Demonstration of Typical Enzymes and Factors Affecting Enzyme Activity

Vocabulary flashcards covering Experiments 4 and 5 on enzyme demonstrations and factors affecting enzyme activity.

Experiment 4 Title

Demonstration of Typical Enzymes

Experiment 5 Title

Factors Affecting Enzyme Activity

Pre-boiled starch solution with saliva (Benedict's Reagent result)

Produces a blue color reaction, indicating no reducing sugars were formed.

Pre-boiled starch solution with saliva (Iodine Solution result)

Produces a purple blue color reaction, indicating starch is still present.

Unboiled starch solution with saliva (Benedict's Reagent result)

Produces a brick red precipitate, indicating starch was hydrolyzed into reducing sugars by salivary amylase.

Unboiled starch solution with saliva (Iodine Solution result)

Produces a yellow-color reaction, indicating that starch has been digested.

Boiled enzyme extract with $H_2O_2$

Shows almost no bubbling with an oxygen height of $2\,\text{mm}$ ($0.2\,\text{cm}$) in Experiment 4 Part II.

Unboiled enzyme extract with $H_2O_2$

Shows vigorous bubbling with an oxygen height of $50\,\text{mm}$ ($5\,\text{cm}$) in Experiment 4 Part II.

Enzyme extract control with $0.3\,\text{M}$ urea

Red litmus paper remains red in Experiment 4 Part III.

Unboiled enzyme extract with $0.3\,\text{M}$ urea

Turns red litmus paper blue, indicating the production of basic products (ammonia) by active urease.

Boiled enzyme extract with $0.3\,\text{M}$ urea

Red litmus paper remains red due to thermal inactivation of the urease enzyme.

Experiment 4 Laboratory Data Sheet

Data page recording results for Part I (Enzyme A), Part II (Enzyme B), and Part III (Enzyme C).

Effect of pH Test Tube 1 ($2\,\text{mL}$ of $0.01\,\text{M}$ HCl)

Results in no foam in Experiment 5 Part II.

Effect of pH Test Tube 2 ($2\,\text{mL}$ of pH 4 buffer)

Results in low foam ($1\,\text{cm}$) in Experiment 5 Part II.

Effect of pH Test Tube 3 ($2\,\text{mL}$ of pH 7 buffer)

Results in high foam ($3\,\text{cm}$), representing maximum catalase activity in Experiment 5 Part II.

Effect of pH Test Tube 4 ($2\,\text{mL}$ of $0.1\,\text{M}$ $Na_2CO_3$)

Results in low foam ($1\,\text{cm}$) in Experiment 5 Part II.

Substrate Concentration Test Tube 1 ($4\,\text{mL}$ $H_2O_2$)

Yields the highest foam height of $2.6\,\text{cm}$ in Experiment 5 Part III.

Substrate Concentration Test Tube 2 ($2\,\text{mL}$ $H_2O_2$)

Yields a moderate foam height of $2.4\,\text{cm}$ in Experiment 5 Part III.

Substrate Concentration Test Tube 3 ($1\,\text{mL}$ $H_2O_2$)

Yields a low foam height of $2\,\text{cm}$ in Experiment 5 Part III.

Substrate Concentration Test Tube 4 ($0.5\,\text{mL}$ $H_2O_2$)

Yields the lowest foam height of $1.6\,\text{cm}$ in Experiment 5 Part III.

Enzyme Concentration Test Tube 1 ($2\,\text{mL}$ potato extract)

Yields the highest foam height ($2\,\text{cm}$) in Experiment 5 Part IV.

Enzyme Concentration Test Tube 2 ($1\,\text{mL}$ potato extract + distilled water)

Yields a moderate foam height ($1\,\text{cm}$) in Experiment 5 Part IV.

Enzyme Concentration Test Tube 3 ($0.5\,\text{mL}$ potato extract + distilled water)

Yields the lowest foam height ($0.75\,\text{cm}$) in Experiment 5 Part IV.

Effect of Temperature Test Tube 1 (Ice bath at $0\,^\circ\text{C}$)

Produces very little foam ($2\,\text{mm}$) due to low thermal kinetic energy.

Effect of Temperature Test Tube 2 (Room temperature at $20\text{--}25\,^\circ\text{C}$)

Produces moderate foam ($7\,\text{mm}$) in Experiment 5 Part V.

Effect of Temperature Test Tube 3 (Body temperature at $37\,^\circ\text{C}$)

Produces the highest foam height ($16\,\text{mm}$), indicating optimal enzyme activity.

Effect of Temperature Test Tube 4 (High temperature at $70\,^\circ\text{C}$)

Produces no foam due to thermal denaturation of catalase.

Effect of Inhibitor Test Tube 1 (Potato extract control)

Yields a higher foam height of $2.1\,\text{cm}$ in Experiment 5 Part VI.

Effect of Inhibitor Test Tube 2 (Potato extract with $CuSO_4$)

Yields a lower foam height of $1.25\,\text{cm}$ in Experiment 5 Part VI.

Optimum pH for Catalase

pH 7, as demonstrated by the maximum foam height ($3\,\text{cm}$) in Experiment 5 Part II.

Optimum Temperature for Catalase

$37\,^\circ\text{C}$ (body temperature), as demonstrated by the highest foam height ($16\,\text{mm}$) in Experiment 5 Part V.

Effect of $CuSO_4$ on Catalase Activity

Decreases catalase activity, reducing foam height from $2.1\,\text{cm}$ to $1.25\,\text{cm}$.

Classification of $CuSO_4$ as an Inhibitor

Act as an enzyme inhibitor that reduces the rate of catalase-catalyzed decomposition of hydrogen peroxide.

Benedict's Reagent

A chemical reagent that tests for reducing sugars; forms a brick red precipitate when positive.

Iodine Solution

A chemical reagent that tests for starch; produces a dark purple/blue color when positive and yellow/brown when negative.

Enzyme Denaturation

The loss of enzymatic activity caused by extreme conditions such as boiling at high temperatures ($70\,^\circ\text{C}$) or extreme pH levels.

Urease

The enzyme (Enzyme C) that breaks down $0.3\,\text{M}$ urea, producing basic products that turn red litmus paper blue.

Potato Extract

The source of the enzyme catalase used in Experiment 5.

Hydrogen Peroxide ($H_2O_2$)

The substrate broken down by catalase to generate oxygen gas foam in Experiments 4 and 5.

Effect of Temperature on Enzymatic Reaction Rate

The rate of reaction initially increases with rising temperature due to higher kinetic collisions, then sharply declines as high temperatures cause protein denaturation.