HSC Biology Question Thread

[Sukakadonkadonk]

Hey guys,
Is a line of best fit curved or straight?? In what cases would you do that in comparison to joining the dots on a graph?

I remember I got marked up for drawing a straight line of best fit. I asked my teacher and she said that it should be a curve NOT a straight line, pretty much contradicts what I've learned for the past few years.
But I would ask your teacher to make sure. Did you get deducted marks or something?

[ajajaj]

I remember I got marked up for drawing a straight line of best fit. I asked my teacher and she said that it should be a curve NOT a straight line, pretty much contradicts what I've learned for the past few years.
But I would ask your teacher to make sure. Did you get deducted marks or something?

Yeah, it does happen quite often. Whenever I ask the answer isn't always concrete - it varies between teachers.

[sophiemacpherso]

Hey, I'm really confused with the difference between a pair of homologous chromosomes and chromatids?

[1937jk]

Hey, I'm really confused with the difference between a pair of homologous chromosomes and chromatids?

Hey! How I think of it is you have an X shape for your chromosome in which is made up of two chromatids after cell division (If you think of each line of an X being a chromatid) so then x2 chromatids = 1 chromosome. The chromatids are joined together via the centromere where there are two identical copies of the DNA and each copy being a chromatid.
Before a chromosome undergoes cell division there is one chromosome that is made up of one chromatid. After cell division you get two copies hence where the X shape comes from

[kiiaaa]

Hi all,

I have a biology test on Thursday and when doing last minute revision, i realised i don't know or remember anything about the kidney for Maintaining a Balance. Does anyone have any tricks to remember where filtration, re-absorption etc occurs and stuff on those lines please? thanks you so so so much

[1937jk]

So in terms of the dot point
"Analyse information from secondary sources to identify the products extracted from donated blood and discuss the uses of these products"
With the platelets and plasma derived from donated blood, can anyone please explain what the difference is in terms of their uses?

[kiiaaa]

hi im extremely confused about random segregation and homologous pairs and lining up all that stuff. could some one help me out please?

[cookiedream]

hi im extremely confused about random segregation and homologous pairs and lining up all that stuff. could some one help me out please?

Hello!
In meiosis, random segregation basically describes that when homologous chromosomes separate and go into different gametes, you can't tell which chromosome ends up in which gamete (i.e. the allocation of chromosomes is random).
Homologous pairs are two chromosomes which have very similar sizes and the place where the centromere is on the chromosome is pretty much the same for both chromosomes. During prophase 1 of meiosis, they come together side by side (they align) and when metaphase 1 starts, these aligned pairs formed a straight line down the centre of the cell.

[kiiaaa]

Hello!
In meiosis, random segregation basically describes that when homologous chromosomes separate and go into different gametes, you can't tell which chromosome ends up in which gamete (i.e. the allocation of chromosomes is random).
Homologous pairs are two chromosomes which have very similar sizes and the place where the centromere is on the chromosome is pretty much the same for both chromosomes. During prophase 1 of meiosis, they come together side by side (they align) and when metaphase 1 starts, these aligned pairs formed a straight line down the centre of the cell.

THNK YOU SO MUCH! that makes much more sense now.

[annablackledge]

Hey, I'm really confused with the difference between a pair of homologous chromosomes and chromatids?

Homologous Chromosomes are Maternal and Paternal versions of the same chromosome. That code for the same genes
Chromatids are each of the 'arms' of a chromosome.

[bananna]

Hi wondering what's the best way to determine if a condition is sexlinked dom/recessive/non sex linked Dom/recessive.

Thanks !

[Quantum44]

Hi wondering what's the best way to determine if a condition is sexlinked dom/recessive/non sex linked Dom/recessive.

Thanks !

First you determine if the condition is dominant or recessive. This can easily be discovered by checking if all affected individuals have at least one affected parent. If the condition skips a generation, it must be recessive and if it is shown to never skip a generation it is dominant.

Then you can move into X-linked and autosomal. You have to do some trial and error here using mental Punnett squares.

If recessive:
X-linked will definitely favour males over females and an affected mother must pass it onto her son. The gender ratios will be roughly equal in autosomal so the key is to try and rule out X-linked by seeing if an affected mother doesn't pass it onto her son.

If dominant:
X-linked will favour females and an affected father must pass it onto his daughter and an unaffected mother cannot have an affected son. As with recessive, proving the condition is autosomal relies on ruling out X-linked, such as the fact that two affected parents can only have an unaffected child if the condition is autosomal.

[Youssk]

Hi guys,
I just have a question on antibiotic resistance and natural selection. Is the selection/ environmental pressure placed on the bacteria the antibiotic?

thanks

[annablackledge]

Hi guys,
I just have a question on antibiotic resistance and natural selection. Is the selection/ environmental pressure placed on the bacteria the antibiotic?

thanks

Antibiotics act on bacteria in various ways such as damaging the cell wall or disrupting functioning inside the cell. This is a pressure on the bacteria, this is the factor that determines which bacteria will live and reproduce or die; whether bacteria that has mutated to resit the damage or not.

[DalvinT]

Hey!

I'm not sure on how to answer questions with the verb "Critically evaulate"... I searched it up on what it means in HSC terms... And it seems like there's so much to discuss and I'm not sure where/how to start answering the quesiton..