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March 29, 2024, 01:50:57 am

Author Topic: VCE Biology Question Thread  (Read 3570617 times)  Share 

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alchemy

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Re: VCE Biology Question Thread
« Reply #1470 on: April 17, 2014, 05:40:30 pm »
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What are the differences between animal and plant hormones? :/

Animal hormones act much more rapidly than plant hormones.
Animal hormones usually travel through the bloodstream whereas plant hormones travel through the phloem or xylem or even in the air (like ethylene, since it's a gas). 
Animal hormones aren't necessarily produced in response to environmental factors, whereas plant hormones are always (or almost always) produced in response to some environmental factor.
Plants don't secrete hormones from glands, whereas most animal hormones are secreted by ductless glands.

alchemy

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Re: VCE Biology Question Thread
« Reply #1471 on: April 17, 2014, 05:46:28 pm »
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3. What is the difference between hydrogen and covalent bonding. Is there even a difference?

I suppose this question touches on some chem knowledge. Hydrogen bonding occurs between Hydrogen and Nitrogen/Oxygen/Fluorine. Note, that hydrogen forms covalent bonds with  Nitrogen/Oxygen/Fluorine, but hydrogen bonds form in between separate molecules (for example, between water molecules). It is a relatively strong 'intermolecular' bond, while covalent bonding is a stronger 'intramolecular' bond.

nerdmmb

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Re: VCE Biology Question Thread
« Reply #1472 on: April 17, 2014, 05:53:49 pm »
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If endocrine glands produce hormones and secrete them straight into the bloodstream then what do exocrine hormones produce?

Or do exocrine hormones also produce hormones but secrete them differently?

Frozone

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Re: VCE Biology Question Thread
« Reply #1473 on: April 17, 2014, 06:10:51 pm »
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When explaining the difference between pheromones and hormones can i just say that pheromones are secreted externally whilst hormones are secreted internally?
VCE 2013 - 2014:  Biology |English|Geography| Literature |Mathematical Methods [CAS] |Physical Education | Psychology

vox nihili

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Re: VCE Biology Question Thread
« Reply #1474 on: April 17, 2014, 06:42:24 pm »
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If endocrine glands produce hormones and secrete them straight into the bloodstream then what do exocrine hormones produce?

Or do exocrine hormones also produce hormones but secrete them differently?

Endocrines go into the blood system, exocrines are excreted onto external surfaces (remember that the duodenum would technically be external)
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jessica666

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Re: VCE Biology Question Thread
« Reply #1475 on: April 17, 2014, 07:24:54 pm »
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1. which organelle would synthesis the hormones insulin and then testosterone? Is it protein and lipids?

Insulin is a peptide hormone, so it would be synthesised in the ribosomes attached to the rough ER. Testosterone is a steroid so it would be synthesised in the smooth ER

Frozone

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Re: VCE Biology Question Thread
« Reply #1476 on: April 17, 2014, 07:53:31 pm »
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Insulin is a peptide hormone, so it would be synthesised in the ribosomes attached to the rough ER. Testosterone is a steroid so it would be synthesised in the smooth ER
Why is that so?
And isn't testosterone a lipid? I thought the smooth ER just transported things.
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gohfish

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Re: VCE Biology Question Thread
« Reply #1477 on: April 17, 2014, 07:59:42 pm »
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Yes, testosterone is a lipid hormone. Both rough and smooth ER transport substances and the smooth endoplasmic reticulum also synthesises lipids.

vox nihili

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Re: VCE Biology Question Thread
« Reply #1478 on: April 17, 2014, 08:01:57 pm »
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Why is that so?
And isn't testosterone a lipid? I thought the smooth ER just transported things.

There are a number of roles related to the smooth ER. It starts lipid synthesis, Golgi finishes it. Any lipid that is exported will pass through both.
Rough ER is involved in the synthesis of exported proteins.
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nerdmmb

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Re: VCE Biology Question Thread
« Reply #1479 on: April 17, 2014, 11:31:10 pm »
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Do we need to know about amoeba related diseases, giardiasis, Malaria, cattle tick or athropods.
The NOB book has a lot of irrelevant info, it's hard to know what is related to the bio course..

vox nihili

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Re: VCE Biology Question Thread
« Reply #1480 on: April 17, 2014, 11:40:51 pm »
+1
Do we need to know about amoeba related diseases, giardiasis, Malaria, cattle tick or athropods.
The NOB book has a lot of irrelevant info, it's hard to know what is related to the bio course..

God no. Just know that amoebae can cause disease.
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alchemy

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Re: VCE Biology Question Thread
« Reply #1481 on: April 18, 2014, 09:55:09 am »
+1
The NOB book has a lot of irrelevant info, it's hard to know what is related to the bio course..

^^^THIS!!!^^^

magpiesrule

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Re: VCE Biology Question Thread
« Reply #1482 on: April 18, 2014, 12:13:11 pm »
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Can someone please explain what exactly happens in protein synthesis? (Like the RNA, transcription stuff)

nhmn0301

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Re: VCE Biology Question Thread
« Reply #1483 on: April 18, 2014, 01:16:29 pm »
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Can someone please explain what exactly happens in protein synthesis? (Like the RNA, transcription stuff)
I'll try to cover as much as I can (in a VCE level obviously)

1. Transcription: when a gene becomes active, it will make a "mobile" copy of its genetic instructions that can transfer to the ribosome, since it cannot leave the nucleus. This genetic copy take form of RNA.
RNA polymerase unzips DNA, this enzyme (RNA polymerase) collects free RNA nucleotides that can complementary pair with the DNA template strand. A three base sequence of DNA is called "triplet", a three base sequence mRNA is called a "codon" and a three base sequence tRNA is an "anticodon", all of these 3 base sequence codes for an amino acid.

2. Translation: this is where the synthesis of protein start to take place, everything is determined by the codon of mRNA. Ribosomes will attach to mRA and start translation. Firstly, each codon on mRNA is translated by the process where tRNA carries a complementary amino acid  (i.e anticodon) to fit the codon of mRNA and make sure we obtain an exact amino acid sequence. Codon and anticodon pair using H-bond, and the polypeptide starts to grow from peptide bond. After this tRNA that carries a specific amino acid finish its mission, it will be released back and again can be used to supply the same type of amino acid over again. Finally, in order for translation to stop, a protein molecule, called release factor will occupy the codon site, create a "stop codon", also the bond between the last amino acid and the last tRNA is broken, release a free polypeptide. the ribosomal subunit ultimately break free the mRNA.
Still confused, try this video which contains more detailed and visual explanation https://www.youtube.com/watch?v=ZNl1z6Lev1E
Hope this helps!
2015-2017: Bachelor of Biomedicine

MM1

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Re: VCE Biology Question Thread
« Reply #1484 on: April 18, 2014, 04:17:12 pm »
+1
Why do interneurons lack myelin?