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    Autonomic nervous system
    :involves all motor nuerones that supply the internal organs transferig impulses to smooth muscle of the viscera.

    Sympathetic nervous system - Prepares the body for 'fight or flight ' situatios.
    The motor nuerone cell body lies outside the spinal chord in the autonomic gaglion. The preganglionic nuerone is in the spinal chord and its axon passes out through the ventral root where it syapses with the motor nuerone.
    NB: the ganlia are joined by nuerones which connect one to another , from here the axon of motor nuerones pass too all internal organs.
    stimaltion the leads to secretion of noradrenaline.

    1) stimulation by the vagus nerve that supplies sino- atrial node increases the rate at which san fires increasing the contraction force of cardiac muscle. This means for every beat a greater volume of blood is pumped into the aorta thus increasing the rate at which oxygen is supplied to the muscle fibres. This then increases the rate of araebic respiration and faster generation of ATP for contraction of muscle to run or fight.

    2) slowing down of digestion ................................ .........

    3) relaxation of spinchter of urethra means increased urination which ................................ ..........

    4) dilatio of pupils enables animal to ................................ ..

    Fill in spaces , basically how the sympathetic system gets an animal ready for danger situations.
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    Would anyone mind helping me figure the similarities and differences between synapses and neuromuscular junctions?

    Similarities
    - Acetylcholine is the neurotransmitter released
    - Acetylcholinesterase is present and breaks down acetylcholine
    - Acetylcholine binds to receptors on the sarcolemma or post synaptic neurone
    - There's a depolarisation along the sarcolemma and post synaptic neurone membrane
    - Impulses are transmitted (is this technically correct???)
    - ????

    Differences
    - Neuromuscular junctions involve the T-system being depolarised, post synaptic neurones dont (???)
    - Ca2+ ions diffuse into the pre-synaptic knob whereas at neuromuscular junctions they are released from the sarcoplasmic reticulum and bind to protein in muscle
    - At synapses, an action potential is achieved in the post synaptic neurone whereas at neuromuscular junctions a contraction occurs in the muscle cells.
    -???

    Would anyone mind correcting it (especially the purple bits) or adding to the list, or making it more detailed seeing as there isn't one in the textbook?
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    What are the codes for the modules of the previous specification that correspond to our module if we want to do some past papers?
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    (Original post by The TSR Star.)
    Would anyone mind helping me figure the similarities and differences between synapses and neuromuscular junctions?

    Similarities
    - Acetylcholine is the neurotransmitter released
    - Acetylcholinesterase is present and breaks down acetylcholine
    - Acetylcholine binds to receptors on the sarcolemma or post synaptic neurone
    - There's a depolarisation along the sarcolemma and post synaptic neurone membrane
    - Impulses are transmitted (is this technically correct???)
    - ????

    Differences
    - Neuromuscular junctions involve the T-system being depolarised, post synaptic neurones dont (???)
    - Ca2+ ions diffuse into the pre-synaptic knob whereas at neuromuscular junctions they are released from the sarcoplasmic reticulum and bind to protein in muscle
    - At synapses, an action potential is achieved in the post synaptic neurone whereas at neuromuscular junctions a contraction occurs in the muscle cells.
    -???

    Would anyone mind correcting it (especially the purple bits) or adding to the list, or making it more detailed seeing as there isn't one in the textbook?

    ca2+ ions diffuse into the pre-synaptic knob whereas at neuromuscular junctions they are released from the sarcoplasmic reticulum and bind to protein in muscle

    CA 2+ Ions also diffuse into presynaptic membrane at a nueronmuscular junctions so im not sure if thats a difference.

    but here are some good differences

    1) nueronmuscular junctions are always excititory never inhibitory
    however at a synapse action potentials arriving could be inhibotory
    excitatory.
    2) An action potential arriving along a motor nuerone will always elicit
    action potential in a muscle fibre.
    however at for an action potential to be eliceted at a nuerone it will
    normally involve several synapses inorder to pass on action potential.

    3) both involve difussion of Acetyl choline across a synaptic cleft.

    hope that helps
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    Can someone please explain the difference between DNA replication and translation.

    Also, what chapter is DNA replicatin in? Ta
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    Unit 2 , module 1 :celluar control
    Dna replicates to get info of some genes. Translation is makeing it into protein in ribosome. I think
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    (Original post by Jacker956)
    Unit 2 , module 1 :celluar control
    Dna replicates to get info of some genes. Translation is makeing it into protein in ribosome. I think
    Thanks, have looked at this Chap but there's hardly anything on DNA rep. Did the following Q n wasn't sure what DNA rep referred to, can't be translation.

    Also, how can C and H be correct for transcription? Surely its either or.

    Edit: Questions are from dopey... who posted the other day
    Attached Files
  1. File Type: rtf protein synthesis EBA.rtf (117.6 KB, 1000 views)
  2. File Type: rtf protein synthesis EBA MS.rtf (50.7 KB, 87 views)
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    (Original post by zoop)
    Thanks, have looked at this Chap but there's hardly anything on DNA rep. Did the following Q n wasn't sure what DNA rep referred to, can't be translation.

    Also, how can C and H be correct for transcription? Surely its either or.

    Edit: Questions are from dopey... who posted the other day
    Nope they can both be correct for transcription. If on the template DNA strand that is being transcribe to mRNA, there is Adenine, then its complementary base with be Urasil. But if there is Tymine present on the template strand its complemetary base is Adenine.
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    Explain how genetic drift causes large changes in small populations (5 marks) Anyone?
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    (Original post by ViolinGirl)
    Nope they can both be correct for transcription. If on the template DNA strand that is being transcribe to mRNA, there is Adenine, then its complementary base with be Urasil. But if there is Tymine present on the template strand its complemetary base is Adenine.
    True, but also what is the DNA replication process the Q refers to? Not too sure where its in the book, n pretty sure its not translation.
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    (Original post by zoop)
    Can someone please explain the difference between DNA replication and translation.

    Also, what chapter is DNA replicatin in? Ta
    DNA replication is making copies of a DNA molecule. 2 DNA molecules are produced. The DNA to be replicated unwinds and unzips, the hydrogen bonds between the complementary bases break by action of DNA helicase enzymes. Free nucleotides present within the nucleus will bind to the complementary molecules on the DNA template strand to reform the DNA molecule. Hydrogen bonds reform by action of enzyme DNA polymerase. The semi-conservative theory refers to the fact that each DNA molecule now consisits of one orginal strand and one new strand, that are used to form the double helix molecule.

    Translation is the second stage of protein synthesis, whereby the amino acids are assembled to make polypeptides, and this sequence is dictated by the codons on the mRNA coding strand that fits into the ribosomal subunits. In translation the mRNA will fit into the ribosomal groove, and 2 codons with be exposed to the larger subunit. The first exposed codon is always AUG, so a tRNA molecule with an amino acid bearing the code for methionone attached to this via the anticodon. Another tRNA bearing a different amino acid binds to the second codon, and a peptide bond is formed betweeen the 2 amino acids. The process continues, with each tRNA then leaving the mRNA molecule to pick up more amino acids until a stop codon is reached that indicates the amino acid chain is complete.
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    (Original post by zoop)
    True, but also what is the DNA replication process the Q refers to? Not too sure where its in the book, n pretty sure its not translation.
    See my full scale explanation below!
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    (Original post by ViolinGirl)
    Explain how genetic drift causes large changes in small populations (5 marks) Anyone?
    I'll give it a go.


    Genetic drift is fluntuations in allele frequency in a population over time. Genetic drift is more pronounced in small populations due to their being less genetic diversity and the probability of inbreeding and the elimination of an allele being greater. This would result in large changes in phenotypes as a result of alleles being eliminated and large changes in allele frequency. Also, a mutation would be more likely to be passed on due to the small population.

    Meh, pretty poor.


    EDIT: Allele frequencies change greatly from generation to generation.
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    (Original post by ViolinGirl)
    Explain how genetic drift causes large changes in small populations (5 marks) Anyone?
    Wow 5 marks? lets see If I remember a fraction. Ok
    Genetic drift is simply change in the allele frequency number which is caused by randomness(Un-related to recombination,natural selection or mutation).In some cases it increases the net. hybrid allele in others it depreciates them.The rise of the new allele could be give the specie advantage over the rest of the individuals such that over the period of time its population increases this change in pattern is your genetic drift.
    For example, consider what would happen if ... wildflower population ... consisted of only 25 plants. Assume that 16 of the plants have the genotype AA for flower color, 8 are Aa, and only 1 is aa. Now imagine that three of the plants are accidently destroyed by a rock slide before they have a chance to reproduce. By chance, all three plants lost from the population could be AA individuals. The event would alter the relative frequency of the two alleles for flower color in subsequent generations. This is a case of microevolution caused by genetic drift..
    There are two types of driftage:
    Bottleneck effect : Is caused by natural processes such as earthquake,flood and fire reducing the variety level.
    Founder effect: Here a small group goes onto a different path and forms a different population.
    Arghh... 8 exams to go! :/
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    (Original post by ibysaiyan)
    Wow 5 marks? lets see If I remember a fraction. Ok
    Genetic drift is simply change in the allele frequency number which is caused by randomness(Un-related to recombination,natural selection or mutation).In some cases it increases the net. hybrid allele in others it depreciates them.The rise of the new allele could be give the specie advantage over the rest of the individuals such that over the period of time its population increases this change in pattern is your genetic drift.
    For example, consider what would happen if ... wildflower population ... consisted of only 25 plants. Assume that 16 of the plants have the genotype AA for flower color, 8 are Aa, and only 1 is aa. Now imagine that three of the plants are accidently destroyed by a rock slide before they have a chance to reproduce. By chance, all three plants lost from the population could be AA individuals. The event would alter the relative frequency of the two alleles for flower color in subsequent generations. This is a case of microevolution caused by genetic drift..
    There are two types of driftage:
    Bottleneck effect : Is caused by natural processes such as earthquake,flood and fire reducing the variety level.
    Founder effect: Here a small group goes onto a different path and forms a different population.
    Arghh... 8 exams to go! :/
    Enviromental factors can have a large effect on survivial and therefore transfer of certain alleles. :doh:
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    (Original post by Sakujo)
    Enviromental factors can have a large effect on survivial and therefore transfer of certain alleles. :doh:
    Yep I see^^ but it carried 5 marks =}
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    (Original post by ibysaiyan)
    Yep I see^^ but it carried 5 marks =}
    It'd be good if we could get an "official" answer.
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    We Have No Questions On Module 1 At All!

    Does Anyone Have Any Questions?


    Im Really Desperate For Some!
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    (Original post by Sakujo)
    It'd be good if we could get an "official" answer.
    Such as? to be honest there isn't much to add to that.
    EDIT: Formula xD

    Pr(k|p,N) = [N!/k!(N-k)!]pk(1-p)N-k
    Alright folks gonna rest for awhile then bolt over maths,physics,biology. 8 exams whoop whoop :ninja2: First I need to wonder around my fairyland. ^.^
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    (Original post by ibysaiyan)
    Such as? to be honest there isn't much to add to that.
    EDIT: Formula xD

    Pr(k|p,N) = [N!/k!(N-k)!]pk(1-p)N-k
    Dude you're on a different level. :laugh:

    Could you expand on the Founder effect, I get the idea but I can't explain it consicely.
 
 
 
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