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biology > Enzymes > Flashcards

Enzymes Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

metabolism

A

is the sum of all the chemical reactions in a cell or an organism.

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2
Q

source of energy

A

solar energy

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3
Q

solar energy

A

source of all living material through photosynthesis

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4
Q

chemosynthetic

A

get their energy from chemical reactions

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5
Q

cellular energy

A

stored and released by the cells

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6
Q

enzymes

A

a protein biological catalyst

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7
Q

Enzymes role in metabolism

A
  1. control metabolic reactions

2. allow reactions to occur at a rate suitable to sustain life

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8
Q

substrate

A

substance on which an enzyme works on

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9
Q

enzyme is affected by

A

pH and temperature

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10
Q

optimum (activity, pH, temperature)

A

. when an enzyme is working at its maximum rate

. the pH or temperature the enzyme works best at

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11
Q

denatured

A

enzyme has lost its structure and can no longer function

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12
Q

specific

A

only act on one particular substrate

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13
Q

mechanism of enzyme activity

A
  1. The Substrate binds to active site of enzyme
  2. An Enzyme-substrate complex is now formed
  3. The enzyme changes shape to fit better around the substrate
    [This is called Induced Fit]
  4. The Product(s) are formed and then released.
  5. The enzyme returns to its original shape ready to be used again
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14
Q

Anabolic

A

Complex molecules are formed from simpler ones. Needs energy
examples : photosynthetic and protein synthetic

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15
Q

Catabolic

A

Simpler products are formed from a more complex molecule Releases energy
example : digestion and respiration

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16
Q

Effect of pH on the Rate of Catalase Activity

A

add to graduated cylinder
5g chopped celery
pH 4 buffer
one drop of washing up liquid
add 10cm3 of hydrogen peroxide using syringe
stand both in water bath at 25 degrees cellules
calculate rate enzyme activity
at 25 add substrate to enzyme
measure and record foam height per minute
repeat using different buffers 9, 13
A control using the same set-up, but do not add enzyme
.Results
a. Catalase activity varies with ph.
b. The most foam is produced at pH9 as this is the optimum pH for catalase activity
.c. At pH 4 and13 no foam is produced, as the enzyme catalase is denatured at these pH values.
d. At pH 7 and11 catalase did show activity, but produced less foam.

graph

17
Q

Effect of Temperature on the Rate of Catalase Activity

A

add to graduated cylinder
5g chopped celery
pH 9 buffer
one drop of washing up liquid
add 10cm3 of hydrogen peroxide using syringe
stand both in water bath at 0 degrees cellules
calculate rate enzyme activity
at 0 add substrate to enzyme
measure and record foam height per minute
repeat using different water baths 25 and 60
A control using the same set-up, but do not add enzyme
Results
a. Temperature does affect the rate of catalase activity
b. The optimum temperature for catalase is 25 C as most foam was produced
c. At 60 C –‘catalase was denatured’ as no foam was formed
d. At 0oC –‘catalase was inactive’, producing little/no foam. But increasing the temperature showed enzyme activity resume

graphs

18
Q

Effect of Heat Denaturation on the Activity of Catalase

A

denature enzyme by boiling at 100 C for 5mins.
add denatured enzyme to graduated cylinder with pH 9 buffer and one drop of washing up liquid
Add 10cm3 of hydrogen peroxide to test tube using syringe
Stand both the graduated cylinder and the test tube in a water bath at 25 C
Calculate the rate of enzyme activity
a. At 25 C , **add the substrate to the enzyme in the cylinder
b.Measure and record the foam height , per minute
prepare a control using same set up but leave the enzyme untreated
provide optimum conditions for both experiment and control

pH 9 buffer and 25 using water bath

results

a. experiment- no activity
b. control - foam is produced

19
Q

Bioprocessing

A

use of living organisms to make useful substances

20
Q

• Bioreactor

A

vessel in which products are made by cells (or organisms)

21
Q

• Immobilized

A

trapped in a gel or are fixed to each other

22
Q
  1. Immobilizing the enzyme
A
  1. Mix enzyme [yeast] with sodium alginate solution
  2. Using a syringe drip this into calcium chloride solution
  3. Beads form
  4. Leave to harden for 10 minutes
  5. Filter off beads using sieve and wash with distilled water
23
Q

Using the Immobilized Enzyme

A

add substrate sucrose to the immobilized enzyme in separating funnel.
enzyme sucrase in yeast will digest sucrose to form glucose
control - use free yeast in the same set up
results- test for glucose
open taps in each funnel and run some liquid in beakers
use clinistix to test for glucose in each beaker
repeat at 2 minute intervals until glucose appears turns purple
TURBIDITY - run remaining product from each and compare both

control free yeast - cloudy product not pure.
immobilized clear pure product

24
Q

Applications of Immobilized Enzymes

A
  1. Making ethanol using yeast working on glucose

2. Using glucose isomerase [enzyme] to convert glucose [substrate] to fructose [product]

25
Q

Advantages of Enzyme Immobilization

A

a) Product easily recovered
b) Enzyme lasts longer
c) Easier to purify product

26
Q

Role of Adenosine Triphosphate (ATP)

A

a) Stores, transports and releases energy within the cell
b) Energy stored using the reaction ADP + P + energy = ATP
c) Energy is stored in the final P~P bond
d) Energy released using the reaction ATP = ADP + P + energy

27
Q

Role of Nicotinamide Adenine Dinucleotide (NAD)

respiration and photosynthesis

A

a) In respiration
• NAD+ traps and transfers electrons and hydrogen ions
• From Krebs Cycle to Cristae of mitochondria

b) In photosynthesis
• NADP+ picks up 2 e- to become NADP-
• NADP- picks up H+ to become NADPH
• It passes on the H+ and the e-s to reduce CO2 in the Dark Stage to produce carbohydrates

28
Q

sodium alginate

A

gel substance to trap the enzyme

29
Q

calcium chloride

A

make gel insoluble forms the beads

biology (17 decks)

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