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March 28, 2024, 07:46:37 pm

Author Topic: VCE Biology Question Thread  (Read 3570304 times)  Share 

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Billuminati

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Re: VCE Biology Question Thread
« Reply #13740 on: November 21, 2021, 08:41:32 pm »
+1
oxygen - photosynthesis product

That's it, I just don't like giving out answers right away because guiding you along helps you remember it better
VCE 2016-2018

2017: Biology [38], Further Maths [44]

2018: Methods [37], French [38], Chem [40], English [44]

UMAT: 56/43/80, 57th percentile (LLLLOOOOOOOOOLLLLLLLL)

ATAR: 98.1

2019-2021: Bachelor of Biomedical Science at Monash (Scholars), minoring in Chemistry

GAMSAT September 2021: 65/67/86, 76 overall (98th percentile)

2022: Chilling

2023+: Transfer to teaching degree

Billuminati

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Re: VCE Biology Question Thread
« Reply #13741 on: November 21, 2021, 08:57:03 pm »
+4
hello,
would the answer be x- linked dominant.
thank you

I'll just share my uni hack of quickly identifying pedigrees for those of you with a similar question. It's kind of like a choose-your-own-adventure story. You will start with the question "does the condition skip generations ie can 2 unaffected parents give birth to an affected child?". If yes, it's recessive and if no, it's dominant. You will then ask "does it affect males and females equally?" If yes, it's autosomal and if no, it's sex-linked (most often X-linked in VCE bio). Note that you can rule out both X-linked recessive and X-linked dominant if you see an affected father having an affected son as male-male transmission isn't possible for any X-linked traits. X-linked recessive traits tend to affect men more often, whereas X-linked dominant ones usually affect women more.

There are some rare conditions that are Y-linked or mitochondrial. Y-linked traits only affect males and all of an affected male's sons will also be affected. Mitochondrial inheritance is where all children (regardless of sex) of an affected mother will be affected, as mtDNA is inherited maternally.
« Last Edit: November 21, 2021, 08:58:59 pm by Billuminati »
VCE 2016-2018

2017: Biology [38], Further Maths [44]

2018: Methods [37], French [38], Chem [40], English [44]

UMAT: 56/43/80, 57th percentile (LLLLOOOOOOOOOLLLLLLLL)

ATAR: 98.1

2019-2021: Bachelor of Biomedical Science at Monash (Scholars), minoring in Chemistry

GAMSAT September 2021: 65/67/86, 76 overall (98th percentile)

2022: Chilling

2023+: Transfer to teaching degree

Chocolatepistachio

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Re: VCE Biology Question Thread
« Reply #13742 on: December 13, 2021, 01:37:12 pm »
0
The tertiary structure of a protein refers to:
A the unique three dimensional folding of the amino acid chain of the protein
B the interaction between two or more amino acids chains of the protein
C the sequence of amino acids
D the presence of alpha helices and beta pleated sheets

Would this be a but also b

caffinatedloz

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Re: VCE Biology Question Thread
« Reply #13743 on: December 13, 2021, 05:39:14 pm »
+7
The tertiary structure of a protein refers to:
A the unique three dimensional folding of the amino acid chain of the protein
B the interaction between two or more amino acids chains of the protein
C the sequence of amino acids
D the presence of alpha helices and beta pleated sheets

Would this be a but also b

I understand why b seems like a valid option but interactions between chains (plural) is the quaternary structure of a protein. If you double-check the rest it is clear that option c is the description of primary structure and option d of secondary structure. So you can be confident selecting a.

Istupied

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Re: VCE Biology Question Thread
« Reply #13744 on: December 20, 2021, 09:55:02 pm »
0
Hi all,

I received my statement of marks today for 2021 biology exam, and was surprised when i lost marks on these two questions. I don't want to waste $25 inspecting the exam because I made a mistake. So if possible, can someone please explain to me why my responses are incorrect?

For Question 5: b. I did... (I lost 1 mark here)
X: TNF (example of signalling molecule), virally infected cell (example of target cell)
Y: neurotransmitter such as acetylcholine (example of signalling molecule), muscle cell (example of target cell)

For Question 7: a. I did... (I lost 1 mark here)
-Opposable thumb
-3 dimensional stereoscopic vision

Thanks!

Billuminati

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Re: VCE Biology Question Thread
« Reply #13745 on: December 20, 2021, 10:27:49 pm »
+2
Hi all,

I received my statement of marks today for 2021 biology exam, and was surprised when i lost marks on these two questions. I don't want to waste $25 inspecting the exam because I made a mistake. So if possible, can someone please explain to me why my responses are incorrect?

For Question 5: b. I did... (I lost 1 mark here)
X: TNF (example of signalling molecule), virally infected cell (example of target cell)
Y: neurotransmitter such as acetylcholine (example of signalling molecule), muscle cell (example of target cell)

For Question 7: a. I did... (I lost 1 mark here)
-Opposable thumb
-3 dimensional stereoscopic vision

Thanks!

I think you lost a mark for the signalling molecule cuz in my microbio unit, TNF can serve both as an autocrine and paracrine signalling molecule and they are probably expecting a strictly paracrine signalling molecule from their diagram.

Binocular vision would be more appropriate than 3D stereoscopic vision. Your term would also be correct if this question were asked in a uni anatomy class, but given how pedantic VCAA is, they probably stole a mark from you that you can't even debate cuz it's not 100% identical to their stock responses
VCE 2016-2018

2017: Biology [38], Further Maths [44]

2018: Methods [37], French [38], Chem [40], English [44]

UMAT: 56/43/80, 57th percentile (LLLLOOOOOOOOOLLLLLLLL)

ATAR: 98.1

2019-2021: Bachelor of Biomedical Science at Monash (Scholars), minoring in Chemistry

GAMSAT September 2021: 65/67/86, 76 overall (98th percentile)

2022: Chilling

2023+: Transfer to teaching degree

Chocolatepistachio

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Re: VCE Biology Question Thread
« Reply #13746 on: December 27, 2021, 09:07:35 pm »
0
how does maltose form an open chain but sucrose cant form an open chain

Billuminati

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Re: VCE Biology Question Thread
« Reply #13747 on: December 27, 2021, 10:07:51 pm »
+3
how does maltose form an open chain but sucrose cant form an open chain

It’s cuz both carbons of the ether bond in sucrose are anomeric carbons, whereas only 1 anomeric carbon in maltose is involved in the ether bond, making the other one available for ring opening
VCE 2016-2018

2017: Biology [38], Further Maths [44]

2018: Methods [37], French [38], Chem [40], English [44]

UMAT: 56/43/80, 57th percentile (LLLLOOOOOOOOOLLLLLLLL)

ATAR: 98.1

2019-2021: Bachelor of Biomedical Science at Monash (Scholars), minoring in Chemistry

GAMSAT September 2021: 65/67/86, 76 overall (98th percentile)

2022: Chilling

2023+: Transfer to teaching degree

Chocolatepistachio

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Re: VCE Biology Question Thread
« Reply #13748 on: January 02, 2022, 02:27:30 pm »
0
At lower temperatures do more saturated fats make up the membrane

Is there a certain temp where it goes from unsaturated to saturated

Billuminati

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Re: VCE Biology Question Thread
« Reply #13749 on: January 03, 2022, 02:46:41 am »
+1
At lower temperatures do more saturated fats make up the membrane

Is there a certain temp where it goes from unsaturated to saturated

Nah lower temperatures = more unsaturated fats in membrane
VCE 2016-2018

2017: Biology [38], Further Maths [44]

2018: Methods [37], French [38], Chem [40], English [44]

UMAT: 56/43/80, 57th percentile (LLLLOOOOOOOOOLLLLLLLL)

ATAR: 98.1

2019-2021: Bachelor of Biomedical Science at Monash (Scholars), minoring in Chemistry

GAMSAT September 2021: 65/67/86, 76 overall (98th percentile)

2022: Chilling

2023+: Transfer to teaching degree

Chocolatepistachio

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Re: VCE Biology Question Thread
« Reply #13750 on: January 04, 2022, 06:47:16 pm »
0
but at lower temperatures dont they need to pack together more tightly and saturated fats can pack together tighter without the kink

Billuminati

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Re: VCE Biology Question Thread
« Reply #13751 on: January 05, 2022, 03:51:54 am »
0
but at lower temperatures dont they need to pack together more tightly and saturated fats can pack together tighter without the kink

This was in 1st year bio and I remember vaguely that the prof said whether the saturated/unsaturated fat content increases or decreases in response to changes in temperature can depend on the species. Then again, we never touched on it very deeply (perhaps the biochem people go over it again) and it's been 2 years so I may most certainly be wrong in this
« Last Edit: January 05, 2022, 03:53:27 am by Billuminati »
VCE 2016-2018

2017: Biology [38], Further Maths [44]

2018: Methods [37], French [38], Chem [40], English [44]

UMAT: 56/43/80, 57th percentile (LLLLOOOOOOOOOLLLLLLLL)

ATAR: 98.1

2019-2021: Bachelor of Biomedical Science at Monash (Scholars), minoring in Chemistry

GAMSAT September 2021: 65/67/86, 76 overall (98th percentile)

2022: Chilling

2023+: Transfer to teaching degree

Rose34

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Re: VCE Biology Question Thread
« Reply #13752 on: January 06, 2022, 01:31:42 am »
0
Hi everyone,

For cellular respiration, do I need to memorise the steps descibed bellow or just memorize what the inputs and outputs are for each stage?

Eg: in the electron transport chain do I need to memorise the following?
1 NADH and FADH2 unload electrons and protons at the first and second protein
complexes of the electron transport chain that reside in the inner mitochondrial
membrane. The following reactions take place:
(1) NADH  NAD+ + H+ + 2 e–
(2) FADH2  FAD + 2 H+ + 2 e–.
2 The excited electrons (from NADH and FADH2) are transferred through a number
of different protein complexes embedded in the electron transport chain, powering
the active transport of protons (H+) from the mitochondrial matrix into the narrow
intermembrane space.
3 This leads to a build-up of protons in the intermembrane space. As this space is very
narrow and small, the proton concentration here quickly increases, creating a steep
concentration gradient across the inner mitochondrial membrane.
4 To move down their concentration gradient, these protons must travel through
the specialised protein channel ATP synthase. As the protons pass through ATP
synthase, they cause the enzyme to spin like a turbine. The kinetic energy of this
movement powers the reaction ADP + Pi  ATP, producing 32 or 34 ATP for each
original glucose molecule.
5 This process produces large amounts of ATP, but also leads to many free protons
and electrons building up in the matrix. Unbound protons and electrons can cause
problems for cells in large concentrations – they can damage DNA, interfere with
enzyme reactions and create dysfunctional proteins. To prevent this from happening,
oxygen acts as the terminal acceptor, binding with these dangerous protons and
electrons to form harmless water. Oxygen is therefore required for the electron
transport chain to proceed.

Same with the kerbs cycle..
• By breaking down acetyl-CoA, protons and high-energy electrons are released.
These protons and electrons are loaded onto NAD+ and FAD molecules to generate
high-energy coenzymes NADH and FADH2.
• The Krebs cycle produces two CO2 molecules for every one acetyl-CoA molecule.
When added to the single CO2 molecule produced from each of the two pyruvates
undergoing the link reaction, this means a total of six CO2 molecules are produced
for every original glucose molecule.
• The Krebs cycle produces a small amount of energy in the form of two ATP (one per
acetyl-CoA molecule).

And for glycolysis...
• 2 ADP + 2 Pi  2 ATP
− The ATP is now free to power cellular reactions.
• 2 NAD+ + 2 H+ + 4 e−  2 NADH
− The electrons (two per NAD+) are often not written in this equation, but they are
necessary for the reaction to proceed.
− The H+ and electrons come from the breakdown of glucose.
− The two NADH molecules will be transported to the mitochondria, where each
molecule will deliver protons and electrons to the electron transport chain, to help
make more ATP. For this reason, we call NADH an ‘electron and proton carrier’.

Golgi Apparatus

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Re: VCE Biology Question Thread
« Reply #13753 on: January 06, 2022, 10:28:31 am »
+1
Hi everyone,

For cellular respiration, do I need to memorise the steps descibed bellow or just memorize what the inputs and outputs are for each stage?

Eg: in the electron transport chain do I need to memorise the following?
1 NADH and FADH2 unload electrons and protons at the first and second protein
complexes of the electron transport chain that reside in the inner mitochondrial
membrane. The following reactions take place:
(1) NADH  NAD+ + H+ + 2 e–
(2) FADH2  FAD + 2 H+ + 2 e–.
2 The excited electrons (from NADH and FADH2) are transferred through a number
of different protein complexes embedded in the electron transport chain, powering
the active transport of protons (H+) from the mitochondrial matrix into the narrow
intermembrane space.
3 This leads to a build-up of protons in the intermembrane space. As this space is very
narrow and small, the proton concentration here quickly increases, creating a steep
concentration gradient across the inner mitochondrial membrane.
4 To move down their concentration gradient, these protons must travel through
the specialised protein channel ATP synthase. As the protons pass through ATP
synthase, they cause the enzyme to spin like a turbine. The kinetic energy of this
movement powers the reaction ADP + Pi  ATP, producing 32 or 34 ATP for each
original glucose molecule.
5 This process produces large amounts of ATP, but also leads to many free protons
and electrons building up in the matrix. Unbound protons and electrons can cause
problems for cells in large concentrations – they can damage DNA, interfere with
enzyme reactions and create dysfunctional proteins. To prevent this from happening,
oxygen acts as the terminal acceptor, binding with these dangerous protons and
electrons to form harmless water. Oxygen is therefore required for the electron
transport chain to proceed.

Same with the kerbs cycle..
• By breaking down acetyl-CoA, protons and high-energy electrons are released.
These protons and electrons are loaded onto NAD+ and FAD molecules to generate
high-energy coenzymes NADH and FADH2.
• The Krebs cycle produces two CO2 molecules for every one acetyl-CoA molecule.
When added to the single CO2 molecule produced from each of the two pyruvates
undergoing the link reaction, this means a total of six CO2 molecules are produced
for every original glucose molecule.
• The Krebs cycle produces a small amount of energy in the form of two ATP (one per
acetyl-CoA molecule).

And for glycolysis...
• 2 ADP + 2 Pi  2 ATP
− The ATP is now free to power cellular reactions.
• 2 NAD+ + 2 H+ + 4 e−  2 NADH
− The electrons (two per NAD+) are often not written in this equation, but they are
necessary for the reaction to proceed.
− The H+ and electrons come from the breakdown of glucose.
− The two NADH molecules will be transported to the mitochondria, where each
molecule will deliver protons and electrons to the electron transport chain, to help
make more ATP. For this reason, we call NADH an ‘electron and proton carrier’.

Someone might want to confirm since I did bio with the old study design.

The new study design says:
“the general structure of the biochemical pathways”
“the main inputs, outputs and locations” of each stage
“details of biochemical pathway mechanisms are not required”

So I think just the inputs and outputs of each stage is all that is needed. However, the steps you wrote can be helpful in understanding the process and may help you answer some questions, so they are probably worth knowing if you’re aiming for a high study score.



VCE
2020: Biology
2021: Chemistry | English Language | Further | Methods | Psychology

2022: Bachelor of Biomedicine (UoM)

Rose34

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Re: VCE Biology Question Thread
« Reply #13754 on: January 06, 2022, 10:52:10 am »
0
Someone might want to confirm since I did bio with the old study design.

The new study design says:
“the general structure of the biochemical pathways”
“the main inputs, outputs and locations” of each stage
“details of biochemical pathway mechanisms are not required”

So I think just the inputs and outputs of each stage is all that is needed. However, the steps you wrote can be helpful in understanding the process and may help you answer some questions, so they are probably worth knowing if you’re aiming for a high study score.

Alright thank you!