HSC Biology Question Thread

[Skidous]

Does anyone understand the polypeptide and how it's formed!! I get extremely confused with this aspect!! I know that there is a ribosome which 'sticks' the amino acids together to form a polypeptide. I don't even think that's right! can someone please help
Thanks in advance!!

The ribosomes can bring in chains for anticodons with correspond to the codons with produce polypeptides, the chain begins with an STA amino acid and ends with a TER amino acid (terminate)

mRNA is produced when the RNA helicase unravels the DNA one rung at a time, then RNA polymerase transcribes it into mRNA

This leaves the nucleus and heads to the ribosome where it translates the mRNA into polypeptides in codons (groups of 3 base pairs) with corresponding anticodons which are free floating and release a specific polypeptide when the codon and anticodon reacts.

There are some codons that code for the same polypeptide as well.

Hope this helps

[g98]

Hi, I was wondering if we need to know all the scientific names for animals/plants etc that we use for examples?
Thank you

[Skidous]

Hi, I was wondering if we need to know all the scientific names for animals/plants etc that we use for examples?
Thank you

That depends on the question
If it's just a plant or animal then no not really

If it's an important organism such as the fruit fly (Drosophila will suffice) in Morgans work or a vector (Anopheles mosquito for Malaria) or a bacteria used in genetic modification (Bacillus thuringiensis for Bt Cotton) you should know the scientific name for that

If you do want to know the scientific name then that's ok as well just make sure you put the binomial name written correctly (capital genus, lower cases species and italics/bold/underlined) and the common name of the organism


Hope it helps

[vox nihili]

The ribosomes can bring in chains for anticodons with correspond to the codons with produce polypeptides, the chain begins with an STA amino acid and ends with a TER amino acid (terminate)

mRNA is produced when the RNA helicase unravels the DNA one rung at a time, then RNA polymerase transcribes it into mRNA

This leaves the nucleus and heads to the ribosome where it translates the mRNA into polypeptides in codons (groups of 3 base pairs) with corresponding anticodons which are free floating and release a specific polypeptide when the codon and anticodon reacts.

There are some codons that code for the same polypeptide as well.

Hope this helps

Super picky: DNA helicase (it's the DNA being unraveled)

[atar27]

The ribosomes can bring in chains for anticodons with correspond to the codons with produce polypeptides, the chain begins with an STA amino acid and ends with a TER amino acid (terminate)

mRNA is produced when the RNA helicase unravels the DNA one rung at a time, then RNA polymerase transcribes it into mRNA

This leaves the nucleus and heads to the ribosome where it translates the mRNA into polypeptides in codons (groups of 3 base pairs) with corresponding anticodons which are free floating and release a specific polypeptide when the codon and anticodon reacts.

There are some codons that code for the same polypeptide as well.

Hope this helps

Thank you!! But is there an easier way by any chance! Sorry I know I am a pain atm

[Skidous]

Super picky: DNA helicase (it's the DNA being unraveled)

Actually no, DNA Helicase unravels the ENTIRE DNA strand where as RNA Helicase only unravels a small section of DNA rung by rung, at least that is what we're taught

Edit: RNA Helicase is used for splicing DNA pre-mRNA

[Blissfulmelodii]

Thank you!! But is there an easier way by any chance! Sorry I know I am a pain atm

This may not be the best use of scientific language but i basically remember it as the DNA unwinds by an enzyme called helicase leaving 2 single strands. One strand is used as a template where nucleotides in the nucleus will match up with so C-G and A-T (this becomes your mRNA strand). Once it is done copying it is released from the nucleus through nuclear pores into the cytoplasm where it attaches to the ribosome and the original DNA will wind back up. tRNA then matches in groups of three to its complementary pair remembering that T is replaced with U. The released strand is your polypeptide.

[Skidous]

Ok, after some further research I've discovered I may be wrong and it may be the RNA polymerase that actually separates the DNA and created the mRNA at the same time. Now I'm just confused

[:3]

Ok, after some further research I've discovered I may be wrong and it may be the RNA polymerase that actually separates the DNA and created the mRNA at the same time. Now I'm just confused

RNA polymerase unzips the DNA (Note: does not separate the DNA completely).

Then it starts pairing up the bases with spare nucleotide to form the mRNA (Note: does not attach to the DNA).

For DNA replication:
1. Enzyme helicase unwinds and separates it.
2. Enzyme polymerase pairs the bases up of each strand with spare nucleotide.

[kevin217]

Thank you!! But is there an easier way by any chance! Sorry I know I am a pain atm

If you're still having trouble understanding polypeptide synthesis, I recommend watching some youtube videos. They're very helpful for simplifying complicated biological processes.

[Skidous]

RNA polymerase unzips the DNA (Note: does not separate the DNA completely).

Then it starts pairing up the bases with spare nucleotide to form the mRNA (Note: does not attach to the DNA).

For DNA replication:
1. Enzyme helicase unwinds and separates it.
2. Enzyme polymerase pairs the bases up of each strand with spare nucleotide.

Yeah that's what I thought cause i remember it being opposite for RNA where in DNA polymerase adds on bases where for RNA it splits

[vox nihili]

Clarification on Helicases


There's clearly some confusion about helicases. I'm not familiar with the HSC course and I don't know what you guys learn and are expected to know. But the reality:

• A single DNA helicase molecule does not unwind the entire molecule of DNA. The reality is that DNA replication takes place at multiple sites along the same molecule; and these smaller strands are then ligated together after replication.
• There is a lot of information out there suggesting that RNA polymerase has helicase activity (i.e. is capable of unwinding DNA). In the case of eukaryotic RNA polymerase, this is simply not true. There are three RNA polymerases in eukaryotes—the one responsible for transcription of mRNA does not contain a helicase domain
• In transcription of mRNA, DNA is unwound by a helicase called TFIIH, which forms part of the pre-initiation complex. Before RNA polymerase can bind to DNA, a host of other proteins have to bind to prepare it; one of these proteins unwinds the DNA, ready for RNA pol
• RNA helicases unwind RNA, DNA helicases unwind DNA; ipso facto an RNA polymerase will not unwind DNA

EDIT: you don't need to know this level of detail obviously, but it seemed to turn into a bit of a shit fight and it was worthwhile stating the facts so that we can put the issue to bed. DNA is unwound by helicase (just call it that) and RNA pol gets in and smashes out a new mRNA

[aimbotted]

If i say that RNA Polyemerase catalyses the complementary stand to create mRNA am i incorrect?

[lha]

In graphing questions, even if it doesnt ask for a line of best fit, do we still do it? And do we do the normal line and the line of best fit as well, and then label it as "line if best fit"?

And also, how do we do line of best fits? What are the rules? Because everyone tells me something different

[kevin217]

In graphing questions, even if it doesnt ask for a line of best fit, do we still do it? And do we do the normal line and the line of best fit as well, and then label it as "line if best fit"?

And also, how do we do line of best fits? What are the rules? Because everyone tells me something different

From doing past papers. If they say draw a CURVE of best fit, your line must be curved. So by saying that, if they ask for a LINE of best fit, your line must be straight. If there isn't any clear instruction then you plot the graph normally.