MYTUTOR SUBJECT ANSWERS

948 views

What is an enzyme?

An enzyme is a protein catalyst

A catalyst is a substance which alters the rate of a chemical reaction. (So it can speed up a chemical reaction). 

The key thing about an enzyme is that it is not itself changed into another compound when it does this. 

Therefore a catalyst is a substance which alters the rate of a chemical reaction without itself being permanently changed into another compound. 

An enzyme is a protein catalyst that works in the  body.

How does it do this?

It decreases the free energy of activation. Each chemical reaction has an activation energy that needs to be reached in order for the chemical reaction to take place. The enzyme lowers this energy requirement, so that the chemical reaction can occur at lower energy levels. 

Enzyme Specificity

Enzymes are specific to different chemical reactions. Each individual enzyme will have a different role and different chemical reactions in the body to speed up. 

This is known as enzyme specificity.

Reason for enzyme specificity:

Lock and Key Theory- This is the old theory of how enzymes exhibitied specificity. The idea that each enzyme has an active site (cluster of amino acids), that will only fit a specific type of substrate (the start substance in the chemical reaction). In the same way that a lock will only have one key that fits it. 

This has given way to the:

Induced Fit Theory- It is now understood that enzymes are more flexible than the lock and key theory suggests. The induced fit theory suggests that there is more flexibility, which means that one enzyme can catalyse different reactions. 

What factors influence the activity of an enzyme?

-PH

-Temperature

-Concentration of enzyme and substrate

At extremes of temperature and PH the enzyme can become denatured which means it is no longer able to perform its role. 

Lauren D. Uni Admissions Test -Medical School Preparation- tutor, Men...

2 years ago

Answered by Lauren, an A Level Biology tutor with MyTutor


Still stuck? Get one-to-one help from a personally interviewed subject specialist

208 SUBJECT SPECIALISTS

£22 /hr

Tavishi K.

Degree: Medicine (Other) - Cambridge University

Subjects offered:Biology, Maths+ 6 more

Biology
Maths
Chemistry
.UKCAT.
.BMAT (BioMedical Admissions)
-Personal Statements-
-Oxbridge Preparation-
-Medical School Preparation-

“Hello! I am about to go into my fourth year of Medicine at Cambridge. I recently graduated in June with a BA degree...”

MyTutor guarantee

|  1 completed tutorial

£26 /hr

Victoria S.

Degree: Physiology (Bachelors) - Liverpool University

Subjects offered:Biology, Maths

Biology
Maths

“Here to help with last minute revision prep! I'm Tory, in my final year studying Physiology at Uni of Liverpool and am a 5* rated tutor here to suit your needs.”

£24 /hr

Beth T.

Degree: Medicine (Bachelors) - Imperial College London University

Subjects offered:Biology, Science+ 5 more

Biology
Science
Maths
Chemistry
.UKCAT.
-Personal Statements-
-Medical School Preparation-

“Second year medical student at Imperial College London. Available for GCSE science and maths tuition, A level biology and chemistry tuition, and medical application guidance”

About the author

Lauren D.

Currently unavailable: for regular students

Degree: Graduate Medicine (Bachelors) - Nottingham University

Subjects offered:Biology, Science+ 2 more

Biology
Science
Chemistry
-Personal Statements-

“Cambridge graduate studying graduate entry medicine. Enthusiastic about Science and looking to tutor GCSE or A Level. I can also help with medical school applications. ”

You may also like...

Other A Level Biology questions

What's the difference between mitosis and meiosis?

Describe the process of translation

How does meiosis achieve genetic diversity?

Explain these 3 terms in relation to cells and osmosis: isotonic, hypertonic and hypotonic?

View A Level Biology tutors

We use cookies to improve your site experience. By continuing to use this website, we'll assume that you're OK with this. Dismiss

mtw:mercury1:status:ok