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March 29, 2024, 02:02:57 am

Author Topic: VCE Biology Question Thread  (Read 3570622 times)  Share 

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Quantum44

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Re: VCE Biology Question Thread
« Reply #9015 on: January 27, 2017, 10:26:32 pm »
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Hey, I was doing chem a few days ago and i read that hydrogen bonds are the strongest types of bonds but in bio, i read that hydrogen bonds are pretty weak and easy to break (so i read about the protein's 3D structure that is held together by weak hydrogen bonds). What am i missing? I am really confused. :(

You really have to consider bonds on two levels. There are intermolecular bonds between molecules and intramolecular bonds within molecules (between atoms). Hydrogen bonds are the strongest type of intermolecular bonding so they can be considered strong by that measure, however they are fairly weak compared to intramolecular bonds such as covalent bonds which hold atoms together. So the 3D structure of a protein is held together by hydrogen bonds (which is why it denatures easily due to changes in heat and pH) but the amino acids in the chain that forms the protein have covalent bonds between them (which can only be broken through a hydrolysis reaction).
« Last Edit: January 27, 2017, 10:29:13 pm by Quantum44 »
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chany23

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Re: VCE Biology Question Thread
« Reply #9016 on: January 29, 2017, 02:56:27 pm »
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Why do different types of cell organelles have different types of transport proteins in their membranes???
Thanks for the help in advance!! 

sweetcheeks

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Re: VCE Biology Question Thread
« Reply #9017 on: January 29, 2017, 03:29:12 pm »
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Why do different types of cell organelles have different types of transport proteins in their membranes???
Thanks for the help in advance!!
Different organelles need to intake and excrete different substances to be able to carry out their functions. Transport proteins have specific shapes that only allow certain substances to move through them. For example, you couldn't use a glucose transport protein to be able to move sodium ions across a membrane, instead you would need a protein that is shaped to accomodate the sodium ion.

Seeing as different organelles carry out different functions, they will require different substances to enter and exit and therefore have transport proteins accomodating their needs.

tasmia

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Re: VCE Biology Question Thread
« Reply #9018 on: January 30, 2017, 08:35:11 pm »
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Hey guys.
I was going through [chapter one] StudyON on JacPlus. The question I attached popped up and I was wondering if we need to know about any organelles other than ribosomes, rough ER, and golgi body (which are the ones mentioned in the first subheading  of the study design)?

(organelles such as eyespots and contractile vacuole which are mentioned in the question attached.)
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sweetcheeks

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Re: VCE Biology Question Thread
« Reply #9019 on: January 30, 2017, 08:48:20 pm »
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Hey guys.
I was going through [chapter one] StudyON on JacPlus. The question I attached popped up and I was wondering if we need to know about any organelles other than ribosomes, rough ER, and golgi body (which are the ones mentioned in the first subheading  of the study design)?

(organelles such as eyespots and contractile vacuole which are mentioned in the question attached.)

From the study design
Quote
the ultrastructure of plant and animal cells in terms of their organelles and identification of these organelles
using the light microscope and electron micrographs

You will definitely need to know more organelles than you listed. The dot-point you are referring to looks specifically at membrane transport and the organelles directly involved. Chloroplasts, mitochondria, the nucleus are examples of other organelles that you will need to learn about. Contractile vacuole is the same as a normal vacuole (used for storage). I have never heard of eyespots before though.

TheAspiringDoc

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Re: VCE Biology Question Thread
« Reply #9020 on: February 07, 2017, 09:33:01 pm »
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My resources have been contradictory over this nugget:
are ions actively transported (ie against conc gradient) through protein carriers or channels?
Thanks!

plsbegentle

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Re: VCE Biology Question Thread
« Reply #9021 on: February 07, 2017, 09:43:33 pm »
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My resources have been contradictory over this nugget:
are ions actively transported (ie against conc gradient) through protein carriers or channels?
Thanks!
carriers but protein carriers can be both active or passive, protein channels are always passive (so with the concentration gradient).
« Last Edit: February 07, 2017, 09:46:10 pm by plsbegentle »
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vcestressed

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Re: VCE Biology Question Thread
« Reply #9022 on: February 13, 2017, 07:09:04 pm »
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What parts of RNA and DNA do carbohydrates form?
Thanks :)

vox nihili

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Re: VCE Biology Question Thread
« Reply #9023 on: February 13, 2017, 07:43:01 pm »
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What parts of RNA and DNA do carbohydrates form?
Thanks :)

Google it and tell us :)
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_Essie_

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Re: VCE Biology Question Thread
« Reply #9024 on: February 15, 2017, 01:11:04 pm »
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Hi guys! I'm having a bit of trouble with my first Bio assignment, it is asking us to conduct an experiment to demonstrate the movement of materials in xylem (in plants). I'm struggling for an idea and I know there's the cliche experiment where you put a plant in water x food dye and you can see the plant change colour but our teacher was strongly suggesting we provide a unique experiment and I don't know what to do! Any ideas?? Thanks :-\ :o
Stay curious <3

Ahmad_A_1999

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Re: VCE Biology Question Thread
« Reply #9025 on: February 18, 2017, 05:55:44 pm »
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Hey guys,

Could someone please explain to me why mRNA has to be synthesised in a 5' end to 3' direction?
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Quantum44

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Re: VCE Biology Question Thread
« Reply #9026 on: February 18, 2017, 06:10:43 pm »
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Hey guys,

Could someone please explain to me why mRNA has to be synthesised in a 5' end to 3' direction?

The 3' end of a nucleotide has a hydroxyl (OH) functional group. Hence nucleotides can only be added to the 3' end of a pre-existing nucleotide since condensation polymerisation requires a hydroxyl functional group so the polymerase enzyme can create a covalent bond between the nucleotides.
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vox nihili

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Re: VCE Biology Question Thread
« Reply #9027 on: February 19, 2017, 02:33:51 pm »
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Hey Guys,
What is the difference between the effect of a detergent and acid substances upon the plasma membrane?
Thanks :)

Detergent disrupts the phospholipid bilayer, acids denature the proteins in the membrane
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zxcvbnm18

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Re: VCE Biology Question Thread
« Reply #9028 on: February 20, 2017, 05:48:38 pm »
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Why is catalase present in potatos?

Gogo14

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Re: VCE Biology Question Thread
« Reply #9029 on: February 20, 2017, 06:51:07 pm »
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Why is catalase present in potatos?
Catalase is an enzyme that breaks down hydrogen peroxide. Its use is detoxify any hydrogen peroxide present (as it is toxic).
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