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BIOLOGY -MODULE 2 > ENZYMES > Flashcards

ENZYMES Flashcards

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1
Q

What are enzymes

A

Biological catalysts
Globular proteins
Cause substrate molecules to interact at a faster rate

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2
Q

What are metabolic reactions

A

All the chemical reactions that take place in a cell

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3
Q

What is a catalyst

A

Substance that increases rate of reaction
Doesn’t take part in reaction
Can be reused

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4
Q

What is the Turnover number

A

Number of substrate moecluels an enzyme can catalyse per second

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5
Q

What is the Vmax

A

Enzymes can only increase rate up to a certain point

Max rate of enzyme catalysed reaction

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6
Q

What is a catabolic enzyme

A

Break substances down into smaller products
Releasing energy
E.g. Glucose

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7
Q

WHat is an anabolic enzyme

A

Build up reactants
Suing energy
E.g. Synthesis of large polymer base compounds

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8
Q

What is a modifying enzyme

A

Change substrate slightly

E.g. Alpha to beta glucose

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9
Q

What are intercellular enzymes

A

Enzyme action takes place inside cells
E..g synthesis of plumbers from monomers
E.g. Polysaccharides from glucose

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10
Q

Extra cellar enzymes

A

Nutrients need to provide substrate to cells for produc making
Nutrients in the form of polymers often - too large - have to be broken down before entering the cell
Enzymes released from cell and work outside cell they were released from

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11
Q

Examples of extra cellular enzymes

A

For fungi and bacteria
Trypsin
Amylase

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12
Q

Trypsin - digestion of protein

A

Breaks down protein into smaller peptides
Then broke. Down into amino acids
Trypsin produced by Pancras, released within pacreatic juices into small intestine
Amino acids absorbed by cells lining digestive system

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13
Q

Digestion of starch

A

Broken down into maltose using amylose
Amylose produced y salivary glands and pancreas
Maltose broken down in small intestine into glucose by Maltase
Glucose - absorbed by cells into blood stream

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14
Q

What part of the enzyme determines the specificity

A

Active site

Tertiary structure

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15
Q

What are the 2 hypothesises for enzyme action

A

Induced fit

Lock and key

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16
Q

Explain the induced fit hypothesis

A

New
Enzyme shape changes slightly as substrate enters
Initial enzyme - substrate interaction is weak but these interactions induc changes in tertiary structure, strengthening binding putting strain on substrate moecluels - weakening bands

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17
Q

Lock and key hypothesis

A

WHne the substrate is bond to active site, enzyme subs state complex is formed
Substrates react adn product formed( enzyme product complex)
Products released and enzyme unchanged
Substrate held by enzyme -atom groups close enough to react. R groups within the active site of the enzyme will also interact with TEH substrate, forming temporary bonds = put strain on bonds in substrate

18
Q

Temperature- how does it affect enzyme activity

A

INCREASING temperature increases kinetic energy of particles

More frequently collide

Too hot - bonds in protein vibrate and strain, break and change 3D shape and active site
Q10 no longer applies

19
Q

Q10

A

Temperature coefficient

Measure of how rate of relation increases with a 10 degree rise in temperature

20
Q

What are thermophiles and how are their enzymes different

A

Extreme temperatures

Enzymes are more stable, high number of h bonds and sulphur bridges in tertiary structure, more resistance to change

21
Q

How does ph affect enzyme activity

A

Change in h+ concentration
Hydrogen and ionic bonds between Amino acid r groups old protein in precise 3D shape, bonds result from interaction between Omar and charged r groups resent on amino acids forming primary structure
Hydrogen ions interact with polar positively charged r groups

22
Q

Renaturation

A

Ph

Returns from post optimum shape,

BUT IF CHANGED SIGNIFICATNLY - denatured

23
Q

How specifically does ph affect interactions

A

Changes degree of interaction and interaction of r groups with each other

MORE h+= less r groups are able to interact with each other, bonds in enzyme. Break , changes shape

Less h+- lots of bonds, changes shape

24
Q

Ph buffer

A

Resists change in ph, mopping up excess h+ ions

25
Q

How does substrate and enzyme concentration affect enzyme activity

A

Increased substrate particles = higher collision rate between susbryaet and active site, more enzyme substrate complexe formed

26
Q

What does a graph look like for increasing. Substrate or enzyme concentration wand the effect on reaction rate

A

Rate of reaction increases up to a certain point
At this point, all active sites are occupied form substrate particles adn no more esc’s can be formed until products are released from active site

If enzyme conc is increased, substrate conc becomes limiting factor

27
Q

Why do we need inhibitors

A

ENSURES NOT WASTING RPDOUCTS
So reaction don’t happen too fast
Leads to build up of excess products

28
Q

WHat is a competitive inhibitor

A

Molecule or part of molecule has similar shape to substrate fo enzyme

Ca to into active site 
Blocks substrate from entering 
TEMPOARILY binds ( few exceptions e.g. Aspirin)
29
Q

How do competitive inhibitors affect reaction rate

A

Susstrate and inhibitor moecluels present in solution will compete with each other to bind to active site
THis reduces number of substrate molecules binding to active site in given time and reduces rate
Vmax can still be reached ,when susbryaet concentration is increased, so much more substrate tan inhibitor

30
Q

How does aspirin work

A

Irreversibly inhibits active site of COX enzymes
Competitive
Prevents synthesis of thromboxane, responsible for producing pain and fever

31
Q

Non competitive inhibition

A

Inhibitor binds to the enzyme at a site other than the active site
Allosteric
The binding of the inhibitor causes the tertiary structure of the enzyme to change = active site changes shape
Active site no longer complementary to substrate
Enzyme can’t carry out function and doesn’t compete with inhibitor for active site
Some irreversible and some not

32
Q

Vmax - non competitive inhibitors

A

after a certain point, increasing concentration of substrate has no effect
Vmax can’t be reached because substrate isn’t competing with enzyme for active site

33
Q

Organosphates

A

Used as insecticides and herbicides

Irreversibly inhibit the enzyme acetyl chlorinetease an enzyme necessary for nerve impulse transition, can lead to muscle cramps, paralysis and even death

34
Q

What is end product inhibition

A

Non competitive reversible inhibition
Enzyme inhibition that occurs when the product of a reaction acts as an inhibitor to the enzyme
Serves as negative feedback mechanism for the reaction , excess RPDOUCTS are not made and resources not wasted
E.g. Respiration and PSK and glucose

35
Q

What is a COFACTOR

A

Non protein helper
May transfer atoms or groups from one reaction to another or form part of active site of the enzyme
Some cofactors change the charge distribution of the surface of the substrate// active site making temporary bonds in the ESC form more easily

36
Q

How are inorganic cofactors obtained

A

Via diet as minerals e,g, iron, calcium ad chlorine

37
Q

Coenzymes

A 
Organic cofactors ( contain C)
Binds temporarily to sub rate 
Chemically changed 
Derived from vitamins 
E.g. Vitamin b3 used to synthesise NAD, responsible for transfer of H atoms between moecluels involved in restoration
38
Q

Prosthetic group cofactors

A

Cofactors containing prosthetic group
Permenantly bound
E.g. Zn2+ , to form part of carbonic anhydrase ( enzyme for metabolism of co2)

39
Q

Precursors activation

A

Many enzymes produced in an inactive form = inactive pecurosor enzymes
Particularly damaging enzymes
Need to undergo a change in tertiary shape -atctive site

40
Q

What is an inactive precursor enzyme called before and after COFACTOR is added?

A

Apoenzyme

After- halo enzyme

41
Q

COFACTOR example

A

Amylase contains cl- ions, necessary for correctly formed activ site

42
Q

What are zymogens and pro enzymes

A

Precursor enzymes activated by change in tertiary structure by another enzymes action or change in conditions such as ph or temperature

BIOLOGY -MODULE 2 (24 decks)

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