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Anonymous
Anonymous asked in Science & MathematicsBiology · 1 decade ago

Biology Help Please.?

Can you please describe and explain the process of gene to protein process in a cell. Please focus about the introns and extrons and spliceosomes. What were to happen if something goes wrong if it were read wrong? What about if it had an extra base how would this affect the cell? Would the coding get messed up? I would be grately appreciated if you can answer these. Thanks

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    1.Transcription- RNA poly enzyme -> DNA to RNA

    2.RNA progressing, introns cut out by splicesomes and other enzymes. cap and poly A tail is added.

    a) one RNA strand during processing can be cut into form two or more strands coding different proteins.

    3. RNA is transported into the cytoplasm

    4.Translation - tRNA brings the correct AA to the ribosomes to start the translation with the aid other factor proteins

    a) each AA has it own specific tRNAs

    b) 3 steps - initiation, elongation and termination

    some thing can go wrong if a(one or factors of two) base(s) is inserted or deleted from the DNA. This would cause a frame shift. if 3 bases or factors of 3 is inserted or deleted then there will be extra or missing amino acid respectively.

    There are 4 types mutations of that can occurs due to single base insertion or deletion.

    Missense is this change cause different base in the 3rd position i.e AUG -> AUC

    Nonsense is changes to termination seqz e.g UAC -> UAG

    Silent mutation change does not change AA e.g UAA>UAG

    Read thru is termination to changed to termination seq thus does not stop transcription. e.g UAG->UAC

    Depending on the type of mutation and where is it occurred can cause the result of the mutation to vary.

    Source(s): Hope this helps a little.
  • 1 decade ago

    aww, theres so much to say...

    okay. so the first process is Transcription: helicase "unzips" the DNA strand. DNA is transcribed or copied by an mRNA strand. THe enzyme that synthesizes RNA in transcription is RNA polymerase, which adds RNA nucleotides

    DNA: TACGGCACCATC

    mRNA: AUGCCGUGGUAG

    but before this strand exits to the cytoplasm another process occurs. The mRNA stand is composed of extrons and introns. Extrons are the nessecary nuleotides for that specifc protein. The intron are the extra unnecessay nucleotides. Exons and introns combine with small nuclear ribonucleoproteins (snRNPs) and other proteins to form a molecular complex called splicesome. Whithin the splicesome, snRNA base-pairs with nucleotides at the end of the intron. The RNA transcript is cut to release the intron, and the exons are spliced together. THe splicesome then comes apart, releasing mRNA,, which now contains only exons. this process only occurs in Eukaryotic cells only.

    the start of the mRNA strand is a 5 prime and ends with a

    poly-A tail. then the mRNA leaves the nucleus and enters the cytoplasm.

    Translation:

    During translation, this copied mRNA stand attaches to a ribosome. Then tRNA(transferRNA)molecules, loaded with amino acids, move into the ribosome and attach their anticodon end to the codons on the mRNA strand. the anticodon and codon are complementary. the tRNA first enters and attaches to the A site, then the amino acids on the P site transfer to the A site, the A site "kicks" the tRNA in the P site out were it exits at the E site and this keeps on going.this process continues until all amino acids are loaded and a polypeptide chain is made. a stop codon ends the completed translation.

    AUGCCGUGGUAG

    Met, Pro, Trp, stop------amino acids

  • 1 decade ago

    Transcription and translation.

    1. First, your DNA unzips, and mRNA copies the complementary bases. This is transcription. The copied strand is the template while the other unused strand is the coding strand. DNA rezips and is error checked.

    2. Then this is where the splicesomes are come in. They remove the introns (non coding bases of mRNA), and then splice (or rejoin) the exons (the useful coding strands). A cap and tail are also added to the mRNA to prevent digestion.

    3. Now translation. The mRNA leaves the nucleus to a ribosome, where it starts at AUG - methionine, and tRNA brings in complementary bases, until you hit a STOP codon. Then a protein called release factor breaks it and sends it out the ribosome. Ribosomes and tRNA can then be reused.

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