exchange and tissue gas exchange
C gas transport and pulmonary ventilation
D gas transport only

Would this be b

Correct, remember since partial pressure is a gas’ concentration, the partial pressure gradient is identical to the concentration gradient for a gaseous substance. Both processes in B rely on diffusion

[Chocolatepistachio]

Thanks

Is glutamate a second messenger can someone explain a signaling pathway that uses this messenger

[Billuminati]

Thanks

Is glutamate a second messenger can someone explain a signaling pathway that uses this messenger

No, glutamate is a neurotransmitter. It binds to and causes the opening of special Na+ channels (NMDA) that causes Na+ influx into the cell (depolarising the membrane in an EPSP). That’s about as much detail covered in 1st year biomed neurobio.

[Chocolatepistachio]

What would happen to the equilibrium potential as well as the resting membrane potential if the temperature is lowered

[Billuminati]

What would happen to the equilibrium potential as well as the resting membrane potential if the temperature is lowered

They would decrease too because if you have a look at Nernst's equation, as T increases Vm also increases

[Chocolatepistachio]

What would happen if calcium ion channels in the membrane of the presynaptic axon terminal are blocked?
A the neurons increase the synthesis of neurotransmitters
B the neurons decrease the synthesis of neurotransmitters
C the release of neurotransmitters from the presynaptic terminal into the synapse decreases
D the release of neurotransmitters from the presynaptic terminal into the synapse increases

Would this be c

[Billuminati]

What would happen if calcium ion channels in the membrane of the presynaptic axon terminal are blocked?
A the neurons increase the synthesis of neurotransmitters
B the neurons decrease the synthesis of neurotransmitters
C the release of neurotransmitters from the presynaptic terminal into the synapse decreases
D the release of neurotransmitters from the presynaptic terminal into the synapse increases

Would this be c

Correct because NT release is reliant on a Ca2+ influx triggered by the action potential reaching the axon terminal

[Chocolatepistachio]

Can cilia also increase surface area like microvilli

[Sine]

Can cilia also increase surface area like microvilli

maybe slightly but it is not really known for the increase of surface area, the main function of cilia is motility

things like microvilli/villi actually need the increase in surface area to maximise absorption/secretion

[Billuminati]

Can cilia also increase surface area like microvilli

Adding to what Sine said, cilia also has debris removal (in the respiratory system) and feeding (in protists like Paramecium) functions but yeah they're not really used for increasing surface area for absorption purposes

[Chocolatepistachio]

Thanks

Can someone explain how surfactants lower the surface tension at the air water interface of alveoli

[Billuminati]

Thanks

Can someone explain how surfactants lower the surface tension at the air water interface of alveoli

In 2nd year physiology we were taught that the surfacant is there to distrupt the H bonds between H2O molecules (H2O doesn't bond intermolecularly as strongly with the surfacant as other H2O molecules), and remember stronger intermolecular forces= stronger surface tension= decreased lung compliance

[Chocolatepistachio]

would this be bt

[Chocolatepistachio]

wouldn't this be O

[Billuminati]

wouldn't this be O

1st question: answer should be bbtt because both traits are recessive so it must be homozygous for both genes to express these traits

For the 2nd question yes it's O-type child with A-type and B-type parents. One parent is IAi (A-type), the other is IBi (B-type) and if you do a Punnett square, 1/4 of their children will be expected to be ii (O-type)