2.5 : Enzymes Flashcards Preview

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Flashcards in 2.5 : Enzymes Deck (22)
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1
Q

what type of collisions occur in the absence of enzymes?

A

random collisions

2
Q

what effect do enzymes have on a reaction? why?

A

they increase the rate of reaction, as molecules will be attracted to these biological catalysts

3
Q

what binds to the active site?

A

a substrate molecule binds to an enzymes active site

4
Q

what is the active site?

A

region on an enzyme molecule where the substrate molecule binds

5
Q

when an enzyme-substrate complex formed, what state is it raised to?

A

raised to transitional state (short period) –> before substrate is formed into product or broken down into others by catalytic properties of the active site.
(product molecules are released with the unchanged enzyme)

6
Q

what is enzyme specificity?

A

the way in which enzymes are specific in the way that a substrate molecule binds to their active site, therefore conducts a specific action.

7
Q

how does an enzyme-substrate complex form?

A

at the active site, the arrangement of a few amino acid molecules in an enzyme matches the certain groupings on the substrate molecules –> bind –> enzyme-substrate complex formed;

8
Q

what occurs when an enzyme-substrate complex is formed? what is this called? why is this important?

A

during the formation of an enzyme-substrate complex –> a slight change of shape is induced in the enzyme = induced-fit hypothesis.
–> slight change in shape is important in raising the substrate molecule to the transitional state –> able to react & form enzyme-substrate complex (temporarily).

9
Q

what role do enzymes play in metabolism?

A

allow some reaction to take place –> many metabolic reaction only occur in presence of specific enzymes.

10
Q

what are extracellular enzymes?

A

enzymes that work externally

–> parcelled up & secreted out of cell

11
Q

what are intracellular enzymes?

A

enzymes that remain and function within a cell

-_> found inside organelles & inside membranes of organelles & in cytosol around organelles & plasma membrane.

12
Q

what effect on metabolic reactions do cells have by controlling the producing of certain enzymes at certain times?

A

cells are able to control what chemical reactions occur in the cytoplasm, based on the enzyme produced & present.

13
Q

what is denaturation? when does this occur?

A
  • a structural change in a protein that alters its three-dimensional shape.
  • occurs when bonds, formed between different amino acid residues, within the enzyme break and change the shape of the active site.
14
Q

how does temperature cause denaturation of an enzyme? is this reversible?

A

-when there is an increase in temperature –> atoms vibrate more violently as molecules have increased active energy –> disrupts bonds within the enzyme causing a change in its chemical characteristics
(proteins are denatured by heat)
-irreversible
(also increased reaction rate as molecules vibrate more
–> more likely to collide & react)

15
Q

what is a temperature coefficient?

A

a measure of the rate of change in a biological system as a consequence of increasing the temperature by a certain factor (10°).

16
Q

what is the effect of pH on enzyme shape and activity? is this reversible?

A
  • structure of enzyme/protein changes when a change in pH alters the ionic charge on the acidic and basic groups in the peptide chain –> shape of active site is lost.
  • change in pH from the enzymes optimum –> alters bonding patterns.
  • reversible –> if the change in acidity/alkalinity is not too extreme (pH returns to optimum –> active site reforms)
17
Q

why are enzymes beneficial in industrial uses/processes?

A
  • they are efficient : tiny quantity can catalyse a large amount of product.
  • they are effective at normal temperatures and pressures : only require a limited input of energy (as heat & high pressure.
  • are highly specific : able to catalyse changes in one particular compound / type of bond.
18
Q

why are some industrial enzymes obtained from microorganisms?

A
  • able to be grown economically in fermenters throughout years (rather than a short growing system)
  • grow quickly and produces a large quantity of enzymes relative to cell mass.
  • may be modified genetically with comparative ease (production of insulin - human)
  • may be bacteria from extreme environments : adapted to function under abnormal conditions of pH or temp (don’t have to worry about denaturation)
19
Q

what are examples of enzymes from microorganisms in industrial uses?

A
  • production of lactose free milk : using lactose from bacteria –> converts milks sugar into glucose & galactose.
  • photographic industry : uses protease to digest the gelatine of old films –> able to reclaim silver residues.
  • medical treatment of thromboses : use proteases (trypsin) or similar enzymes.
  • brewing industry : use protease from bacteria to prevent cloudiness of beer.
20
Q

what is enzyme immobilisation?

A

Attachment of enzymes to insoluble materials which provide support & prevented from being leached away (entrapped between inert fibres)

21
Q

what are the advantages of enzyme immobilisation?

A
  • permits reuse of enzyme preparation (doesn’t get leached away)
  • product is enzyme free (doesn’t have to undergo additional processes)
  • enzyme may be more stable & long lasting (protected by inert matrix)
22
Q

what are the steps in the production of lactose free milk?

A

-produced by application of enzyme technology using lactose obtained from bacteria = obtained by passing skimmed milk through a column containing immobilised lactose.
PROCESS –> skimmed milk is input through a pasteurisation process (kills bacteria & prolongs shelf life) –> enters a column of immobilised lactose –> enters a quality control phase (examination of product for minimum level of quality) –> enters packaging plant