Unit 3 Flashcards
1
Q
How do enzymes accelerate rate of chemical change
A
- by lowering the activation energy
2
Q
What is activation energy
A
- it’s the minimum energy needed to convert reactant to product
3
Q
Cells undergo a biochemical activity called
A
metabolism
4
Q
What is metabolism
A
- its the process of chemical and physical changes, including the breakdown (catabolism) and synthesis (anabolism) of molecules.
5
Q
Do enzymes change or remain unchanged after they act on substrates
A
they remain unchanged
6
Q
Do enzymes affect the nature of the product
A
No they don’t
7
Q
List the physical properties of enzymes
A
- Denaturation
- solubility
- colloidal
- enzyme precipitation
- molecular weight
- enzymatic activity
- biocatalyst property
8
Q
List the chemical properties of enzymes
A
- heat and ph sensitivity
- regulation
- catalysis
- reversiblity
- specificity
9
Q
What is denaturation
A
is the process of breaking the intra and inter-molecular non-covalent bonds that distort the shape and active site of the enzymes.
10
Q
Enzymes are denatured by
A
- high heat ( above 40 c)
- change in ph
- heavy metal
- high salt concentration
- solvent
11
Q
Enzymes are soluble in
A
- water
- salt (NaCl)
- diluted glycerol
-alcohol
They cause denaturation.
12
Q
What is the colloidal nature of enzymes
A
nature of enzyme is the tendency of having little or no dialysis cross the semipermeable membrane due to the large size or high molecular weight
13
Q
What is the biocatalyst property
A
is the activity of enzymes in which very small quantities or a small amount of enzyme is enough to convert a large quantity of substrate and remain unchanged after the reaction
14
Q
What is enzyme precipitation
A
is the separation of enzymes for analysis using different aqueous or ethanol solvents
15
Q
What is molecular weight of enzymes
A
Enzymes are large protein bio molecules that hold polypeptide chains of various amino acid sequences
Because of this they have high molecular weight
16
Q
What is enzymatic activity
A
Is the general catalytic properties of an enzyme
17
Q
The enzymatic activity depends on factors such as
A
- temperature
- ph
- concentration of substrates and enzymes
18
Q
What is regulation
A
is the process of controlling the activity of enzymes by activator and inhibitor molecules
19
Q
What is catalysis
A
- is the process of the acceleration of a chemical reaction by a catalyst
- Enzymes are biological catalysts that possess high catalytic efficiency
- They can transform about 100-10,000 substrates per second
- The reactions catalyzed by the enzymes show a 10^3-10^8 times faster reaction rate in comparison to the non-catalyzed reactions
20
Q
What is reversiblity
A
- is the ability of enzymatic biomolecules to catalyze forward and reverse reaction
21
Q
What is bond specificity
A
is a relative specificity of enzymes, which indicates that enzymes
are specific for a bond
22
Q
What is group specificity
A
Is a structural specificity of enzymes which describes that enzymes are specific for a group
23
Q
What is substrate specificity
A
is the feature of enzymatic activity where an enzyme acts
only on a particular substrate
24
Q
What is optical specificity
A
is when enzymes act on the substrate optical configuration
25
What is co factor specificity
is the enzymatic specificity to the substrate and co-factors
26
What is the turn over number of molecules
is the number of substrates converted by one enzyme molecule per second at saturated ( fully occupied)active sites
27
Enzymes are markers of the states of various diseases like
- myocardial infraction
- jaundice
- pancreatitis
- cancer
- neurodegenerative disorders
28
Sucrase
Brakes down sugar called sucrose
29
Lactase
Breaks down sugar called lactose into glucose and galactose
Is found in the small intestine
30
Carbohydrase
Breaks down carbohydrates into sugar
31
Lipase
Breaks down fats into fatty acids
Found in the blood, gastric juices, pancreatic secretions, intestinal juices
Adipose( fatty) tissues and participate in digestion
32
Protease and trypsin
Breaks down protein into amino acids
33
Amylase
Breaks down starch into sugar
Is found in the saliva
34
Maltase
Breaks down sugar maltose into glucose
- found in foods such as potatoes, pasta , beer and saliva
35
Helicase
Unwinds dna
36
DNA polymerase
Is responsible for forming new copies of dna in the form of nucleic acids molecules
37
Acetyl cholinesterase
Breaks down the neurotransmitter acetylcholine in nerves and muscles
38
What is protein structure
It’s a polymer of amino acids joined by peptide bonds with three dimensional arrangements of atoms in amino acid chain molecules
39
When is a polypeptide called a protein
One it’s folded and it becomes functional
Some proteins are made of more than one folded polypeptide chain
40
What are the four structural levels of proteins
1 primary structures
2 secondary structures
3 tertiary structures
4 quaternary structures
41
What is primary structures
It’s the linear sequence of amino acids
42
How many sequences of amino acids do we need to form polypeptide
- if it’s less than 50 sequences it’s peptides
- if it’s greater that 50 sequences it’s polypeptide
43
How many amino acids do our body require and where do we get these
- require 20 amino acids
- 10 are synthesized in the body
- 10 are obtained from diets
44
Cells use 20 different standards of L-a- amino acids containing
Basic amino acids and acidic carboxyl groups
45
What is secondary structures
It’s a folded structure formed within a polypeptide due to interactions between atoms of the backbone based on hydrogen bonding
46
The two types of strands in secoundary structures are
- the alpha helix
- beta pleated sheet
47
Is the alpha helix a right handed coiled strand or a left handed coiled strand
Right handed coiled strand
48
The side chain substituents of amino acids is extend to
The outside
49
The hydrogen bond occurs between the
Oxygen ( c=o ) with the hydrogen ( N-H) in groups of four amino acids
50
The hydrogen bonding in beta pleated sheets is between
The inter- strand and intra - strand in which the sheet conformation of the beta pleated sheet consists of pairs of strands lying side-by- side
51
What is the tertiary structure of proteins
is the three-dimensional shape of protein molecules that bend and twist to achieve the maximum stability or the lowest energy state
- it’s fashioned by many stabilizing forces
52
What is the quaternary structure of proteins
All polypeptide chains are held together by a specific spatial arrangement and interactions
53
What are the two enzyme substrate binding models
- enzyme lock and key model
- enzyme induced for model
54
List some characteristics of lock and key model
- there is no change in the active site before and after a chemical reaction
- non covalent interaction
- the enzymes must bind to substrates before they catalyze a chemical reaction
55
List some properties of enzymes induced fit model
- enzyme changes shape upon substrate binding which either suppresses or enhances the activity of the enzyme
- the amino acid side chains that make up the active site mold into a precise position
- they lower the activation energy by putting the active site under strain which makes the transition stable
56
How does the transition state determine the reaction rates of elementary chemical reaction
Because the enzymatic rate is directly influenced by the stability of the transition state
57
In the transition state there is chemical equilibrium between _____________ and __________________
- reactant
- activated transitions
58
The transition state describes how the chemical reaction is taking place ____________ in the activated enzyme substrate complex
-qualitatively
59
What is enzyme regulation
It is adapting enzymatic activities by other molecules or metabolic cells to either increase or
decrease the activities.
60
Regulatory enzymes require______________to become active and pass through some modifications and function
- An extra activation process
61
What are allosteric enzymes
Are enzymes that have an additional binding sites for effector molecules that cause conformational change
62
List some characteristics of effectors in allosteric enzymes
- can be inhibitor or activator
- lead to structural changes in the concrete part, which affects the structure of the active site , which causes change In the activity of the reaction
- adjust the enzyme activity through reversible non covalent binding
63
What do genetic and covalent modification modify?
-modify the protein surface and facilitate intracellular delivery
64
What are covalent modifications
are enzyme-catalyzed alterations of synthesized proteins by the
addition or removal of chemical groups
65
__________ is the most common regulatory modifications
Phosphorylation (addition of phosphate group to protein)
66
What is enzyme inhibition
Is a decrease in enzyme activity by enzyme inhibitors
67
Enzyme inhibition is classified into
- reversible inhibition
- irreversible inhibition
68
What is irreversible inhibition
A substance that permanently blocks the action of an enzyme
69
What is reversible inhibitor? It can be classified into?
- it inactivates an enzyme through non covalent easily reversed interactions
- it’s classified into competitive,uncompetitive and non competitive inhibition
70
What is competitive inhibitor
It is a molecule that blocks the binding of the substrate to the active site
It depends on the concentration
71
What is a non competitive inhibitor
It binds to the allosteric site
Decreases the efficiency of the enzymes
72
What is uncompetitive inhibitor
Doesn’t bind to the free enzyme
Occurs in reactions with two or more substrates or products
73
Enzymes types are based on
- enzymes that bind specific molecules together
to form new molecules
- enzymes that break specific molecules apart into separate molecules.
74
Enzymes are structural classified into
- simple protein( active )
- conjugated protein ( holoenzyme )
75
Conjugated protein (holo enzyme) is classified into
- Protien part (Apoenzyme )
- non protein part(co factor)
76
Non protein part( cofactor) is classified into
- firmly attached ( usually metal ion ) (prothetic group)
- loosely attached( usually vitamin B complex) (coenzyme)
77
Enzymes are composed of six classes based on
- what and how they react
- the type of reaction they catalyze
- the end suffix “ase”
78
Oxidoreductase
catalyzes oxido-reduction reactions
79
Transferase
transfers methyl groups from one compound donor as a cofactor to another compound (acceptor), carry and transfers
80
Hydrolases
catalyze the hydrolysis of various bonds
81
Lyases
are enzymes that cleave bonds by other means rather than hydrolysis or
oxidation in which two or more substrates are involved in one reaction
82
Isomerases
convert molecules from one isomer to another isomer
83
Ligases
are enzymes that catalyze the joining of two molecules with concomitant hydrolysis of the di-phosphate bond in ATP or a similar triphosphate
84
Factors that affect enzyme activity are
- temperature
- ph
- inhibitor
- water
- radiation
- activator
- substrate
- enzyme
- end product concentration
85
Ph is ________ written in short
Potential of hydrogen ions
86
How does radiation affect enzyme activity
- reduces enzymatic efficiency
- creates disorders in the macromolecules
87
Give an example of a feedback inhibition
- the drug Tipranivir used to treat HIV blocks the activity of a viral genome enzyme ( this enzyme produces more copies of the virus )
- the drug is a reversible inhibitor
88
Enzyme kinetics describes
- the rate of chemical reactions catalyzed by enzymes
- the binding affinities of substrates
- the maximal catalytic rate
- inhibitor
89
______________ and __________ determine production volumes per unit time( rate of reaction)
- the concentration of enzymes
- the concentration of substrates
90
The most common model of enzyme kinetics is
Michaels- Menten formula
91
The Micheal - menten formula describes the rate of enzymatic reaction by relating ___________ and _____________ with _______________
- the reaction rate
- rate of formation of product
With
- concentration of substrate
92
Enzyme catalyst is ____to _____ times higher than inorganic catalyst
100s to 1000s
93
Enzymes used for food industry were extracted from
from the internal organs of animals and plants, but now most enzymes are obtained by microbial fermentation
94
Cellulases
- Biofuel industry
- Breakdown cellulose into sugars and ferment to produce cellulosic ethanol
95
Ligninase
-Biofuel industry
-Pre-treatment of biomass for biofuel production
96
Protease,Amylase, Lipase
- biological detergent
- Remove protein, starch, and fat or oil stains from laundry and dishware.
97
Mannanase
Biological detergent
98
Betaglucanase
- Brewing industry
- Improve beer filtration
99
Papain
- Culinary uses
- Tenderize meat for cooking
100
Rennin
-Dairy industry
- It hydrolyses protein in the manufacture of cheese
101
Trypsin
-Food processing
- Manufacture hypo-allergenic baby foods
102
Cellulases, Pectinase
- Food processing
- Clarify fruit juices.
103
Nuclease, DNA Ligase, Polymerase
- Molecular biology
- Uses restriction digestion and polymerase chain reaction to create recombinant DNA
104
Steeping is the process of
-cleaning the grain kernels
- activating enzymes and simulating the production of enzymes by immersing it in water and air for a specific time period
- occurs over a period of 24-48 hours
105
Germinating
- is continuing the process with the growth and modification of the grain
- growth : rootlets emerge from the kernel to the outside of the grain and within the outer husk a shoot or acrospires grows
106
Kilning is a heating treatment which
- drys the green malt
- gets the moisture so it stops germinating
- prepares the malt for flavour and colour development
107
The killing process achieves
- enzymatic activity
- friablity
- a wide range of malt colours and flavours
- distinctive ales and lagers
108
What would happen if the killing process didn’t stop the germination
- the kernel would keep growing and the growing plant would use all of the starch reserves needed by the brewer
109
In the killing process we first remove the moisture for _________ and we further remove for _________
- withering
- we further remove the moisture to prepare the malt for flavour and Color development
