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Q's-Can someone please check my answers

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Q's-Can someone please check my answers

Postby biology_06er » Sun May 21, 2006 8:40 am

can someone pls see ifi have these right?

Which of the following statements about muscle fibres are TRUE?
1-When a sarcomere contracts, the width of the A-band remains unchanged.
2-When a muscle contracts, the width of the sarcomeres shrink, and the length of the myofibrils decreases.
3-The length of the thick filaments in a sarcomere corresponds to the width of the A-band.
4-A sarcomere is a portion of a muscle fibre bounded by the Z-lines.
5-According to the Sliding Filament Model, muscles contract when the thin filaments slide towards the centre of each sarcomere.

i think 1, 3 and 4

In Lab 6, you are supplied with muscle tissue which has been pre-treated with a chemical "cocktail". Which of the following statements about the treatment is FALSE?
1-KCl and MgCl2 are added to mimic the salt composition of a normal cell.
2-The solution is buffered to a pH = 7.0 which is the intracellular pH of an intact muscle fibre.
3-EDTA is added to "mop-up" Ca and Mg ions which have leaked from the disrupted membranes.
4-The glycerol denatures the actin and myosin proteins.
5-Glycerol destroys the membranes inside the muscle fibres.

I think...3 and 5

you are supplied with a 2 mM solution of ATP. If the molecular weight of ATP is 507 g/mol, how much ATP was used to make 4 L of solution?
1-4.058 g
2-0.3 g
3-4.058 mg
4-45 g
5-2.536 mg

I have no idea how do to this question!!!!

thanks you
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Postby canalon » Sun May 21, 2006 7:12 pm

2 mM= 2 thoushandth of a mole/Litre of solution
with that you know how many moles in 4L of your solution, and you just have to convert in grams with the Molecular weight.
Patrick

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any proof. (Ashley Montague)
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Postby biology_06er » Mon May 22, 2006 10:49 am

Hi there

Thanks!
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Re: Q's-Can someone please check my answers

Postby ComputerStud » Wed May 31, 2006 2:25 am

Which of the following statements about muscle fibres are TRUE?
1-When a sarcomere contracts, the width of the A-band remains unchanged.
2-When a muscle contracts, the width of the sarcomeres shrink, and the length of the myofibrils decreases.
3-The length of the thick filaments in a sarcomere corresponds to the width of the A-band.
4-A sarcomere is a portion of a muscle fibre bounded by the Z-lines.
5-According to the Sliding Filament Model, muscles contract when the thin filaments slide towards the centre of each sarcomere.

All of it is correct however as for #3 the first part is absolutely correct because H width will decrease during contraction and hence bringing the Z-line together. However, I'm unsure if the myofibrils' length decreases.
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Re: Q's-Can someone please check my answers

Postby victor » Wed May 31, 2006 2:35 am

biology_06er wrote:can someone pls see ifi have these right?

In Lab 6, you are supplied with muscle tissue which has been pre-treated with a chemical "cocktail". Which of the following statements about the treatment is FALSE?
1-KCl and MgCl2 are added to mimic the salt composition of a normal cell.
2-The solution is buffered to a pH = 7.0 which is the intracellular pH of an intact muscle fibre.
3-EDTA is added to "mop-up" Ca and Mg ions which have leaked from the disrupted membranes.
4-The glycerol denatures the actin and myosin proteins.
5-Glycerol destroys the membranes inside the muscle fibres.

I think...3 and 5

thanks you
biology_06er


1 = right, because both of them are salts.
2 = I think so...:wink:
3 = This also right. I'm sure you'll need Na-EDTA to clean up the water which has Ca2+ and Mg2+ ions before you start using it for washing your clothes
4 & 5 = Glycerol mimics the structure of polyvalenic alcohol and also grouped into alcohol group. It's you job now to search the interaction between alcohol and protein...:lol:
Q: Why are chemists great for solving problems?
A: They have all the solutions.
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