VCE Biology Question Thread

[sunshine98]

Hey everyone, I have a question - it would be awesome if someone could tell me which of these match up with the other.

1. Facilitated diffusion
2. Active transport
3. Bulk transport (endocytosis and exocytosis)

and they each need to be matched up with one of these...

1. Substances which are small can pass rapidly through pores in the lipid bilayer. These substances must:

• be polar/soluble in water
• uncharged

Examples are water, and gases such as carbon dioxide and oxygen.
Usually simple diffusion especially given the examples you've provided

2. Lipid soluble substances which readily pass through the lipid layer. These substances must:

• be non-polar

Examples are steroids and fatty acids.
Simple diffusion ...ik this isn't an option but If it said that it was against the concentration gradient I would say active transport

3. Substances which are too large for the pores, or not lipid soluble by nature, or charged, may pass through protein channels. The substances must:

• be polar

Examples are monomers, which go through carrier proteins, and ions, which go through channel proteins.
Facilitated diffusion cause says protein channels  and polar

It would be great if someone could help match each description with its name! Thanks



ALSO (sorry for so many questions, haha) can anyone list the properties that substances MUST have in order to undergo the following (through a cell membrane):

• Diffusion

:mainly small and non polar /uncharged/ hydrophobic/lipophilic stuff.

• Osmosis

: Osmosis=water only water

• Facilitated diffusion

: big, charged/polar/ lipophobic /hydrophilic stuff

• Active transport

: this only occurs when we are going against the concentration gradient so in that sense it could be any molecules because it uses membrane proteins anyways

• Bulk transport (endocytosis + exocytosis)

: This is for super large things that the cell wants to take in. Eg a macrophage will want to engulf a pathogen through endocytosis
[/list]

Idk the first question seems weird tho
Hope it helps 

[Butterflygirl]

Rhubarb is a plant with edible pink stems or stalks. The rhubarb stalks are pink because the epidermal cells contain a pink pigment. The pink pigment is packaged within the cell in the large vacuole that occupies most of the volume of the cell.

The pigment is a type of molecule called an anthocyanin. These molecules are relatively large and consist of three hydrocarbon rings to which sugar molecules are bonded at several positions.

Based on your knowledge of membrane structure and your knowledge of factors that determine whether a molecule can permeate a membrane or not by simple diffusion, suggest whether the pink pigment molecule in rhubarb stalks is water soluble or lipid soluble. Justify your choice.

---
I don't exactly know how to structure this response. I understand that its water soluble because of the sugar molecules containing the OH group but I'm not sure if I need to refer to membrane structure and simple diffusion.

Help is appreciated

[purplegiraffe]

NADH, FADH₂, ATP and Oxygen

How much of each though?

[geminii]

Idk the first question seems weird tho
Hope it helps 

Thanks so much, this helps heaps!

ah Only number 3 matches up with facilitated diffusion. The rest do not

Ah ok, thanks! What would you say the others match up to?[/list]

[Photon]

How much of each though?

Sorry that was my bad. :p

Input: 8 NADH, 2 FADH2 and 6 O2

Output: 32 ATP and 6 H2O

[Photon]

Hey everyone, I have a question - it would be awesome if someone could tell me which of these match up with the other.

1. Facilitated diffusion
2. Active transport
3. Bulk transport (endocytosis and exocytosis)

and they each need to be matched up with one of these...

1. Substances which are small can pass rapidly through pores in the lipid bilayer. These substances must:

• be polar/soluble in water
• uncharged

Examples are water, and gases such as carbon dioxide and oxygen.

2. Lipid soluble substances which readily pass through the lipid layer. These substances must:

• be non-polar

Examples are steroids and fatty acids.

3. Substances which are too large for the pores, or not lipid soluble by nature, or charged, may pass through protein channels. The substances must:

• be polar

Examples are monomers, which go through carrier proteins, and ions, which go through channel proteins.


It would be great if someone could help match each description with its name! Thanks



ALSO (sorry for so many questions, haha) can anyone list the properties that substances MUST have in order to undergo the following (through a cell membrane):

• Diffusion
• Osmosis
• Facilitated diffusion
• Active transport
• Bulk transport (endocytosis + exocytosis)

Thanks once again everyone!!

Where did you get that question from?

[geminii]

Where did you get that question from?

Nowhere - my notes are muddled up (from class) and I was trying to match everything up. I'm reading ahead for 3/4 Bio in 2016 and was trying to find out more info about what sort of molecules go through what method to enter into a cell via the cell membrane.
It's not actually a question I found somewhere - I got my notes and just asked a question about them

[Biology24123]

Thanks so much, this helps heaps!

Ah ok, thanks! What would you say the others match up to?[/list]

Look at the other posts

[TheAspiringDoc]

Rhubarb is a plant with edible pink stems or stalks. The rhubarb stalks are pink because the epidermal cells contain a pink pigment. The pink pigment is packaged within the cell in the large vacuole that occupies most of the volume of the cell.

The pigment is a type of molecule called an anthocyanin. These molecules are relatively large and consist of three hydrocarbon rings to which sugar molecules are bonded at several positions.

Based on your knowledge of membrane structure and your knowledge of factors that determine whether a molecule can permeate a membrane or not by simple diffusion, suggest whether the pink pigment molecule in rhubarb stalks is water soluble or lipid soluble. Justify your choice.

---
I don't exactly know how to structure this response. I understand that its water soluble because of the sugar molecules containing the OH group but I'm not sure if I need to refer to membrane structure and simple diffusion.

Help is appreciated

Questions like this annoy me a bit - it does indeed seem as though there is no need for them to ask you to refer to such things as the membrane etc., but seeing as they've mentioned it, I suppose you'd really want to do so anyway in order to attain full marks.

they've mentioned that it is "relatively large" which appears to defy one of the fundamental criterion for simple diffusion..

You're on the money in saying that the properties of the carbohydrates give it polarity, leading to water solubility (although I wonder, does the fact that the sugars are attached to the presumably-non-carbohydrate hydrocarbon-rings have any effect on the molecule's water solubility?)

I'm thinking aloud here as I'm not sure yet, but perhaps the text you've cited gives us a membrane-transport-related clue as to why the molecule would not be able to pass thtrough, and hence that tells us that the molecule is indeed water soluble (e.g., if it's stored in the vacuole (which is membrane-bound), it can't be lipophilic as then it couldn't be stored )

EDIT: The more I think about it, the more I think that the bit I've bolded is the key point here (other than of course the polarity of the carbs)

[purplegiraffe]

Sorry that was my bad. :p

Input: 8 NADH, 2 FADH2 and 6 O2

Output: 32 ATP and 6 H2O

Sweet! Thank you very much

[TheAspiringDoc]

It's often said that one should read widely when studying biology. Would anyone be able to recommend some relatively advanced (i.e. not fluffy newspaper article type stuff) reading material?

Thanks

EDIT: Guys I had an idea (ikr - how amazing!)

I thought maybe we could make a thread on AN where rather than asking questions, we actually just post things that we've learnt (in bio) that we find intersting/cool etc?

[The Usual Student]

It's often said that one should read widely when studying biology. Would anyone be able to recommend some relatively advanced (i.e. not fluffy newspaper article type stuff) reading material?

Thanks

EDIT: Guys I had an idea (ikr - how amazing!)

I thought maybe we could make a thread on AN where rather than asking questions, we actually just post things that we've learnt (in bio) that we find intersting/cool etc?

That seems cool but don't limit it to bio, how about for all sciences?

[TheAspiringDoc]

Hey

A few Unit 4 AoS1 questions if anyone would be so kind as to help

-If introns are 'non-coding segments of DNA', then how does it make sense for 'alteranative exon/intron splicing' to affect gene regulation and protien products (as long as the same exons are retained obviously )

-intuitively, why do chromosomes condense during prophase and remain so until telophase?

-does it count as a nonsense mutation if the 'met' (start) base triplet in DNA is mutated and that effectively stops the translation of the protein before its synthesis ever even begins?

Thank you!!

What do go-karts do to each other?

Spoiler

bump!

[qazser]

What do go-karts do to each other?

Spoiler

bump!

I think bumping another go kart at high speed will....

Btw, how do you create spoilers?

[TheAspiringDoc]

I think bumping another go kart at high speed will....

Btw, how do you create spoilers?

uh I meant dodgem karts LOL
And click on the 'Sp' icon (towards right)