VCE Biology Question Thread

[millie96]

Do we have to know detail about the negative feedback response? Someone said we didn't but its in a 2013 prac exam

[shivaji]

Do we have to know detail about the negative feedback response? Someone said we didn't but its in a 2013 prac exam

no, only at the cellular level, not on the organism level.
quite sure it wasn't in the 2013 prac exam

[shivaji]

Slower mutation rate

doesn't the d-loop mutate at a faster rate than nuclear dna, so that it is easier to establish evolutionary relationships?

[vox nihili]

does cytokinesis occur at the end of meiosis 1?

Yes

doesn't the d-loop mutate at a faster rate than nuclear dna, so that it is easier to establish evolutionary relationships?

Yes sorry, you're absolutely right. It's actually a faster mutation rate. There are some genes that mutate pretty slowly though, because of how important they are to survival. Those genes involved in metabolism are obviously going to be pretty key, and will not deal well with mutation.

Do we have to know detail about the negative feedback response? Someone said we didn't but its in a 2013 prac exam

Negative feedback has been taken from the course and should not appear on exams after 2012

[dankfrank420]

Slower mutation rate

Doesn't mitochondrial DNA mutate faster?

Edit: Just saw the above correction, nevermind.

[howlingwisdom]

Slower mutation rate

How exactly is that advantageous though? Can evolutionary relationships be tracked more easily as a result of a slower mutation rate?

[Reus]

How exactly is that advantageous though? Can evolutionary relationships be tracked more easily as a result of a slower mutation rate?

No it mutates faster hence more evidence of biological evolution. He corrected himself earlier.

[dankfrank420]

Is anything wrong with my description of the following processes?

Light-dependant Photosynthesis

- Chlorophyll absorbs light, energising the electrons so they move down the Electron Transport Chain and produce ATP
- Water is split into Hydrogen ions and oxygen
- Hydrogen ions are taken up by the NADPH acceptor molecule
- Oxygen gas is produced as a byproduct

Light-independent photosynthesis

- Hydrogen ions from NADPH react with carbon dioxide to produce glucose, ATP (produced in LD photosynthesis) is used as an energy source for this reaction
- Water is produced as a byproduct

Electron transport chain

- Loaded acceptor molecules NADH and FADH2 pump electrons into the cristae, releasing energy when the electrons move from one molecule to the other
- This energy is used for the phosphorylation of ADP to convert it to ATP
- Hydrogen ions are also released by the acceptor molecules, which combine with oxygen to produced water as a byproduct

Passing an impulse from one neuron to another

- Impulse reaches the axon terminal
- Neurotransmitter is secreted and travels across the synapse to bind the the receptors on the dendrites of the next neurone
- The reaction between the neurotransmitter and the receptors generate and impulse

An impulse travelling along an axon

- Threshold reached
- Sodium enters the neurone through sodium channels, making the inside of the cell positive (depolarising it)
- This propagates the impulse
- To correct this, Potassium ions leave the neurone through channels, restoring the inside of the cell as negative (re-polarising it)

[dankfrank420]

No it mutates faster hence more evidence of biological evolution. He corrected himself earlier.

It also mutates at a constant rate, so we can derive a molecular clock from it.

[Reus]

What would the opposite of phosphorylation be?

[simpak]

What would the opposite of phosphorylation be?

Literally, dephosphorylation.

[Reus]

Literally, dephosphorylation.

LOL originality at its finest. Thanks!

[shivaji]

do we need to know about the lac operon?

[vox nihili]

do we need to know about the lac operon?

Nope. Just the principal of switching genes on and off

[Reus]

Nope. Just the principal of switching genes on and off

Damn it I wasted my time then -.-