Section 2.4 Enzymatic reactions

Formative assessment

1. An enzyme is what type of molecule?A. CarbohydrateB. LipidC. Nucleic acidD. ProteinE. Sugar

Carbohyd

rate

Lipid

Nucleic

acid

Protein

Sugar

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2. Cells need enzymes because they:A. Speed up chemical

reactions for their particular substrate

B. Act as biological (organic) catalysts

C. Lower activation energy, making the reaction more likely to start

D. A and BE. A, B, and C

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3. Activation energy is :A. Chemical potential energy

stored in the substrate

B. Chemical potential energy stored in the product

C. Energy released after the chemical reaction

D. Energy needed to start the chemical reaction

E. Energy needed to allow the substrate to bind to the active

site.Chemica

l pote

ntial energ.

..

Chemical p

otential e

nerg...

Energy r

eleased after t

he...

Energy n

eeded to st

art t..

Energy n

eeded to allo

w t..

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5. Which part of the graph shows the activation energy for the enzyme catalyzed reaction?

A. AB. BC. CD. D

A B C D

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AD

C

B

6. The part of an enzyme where substrate binds is?

A. ProductB. Active siteC. Enzyme substrate

complexD. ProteinE. Sugar

Product

Active

site

Enzyme su

bstrate

complex

Protein

Sugar

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7. All enzymes require an optimal pH, salt concentration, and temperature because under other conditions the protein may _____?

A. Be denatured.B. Be converted to a

carbohydrate.C. Be broken down to

amino acids.D. Be converted to a lipid.E. Be too active as a

catalyst.Be denatu

red.

Be conve

rted to

a carb

o...

Be broke

n down to am

in...

Be conve

rted to

a lipid.

Be too acti

ve as a ca

talys

t.

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8. Which is(are) the reactants of the chemical reaction described in this chemical equation ? C12H22O11 + H2O 2C6H12O6

A. C12H22O11

B. C12H22O11 & H2O

C. C6H12O6

D. H2O and C6H12O6

E. C12H22O11 & H2O & C6H12O6

C12H22O11

C12H22O11 & H

2O

C6H12O6

H2O and C6H12O6

C12H22O11 & H

2O

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9. When they are bound to an enzyme, thereactants of a chemical equation are called:

A. ProductsB. Active sitesC. Substrates

Products

Active

sites

Substrate

s

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10 Enzymes are specific types of which biological macromolecule?

A. CarbohydratesB. ProteinsC. LipidsD. Nucleic acids

Carbohyd

rates

Proteins

Lipids

Nucleic

acids

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11 The molecule on which an enzyme acts:

A. CatalystB. SubstrateC. MetabolismD. Homeostasis

Catalys

t

Substrate

Meta

bolism

Homeostasis

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12 Enzymes stop functioning if:

A. They act on a substrate

B. They become denatured due to improper pH or temperature

C. They catalyze too many reactions

D. They bind with the wrong substrate They a

ct on a su

bstrate

They beco

me denatured...

They cata

lyze to

o many ...

They bind w

ith th

e wro

..

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13 When proteins, such as enzymes, lose their specific shape they have become __________.

A. PassiveB. EndothermicC. ExothermicD. Denatured

Passiv

e

Endotherm

ic

Exoth

ermic

Denatured

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14 What is the optimum pH for the enzyme pepsin, the stomach enzyme that digests protein?

A. 1B. 2.5C. 5D. 6.5

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10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

1 2.5 5 6.5

pepsin trypsin

15 What is the optimum pH for the enzyme trypsin, the small intestinal enzyme that digests protein?

A. 1B. 2.5C. 5D. 6.5

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10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

1 2.5 5 6.5

pepsin trypsin

16 Examine the graph of enzyme activity versus temperature, then choose the most probable explanation of the data.

A. The enzyme whose rate is shown in blue has optimal activity at 37°C but is denatured at 4°C

B. The enzyme shown in red has a optimal temperature of 37°C, but is denatured at 4°C

C. The organism which uses the enzyme shown in blue is likely to be a mammal, but the enzyme shown in green is likely an extremophile bacterium that lives in a geyser

D. The enzyme shown in red has an optimal temperature of 37°C, but is denatured at 95°C and has too little activation energy at 4 °C

The enzyme w

hose ra

te i..

.

The enzyme sh

own in re

...

The organism

which

uses..

.

The enzyme sh

own in re

...

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17 Why won’t the enzyme that breaks down sucrose also break down maltose?

A. Organisms who eat sucrose don’t eat maltose

B. Maltose is rareC. The enzyme that

breaks down sucrose is denatured at the pH where maltose is active

D. The substrate maltose has the wrong shape so can’t fit the active site of the sucrose digesting enzyme

Organism

s who eat s

ucr...

Malto

se is

rare

The enzyme th

at bre

aks...

The substr

ate m

altose

h..

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18 Lactase is likely:

A. An enzyme that digests lactose

B. A carbohydrate found in milk

C. A protein found in milk

D. An enzyme that digests sucrose

An enzyme th

at dige

sts l..

.

A carb

ohydrate

found in

...

A prote

in found in

milk

An enzyme th

at dige

sts s.

..

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19 Which is NOT true of all enzymes?

A. All enzymes have an optimal pH of 7 & optimal temperature of 37°C

B. All enzymes are specific for a particular substrate because of the shape of the active site

C. All enzymes are re-useable unless they become denatured

D. All enzymes can be denatured when physical conditions are extremely different from their normal conditions

All enzy

mes have an

opt...

All enzy

mes are sp

ecific f

..

All enzy

mes are re

-useab..

All enzy

mes can

be dena...

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Building Macromolecules• Polymer – large biomolecules made by linking together a large

number of the same type of subunit • Monomer- small molecule that is a subunit of a polymer

(building blocks)

• Chemical reactions link monomers together to build polymers or break down polymers into monomers– Enzymes help speed up these reactions!!

Organic Macromolecules (Polymers)

MONOMER POLYMER

Amino Acid Protein

Sugar(monosaccharide)

Carbohydrate(polysaccharide)

Nucleotide Nucleic Acid

https://www.youtube.com/watch?v=hzFn3jH1tK0 potato catalase enzyme activity lab video—pH

https://www.youtube.com/watch?v=0nwI0xnG8W4 Enter Answer Text

Enter A

nswer T

ext

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Polymers are large biomolecules made of repeated subunits called

A. EnzymesB. SugarsC. MonomersD. Proteins

Enzymes

Sugars

Monomers

Proteins

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