UNIT#07 ENZYMES Flashcards
If enzymes stop their functions, then biochemical reactions would:
Be slowed downs
All of the following are true or an enzyme except:
Increase the energy of activation
Enzymes catalyze all of the following except:
Breathing
The lower the activation energy, the ____ the reaction will be:
Faster
Most of the enzymes are:
Attached with organelles
Enzymes related to fatty acids oxidation are present in/at:
Mitochondria
(Fatty acid metabolism)
All enzymes are ____.
Globular proteins
The reactants on which enzymes work are:
Substrates
What is true about enzymes?
No effect on the end product
The main difference between catalysts and enzymes is:
Catalysts are inorganic while enzymes are organic in nature
The type of energy reduced by the enzymes for biological reactions to occur is called the:
Activation energy
It is false about enzymes:
➡All enzymes require a co-factor for proper functioning✅
➡Only a small amount of enzymes is required❌
➡THey work in vitro as well as in vivo conditions❌
➡They lower activation energy❌
Biochemically enzymes are:
(all enzymes are globular)
Proteins
All enzymes are proteins:
Globular
Three-dimensional globular protein is:
Enzymes
Which of the following is NOT a globular protein?
Myosin
Enzymes involved in cellular respiration are found in:
Mitochondria
Which of the following is an example/s of enzymes attached to membrane systems inside the cell in a specific and orderly arrangement?
➡Mitochondira
➡Chloroplast
The reaction will proceed faster if the activation energy is?
Low
The energy required to start a reaction is called?
Activation energy
An enzyme that requires a biological change in order to become active is called?
Zymogen
AN enzyme without its cofactor is called:
Apoenzyme
If the non-protein part of the enzyme is covalently bonded to the enzyme it is known as?
Prosthetic group
Small organic, the non-protein part that helps in enzyme reactions:
Co-factor
An activated enzyme made up of a polypeptide with its cofactor is:
Holoenzyme
Nicotinamide adenine dinucleotide is an example of:
Co-enzyme
Co-enzyme requires:
Vitamins
Which of the following form weak linkage with an enzyme?
Co-enzyme
Co-factors are divided into groups:
3
The substrate binds to a specific region of an enzyme called?
Active site
All enzymes are:
Globular proteins
What does the active site of the enzyme determine?
Determines by its structure the specificity of an enzyme
Enzymes showing substrate specificity are specific to how many substrates?
1
Which term is used to refer to an inactive enzyme precursor?
Zymogen
Catalysts that increase the rate of biological chemical reactions are called?
Enzymes
Which of the following best describes a co-enzyme?
Loosely bonded non-protein part of an enzyme
Which statement about enzymes is incorrect?
➡Some of them consist solely o protein with no non-protein part❌
➡They catalyze a chemical reaction without being utilized❌
➡They without their cofactor are called apoenzyme❌
➡All enzymes are fibrous proteins ✅
The active form of an enzyme:
Holoenzyme
A cofactor made of inorganic ion which is detachable is called
Activator
Enzymes are globular proteins because:
They have a tertiary structure
A small organic, non-protein molecule that carries chemical groups between enzymes are:
Co-enzyme
Biological molecules which catalyze a biochemical reaction and remain unchanged after completion of the reaction are called:
Enzymes
Enzymes bind with chemical reactants known as:
Substrate
Which of the following vitamin acts as a coenzyme
➡Vitamin B
➡Vitamin B2
If the non-protein part of the enzyme is covalently bonded to the enzyme it is known as?
Prosthetic group
The enzyme reacts with the substrate to form:
Product
Enzymes are ____ in nature:
Proteins
Which type of bond is never formed when the substrate fits into the active site of the enzyme
Hydrophobic interaction
The mechanism of enzyme activation is referred to as:
Catalysis
The specificity of enzyme structure depends upon:
Active site
The catalytic activity takes place at:
Active site
Which statement about the active sites is not true?
➡Acitve site is a spherical shape❌
➡Active site is non-specific✅
➡Active site contains few amino acids❌
➡Active site converts the substrate into product❌
Type of bond present between enzyme and prosthetic group:
Covalent
Which one forms the raw material for coenzymes?
Vitamins
The reaction takes place in a small part of the enzyme is called:
Active site
Coenzymes are closely related to;
Vitamins
The atoms, groups of atoms and molecules that join with enzymes that alter their shape and make them functional
Co-factors
If the cofactor is a non-protein like a metallic ion, it is referred to as a:
Activator
(Metallic ion)
The non-protein part which is organic in nature and detachable is called:
Coenzyme
The function of succinate dehydrogenase is aided by:
FAD+
Prosthetic groups are:
Organic molecules
All coenzymes are derived from:
Vitamins
A co-factor tightly bound to the enzyme on a permanent basis is called:
Prosthetic Group
An enzyme is required Mg+2 to catalyze the substrate. The Mg+2 is the best identified as:
Activator
Which of the following comprises inorganic ions?
Activators
A non-protein part essential for the proper functioning of the enzyme is called:
Co-factor
An enzyme that is non-protein in nature:
Peptidyl transferase
➡Ribozyme(made up of RNA)
An enzyme and substrate react through definite charge-bearing sites.
Active site
The active site of an enzyme:
Determine by its structure, the specificity of the enzyme
The specificity of the enzyme is due to its _____.
Configuration
The lock and key model was proposed by:
Emil Fischer
According to the Lock and Key model, the active site is:
Rigid structure
The lock and key model of enzyme action were proposed by:
Emil Fischer
The complex that forms when a substrate binds to the enzyme is called;
Enzyme-substrate complex
Who proposed the lock and key model of enzyme activity?
Emil Fischer
In the lock and key model of enzyme activity, the substrate acts as the;
Lock
Do enzymes work by which of the following?
Reducing the activation energy
How many models are present for enzyme-substrate complex or reaction?
2
Which statement is incorrect about the lock and key model?
➡Specific enzyme can transform only a specific substrate❌
➡Ative site of an enzyme is a non-flexible structure❌
➡Active site does not change before during or even after reaction❌
➡It explains the mechanism of every chemical reaction✅
Which types are never formed when a substrate fits into the active site of an enzyme?
Covalent linkages
Koshland in 1959 proposed the modified form of which the following?
Induced fit model
The induced fit model was introduced by Koshland in which of the following year?
1959
The lock and key model was proposed by:
Fischer
Which of the following is false concerning enzymes?
Enzymes increase both the forward rate and reverse rate of a reaction
A number of substrate molecules converted into the product by one molecule of enzyme active site per unit time is called:
Turnover number
According to the induced fit model, what happens when an enzyme-substrate complex is formed?
The contact between the substrate and the enzyme causes a change in the shape of the active site
What effect do enzymes have on the activation energy of a reaction?
Decrease
While bound to the active site, the substrate is converted into which of the following?
Product of reaction
The primary function of co-factors is to?
Assist in enzyme activity
In enzyme catalytic reaction the substrate is first converted to a high energy state called?
Transition state
Allosteric enzymes consist of multiple:
Polypeptide chains
The function of enzymes includes all of the following:
Shifting substrates into more favourable positions in the active site
ES complex is converted into the product by:
Catalytic site
____ suggested that each enzyme had a particular shape into which the substrate fits exactly.
Amil Fischer
Allosteric enzymes have ____ major sites.
2
According to the ____ model, the active site of the enzyme is modified as the substrate interacts with the enzyme.
Induced fit model
A modified form of the Lock and model was proposed by:
Koshland
According to Lock and Key model, the enzymes acts as:
Key
The working of sucrase and maltase can be explained by:
Lock and Key Model
With the increase of enzyme concentration in a reaction, more ____ is/are available for the substrate.
Binding sites
The lock and key model for enzyme action proposed by Emil Fischer suggest that:
Enzymes are restricted to one reaction type
The effect of a reversible competitive inhibitor can be neutralized by increasing the concentration of:
Substrate
If the concentration of the substrate molecule is higher than the enzymes then the rate of reaction would be:
Remain constant
Optimum pH of enterokinase is:
Slightly acidic
(pH= 5.50)
Which of the following properties of amino acids is affected by a change in pH?
Ionization of amino acids
Change in tempertue from 30C to 40 C in human body will cause:
First increase then decreases the rate of reaction
Which of the following factor does not affect the rate of enzyme acton?
Light intensity
Which one of the following is the optimum pH of pancreatic lipase enzyme?
➡7.60=Catalase
➡9.00=Pancreatic Lipase
➡8.00=Chymotrypsin
➡9.70=Arginase
The temperature that promotes the maximum activity of enzyme is referred as:
Optimum Temperature
Which type of bond is mostly affected in an enzyme molecule when there is pH fluctuation?
Ionic Bonds
Most enzymes have an optimum temperature of around:
40C
Enzymes which require optimum temperature to be lower than 37C for their proper functioning are present in:
Testes
(Spermatogenesis takes place at 35C)
Which of the following statement is correct?
All enzymes in human body work at same temperature but different pH
Bond sensitive to change in temperatre and pH are respectively:
➡Hydrogen (Temperature)
➡Ionic (pH)
The tempeature where inactive enzyme becomes active is called:
Minimum Temperature
The rate of an enzyme-controlled reaction increases rapidly if the amount of enzyme is doubled in the presence of an unlimited substrate concentration. This is due to:
Number of active sites increase
THe optimum tempearture for enzymes to work at maximum rate in human is:
37C
Enzymes lower down the energy of:
Activation
Optimum pH for pepsin is:
2.00
4.50 is the optimum pH value for the enzyme:
Sucrase
Optimum pH for sucrase is:
4.50
Optimum pH for enterokinase enzyme is:
5.50
Salivary amylase acts best at pH:
6.8
The enzyme with optimum pH=7.60 is;
Catalase
The optimium pH of pancreatic lipase is:
9.0
The optimum pH for enzyme arginase is:
9.70
