VCE Biology Question Thread

[TheAspiringDoc]

umm well " The glycerol backbone is central to all lipids known as triglycerides. "

And what about steroids? They're lipids, and AFAIK they don't have fatty acids/glycerol? (I could defs be wrong though)

[EspoirTron]

umm well " The glycerol backbone is central to all lipids known as triglycerides. "

And what about steroids? They're lipids, and AFAIK they don't have fatty acids/glycerol? (I could defs be wrong though)

Yes that's true, steroids are grouped together as lipids. This is due to their lipophilic nature

[n.a]

Question from NoB book:

Before the introduction of genetically engineered insulin for use by people with diabetes, the protein hormone was extracted from beef or pig pancreas. Explain who you would expect the sequence of amino acids in the beef and pig insulin to compare with that of humans.

Help!!

[cosine]

Question from NoB book:

Before the introduction of genetically engineered insulin for use by people with diabetes, the protein hormone was extracted from beef or pig pancreas. Explain who you would expect the sequence of amino acids in the beef and pig insulin to compare with that of humans.

Help!!

Okay this is an extremely stupid question and you would NEVER be asked something like this on an exam if you are not given background information, if I was you I would skip it.

However, I believe that pig insulin is actually more reliable for humans because human insulin has a amino acid sequence, and hence overall structure that more closely resembles that of the pig insulin. If you are wondering why the two insulins are different though (because all protein should have the same sequence whether it is in humans or bacteria, right?), its basically because the humans and pigs undergo separate mutations to their genetic code (DNA), and hence this mutation is passed down to successive future generations, and hence each animal will have a slightly different 'code' for the expression of insulin. So if you can link it all together, this means that cows have encountered a more higher rate of mutation that affects the expression of insulin, or in other words, they are less closely related to humans as humans to pig. So because the cows have experience a lot of mutations in the region of the gene, the insulin protein will be composed of different amino acids, and we know that the amino acid sequence affects the overall tertiary structure, which in turn affects the function of the protein. So if the structure of the pig insulin is more closely to the structure of the human insulin, then it will more suitably perform the same function as the human insulin than cow's insulin does.

I hope this helped xD

[n.a]

Okay this is an extremely stupid question and you would NEVER be asked something like this on an exam if you are not given background information, if I was you I would skip it.

However, I believe that pig insulin is actually more reliable for humans because human insulin has a amino acid sequence, and hence overall structure that more closely resembles that of the pig insulin. If you are wondering why the two insulins are different though (because all protein should have the same sequence whether it is in humans or bacteria, right?), its basically because the humans and pigs undergo separate mutations to their genetic code (DNA), and hence this mutation is passed down to successive future generations, and hence each animal will have a slightly different 'code' for the expression of insulin. So if you can link it all together, this means that cows have encountered a more higher rate of mutation that affects the expression of insulin, or in other words, they are less closely related to humans as humans to pig. So because the cows have experience a lot of mutations in the region of the gene, the insulin protein will be composed of different amino acids, and we know that the amino acid sequence affects the overall tertiary structure, which in turn affects the function of the protein. So if the structure of the pig insulin is more closely to the structure of the human insulin, then it will more suitably perform the same function as the human insulin than cow's insulin does.

I hope this helped xD

Thanks, that's brilliant! But if I wasn't given background information, I wouldn't know that pig insulin resembles human insulin, would I? Or am I missing something?

[cosine]

Thanks, that's brilliant! But if I wasn't given background information, I wouldn't know that pig insulin resembles human insulin, would I? Or am I missing something?

Background information is required for this type of question, don't worry about it !

[Splash-Tackle-Flail]

Could someone please help explain this question?

[Gogo14]

Guys who did the bio exam,
How do the questions on teh exam compare to questions in textbooks?
Are they relatively similar or are they like extension, hard questions?

[Sine]

Guys who did the bio exam,
How do the questions on teh exam compare to questions in textbooks?
Are they relatively similar or are they like extension, hard questions?

Don't bother with textbook questions best practice will come out of exam style questions.

Textbook questions will usually just test the basic knowledge, I am not too sure as I didn't do a single one.

Get some study guides and work through the relevant review questions to revise a topic after you have gone through all the theory. Then when you have finished the majority of Unit 3 (maybe start of immunity) you can start completing practice exams (non-VCAA, leave VCAA for closer to the exam) you can do them untimed and maybe just 1-2 SA questions per sitting or 5-10 MC. Then when you finish Unit 3 you can go back and do all the immunity quesitons. Same can be done for Unit 4 (at start of evolution)

[cosine]

Could someone please help explain this question?

So you have an mRNA transcript that has migrated form the Nucleus to the cytoplasm. Now, the main function of the mRNA transcript now is to be translated at a ribosome, by tRNA molecules.

a. Large ribosomal subunits bind mRNA
b. Anticodon of methionine-tRNA base pairs with its anticodon on the mRNA.
c. Small ribosomal subunits binds mRNA
d. Anticodon of changed tRNA base pairs with the codon at the A site
e. Peptide linkage forms

Looking at the steps above, we are told that they all exist in the translation of the protein. So, this means that a large ribosomal subunit binds to the mRNA strand independently of the small subunit. Just know that in order for the peptide linkage to form (e), the ribosome must be fully intact, meaning that both the small and large portion of the ribosome must have been bonded to the mRNA. Also, for the peptide linkage to be formed, two or more tRNA molecules must meet the mRNA, and bind with the complementary codons in order to release the specific amino acid, and form a peptide bond. Hence, e is completely out, it is the last step. So we now have 4 more options. Remember, if the anticodon of changed tRNA base pairs with the codon at the A site, this means that the two subunits of the ribosome must have been already linked, hence two separate steps, meaning this could possibly be the third step, but look at option b, this has to occur before the anticodon meets the codon at site A, because if you look at the progressing protein molecule, the start amino acid is Met, and so it will be going from left - right. Hence d cannot be the third step, it is infact the fourth step. Now we have a, b and c left. This part is beyond VCE biology, but anyway, the mRNA strand leaves the nucleus to find a small ribosomal subunit and binds to it, the initiating anticodon on the tRNA comes along and binds to the codon on the mRNA strand (start codon) and then finally a larger subunit of ribosome comes along and seals the tRNA onto the mRNA start codon. The translation process then occurs very complexly xD

[Gogo14]

Don't bother with textbook questions best practice will come out of exam style questions.

Textbook questions will usually just test the basic knowledge, I am not too sure as I didn't do a single one.

Get some study guides and work through the relevant review questions to revise a topic after you have gone through all the theory. Then when you have finished the majority of Unit 3 (maybe start of immunity) you can start completing practice exams (non-VCAA, leave VCAA for closer to the exam) you can do them untimed and maybe just 1-2 SA questions per sitting or 5-10 MC. Then when you finish Unit 3 you can go back and do all the immunity quesitons. Same can be done for Unit 4 (at start of evolution)

I usually would do all the prac exams after all the content is done because I can take the practice exams seriously.
So do you recommend to do them after the end of unit 4 or do just do bits and pieces of the exam relevant to the current lesson?
P.s. What are some good practice exam books/ companies. I am currently just using biozone and check points.Is that enough resources?

[cosine]

I usually would do all the prac exams after all the content is done because I can take the practice exams seriously.
So do you recommend to do them after the end of unit 4 or do just do bits and pieces of the exam relevant to the current lesson?
P.s. What are some good practice exam books/ companies. I am currently just using biozone and check points.Is that enough resources?

There are no comparable exams to the actual VCAA ones. I did all the exams, from 1997-2014, of VCAA three times. I maybe did three or four company exams, just for fun.

[Splash-Tackle-Flail]

So you have an mRNA transcript that has migrated form the Nucleus to the cytoplasm. Now, the main function of the mRNA transcript now is to be translated at a ribosome, by tRNA molecules.

a. Large ribosomal subunits bind mRNA
b. Anticodon of methionine-tRNA base pairs with its anticodon on the mRNA.
c. Small ribosomal subunits binds mRNA
d. Anticodon of changed tRNA base pairs with the codon at the A site
e. Peptide linkage forms

Looking at the steps above, we are told that they all exist in the translation of the protein. So, this means that a large ribosomal subunit binds to the mRNA strand independently of the small subunit. Just know that in order for the peptide linkage to form (e), the ribosome must be fully intact, meaning that both the small and large portion of the ribosome must have been bonded to the mRNA. Also, for the peptide linkage to be formed, two or more tRNA molecules must meet the mRNA, and bind with the complementary codons in order to release the specific amino acid, and form a peptide bond. Hence, e is completely out, it is the last step. So we now have 4 more options. Remember, if the anticodon of changed tRNA base pairs with the codon at the A site, this means that the two subunits of the ribosome must have been already linked, hence two separate steps, meaning this could possibly be the third step, but look at option b, this has to occur before the anticodon meets the codon at site A, because if you look at the progressing protein molecule, the start amino acid is Met, and so it will be going from left - right. Hence d cannot be the third step, it is infact the fourth step. Now we have a, b and c left. This part is beyond VCE biology, but anyway, the mRNA strand leaves the nucleus to find a small ribosomal subunit and binds to it, the initiating anticodon on the tRNA comes along and binds to the codon on the mRNA strand (start codon) and then finally a larger subunit of ribosome comes along and seals the tRNA onto the mRNA start codon. The translation process then occurs very complexly xD

Woah thanks heaps Cosine

[heids]

Have to agree with Cosine.

I don't like textbook questions or trial exam questions much, and I feel they often aren't like real exam questions (though I'm not above cheekily promoting my revision questions for theory practise ).  The best way to find out is to actually check out the real exam!  If anyone hasn't already, I'd recommend downloading a past VCAA exam or two and having a read, so you get an idea of what you're aiming for.  No point walking blindly through the year without knowing where you're supposed to get to (and if you leave them till the end, you often don't get time to do them all thoroughly anyway )

[cosine]

Woah thanks heaps Cosine

np mate, hit me up anytime for help with bio!

Have to agree with Cosine.

But seriously, who doesn't agree with cosine?