Enzymes

Win for the day...

We will explore the structure and function of enzymes by describing how they lower the activation energy of the reaction.

I will be able to explain how enzymes act as biological catalysts.

Multiple Choice

Why are enzymes important for living organisms?

• They provide energy for cells

• They speed up chemical reactions without being used up

• They are the main source of genetic information

• They store nutrients for the cell

Multiple Choice

The enzyme's active site is ___ to the substrate.

• complementary
• neutral
• dissimilar
• identical

Open Ended

Describe the process by which enzymes break down substrates, as illustrated in the diagrams.

Win for the day...

We will explore the structure and function of enzymes by describing how they lower the activation energy of the reaction.

I will be able to explain how enzymes act as biological catalysts.

Match

Match the following letter with its correct name.

• A

• B

• C

• D

• E

Enzyme-Substrate Complex

Substrate

Active Site

Enzyme

Product(s)

• Enzyme-Substrate Complex

• Substrate

• Active Site

• Enzyme

• Product(s)

Multiple Choice

According to the 'lock and key' model, the enzyme's active site is perfectly ___ to the substrate.

• identical
• similar
• complementary
• dissimilar

Win for the day...

We will explore the structure and function of enzymes by describing how they lower the activation energy of the reaction.

I will be able to explain how enzymes act as biological catalysts.

Hotspot

Click the part of the picture that is the SUBSTRATE.

Multiple Choice

What effect do enzymes have on the activation energy of a reaction?

• They increase the activation energy needed.

• They decrease the activation energy needed.

• They have no effect on activation energy.

• They stop the reaction completely.

Multiple Choice

Which environmental factor is described as affecting how well an enzyme functions by changing how acidic or basic a substance is?

• Temperature

• pH

• Concentration

• Light

Win for the day...

We will explore the structure and function of enzymes by describing how they lower the activation energy of the reaction.

I will be able to explain how enzymes act as biological catalysts.

Multiple Choice

Which enzyme has its optimal activity at a lower pH, pepsin or salivary amylase?

• Pepsin

• Salivary amylase

Multiple Choice

Which of the following pH values is considered neutral?

• 2

• 7

• 10

• 14

Multiple Choice

When an enzyme is denatured, the substrate ___ bind to the enzyme.

• cannot
• will always
• can easily
• can partially

Multiple Select

Select all the factors that can cause an enzyme to become denatured.

• High temperature

• pH beyond optimal range

• Low substrate concentration

• Presence of inhibitors

Win for the day...

We will explore the structure and function of enzymes by describing how they lower the activation energy of the reaction.

I will be able to explain how enzymes act as biological catalysts.

Multiple Choice

The process in which an enzyme loses its shape and can no longer catalyze a reaction is called ___.

• activation
• denaturation
• substrate binding
• inhibition

Win for the day...

We will explore the structure and function of enzymes by describing how they lower the activation energy of the reaction.

I will be able to explain how enzymes act as biological catalysts.

Multiple Choice

The enzyme pepsin is found in the highly acidic environment of the stomach and helps break down proteins. If a sample of pepsin were moved to the small intestine, which has a basic (alkaline) environment, what would be the most likely outcome?

• Pepsin will become more active and enhance protein digestion.
• Pepsin will continue to function normally and break down proteins.
• Pepsin will become inactive and unable to break down proteins.
• Pepsin will transform into a different enzyme that works in the small intestine.

Multiple Choice

Why does increasing temperature up to the optimal point increase enzyme activity?

• less substrate
• enzyme denaturation
• more collisions
• lower pH

Multiple Choice

If the temperature gets too high, the enzyme will ___.

• activate
• denature
• multiply
• freeze

Multiple Choice

A patient develops a high fever of 104°F (40°C). Many essential chemical reactions in the body begin to slow down. Based on the presentation, what is the most likely reason for this?

• The higher temperature increases the activation energy needed for reactions.

• The enzymes are working too fast, creating too many products.

• The heat causes the enzymes' active sites to change shape, making them less effective.

• The substrates are moving too quickly to fit into the active sites.

Win for the day...

We will explore the structure and function of enzymes by describing how they lower the activation energy of the reaction.

I will be able to explain how enzymes act as biological catalysts.

Multiple Choice

When a non-competitive Inhibitor binds to an enzyme, what part of the enzyme changes shape?

• active site
• substrate
• enzyme structure
• cofactor

Win for the day...

We will explore the structure and function of enzymes by describing how they lower the activation energy of the reaction.

I will be able to explain how enzymes act as biological catalysts.

Multiple Choice

A scientist is studying a reaction where the sugar maltose is broken down into two glucose molecules. She adds an enzyme called sucrase, which is known to break down sucrose, but she observes that no reaction occurs. Which concept best explains this observation?

• Enzyme concentration
• Temperature effects
• pH levels
• Enzyme specificity

Multiple Choice

Where do competitive inhibitors bind to stop the reaction from taking place?

• active site
• substrate area
• enzyme pocket
• binding site

Open Ended

Explain in your own words how increasing the enzyme concentration will increase the reaction rate?

Multiple Choice

Lactose intolerance is a condition where people cannot digest milk sugar (lactose) because they lack the enzyme lactase. If a person with this condition consumes dairy, the lactose remains undigested. Which concept from the presentation best explains why other enzymes in the digestive system, like pepsin (for protein) or amylase (for starch), cannot break down the lactose?

• Lactose can be broken down by any digestive enzyme.
• Pepsin is specifically designed to digest lactose.
• Amylase can convert lactose into glucose and galactose.
• Lactose requires the specific enzyme lactase for digestion, which is not produced in lactose-intolerant individuals.

Multiple Choice

A scientist sets up an experiment with a fixed amount of an enzyme and an unlimited supply of its substrate. She observes that as she adds more substrate, the rate of the reaction increases, but only up to a certain point. After that, adding more substrate does not make the reaction go any faster. What is the best explanation for this?

• The enzyme becomes saturated with substrate.
• The enzyme is denatured by the substrate.
• The reaction reaches a temperature limit.
• The substrate is converted into a product too quickly.

Multiple Choice

Enzymes are biological ___ that speed up reactions in the body without being used up themselves.

• substrates
• inhibitors
• reactants
• catalysts

Multiple Choice

A food manufacturer wants to create a fruit juice that stays fresh-looking and does not turn brown. The browning of fruits like apples and bananas is caused by an enzyme called PPO. The manufacturer finds that adding lemon juice, which is highly acidic, prevents the browning. What is the most likely explanation for this?

• Lemon juice masks the browning with its strong flavor.
• The acidity of lemon juice causes fruits to ripen faster.
• The acidity lemon juice prevents browning by denaturing the PPO enzyme.

• Lemon juice adds nutrients that enhance fruit color.

Multiple Choice

Imagine a chemical reaction that can be summarized as: Starch → Glucose. In a laboratory setting, this reaction requires a large amount of heat to proceed. However, in the human body, the enzyme amylase allows this reaction to occur rapidly at normal body temperature. How does amylase achieve this?

• Amylase converts glucose back to starch.
• Amylase lowers the activation energy for the reaction.
• Amylase requires high pressure to function.
• Amylase increases the temperature of the reaction.

Win for the day...

We will explore the structure and function of enzymes by describing how they lower the activation energy of the reaction.

I will be able to explain how enzymes act as biological catalysts.

Open Ended

Summarize what you have learned about enzymes and their role as biological catalysts. Why are enzymes important for living organisms?