VCE Biology Question Thread

[psyxwar]

In facilitated diffusion, do carrier proteins aid in the transport of polar molecules and ions across biological membranes, whilst channel proteins purely aid in the transport of onlyions across biological membranes?

I don't think such a distinction is accurate, or necessary for that matter. Aquaporins are a channel protein that facilitates the transport of water molecules, for example.

[anat0my]

Why does translation occur on a ribosome, why can't the tRNA just associate with the mRNA? 

[dankfrank420]

Why does translation occur on a ribosome, why can't the tRNA just associate with the mRNA? 

Because the ribosome synthesises a polypeptide from the amino acid that the tRNA carries. If the tRNA and mRNA simply associated in the cytosol, then there would be no way to synthesise a polypeptide chain.

[anat0my]

How much of gene regulation is required knowledge? Do we need to know about the Lac Operon and repressor proteins, etc? 

Why does DNA need to be cut up by restriction enzymes before analysis? 

[Jason12]

in branching evolution, are splitting and budding two types of branching evolution and how are they different? 

Also what is comparative genomics and phylogeny

Geological time scale - do we need to actually remember the whole diagram? If not what do we need to know?

[Jason12]

why is potassium-argon dating used for older fossils?

why do land animals rarely form fossils?

[dankfrank420]

why is potassium-argon dating used for older fossils?

why do land animals rarely form fossils?

Because Carbon dating has too short a half life (something like 5700 years), so another method is needed for fossils millions of years old.

Because fossilisation needs water to compact the sediment, so unless the land animal is near a water source (eg. lake, river) then it is unlikely that it will be fossilised.

[dankfrank420]

Also what are major trends from genus Australopithecus to genus homo

I've got the habilis tool makers, erectus walking upright and using fire but I don't know what else to add?

 
 

Fora Magnumen (Idk how to spell it) moves central - allows for bipedalism
Shorter arm-to-leg ration - allows for bipedalism
Bipedalism allows us to free up our hands to use tools
Leads to larger brain sizes needed to use these tools
Larger brain also leads to development of primitive culture

[melons]

Because Carbon dating has too short a half life (something like 5700 years), so another method is needed for fossils millions of years old.

Because fossilisation needs water to compact the sediment, so unless the land animal is near a water source (eg. lake, river) then it is unlikely that it will be fossilised.

I thought that they didn't really need water, just marine environments provide better fossilisation conditions (as mentioned by dankfrank) including high pressure, low oxygen and protection due to being rapidly covered by the movement of water through waves.

[Damo23]

Hey anyone know some characteristics of hominoids? And hominins besides bipedal movement, skull, teeth, jaw size?

[dankfrank420]

My SAC notification states that I must be able to explain "how DNA changes over evolutionary time". Is this just referring to mutation?

@Gapster

You're right, my mistake.

@Damo

I think you've confused what a homonoid is. At my school, they taught us that a homonoid is a superfamily containing all apes, so obviously some if them wouldn't be bipedal.

[melons]

My SAC notification states that I must be able to explain "how DNA changes over evolutionary time". Is this just referring to mutation?

Sounds like it.

[Stressedyear11here]

How does genetic drift, selection pressures and gene flow influence natural selection?


Cheers

[dankfrank420]

What is cytochrome C and how can it be used to determine evolutionary relationships.

[grannysmith]

How does genetic drift, selection pressures and gene flow influence natural selection?


Cheers

Genetic drift is a random/chance change in allele frequencies of a population, which may lead to an increase in a certain phenotype (which may or may not be favoured by a particular environment).

Gene flow can rapidly change allele frequencies within a population (due to migration). Genes are exchanged between populations.

Selection pressures are exerted by selective agents which cause differential fitness of certain phenotypes; a certain characteristic (phenotype) is favoured and thus organisms with this certain phenotype have a selective advantage.