Speeding up digestionWALT: To understand how the rate of digestion can be increased.

WILF: Recall knowledge on types of enzymes and factors which affect enzyme action. (C)Describe how different parts of the digestive system are adapted for the optimum pH for different enzymes. (B)Clearly explain the role of bile in the digestion of fats. (A/A*)

Keywords

BileSurface areaEmulsify

Thursday 13 April 2023

What’s wrong with this? Digestive enzymes are made by cells and break down large molecules into smaller, insoluble molecules so they can be absorbed in the stomach. Carbohydrases break down carbohydrates into amino acids. For example, amylase is made in the stomach, pancreas and small intestine. Proteases break down proteins into amino acids. These enzymes are made in the salivary glands, pancreas and large intestine. Lipases break down fats into fatty acids and again these are made in the pancreas and small intestine.

Can you spot the 8 mistakes in this answer? Underline and write the correct answers in your book.

Investigating digestionTest for starch?Use iodine, a positive result is shown as blue-black colour.

Test for sugar (glucose)?Use Benedict’s, a positive result is shown as red colour.

B1 Link

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Adaptation in animals (4.2)

KeywordsSurface area: VolumeInsulationBlubber Camouflage

C: List three adaptations that Arctic animals have to keep warm.B: Describe some of the adaptations animals living in hot and dry climates have to help them survive.A/A*: Explain how a small surface area to volume ratio is a useful adaptation shown in many arctic mammals.

Pgs. 78-79

pH in the digestive systemThe stomach produces hydrochloric acid (pH2).

The enzymes in the stomach (protease) have an optimum pH of pH2.

Hydrochloric acid does not digest food but allows enzymes to work in optimum conditions.

Protein amino acids

pH in the digestive systemEnzymes produced by the pancreas and small intestine work best in alkaline conditions.

So? Bile made in the liver and stored in the gall bladder.

Neutralises stomach acid.

Task 1: Look at the practical picture on pg 170. Explain the results of each test tube on how protein is broken down.

Task 2: Describe how the stomach protects itself from the hydrochloric acid it produces.

Task 3: Copy and complete the following sentences:Bile is produced in the…Bile is stored in the…Bile neutralises…This is important because…

Altering the surface area (SA)Enzymes need the largest SA possible to work as this will increase the rate of reaction.

Large globules of fat provide a small surface area for lipase to work on.

Digestion of FatsBile emulsifies the large fat globules into smaller droplets creating a larger SA for lipase to work on.

Explain the role of enzymes in the digestive system and how the digestive system is adapted for efficient digestion. 6m

What’s wrong with this?

Digestive enzymes are made by cells and break down large molecules into smaller, insoluble molecules so they can be absorbed in the stomach. Carbohydrases break down carbohydrates into amino acids. For example, amylase is made in the stomach, pancreas and small intestine. Proteases break down proteins into amino acids. These enzymes are made in the salivary glands, pancreas and large intestine. Lipases break down fats into fatty acids and again these are made in the pancreas and small intestine.

What’s wrong with this?

Digestive enzymes are made by cells and break down large molecules into smaller, insoluble molecules so they can be absorbed in the stomach. Carbohydrases break down carbohydrates into amino acids. For example, amylase is made in the stomach, pancreas and small intestine. Proteases break down proteins into amino acids. These enzymes are made in the salivary glands, pancreas and large intestine. Lipases break down fats into fatty acids and again these are made in the pancreas and small intestine.