Biology Chapter: Functions of Enzymes

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Questions and Answers

What is the primary role of enzymes in chemical reactions?

Increasing the activation energy required

Lowering the temperature of the reaction

Being consumed by the reaction

Lowering the activation energy required (correct)

Which of the following statements best describes enzyme denaturation?

Enzymes become more effective at higher temperatures

Enzymes lose their shape and cannot perform their function (correct)

Enzymes require lower pH for optimal activity

Enzymes retain their shape and function

At what temperature does enzyme activity typically peak?

At low temperatures close to 0°C

At consistently high temperatures above 50°C

At varying temperatures depending on the enzyme (correct)

At room temperature regardless of the enzyme

Which enzyme works best at an acidic pH?

Pepsin Signup and view all the answers

What happens to enzyme activity as the pH deviates from its optimal level?

Enzyme activity decreases due to changes in shape Signup and view all the answers

What is formed when maltose undergoes hydrolysis?

Glucose Signup and view all the answers

Which of the following best describes the behavior of enzymes at low temperatures?

Molecules collide less frequently, slowing reactions Signup and view all the answers

Which product is formed when lipids are broken down?

Glycerol and fatty acids Signup and view all the answers

What is the role of the micropyle in seed germination?

To facilitate water entry into the seed Signup and view all the answers

Which enzyme is responsible for breaking down starch into maltose during seed germination?

Amylase Signup and view all the answers

What happens to maltose after it is produced during seed germination?

It is converted to glucose Signup and view all the answers

What is the final product of glucose metabolism in the embryo during germination?

ATP Signup and view all the answers

What color change is observed when iodine solution is mixed with starch during an investigation?

Clear to blue-black Signup and view all the answers

Which of the following statements about protease in seed germination is correct?

It breaks down protein to amino acids Signup and view all the answers

How do glucose and amino acids move from the cotyledon to the embryo?

Via phloem tissue Signup and view all the answers

What is the initial step in the process of seed germination?

Absorption of water Signup and view all the answers

Study Notes

Function of Enzymes

Enzymes speed up chemical reactions by acting as biological catalysts.
They can break down large molecules into smaller ones, known as catabolism.
- Examples: Starch breakdown into maltose, Maltose breakdown into glucose, Protein breakdown into amino acids, and Lipids breakdown into glycerol and fatty acids.
Enzymes can also build up large molecules from smaller ones, also known as anabolism.
- Examples: Joining glucose molecules to form Maltose, multiple glucose molecules joining to make Glycogen (in animal cells), and multiple glucose molecules joining to form starch (in plant cells).

Role of Enzymes in Chemical Reactions

Enzymes are reusable and can catalyze multiple reactions.
Enzymes lower the activation energy of a reaction, making it easier for the reaction to occur.

Effect of Temperature on Enzyme Activity

Enzymes have an optimal temperature for maximum activity.
Below optimal temperature, enzyme activity increases as temperature increases due to an increase in kinetic energy.
Above optimal temperature, enzyme activity decreases and eventually stops due to enzyme denaturation.

Denaturation

Denaturation is the loss of an enzyme's shape and function.
Changes in the shape of the active site prevent substrates from binding.

Effect of pH on Enzyme Activity

Each enzyme has an optimal pH at which it functions best.
The pH affects the shape of the active site, influencing substrate binding and enzyme activity.

Examples of Enzyme Activity at Different pH

Pepsin, found in the stomach, works best at acidic pH (pH 1.5).
Amylase, present in saliva, works best at neutral pH (pH 7).
Lipase, located in the small intestine, works best at alkaline pH (pH 8).

The Role of Enzymes in Seed Germination

Seed germination involves the development of a seed into a new plant.
Dry broad beans contain stored food reserves (starch, protein, lipids, and enzymes) in the cotyledons.

Steps of Seed Germination

Absorption of water: This activates enzymes and initiates germination.
Amylase converts starch to maltose: This hydrolysis reaction requires water and releases energy for the embryo.
Maltose is converted to glucose: This provides energy for embryo growth.
Glucose diffuses to cells: This fuels respiration and energy production.
Phloem transports glucose and amino acids: This distributes nutrients from the cotyledon to the growing embryo.
Protease breaks down protein to amino acids: This provides building blocks for embryo growth.

Investigations

Iodine solution is used to detect starch due to its color change from yellow to blue-black in the presence of starch.
The effect of amylase on starch can be observed by comparing the color changes in test tubes with and without amylase.
- Amylase breaks down starch, resulting in a gradual color transition from blue-black to light blue and finally yellow-brown.
- Test tubes without amylase will remain blue-black due to the presence of intact starch.

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Description

Explore the essential functions of enzymes in biological processes through this quiz. Understand how enzymes act as catalysts, their roles in catabolism and anabolism, and the impact of temperature on enzyme activity. Test your knowledge on these crucial biochemical components.