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Biology Year 1 > 2.1.4- Enzymes > Flashcards

2.1.4- Enzymes Flashcards

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1
Q

what are enzymes?

A

enzymes are biological catalysts that speed up reactions without changing in anyway themselves.

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2
Q

how does metabolism occur?

A

it occurs as a result of control and order imposed by enzymes

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3
Q

what reactions do enzymes catalyse?

A

metabolic reactions at cellular and whole organism level.

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4
Q

what is activation energy?

A

the level of energy required to enable a reaction to take place, the substrate to become unstable and for products to be formed

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5
Q

how do enzymes have an affect on activation energy and what affect do they have?

A
  • affect= lowers activation energy
  • when the substrate is binded to the active site, this puts strains on the bonds in the substrate, so they break easily.
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6
Q

what are the 2 types of cellular enzymes and what are their definitions?

A 
1-intracellular= catalyse reactions in a cell
2-extracellular= catalyse reactions outside of a cell
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7
Q

what is an example of an intracellular enzyme?

A

catalase

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8
Q

what are the two example of extracellular enzymes?

A
  • amylase

- trypsin

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9
Q

are enzymes proteins, and what type?

A

yes, globular protein

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10
Q

what type of structure do enzymes have?

A

a complex/unique tertiary structure, made from a single polypeptide.
-others are made from more than one polypeptide and so have a quarternary structure

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11
Q

what is enzyme specificity?

A

an enzyme’s active site is specific (specific shape)/complementary for a substrate, so that an enzyme-substrate complex is formed

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12
Q

for a reaction to occur, what must happen between the substrate and enzyme?

A

when the substrate collides with the enzyme, it must be done at the correct orientation and speed.

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13
Q

what is the shape of the active site determined by?

A

the complex tertiary structure of the protein that makes up the enzyme

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14
Q

what determines the shape of an enzyme?

A

the order of the amino acid chain of the protein

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15
Q

what is the LOCK AND KEY hypothesis?

A

-only the substrate with the correct complementary shape to the active site can fit into the active sit to form a enzyme-substrate complex

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16
Q

who suggested the lock and key and what did he say?

A
  • fischer
  • e suggested that both enzymes and substrates were rigid structures that locked into each other very precisely, much like a key going into a lock
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17
Q

what is the INDUCED FIT hypothesis?

A

when the substrate binds into the active site, the enzyme changes shape to fit around the substrate more closely/tightly

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18
Q

what is the change in enzyme shape in the induced fit theory known as?

A

conformational changes, which ensure that deal binding arrangement between the enzyme and substrate is achieved

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19
Q

what do the conformational changes maximise?

A

they maximise the ability of the enzyme to catalyse a reaction

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20
Q

what is enzyme-substrate complex?

A

when the substrate locks into the active site of the enzyme

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21
Q

what is enzyme-product complex?

A

when a reaction as occured when the enzyme has broken up the substrate into products.

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22
Q

what are the 4 factors that affect enzyme activity?

A
  • pH
  • temperature
  • enzyme concentration
  • substrate concentration
23
Q

what is pH?

A

=the measure of H+ ion concentration,

increased conc=lower pH

24
Q

what is the effcet of pH on enzyme activity?

A
  • change in pH has an effect on the tertiary structure, as the hydrogen bonds are attracted to the - parts, so they interfere with the bonds which holds the shape and active site
  • R groups that are present in the acid in the active site are essential for the function
25
Q

what is the optimum pH?

A

the rate at which enzymes work fastest at

26
Q

what is the shape of the line on the pH and enzyme activity graph?

A

C with flat ends

27
Q

what is the effect of temperature on enzyme activity?

A
  • increase temp, the increased kinetic energy of enzymes/substrates
  • increased ke= enzymes/substrates vibrate, move faster, resulting in more collisions
  • more collisions result in more enzyme-substrate complexes and so an increased rate of reaction
28
Q

what is the optimum temp in mammals?

A

37 degrees

29
Q

what is the effect of enzyme concentration on enzyme activity?

A
  • increased conc= greater chance of collisions, as there is more active sites to bind to
  • if conc increases beyond a certain point, there is no effect on the activity
30
Q

what is the limiting factor of enzyme conc?

A

when there is more active sites that substrates, the substrate concentration becomes the limiting factor.

31
Q

what is the effect of substrate concentration on enzyme activity?

A

-increased conc, increased rate, as there is more enzyme-substrate complex’s are formed

32
Q

what is the limiting factor of substrate conc?

A

when substrate conc reaches a certain point, all enzyme active sites are full, and so enzyme concentration becomes the limiting factor.

33
Q

what is the temperature coefficient?

A

=when the rate of reaction doubles with a 10 degree increase in temperature

34
Q

what is the equation for temperature coefficient?

A

Q10 = R2 / R1

35
Q

what are conenzymes?

A

organic factors that don’t bind permanently, but fasciliate the binding

36
Q

what do coenzymes do?

A

link different enzyme-catalysed reactions into a sequence during metabolic processes, such as photosynthesis and respiration

37
Q

what are the key features of coenzymes?

A

vitamins, such as vitamin B and pantothenic acid

38
Q

what is an example of a coenzyme?

A

NAD, is reduced/oxidised, to transfer energy in the form of hydrogen ions (hydrogen acceptor)

39
Q

what is a cofactor?

A

= a molecule/ion that helps an enzyme to work (non-protein compound)

40
Q

what are the three types of cofactors?

A

1-coenzymes
2-activators
3-prosthetic groups

41
Q

what is an example of a cofactor?

A

chloride is a cofactor for amylase

42
Q

what is an activator?

A

a type of cofactor that binds to an enzyme/substrate, helping to form an enzyme-substrate complex.

43
Q

what are prosthetic groups?

A

a cofactor that permanently attaches to enzyme

44
Q

why are prosthetic groups essential?

A
  • help enzyme function correctly

- help final 3D shape of enzyme

45
Q

what are two example of a prosthetic group?

A
  • carbonic anhydrase contains zinc-based pg

- haemoglobin contains p haem group, contains iron, serves as a means of binding oxygen

46
Q

what are enzyme inhibitors and the two types?

A

they are substances that slow down the rate of enzyme reaction by affecting the enzyme-substrate complexes
1-competitive
2-non-competitive

47
Q

what are competitive inhibitors?

A
  • similar in structure to the substrate, so bind to the active site
  • this decreased enzyme activity, as it competes with the substrate for the enzyme
  • same product amount is produced, but at a slower rate
  • the inhibitor keeps the substrate out of active site
48
Q

what are non-competitive inhibitors?

A
  • binds to the enzymes allosteric site, so changes the shape of the active site to prevent binding
  • this decreases the rate, changing the 3D tertiary structure, so the substrate cannot bind
49
Q

what is reversible inhibition?

A

when the competitive inhibitor leaves the active site, so that the enzyme can work again

50
Q

what is irreversible inhibition?

A

when the non-competitive inhibitor binds to the active site, so denatures the enzyme, meaning that it cannot work again

51
Q

how are metabolic reactions controlled?

A

by using the end-product of a particular sequences of metabolic reactions as a non-competitive, reversible inhibitor

52
Q

why are some non-reversible inhibitors beneficial?

A

in medical contexts, they can be used to inhibit enzymes that can cause harm.

53
Q

what is an example of a non-reversible inhibitor as a medical drug and what it does?

A
  • penicillin

- non-reversible inhibition of transpeptidase results in the destruction of bacteria as their cell wall breaks down.

54
Q

what is another example of a medical drug and what it does?

A
  • aspirin

- non-reversible inhibition of COX, resulting in the reduction of inflammation and provides pain relief

Biology Year 1 (12 decks)

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