3.6 Enzymes Flashcards Preview

HL Biology > 3.6 Enzymes > Flashcards

Flashcards in 3.6 Enzymes Deck (20):
1

What is an enzyme?

An ENZYME is a protein that acts as a catalyst in a living things

2

How does an enzyme work?

An enzyme works by LOWERING the ACTIVATION ENERGY of a chemical reaction

3

How do you name an enzyme?

replace ending at end of substrate with ase

4

What are the 3 characteristics of exergonic reactions?

Downhill
Occur Spontaneously
Produce Energy

5

What are the 3 characteristics of endergonic reactions?

Uphill
Non spontaneous
Needs energy

6

What happens to enzymatic speed with substrate concentration and why?

Enzyme activity increases as substrate concentration increases because there are more collisions between substrate molecules and the enzyme.

7

What happens to enzymatic speed with temperature and why?

As the temperature rises, enzyme activity increases because more collisions occur between enzyme and substrate.
If the temperature is too high, enzyme activity levels out and then declines rapidly because the enzyme is denatured.

8

What happens to enzymatic speed with pH and why?

Each enzyme has an optimal pH at which the rate of reaction is highest.

9

What is inhibition?

active enzyme is prevented from combining with substrate.

10

What is competitive inhibition?

Blocks substrates from entering the active site

11

What is noncompetitive inhibition?

Change formation of enzyme by binding to another site

12

What is feedback inhibition?

The end product of a reaction blocks its own production

13

How does penicillin work?

Block an enzyme that makes the cell wall in bacteria

14

How does aspirin work?

Blocks the enzyme cyclooxygenase

15

How does prozac work?

Inhibits the reuptake of seratonin

16

How does viagra work?

binds to the receptors of the enzyme guanylate cyclase-leads to increased blood flow.

17

What are the 4 characteristics of the enzyme-substrate?

Active site and substrate complement each other in terms of both shape and chemical properties (e.g. opposite charges)

Binding to the active site brings the substrate into close physical proximity, creating an enzyme-substrate complex

The enzyme catalyses the conversion of the substrate into a product (or products), creating an enzyme-product complex

As the enzyme is not consumed in the reaction, it can continue to work once the product dissociates (hence only low concentrations are needed)

18

What is denaturation?

Denaturation is a structural change in a protein that results in the loss (usually permanent) of its biological properties

19

How can lactose free milk be made?

Lactose-free milk can be produced by purifying lactase (e.g. from yeast or bacteria) and binding it to an inert substance (such as alginate beads)

20

What are the 4 uses of lactose free milk?

As a source of milk for lactose-intolerant individuals
As a means to increase the sweetness of milk (glucose and galactose are sweeter in flavour), thus negating the need for artificial sweeteners
As a way of reducing the crystallisation of ice-creams (glucose and galactose are more soluble than lactose)
As a means of shortening the production time for yogurts or cheese (bacteria ferment glucose and galactose more readily than lactose)

Decks in HL Biology Class (66):