VCE Biology Question Thread

[plsbegentle]

I can't actually believe I'm asking this - it seems so simple...
Anyway Edrolo is saying glycolysis and lactic acid fermentation produce water, while my textbook, ATARNotes and my teacher's notes don't mention it?
It's a bit worrying as this directly links to the study design, so hopefully someone could lear this up!
Thnky

I know that glycolysis doesn't produce water, there was a bit of confusion about this last year as well, came up on my mid year-exam.

 Pretty sure its same with fermentation, products are ethanol/alcohol, carbon dioxide and ATP, so no water.

this is kind of a dumb question but im in the early stages of learning bio and what is the really necessary things u need to know about photosynthesis light dependent and independent reactions? everything seems so complicated and i wanna know what is really necessary but in a simpler format too, if that makes sense

Adding to what Doc said , all you need to know are the inputs and outputs of both stages. However, i would suggest learning at least briefly the process of light dependent stage and what occurs as it helps with the understanding. This is according to the study design.
inputs and outputs of the light dependent and light independent (Calvin cycle) stages of photosynthesis in C3
plants (details of the biochemical pathway mechanisms are not required)
 

What is the difference between a receptor cell and a target cell!

google.com

[CCleigh]

Here's a very basic overview of what you do in VCE bio:

Firstly, you have to describe the purpose of photosynthesis

Spoiler

basically just converting solar energy to chemical energy in glucose for later use in the plant

Then, you learn the overall balanced chemical equation

Spoiler

dont forget to say "in the presence of chlorophyll and light energy"

Then, you learn where photosynthesis happens

Spoiler

in different parts of the chloroplast in some plant cells (but not all - eg the roots!)
Note that chloroplasts contain  grana which in turn are made of thylakoids - which have pigments such as chlorophyll in their membranes
Chloroplasts also contain a fluid called "stroma" - which becomes important later
Also, you learn about how chloroplasts have their own circular DNA and ribosomes, and how they have two membranes around the entire chloroplast - all of which is evidence that chloroplasts have prokaryotic* origins!
*google for clarification 

Then, you learn about the stages of photosynthesis

Spoiler

-where each stage occurs in the chloroplast
-when each stage occurs (light dependent comes before light independent)
-the inputs and outputs of each stage

Finally, you learn the effect of different factors on photosynthetic rate

Spoiler

-carbon dioxide concentration (it is an input of photosynthesis)
-temperature (affects activity of photosynthetic enzymes)
-light intensity (needed for pigment excitation in the light dependent stage)
-light wavelength (basically, red is optimal, while green isn't so good)

I'm aware I have really explained the details of photosynthesis, so here's a little excerpt from Cosine's U3 Notes:

Spoiler

Light dependent:
-   The reactions occur in the grana (thylakoid membranes)
-   Light energy is absorbed from the sun light via chlorophyll
-   Water molecules split to form H+ ions and O2 gas. The O2 gas is released via the stomata. Excited electrons flow through the electron transport chain to provide energy for ATP synthesis
-   Unloaded electron acceptor molecules, NADP+, accept H+ ions to form NADPH

Inputs: H2O, ADP + Pi, NADP+
Outputs: O2, ATP, NADPH

Light independent:
-   Occur in the stroma of chloroplasts
-   In the Calvin cycle, CO2 and H+ ions (from the NADPH formed in the light dependent reactions) are used to synthesize sugars.
-   Energy is provided by the ATP molecules produced during the light dependent reactions

Inputs: CO2, ATP, NADPH
Outputs: Glucose, ADP+Pi, NADP+

Glucose is the main product of photosynthesis, however, other organic molecules are also produced:

-   Glucose and fats can be used as energy sources in the process of respiration
-   Cellulose is synthesized from glucose monomers to form the cell wall
-   Proteins have a myriad of functions within the cell.

Note: Oxygen is produced as a waste product of photosynthesis and is released from the chloroplast during the light dependent reactions.

By the way, all of this will make better sense when you've covered other topics (enzymes, biomolecules, cellular respiration) in detail.

thank you so much!! 

[Ahmad_A_1999]

Hey guys,

Could someone explain what this diagram is saying, the answer is A but I don't understand said diagram 

http://imgur.com/a/9njrH

Thanks

[Quantum44]

Hey guys,

Could someone explain what this diagram is saying, the answer is A but I don't understand said diagram 

http://imgur.com/a/9njrH

Thanks

Process 1 involves an enzyme catalysed reaction where substrate becomes product, producing ATP (as indicated by process 2).

D is incorrect as DNA replication does not produce ATP.

C is incorrect as active uptake does not involve substrate becoming product.

B is incorrect as protein manufacture uses ATP instead of producing it.

A is correct as cellular respiration involves enzyme catalysed reactions causing substrate to become products while releasing energy in the form of ATP.

[Ahmad_A_1999]

Process 1 involves an enzyme catalysed reaction where substrate becomes product, producing ATP (as indicated by process 2).

D is incorrect as DNA replication does not produce ATP.

C is incorrect as active uptake does not involve substrate becoming product.

B is incorrect as protein manufacture uses ATP instead of producing it.

A is correct as cellular respiration involves enzyme catalysed reactions causing substrate to become products while releasing energy in the form of ATP.

Thanks Quantum, I think a process of elimination was probably the best way to go :/

[Ahmad_A_1999]

Could I please get help with these two Multiple Choice 
I don't have answers for them unfortunately.

http://imgur.com/a/KR61Y

Question 6 and 7

[LPadlan]

Could I please get help with these two Multiple Choice 
I don't have answers for them unfortunately.

http://imgur.com/a/KR61Y

Question 6 and 7

Question 6:should be 'A' "Carbon dioxide production was the variable". SInce carbon dioxide is what was being measured. The variable being measured is located in the y-axis
Question 7:Should be 'B' "Seed type A is more likely to survive" since it is more productive at respiring. It cant be "A" since in the question it says that both beans had similar mass

[Ahmad_A_1999]

Question 6:should be 'A' "Carbon dioxide production was the variable". SInce carbon dioxide is what was being measured. The variable being measured is located in the y-axis
Question 7:Should be 'B' "Seed type A is more likely to survive" since it is more productive at respiring. It cant be "A" since in the question it says that both beans had similar mass

Hey LPadlan

I'm still confused with both, I thought that if something is respiring it is producing energy which it can ultimately use to grow, (I could be very wrong here  )
And with 6 I see what you are saying with it being the variable but why is B incorrect given that it says on the graph the temperature was 20 degrees?

[peanut]

Hey LPadlan

I'm still confused with both, I thought that if something is respiring it is producing energy which it can ultimately use to grow, (I could be very wrong here  )
And with 6 I see what you are saying with it being the variable but why is B incorrect given that it says on the graph the temperature was 20 degrees?

You're right, 6 is B. 7 should be C, because the graph of seed A has a smaller gradient at 20 hrs than the gradient of the graph of seed B, at 20 hours.

[LPadlan]

You're right, 6 is B. 7 should be C, because the graph of seed A has a smaller gradient at 20 hrs than the gradient of the graph of seed B, at 20 hours.

7 cant be 'C' since B is lower than A(The amount of CO2 produced is represented by the little squares, not the lines)

[LPadlan]

Hey LPadlan

I'm still confused with both, I thought that if something is respiring it is producing energy which it can ultimately use to grow, (I could be very wrong here  )
And with 6 I see what you are saying with it being the variable but why is B incorrect given that it says on the graph the temperature was 20 degrees?

With question 6, i believe the temperature is a constant(since it does not change) If the temperature is being controlled then the temperature would change(bunsen burner or those heat pan things). Dont mix it up with being the 'control'.
Question 7, i see where you're coming from since respiration provides the energy for growth. So now that i think of it, i believe you have the right answer. It makes the most sense

[Ahmad_A_1999]

Could someone please give me a concise summation of 'translation' specifically the part where the tRNA comes into play, I take too long to state it in short answer questions 

[cookiedream]

Could someone please give me a concise summation of 'translation' specifically the part where the tRNA comes into play, I take too long to state it in short answer questions 

- Post-messenger RNA (mRNA) binds to ribosome and is read two codons at a time from 5' to 3'
- Transfer RNA (tRNA), with an anti-codon complementary to an mRNA codon, arrives at the ribosome with a specific amino acid
- Amino acids form peptide bonds between each other and form a polypeptide chain

This is about as concise as I can make it...
Feel free to make any corrections ^^

[Ahmad_A_1999]

Thanks Cookie  ^

Can someone please help me with this:
In this experiment, http://imgur.com/a/VJNvT

for part B, one suggestion is to include a control group that keeps the same conditions in the experiment but lacks the enzymes, the suggested answers state that this is to demonstrate that pH changes alone do not cause the cloudy suspension to be broken down.

I'm having trouble understanding why this control group assists the experiment in any way, how does it link to the purpose of the experiment to investigate the effect of different pH levels on enzyme activity.

[psychologie]

Hi there! I would really appreciate it if someone could help me out with the following questions mainly about gene expression

1. are homeotic genes the same as regulatory genes?
2. the start/stop triplets in a gene, are they exons? are they part of the coding region of DNA or not?
3. in prokaryotes, one promoter codes for multiple genes and in eukaryotes, one promoter codes for one gene. is this correct?
4. substation point mutation: when one nucleotide is replaced with another nucleotide of the same genetic materials (what does ‘of the same genetic materials’ mean?)
5. is the operator region of a gene considered a regulatory gene?
6. 'regulatory genes produce transcriptional factors/RNA that control the expression of other genes'. if this is correct, how does RNA control expression of genes? i thought it was just the repressor/activator PROTEINS
7. is it correct to say ‘lactose binds NON-COMPETITIVELY to active repressor protein’
8.  do we repeat experiments to improve accuracy or reliability?

Thanks in advance