A level biology help

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Azotic
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#1
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#1
I'm really struggling to understand alleles, DNA and genes found on chromosomes, even though i have read through the topic many times. I know that alleles are different versions for a gene, so a gene can code for different characteristics, but how are genes found on chromosomes and how do chromosomes have genes which code for a polypeptide when the DNA has 2 polynucleotide strands, which have triplets coding for amino acids which in turn code for a polypeptide. How are chromosomes even linked to DNA? Overall i dont know how chromosomes, DNA and alleles/genes are linked, and i do not understand how a cell undergoes meiosis to produce 4 genetically different offspring, because wouldnt that need a change in DNA, not chromosomes? I would appreciate any help.
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Reality Check
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#2
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(Original post by Azotic)
I'm really struggling to understand alleles, DNA and genes found on chromosomes, even though i have read through the topic many times. I know that alleles are different versions for a gene, so a gene can code for different characteristics, but how are genes found on chromosomes and how do chromosomes have genes which code for a polypeptide when the DNA has 2 polynucleotide strands, which have triplets coding for amino acids which in turn code for a polypeptide. How are chromosomes even linked to DNA? Overall i dont know how chromosomes, DNA and alleles/genes are linked, and i do not understand how a cell undergoes meiosis to produce 4 genetically different offspring, because wouldnt that need a change in DNA, not chromosomes? I would appreciate any help.
Not being rude, but this suggests a fundamental lack of understanding of basic GCSE genetics, not just a confusion with detail. It's not something that could be solved by my posting on TSR, much as I'd like to help you.

I think you need to go back to brass tacks with this. What basic biology texts do you have? I'd suggest you start off with DNA and its structure and organisation before moving on to chromosomes and cell division. Make sure you know the difference between mitosis and meiosis. Once you've looked at this, have a go at DNA replication, transcription and translation. It's a lot of work I'm afraid, but really really fundamental and important that you understand it in detail. Give me a shout if you come across stuff in your readings which you're unsure of.
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Azotic
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#3
Report Thread starter 2 years ago
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(Original post by Reality Check)
Not being rude, but this suggests a fundamental lack of understanding of basic GCSE genetics, not just a confusion with detail. It's not something that could be solved by my posting on TSR, much as I'd like to help you.

I think you need to go back to brass tacks with this. What basic biology texts do you have? I'd suggest you start off with DNA and its structure and organisation before moving on to chromosomes and cell division. Make sure you know the difference between mitosis and meiosis. Once you've looked at this, have a go at DNA replication, transcription and translation. It's a lot of work I'm afraid, but really really fundamental and important that you understand it in detail. Give me a shout if you come across stuff in your readings which you're unsure of.
Okay, will do, thank you
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