enzyme --- 重要bio concept 中四

Q: enzyme 是不是 living things???
A: No, they are non living , they are just proteins in a complex stucture

Q:it catalysts reaction, then why doesn't it require energy?
A: Enzyme do catalyst a reaction, It does not requires energy at all, because the definition of a catalyst (enzyme in this case) is a reagent that provides a reaction pathway that requires less activation energy than a normal reaction would need. In an reaction , not all of the molecule can react with each other, ONLY the ones have more than ENOUGHT energy can undergo a reaction.

Lets assume that minimum energy reuired to let the reaction happened is X. If a correct enzyme comes in , the energy require to let the reaction happened is less than X. Therefore, more product is form.

In other words, enzyme do not speed up the reaction by providing energy, instead, they let more molecules react.


Q:enzyme 在high pH value 和 low temperature 的condition 下, 會不會denature? or just inactive???

A:
pH value
ph value represents the amount of H+ or OH- ions that the enzyme is exposed to. Under Extremes of ph , H+ or OH- will react will react with the enzyme , and DENATURE the enzyme.

Low temperature:
Again, I repeat my point, only molecule have more than enough energy can react, if the reactant are experiencing COLD environment, that implies they have less energy to react. But low temperature can only make the enzyme INACTIVE.

But under HIGH ph , and LOW temperature, the enzyme will denature, since the denaturation is cause by high pH and it is INREVESIBLE.

Q: Carbohydrates catalysts the breaking down of carbohydrates. then without them, can carbohydrates be broken down into monosacchurides? If yes, then what is the cause of the reaction?

A: Carbohydrates will break down into monosaccharides without the presence of carbohydrate. And the main cause of the reaction of reaction is again, whether the molecule has sufficient energy to react or not. If they have more than enough, they will react.

With the presence of the enzyme the process would normally only take few hours, BUT WITHOUT the presence of enzyme , it would take years

Hope it is not too long for you to read. It is very interesting concept to understand (in person..)

enzyme 是不是 living things???
enzyme is a protein MOLECULE, do u think a molecule can possibly be living?? the smallest living organism at least have a complete CELL.

it catalysts reaction, then why doesn't it require energy?
energy is provided by the surroundings, i.e. temperature/heat. u see, it's why enzymatic activities depends on the temperature.

enzyme 在high pH value 和 low temperature 的condition 下, 會不會denature? or just inactive???
pH: either too high or too low would cause denaturation
temperature: too low inactivate, too high denature.

Carbohydrases catalysts the breaking down of carbohydrates. then without them, can carbohydrates be broken down into monosacchurides? If yes, then what is the cause of the reaction?
yes, but in very high temperature with suitable chemicals, e.g. strong acid.
u dun have to learn what acid is it for f.4, or even for alevel i think, for the sake of exams.

wat is activation energy? is it in the syllabus of HKCEE?
it's briefly mentioned in chem, but not bio.
if u study chem too, try to related it to bio.
activation energy is the energy needed for a reaction to -start-. if the reaction is exothermic, the energy given out by the reaction will continute to provide energy for the reaction to go on, if it's endothermic, then u have to give continuous engery input in order to maintain the energy level to at least the activation energy to go on.
for enzymatic reaction, just as any catalysts(in chem), the activation energy will be lowered, so less enery is needed to start the reation. for the same level of engery, the reaction can occur at the higher rate

at this stage, energy level refers(directly proportaional) to temperature

my ans is within the scope of ce syllabus

Enzyme is not a living things because it does not have the characteristics of living organisms. It is only a kind of protein with a particular structure.
Enzyme does not require energy but the metabolic reaction requires energy. Enzyme just serves to lower the activation energy.
At extreme pH out of the optimum pH, it will denature and the reaction becomes irreversible. It loses its catalytic properties.
At low temperature, it just becomes inactive since the kinetic energy of the enzyme molecule is low. It will become active again when temperature rises.
Without carbohydrases, carbohydrates can still be broken down into monosacchurides. The reaction is just much slower and more energy is needed to carry out the reaction.

emzyme is a biological catalysts which speed up chemical recation. But for is it a living thing , I am not so sure with it.

At extreme pH, denature
At low temperature, inactive

I am sorry that I can't answer all your question.

No
It provides suitable condition only
it depends
can
最後不懂sorry