Digestion and Enzymes

Digestion flashcards

True or False?

The digestive and respiratory systems are examples of organ systems.

True.

The digestive and respiratory systems are examples of organ systems.

List the levels of organisation in complex multicellular organisms.

The levels of organisation should be listed in the following order:

• Organelles

• Cells

• Tissues

• Organs

• Organ systems

What is the function of the stomach?

The stomach has three roles:

• To mechanically digest food through the churning of food

• To produce the enzyme protease

• To produce hydrochloric acid (stomach acid)

Name the organ system the stomach is part of.

The stomach is part of the digestive system.

Name two organs of the digestive system, other than the stomach.

Two other organs of the digestive system:

• Mouth/tongue/salivary glands

• Oesophagus

• Liver

• Gall bladder

• Pancreas

• Small intestine

• Large intestine

• Rectum

What is the function of the digestive system?

The function of the digestive system is to break down large, insoluble food molecules into small, soluble molecules that can be absorbed.

Name the organs of the digestive system through which food passes during digestion.

The organs of the alimentary canal through which food passes are:

• Mouth

• Oesophagus

• Stomach

• Small intestine (duodenum and ileum)

• Large intestine

• Rectum

Other organs, e.g. the pancreas, are not in this list because food does not directly pass through them.

True or False?

Mechanical digestion takes place in the mouth.

True.

Teeth grind food in the mouth; this is mechanical digestion.

What is the role of saliva in digestion?

Saliva contains amylase enzymes that begin the chemical breakdown of starch into sugars. Saliva also moistens food to aid in swallowing.

What is the role of the oesophagus in digestion?

The oesophagus is the tube through which food passes between the mouth and the stomach.

True or False?

Both mechanical and chemical digestion take place in the stomach.

True.

Muscular contractions of the stomach wall play a role in mechanical digestion, while protease enzymes start to chemically break down the proteins in food.

What is the role of the large intestine in digestion?

The role of the large intestine is to allow absorption of water from solid waste before it is egested; the remaining solid waste makes up the faeces.

True or False?

The pancreas is part of the alimentary canal.

False.

Accessory organs, such as the pancreas, are not part of the tube through which food passes. Their role is to produce substances, such as enzymes, needed for digestion.

Name three organs of the digestive system that release enzymes.

Three organs of the digestive system that release enzymes include:

• Salivary glands

• Stomach

• Small intestine

• Pancreas

Which organ is bile released from?

Bile is released from the gallbladder.

Define the term enzyme.

An enzyme is a protein that acts as a biological catalyst to speed up the rate of a chemical reaction.

What does a catalyst do?

A catalyst speeds up the rate of a chemical reaction without being used up or changed in the reaction.

True or False?

Enzymes are changed or used up in the reactions they catalyse.

False.

Enzymes are not changed or used up in the reactions they catalyse; they can be recycled and used in further reactions.

What are the three main types of digestive enzymes?

The three main types of digestive enzymes are:

• Carbohydrase

• Protease

• Lipase

What is the role of carbohydrase enzymes?

Carbohydrase enzymes break down carbohydrates into simple sugars, e.g. glucose.

Amylase is an example of a carbohydrase enzyme which digests starch

Where is the enzyme amylase produced in the digestive system?

The enzyme amylase is produced in the:

• Salivary glands

• Pancreas

• Small intestine

True or False?

Protease enzymes break down proteins into fatty acids.

False.

Protease enzymes break down proteins into amino acids. Fatty acids are a product of lipid digestion.

Name the type of enzyme responsible for lipid digestion.

Lipase enzymes carry out lipid digestion.

What are the products of lipid digestion?

Lipids (fats) are broken down into glycerol and fatty acids by lipase enzymes.

What is the role of the pancreas in digestion?

The pancreas produces the following digestive enzymes:

• Lipase

• Amylase

• Protease

Name the type of enzyme that digests protein.

The type of enzyme that digests protein is protease.

What are the products of protein digestion?

The products of protein digestion are amino acids.

Which organ(s) of the digestive system produce the enzyme lipase?

The organ that produces the enzyme lipase is the pancreas.

What is the test for glucose (a reducing sugar)?

The test for glucose involves adding Benedict's solution to a sample and heating it in a boiling water bath. A positive result is a colour change from blue to brick red.

What is the test for starch?

The test for starch involves adding iodine solution to a food sample. A positive result is a colour change from orange-brown to blue-black.

What is the protein food test?

The protein food test involves adding Biuret solution to a food sample. A positive result is a colour change from blue to violet/purple.

What is the test for lipids?

The test for lipids involves mixing a sample with ethanol and then adding the ethanol solution to cold water. A positive result is a cloudy white emulsion forming.

Note that a sample containing solid pieces of food may need to be strained before a positive result can be clearly seen.

True or False?

A positive iodine test will turn the solution from red to blue-black.

False.

A positive test for starch using iodine will turn the solution from brown/orange to blue-black.

What is the starting colour of Benedict's solution?

The starting colour of Benedict's solution is blue.

What is the starting colour of Biuret solution?

The starting colour of Biuret solution is blue.

Which of the food tests must be heated to observe the results?

The Benedict's test for glucose (a reducing sugar) must be heated to observe the results.