VCE Biology Question Thread

[larissaaa_]

My textbook explains this a bit weird to just to clarify:

The part of a gene that contains the coded information for making a protein is called the coding region which has flanking regions on either side. That coding region contains both exons and introns? Or is the coding region one big exon which is separated from the next exon by introns?

Hope this makes sense! Thank you in advance

[HighTide]

My textbook explains this a bit weird to just to clarify:

The part of a gene that contains the coded information for making a protein is called the coding region which has flanking regions on either side. That coding region contains both exons and introns? Or is the coding region one big exon which is separated from the next exon by introns?

Hope this makes sense! Thank you in advance

Coding region---> exons expressed
Non-coding--> introns   intervening

[larissaaa_]

Coding region---> exons expressed
Non-coding--> introns   intervening

So my first guess was correct or my second one? I'm just so confused with all this !

[sweetcheeks]

Why hybrids are sterile and which phase of meiosis is affected

Hybrids don't have homologous chromosomes. An important step during meiosis is the pairing up of homologous chromosomes, occurring during prophase 1 (this allows crossing over and even distribution of genetic material). If there are a lack of chromosomes, meiosis is interrupted and viable gametes cannot be produced.

There are also hybrids (seedless watermelon is an example) where there is an odd number of chromosome sets (e.g. 3 sets in seedless watermelons). The chromosomes cannot be evenly distributed between the subsequent cells and again, viable gametes cannot be produced.

[solution]

Are these definitions correct?
Chromosome insertion: when part of a chromosome breaks off and attaches onto another chromosome
Chromosome translocation: when two chromosomes break off a part, and these broken parts are switched to different chromosomes

[plsbegentle]

Are these definitions correct?
Chromosome insertion: when part of a chromosome breaks off and attaches onto another chromosome
Chromosome translocation: when two chromosomes break off a part, and these broken parts are switched to different chromosomes

Chromosome translocation: A chromosome segment which is attached to a different chromosome (non-homologous).
 I'm not sure if "break off a part" is acceptable.
I haven't heard of chromosome insertion, maybe someone else can give us both some insight

[88mimi12345]

I'm going to assume that you're referring to gene mutations?
If that is the case:
Insertion is the addition of one or more nucleotides in a gene sequence.
So by adding new nucleotides to the sequence, every codon after the insertion changes because nucleotides are read in groups of three. Therefore if the codons are altered, there will be a large effect on the polypeptide produced because it is a frameshift mutation.
(If anyone has anything to add on that would be great!!)

[solution]

I'm going to assume that you're referring to gene mutations?
If that is the case:
Insertion is the addition of one or more nucleotides in a gene sequence.
So by adding new nucleotides to the sequence, every codon after the insertion changes because nucleotides are read in groups of three. Therefore if the codons are altered, there will be a large effect on the polypeptide produced because it is a frameshift mutation.
(If anyone has anything to add on that would be great!!)

Nah, I mean chromosome insertions. https://en.wikipedia.org/wiki/Insertion_(genetics)

"On a chromosome level, an insertion refers to the insertion of a larger sequence into a chromosome."

[solution]

Experimental design questions are worth 3 marks. What are those marks allocated to? Is it:
1. Hypothesis
2. Sensible method (control, controlled variables)
3. "Repeat experiment"

Also, is there any way to concisely write these? I tend to write too much (over the provided lines)

[solution]

Another quick question, is this the VCE accepted answer for ATP produced in each stage of aerobic cellular respiration?

2 ATP in glycolysis, 2 Kreb's Cycle, 32 ATP in ETC. Therefore, total of 36 ATP.

Does VCE ignore the link reaction before Kreb's?

Thanks 

[Gogo14]

Do polymerase enzymes need primers to be able to synthesise new strands? I heard DNA polymerase does, but not RNA. What is that all about?

[vox nihili]

Do polymerase enzymes need primers to be able to synthesise new strands? I heard DNA polymerase does, but not RNA. What is that all about?

That's correct (for the VCE course anyway )

DNA polymerase can only extend strands, so it needs to be primed. Whereas RNA polymerase can make new strands from scratch.

If you think about what a primer actually is, you might recognise that primase is actually a type of RNA polymerase

[instax101]

Is artificial insemination and artificial pollination a part of Unit 4?

[plsbegentle]

Hi, ive got a few questions.

Consider a cross between the following plants:
Parent 1: +-     +-    +-
Parent 2:+-      +-    +-
How many kinds of gametes can be produced?
So considering its a polygene, is there a specific formula i can use, or do i have to manual work them out.

Q2. An autosomal gene in a population of diploid organisms has eight different alleles. How many different alleles could be present in:
a) one member of this population
b) the gene pool of this population

Thanks

[solution]

Hi, ive got a few questions.

Consider a cross between the following plants:
Parent 1: +-     +-    +-
Parent 2:+-      +-    +-
How many kinds of gametes can be produced?
So considering its a polygene, is there a specific formula i can use, or do i have to manual work them out.

Q2. An autosomal gene in a population of diploid organisms has eight different alleles. How many different alleles could be present in:
a) one member of this population
b) the gene pool of this population

Thanks

1. I don't understand what that diagram is (sorry)
2a. 2. No matter how many different alleles there are, a diploid organism can only have 2 (one on each chromosome)
b. 8. Pretty much stated in the question.