Yacoubb's Bio 3+4 Questions

[coezooke]

I thought the species had to have recent common ancestry?

[Yacoubb]

I thought the species had to have recent common ancestry?

As simpak mentioned, all species of organisms to some extent have common ancestry. But some are more recent than others.

[Yacoubb]

I have some things I'd like clarified.

+ Are operons only located on the single circular chromosome eukaryotic cells?

+ If a spontaneous mutation occurred in a sterile hybrid where the number of chromosomes doubled, would that make the hybrid fertile because as a result of the doubling process, the chromosomes are present in homologous pairs --> the chromosomes are able to line up during meiosis > functional gametes can be produced.

+ On the actual exam, I was contemplating on not reading through the MC during reading time & only focussing on short answer. I dunno, I feel like its probably not a good idea. If so, what are you all doing during reading time? I was thinking of maybe spending 5 mins reading through MC and then spend around 10 mins skimming through the short answer. Tips/advice would be appreciated.

Thank you (:

[alondouek]

+ Are operons only located on the single circular chromosome eukaryotic cells?

I'm not sure what you mean by this; you're more likely to find circular chromosomes in prokaryotic cells for starters.

The operon model is a way of describing a set of genes regulated by the same promoter. For example, the lac operon consists of a promoter, an inducer, an operator, a series of genes that code for several mRNA products that lead to multiple proteins, and a terminator. These genes are adjacent to one another.

Note that the lac operon is a prokaryotic mechanism. Eukaryotic operons are far less common (based on current findings).

+ If a spontaneous mutation occurred in a sterile hybrid where the number of chromosomes doubled, would that make the hybrid fertile because as a result of the doubling process, the chromosomes are present in homologous pairs --> the chromosomes are able to line up during meiosis > functional gametes can be produced.

It's possible, and if I recall correctly it's been induced experimentally in plants. The process you have described is correct. However, in the case of the mutated sterile hybrid, it's possible (or even likely) that there are other factors that will make the gametes unviable.

+ On the actual exam, I was contemplating on not reading through the MC during reading time & only focussing on short answer. I dunno, I feel like its probably not a good idea. If so, what are you all doing during reading time? I was thinking of maybe spending 5 mins reading through MC and then spend around 10 mins skimming through the short answer. Tips/advice would be appreciated.

A 5 min/10 min split is fine; what I found to be the case in the exam is that I'd read over both sections fairly quickly to get an idea of what I'd need theory-wise, then return to the beginning and read it again more thoroughly as much as possible. Often this second reading would only get me through the MCQs, but it definitely saved time later on as I had already considered the answers.

[Irving4Prez]

What plant hormone/s are responsible for abscission in deciduous plants? I thought it was ABA hence the name, but has recent research proved otherwise?

[alondouek]

What plant hormone/s are responsible for abscission in deciduous plants? I thought it was ABA hence the name, but has recent research proved otherwise?

ABA was initially thought to be a hormonal cause of abscission (there are a number of other causes, such as structural or chemical causes), but recent research has found that auxin and ethylene are instead likely to be hormonal causes.

[Irving4Prez]

ABA was initially thought to be a hormonal cause of abscission (there are a number of other causes, such as structural or chemical causes), but recent research has found that auxin and ethylene are instead likely to be hormonal causes.

Thanks alondouek so if a question does pop up on VCAA, would we be expected to mention both ethylene and auxin?

[alondouek]

Thanks alondouek so if a question does pop up on VCAA, would we be expected to mention both ethylene and auxin?

Good question - last year, ABA was an accepted answer even though the research that contradicted this is older than 2012. First things first, check the VCAA site for any document outlining amendments to theory (they usually release on each year); otherwise, check with your teacher.

If I were a marker, giving both ethylene and auxin would be the correct answer - but I don't know if VCAA has moved away from ABA causing abscission. You'd definitely have a case to argue if they marked you as wrong!

[fridge]

Thought plant hormones were removed from the course?

This is from the VCAA Bio FAQs:
The distinction between different types of growth regulators (auxins, cytokinins, gibberellins, abscisic acid and ethylene) are not required

Can someone clarify?

[swagsxcboi]

Thought plant hormones were removed from the course?

This is from the VCAA Bio FAQs:
The distinction between different types of growth regulators (auxins, cytokinins, gibberellins, abscisic acid and ethylene) are not required

Can someone clarify?

plant growth regulators are definitely on the study design.

[Yacoubb]

I'm not sure what you mean by this; you're more likely to find circular chromosomes in prokaryotic cells for starters.

The operon model is a way of describing a set of genes regulated by the same promoter. For example, the lac operon consists of a promoter, an inducer, an operator, a series of genes that code for several mRNA products that lead to multiple proteins, and a terminator. These genes are adjacent to one another.

Note that the lac operon is a prokaryotic mechanism. Eukaryotic operons are far less common (based on current findings).


It's possible, and if I recall correctly it's been induced experimentally in plants. The process you have described is correct. However, in the case of the mutated sterile hybrid, it's possible (or even likely) that there are other factors that will make the gametes unviable.

A 5 min/10 min split is fine; what I found to be the case in the exam is that I'd read over both sections fairly quickly to get an idea of what I'd need theory-wise, then return to the beginning and read it again more thoroughly as much as possible. Often this second reading would only get me through the MCQs, but it definitely saved time later on as I had already considered the answers.

Yeah sorry that was a typo; I meant circular chromosomes in prokaryotic cells.

Thanks so much!

And I think I'll do that for the exam. During reading time I'll quickly read over the paper & look at what I need, then skim through short answer first, leaving a few minutes for mc.

[fridge]

http://www.vcaa.vic.edu.au/Documents/vce/biology/Biology-faqs.doc

This is what I've been reading for course info. Is this what everyone else is going off? If not, can someone give me a brief summary of what's been taken out of the course? So confused

[Snorlax]

BASE YOUR STUDIES ON THE STUDY DESIGN.
The FAQ pretty much tells you what the study design tells you.

[Irving4Prez]

BASE YOUR STUDIES ON THE STUDY DESIGN.
The FAQ pretty much tells you what the study design tells you.

Not necessarily, the FAQs were released afterwards and consolidates the required knowledge for the biology syllabus. The board may have rushed to release the study design PDF and may have included dot points that were irrelevant. I'm going off the FAQ, cross checking with the study design and if there's a misleading point/question, I'll revise it anyways

[Snorlax]

Not necessarily, the FAQs were released afterwards and consolidates the required knowledge for the biology syllabus. The board may have rushed to release the study design PDF and may have included dot points that were irrelevant. I'm going off the FAQ, cross checking with the study design and if there's a misleading point/question, I'll revise it anyways

The FAQ, just summarises what the Study design tells you..
I'd like to know what points on the study design is misleading, or irrelevant...