Preparation - Tasks For Assessment - Class 9

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| By MsDagmara

MsDagmara

Community Contributor

Quizzes Created: 1 | Total Attempts: 40

Questions: 13 | Attempts: 40 | Updated: May 5, 2023

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Questions and Answers

1.

Write 2 differences between animal and plant cell.
2.

Write 3 differences between prokaryotic and eukaryotic cell
3.

Please select the active site in the given image.
4.

Enzymes are belong to which group of organic molecules?
- A.
  
  Carbohydrates
- B.
  
  Lipids
- C.
  
  Nucleic Acids
- D.
  
  Proteins
Correct Answer
D. Proteins

Explanation
Enzymes are proteins that act as catalysts in biochemical reactions. They are responsible for speeding up the rate of these reactions by lowering the activation energy required. Enzymes are made up of amino acids and have a specific three-dimensional structure that enables them to bind to specific substrates. This binding allows the enzyme to facilitate the conversion of substrates into products. Therefore, the correct answer is proteins.

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5.

The graphs show the reaction rate for an enzyme across a range of temperatures and pH. Based on these data, this enzyme functions best at what temperature and pH?
- A.
  
  Temperature of 27^oC and pH of 4.
- B.
  
  Temperature of 37^oC and pH of 6.
- C.
  
  Temperature of 40^oC and pH of 8.
- D.
  
  Temperature of 50^oC and pH of 10.
Correct Answer
B. Temperature of 37^oC and pH of 6.

Explanation
The correct answer is Temperature of 37oC and pH of 6. This is because the graph shows that the reaction rate is highest at this temperature and pH level. At lower temperatures and pH levels, the reaction rate is slower, indicating that the enzyme is less active. At higher temperatures and pH levels, the reaction rate also decreases, suggesting that the enzyme becomes denatured or less efficient. Therefore, the optimal conditions for this enzyme's function are a temperature of 37oC and a pH of 6.

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6.

What affect does extremely high pH have on enzymes?
- A.
  
  Denatures them
- B.
  
  Kills them
- C.
  
  Destroys them
Correct Answer
A. Denatures them

Explanation
Extremely high pH levels can denature enzymes, which means it alters their structure and causes them to lose their function. Enzymes have specific three-dimensional shapes that are crucial for their catalytic activity. However, high pH disrupts the hydrogen bonding and ionic interactions that maintain the enzyme's shape, leading to a loss of its functional structure. As a result, the enzyme becomes inactive and unable to perform its intended biological functions.

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7.

What type of enzymes break down carbohydrates?
- A.
  
  Protease
- B.
  
  Lipase
- C.
  
  Carbohydrase
Correct Answer
C. Carbohydrase

Explanation
Carbohydrase is the correct answer because this type of enzyme is specifically designed to break down carbohydrates. Carbohydrases, also known as amylases, help in the digestion and absorption of carbohydrates by breaking them down into smaller molecules such as glucose. These enzymes are produced in the mouth (salivary amylase) and in the pancreas (pancreatic amylase) to aid in the digestion of starches and other complex carbohydrates. Protease is an enzyme that breaks down proteins, while lipase is responsible for breaking down fats.

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8.

Which of the following emulsifies fats so they can be further digested by the enzyme lipase?
- A.
  
  Hydrochloric acid
- B.
  
  Mucus
- C.
  
  Bile
- D.
  
  Saliva
Correct Answer
C. Bile

Explanation
Bile is the correct answer because it emulsifies fats. Emulsification is the process of breaking down large fat droplets into smaller droplets, increasing the surface area for the enzyme lipase to act upon. Bile contains bile salts, which have hydrophobic and hydrophilic regions. These bile salts surround the fat droplets, forming micelles and dispersing the fats in water-based digestive fluids. This allows lipase to efficiently break down the fats into smaller components that can be absorbed by the body.

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9.

Protease enzymes break down proteins into what?
- A.
  
  Fatty acids
- B.
  
  Amino acids
- C.
  
  Carboxylic acids
- D.
  
  Hydrochloric acid
Correct Answer
B. Amino acids

Explanation
Protease enzymes are responsible for breaking down proteins into smaller units called amino acids. This process, known as proteolysis, is essential for the digestion and absorption of proteins in the body. Amino acids are the building blocks of proteins and play crucial roles in various biological processes, including the synthesis of new proteins, hormone production, and cellular signaling. Therefore, the correct answer is amino acids.

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10.

Which enzyme converts starch into sugars in the mouth and small intestine?
- A.
  
  Protease
- B.
  
  Lipase
- C.
  
  Isomerase
- D.
  
  Amylase
Correct Answer
D. Amylase

Explanation
Amylase is the correct answer because it is the enzyme that converts starch into sugars in the mouth and small intestine. Amylase is produced by the salivary glands in the mouth and the pancreas in the small intestine. It breaks down the complex carbohydrates present in starch into simpler sugars like maltose and glucose, which can be easily absorbed by the body. This process of digestion begins in the mouth when amylase present in saliva starts breaking down starch into smaller molecules. It continues in the small intestine, where pancreatic amylase further breaks down starch into sugars for absorption.

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11.

Which enzyme converts fats into 3 fatty acids and glycerol?
- A.
  
  Amylase
- B.
  
  Protease
- C.
  
  Lipase
- D.
  
  DNA polymerase
Correct Answer
C. Lipase

Explanation
Lipase is the enzyme responsible for converting fats into 3 fatty acids and glycerol. It breaks down the ester bonds in triglycerides, which are the main form of dietary fats, into their component parts. This process is essential for the digestion and absorption of fats in the body. Lipase is produced in the pancreas and released into the small intestine, where it acts on the fats present in the food we consume. Without lipase, our bodies would not be able to properly break down and utilize dietary fats.

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12.

Protease enzymes are located in which organ?
- A.
  
  Mouth
- B.
  
  Oesophagus
- C.
  
  Stomach
- D.
  
  Colon
Correct Answer
C. Stomach

Explanation
Protease enzymes are located in the stomach. The stomach secretes gastric juice, which contains various enzymes including protease. Protease enzymes are responsible for breaking down proteins into smaller peptides and amino acids, aiding in digestion. The stomach's acidic environment helps activate these enzymes, allowing them to function properly. Therefore, the correct answer is the stomach.

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13.

Which of the following does not affect the initial rate of an enzyme controlled reaction?
- A.
  
  A change of pH
- B.
  
  An increase in the duration of the reaction
- C.
  
  A decrease in the concentration of substrate
Correct Answer
B. An increase in the duration of the reaction

Explanation
An increase in the duration of the reaction does not affect the initial rate of an enzyme controlled reaction because the initial rate is determined by the concentration of the substrate and the efficiency of the enzyme. The duration of the reaction refers to the overall time it takes for the reaction to complete, but it does not impact the rate at which the reaction initially occurs.

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Preparation - Tasks For Assessment - Class 9

Write 2 differences between animal and plant cell.

Write 3 differences between prokaryotic and eukaryotic cell

Please select the active site in the given image.

Enzymes are belong to which group of organic molecules?

The graphs show the reaction rate for an enzyme across a range of temperatures and pH. Based on these data, this enzyme functions best at what temperature and pH?

What affect does extremely high pH have on enzymes?

What type of enzymes break down carbohydrates?

Which of the following emulsifies fats so they can be further digested by the enzyme lipase?

Protease enzymes break down proteins into what?

Which enzyme converts starch into sugars in the mouth and small intestine?

Which enzyme converts fats into 3 fatty acids and glycerol?

Protease enzymes are located in which organ?

Which of the following does not affect the initial rate of an enzyme controlled reaction?