joy1010's qs

[joy1010]

can someone please explain why gene flow is classified as the interbreeding of two populations...this is what it says in one of the neap question books.

is it because when individuals migrate in they reproduce and therefore there a new alleles?

[joy1010]

what is adaptive radiation?

[Yacoubb]

can someone please explain why gene flow is classified as the interbreeding of two populations...this is what it says in one of the neap question books.

is it because when individuals migrate in they reproduce and therefore there a new alleles?

Gene flow refers to the movement of genes (alleles) between two populations of the same species. How do these genes (alleles) actually move from the gene pool of one population to another? Through interbreeding. Just remember, that the two populations have to be of the same species.

what is adaptive radiation?

Adaptive radiation is the diversification of one ancestral species into many different forms that each exploit different niches in a given environment. It really is divergent evolution; where an different members of ancestral species become more genetically dissimilar over time as a result of being subjected to different selection pressures in different habitats.

[joy1010]

Gene flow refers to the movement of genes (alleles) between two populations of the same species. How do these genes (alleles) actually move from the gene pool of one population to another? Through interbreeding. Just remember, that the two populations have to be of the same species.

Adaptive radiation is the diversification of one ancestral species into many different forms that each exploit different niches in a given environment. It really is divergent evolution; where an different members of ancestral species become more genetically dissimilar over time as a result of being subjected to different selection pressures in different habitats.

so does migration need to happen for alleles to move to another population?

[Yacoubb]

so does migration need to happen for alleles to move to another population?

Migration is just the movement of an organism from one location to another. So, if organisms interbreed because one organism moves from one population to another, then technically, migration needs to happen. Remember, if one organism from another population enters the population, they become a part of the population, and they contribute to the gene pool.

[joy1010]

Migration is just the movement of an organism from one location to another. So, if organisms interbreed because one organism moves from one population to another, then technically, migration needs to happen. Remember, if one organism from another population enters the population, they become a part of the population, and they contribute to the gene pool.

okay, thanks so much 

[joy1010]

is it just me or are neap exams actually quite difficult...

[Yacoubb]

is it just me or are neap exams actually quite difficult...

NEAP exams tend to be difficult. Just make sure you go over and evaluate your errors & really rectify errors associated especially with how you express your answers/use biological terminology.

[joy1010]

CAN SOMEONE PLEASE EXPLAIN TO ME THE WHOLE GENE EXPRESSION/REGULATION STUFF...GOING THROUGH IT NOW AND I'M A TAD CONFUSED....WHAT IS THIS WHOLE LAC OPERON STUFF??

[Yacoubb]

CAN SOMEONE PLEASE EXPLAIN TO ME THE WHOLE GENE EXPRESSION/REGULATION STUFF...GOING THROUGH IT NOW AND I'M A TAD CONFUSED....WHAT IS THIS WHOLE LAC OPERON STUFF??

Transcript:
- RNA polymerase transcribes the DNA template strand.
- pre-mRNA is synthesised 5' to 3' by complementary base pairing.
- pre-mRNA undergoes post-transcriptional modification (includes intron removal).
- mRNA leaves the nucleus & enters the cytoplasm via nuclear pores.

Translation:
- mRNA is read by the ribosome.
- When an mRNA codon is read, the anticodon of a loaded tRNA molecule binds to the mRNA codon by complementary base pairing.
- The loaded tRNA then deposits the amino acid, which is added to the growing polypeptide chain.
- A polypeptide is synthesised.

^^ Thats all you need!

The lac operon is found in bacteria. It shows how gene regulation occurs in prokaryotes. In the absence of lactose, a repressor protein binds to the promotor, preventing RNA polymerase from binding to the promotor, thus preventing the transcription of the gene for lactase.

However, when lactose is present, lactose binds to & induces a change in the repressor protein. The promotor is unoccupied, RNA polymerase can bind to the promotor, and transcription of the lactase gene can occur.

Remember that gene regulation is needed to conserve energy, and produce proteins only when and where they are required.

[joy1010]

Transcript:
- RNA polymerase transcribes the DNA template strand.
- pre-mRNA is synthesised 5' to 3' by complementary base pairing.
- pre-mRNA undergoes post-transcriptional modification (includes intron removal).
- mRNA leaves the nucleus & enters the cytoplasm via nuclear pores.

Translation:
- mRNA is read by the ribosome.
- When an mRNA codon is read, the anticodon of a loaded tRNA molecule binds to the mRNA codon by complementary base pairing.
- The loaded tRNA then deposits the amino acid, which is added to the growing polypeptide chain.
- A polypeptide is synthesised.

^^ Thats all you need!

The lac operon is found in bacteria. It shows how gene regulation occurs in prokaryotes. In the absence of lactose, a repressor protein binds to the promotor, preventing RNA polymerase from binding to the promotor, thus preventing the transcription of the gene for lactase.

However, when lactose is present, lactose binds to & induces a change in the repressor protein. The promotor is unoccupied, RNA polymerase can bind to the promotor, and transcription of the lactase gene can occur.

Remember that gene regulation is needed to conserve energy, and produce proteins only when and where they are required.

thanks so much
good luck for Thursday!!