15mohsinfa
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Describe, in detail, how two molecules of lactose are hydrolysed, in turn, by one molecule of lactase. In your answer give the features that are typical of enzyme reactions.
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Kallisto
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(Original post by 15mohsinfa)
Describe, in detail, how two molecules of lactose are hydrolysed, in turn, by one molecule of lactase. In your answer give the features that are typical of enzyme reactions.
Glucose and galactose make a bond by their OH-groups that leads to water elimination and a glycosidic bond, the 2-alpha-4-alpha-glycosidic-bond to be more exact.

That means that the reaction is between the 2nd C-atom of aplha-glucose and the 4th C-atom of alpha-galactose where the OH-groups are linked.

By the help of a water molecule lactase as enzyme cracks the lactose in the component parts back, so back to glucose and galactose by removing the glycosidic bond. In this process the water molecule ruptures this bond (hydrolysis!).
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ᴋ-ᴘᴏᴘ ꜰᴏʀᴇᴠᴇʀ
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(Original post by Kallisto)
Glucose and galactose make a bond by their OH-groups that leads to water elimination and a glycosidic bond, the 2-alpha-4-alpha-glycosidic-bond to be more exact.

That means that the reaction is between the 2nd C-atom of aplha-glucose and the 4th C-atom of alpha-galactose where the OH-groups are linked.

By the help of a water molecule lactase as enzyme cracks the lactose in the component parts back, so back to glucose and galactose by removing the glycosidic bond. In this process the water molecule ruptures this bond (hydrolysis!).
I'm sorry but may I know what topic is this?
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Kallisto
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(Original post by ᴋ-ᴘᴏᴘ ꜰᴏʀᴇᴠᴇʀ)
I'm sorry but may I know what topic is this?
Of course, you may! it is about (poly-)saccharides, their bondings, components and how they react each other when they are bonded or ruptured.
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ShadowKing132
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(Original post by Kallisto)
Glucose and galactose make a bond by their OH-groups that leads to water elimination and a glycosidic bond, the 2-alpha-4-alpha-glycosidic-bond to be more exact.

That means that the reaction is between the 2nd C-atom of aplha-glucose and the 4th C-atom of alpha-galactose where the OH-groups are linked.

By the help of a water molecule lactase as enzyme cracks the lactose in the component parts back, so back to glucose and galactose by removing the glycosidic bond. In this process the water molecule ruptures this bond (hydrolysis!).
Could you also help me with this question:

https://imgur.com/98RU18q

Here is a diagram and graph of the experiment in the link.

a) During the experiment, the marine worm increased the volume of urine excreted. Describe how this may have influenced the mass changes of the marine worm [1].

Answer: As the marine worm excreted a larger volume of urine, this causes less/no water to be absorbed so less/no increase in mass.

Part (b) Talks about another adaptation regarding how the marine worm can reduce it's salt content so I figured the decline in the curve would be due to that.

What is the correct answer?
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Kallisto
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(Original post by ShadowKing132)
Could you also help me with this question:

https://imgur.com/98RU18q

Here is a diagram and graph of the experiment in the link.

a) During the experiment, the marine worm increased the volume of urine excreted. Describe how this may have influenced the mass changes of the marine worm [1].

Answer: As the marine worm excreted a larger volume of urine, this causes less/no water to be absorbed so less/no increase in mass.

Part (b) Talks about another adaptation regarding how the marine worm can reduce it's salt content so I figured the decline in the curve would be due to that.

What is the correct answer?
That sounds like osmosis: in the seawater, there are salt molecules. These molecules are also in the marine worm and the visking tubing bag by absorbing them. The salt molecules aim to come to an equilibrium, that is to say the concentration of salt both in seawater and in the marine worm tends to be the same. Under these circumstances, the increased volume of urine (in sea water) shows that salt is emitted to the seawater to come back to equilibrium. That is why the marine worm does not absorb more seawater. His mass didn't increase, yes.
Last edited by Kallisto; 6 months ago
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ShadowKing132
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(Original post by Kallisto)
That sounds like osmosis: in the seawater, there are salt molecules. These molecules are also in the marine worm and the visking tubing bag by absorbing them. The salt molecules aim to come to an equilibrium, that is to say the concentration of salt both in seawater and in the marine worm tends to be the same. Under these circumstances, the increased volume of urine (in sea water) shows that salt is emitted to the seawater to come back to equilibrium. That is why the marine worm does not absorb more seawater. His mass didn't increase, yes.
Since part (b) suggests the marine worm tends to reduce the salt content to something closer to salt content of external solution would this be the horizontal part of the graph, and the decline in mass is then maybe due to the increased volume of urine excreted?
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