Biology Chapter 4 Flashcards

1
Q

enzymes are used in all…

A

Enzymes are used in all metabolic reactions that occur in cells. All chemical reactions
that occur in the cells are often termed as metabolic reactions.

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1
Q

2 types of reactions

A

anabolic reactions and
catabolic reactions.

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2
Q

Catalyst def

A

catalyst is a substance that can speed up chemical reatcion without itself being chemically changed at the end of the reaction

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3
Q

anabolic reaction def

A

Anabolic reactions refer to the process of synthesizing complex molecules from simpler
molecules. Eg: synthesis of proteins from amino acids

BUILD UP

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4
Q

cataboic reaction def

A

Catabolic reactions refer to the process of breaking of complex molecules into simpler
molecules. Eg: catalase breaks down hydrogen peroxide into oxygen and water

BREAK DOWN

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5
Q

enzymes definition

A

enzymes are proteins. that function as biologicl caltalysts. they catalyse/speed up the rate of chemical reaction. they remain chemically unchanged at the end of the reaction.

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6
Q

enzymes are made up of?

A

protein molecules folded to take on a 3d globular shapes.

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7
Q

activation energy def.

A

the energy needed tpo start a chemical raction

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8
Q

reactant? product?

A

R - the main thing eg a rock
P - Smaller pieces eg small pieces of a rock

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9
Q

Enzymes linked with aftivation energy. how do they help?

A

enzymes provide an alternative pathway with lower activation energy needed to start a CR. enzymes catalyse chemical reactions. they speed up the rate of CR by lowering AE

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10
Q

why are enzymes required to break large molecules into simpler and smaller substances?

A
  • solube in water
  • small enough to diffuse through cell membrane
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11
Q

DIGESTIVE ENZYMES

A

amylase - starch into maltose
maltase - maltose into glucose
protease - proteins to polypeptides the. amino acid
lipase - fats to fatty acid to glycerol

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12
Q

HOW ARE ENZYMES CLASSIFIED?

A

carbohydrases - digestst carbohydrates
proteases - digest proteins
lipases - digestts lipds/fats

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13
Q

Enzyme specificty

A

each CR in a cell is catalysed by a unique enzyme

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14
Q

Substrates def

A

the substance on which enzymes act.

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14
Q

Why is an ezyme specific in its actions?

A

because of its 3d shape. the lock and key hypothysis explains how the shape of an enzyme affects its funtion

15
Q

What does enzyme reactions depedn on?

A

the active site.

16
Q

Lock: ?
Key: ?

A

enzyme
substrate

17
Q

What is an active site?

A

grooves on the surface of an enzyme molecule into whicg the substrate molecules with the matching shape fot.

18
Q

what happened when the substrate binds to the active site?

A

an enzyme-substrate complex is formed.

19
Q

what is enzyme-substrate complex

What happens after bidning?

A

a temporary molecule formed when substrate binds to the enzyme. reatcions occcur at active site to convert substrate molecules into product molecules. the product molecule then separates from enzyme.

20
Q

what happenes to enzyme molecule after product moelcuels separates from it?

A

enzyme molecules remain unchange. free to combine again.

21
Q

what are the 5 characteristics of enzymes?

A
  1. speed up chemical reactions
  2. specific in action
  3. affected by temp
  4. required in minute amounts and remain unchanged at the end of a reaction
  5. affected by pH
22
Q

what are the 5 things of how enzymes are affected by temp?

A
  1. less active at low temp
  2. temp increases, rate pf enzyme reaction increases
  3. optimum temp where enzyme is most ative
  4. increasing temp above optimum causes decrease in the rate of enzyme reaction
  5. enzymes have becme denatured
23
Q

enzymes are less active at low temp

A

at low temp:
- KE of molecule is low
- enzyme and substrate molecules move slowly
- rate of substrate molecules colliding with enzymes is low

24
Q

temp increases, rate pf enzyme reaction increases

A
  • increaese in KE
  • rate of effective collision has increased
  • increase in rate of ESC formation
24
Q

optimum temp for enzymes

A

in humans, its about 40-45. optimum temp where enzyme is most ative

25
Q

Effect of Substrate Concentration REGION Y

At high concentration of the substrate…
All the active sites…
When this occurs there are more…

A

At high concentration of the substrate, the rate of enzyme reaction plateaus (at maximum).

● All the active sites available are occupied and engaged in the reaction. The enzymes are saturated.

● When this occurs, there are more substrate molecules present than enzyme molecules. Enzyme concentration is the limiting factor.

25
Q

What is a limiting factor??

A

A limiting factor directly affects the rate of a chemical reaction.

26
Q

Effect of Substrate Concentration REGION X
At a low concentration of the substrate, the enzyme..
At a low concentration of the substrate available…
As substrate concentration increases…
More ESC

A

At a low concentration of the substrate, the enzyme occurs in excess.

● At a low concentration of the substrate available, all substrate molecules can bind to the active site of enzymes immediately.

● As substrate concentration increases, the frequency of effective collisions between the active site of enzymes and substrates increases.

  • More enzyme-substrate complexes are formed resulting in more products formed per unit time, hence the rate of enzyme reaction increases.
27
Q

Effect of enzyme concentration REGION X

At a low enzyme concentration…
This is because…
The frequency of…
More ESC…

A

At low enzyme concentrations, the rate of reaction increases as enzyme concentration increases.

● This is because more active sites are available to bind with the substrate molecules.

  • The frequency of effective collisions between the active site of enzymes and substrates increases.

● More enzyme-substrate complexes are formed resulting in more products formed per unit time.

28
Q

Effect of enzyme concentration REGION Y
- As enzyme concentration increases…
- This is because
- All of the substrate molecules
- Substrate concentration

A
  • As enzyme concentration increases to higher concentrations, rate of reaction plateaus and remains constant.

● This is because the number of substrate molecules is fixed and there is now an excess of enzyme molecules present.

  • All of the substrate molecules are bound to an enzyme’s active site and are engaged in the reaction.

● Substrate concentration is the limiting factor.

29
Q

Enzymes are affected by pH. Example of enzymes that work best in alkali and acid

A

Proteases
Intestinal Enzyme

29
Q

DEFINE DENATURATION

A

the change in the 3d structure of an enzyme or any ither soluble protein, caused by heat or chemicals such as acids or alkalis.

29
Q

Increasing the temp above the optimum causes a rapid decrease in the rate of enzymes reaction

A

The active site of the enzyme molecule begins to lose its og shape and is no longer complementary to the substrate shape

29
Q

enzyme molecules when temp is too high?

enzyme molecules when temp is too low??

A

denatured

inactive

30
Q

what happens when enzymes are placed in pH conditions that vary from the optimum?

A

START TO DENATURE BRO NOT THAT DEEP

31
Q

optimum pH of the followinh:
protease in stomache

amylase

protease in samll intestine

A

1

6

a little shy of 8