What’s wrong with this?

Monosaccharides are sweet tasting, insoluble substances, e.g. glucose. To test for this non-reducing sugar you carry out the Benedict’s test where a red precipitate of copper sulphate is produced if the sugar is present. Disaccharides are when two monosaccharides are linked by a glucose bond, this happens due to a condensation reaction where a molecule of water is added. E.g. glucose linked with fructose forms maltose. Polysaccharides are when many monosaccharides are linked, e.g. glucose. To test for this add iodine and a blue-black colour indicates a polysaccharide.

Can you spot the 7 mistakes in this answer? Underline and then correct at the side of the text.

Carbohydrate digestion

Objective: To understand in detail how carbohydrates are digested.

Outcomes:~ Identify specific carbohydrases and describe how they hydrolyse polysaccharides into their monosaccharides.~ Explain how lactose intolerance occurs.

Keywords

AmylaseMaltaseSucraseLactase

Thursday 13 April 2023

Mouth & salivary glandsPhysical digestion

Chemical digestion salivary amylase is produced.

Starch maltose

Also in saliva are mineral salts to provide neutral conditions for this enzyme.

StomachAcidic conditions so amylase is denatured.

Small intestine Chyme mixed with pancreatic juice.

Pancreatic amylase.

Hydrolyses starch to maltose.

Maltase is secreted which hydrolyses maltose to glucose.

Sucrose? Small intestine secretes sucrase.

Hydrolyses sucrose into glucose and fructose.

Lactose? Small intestine

secretes lactase.

Hydrolyses lactose into glucose and

galactose.

Lactose intolerance1.Explain why babies produce

larger amounts of lactase compared to adults.

2.Explain how some adults become lactose intolerant.

3.List some symptoms of this disorder and explain how they occur.

4.Lactose intolerance is not life threatening however describe other problems sufferers may have.

Read through the information on pg 25 and answer the following qu’s.

Better milk for cats?!Cats are unable to digest large amounts of lactose. Milk can be treated with the enzyme to make a lactose- reduced milk suitable for cats or humans who are lactose intolerant.

The milk is treated by injecting enzyme into the carton by using an immobilised enzyme.

What’s wrong with this?

Monosaccharides are sweet tasting, insoluble substances, e.g. glucose. To test for this non-reducing sugar you carry out the Benedict’s test where a red precipitate of copper sulphate is produced if the sugar is present. Disaccharides are when two monosaccharides are linked by a glucose bond, this happens due to a condensation reaction where a molecule of water is added. E.g. glucose linked with fructose forms maltose. Polysaccharides are when many monosaccharides are linked, e.g. glucose. To test for this add iodine and a blue-black colour indicates a polysaccharide.

What’s wrong with this?

Monosaccharides are sweet tasting, insoluble substances, e.g. glucose. To test for this non-reducing sugar you carry out the Benedict’s test where a red precipitate of copper sulphate is produced if the sugar is present. Disaccharides are when two monosaccharides are linked by a glucose bond, this happens due to a condensation reaction where a molecule of water is added. E.g. glucose linked with fructose forms maltose. Polysaccharides are when many monosaccharides are linked, e.g. glucose. To test for this add iodine and a blue-black colour indicates a polysaccharide.

Carbohydrate digestion

Produced where?

Enzyme? Poly/disaccharide

Monosaccharide

Salivary amylase

Pancreas

Small intestine (Ileum) Sucrose

Glucose

Glucose + galactose

Complete the boxes to describe how carbohydrates are hydrolysed by enzymes in the digestive system.

Then summarise these notes by completing the table below.

Produced where? Enzyme? Poly/disaccharide

Monosaccharide

Salivary glands Salivary amylase Starch Maltose

Pancreas Pancreatic amylase Starch Maltose

Small intestine (Ileum) Maltase

Sucrase

Lactase

Maltose

Sucrose

Lactose

Glucose

Glucose + fructose

Glucose + galactose

Produced where? Enzyme? Poly/disaccharide

Monosaccharide

Salivary amylase

Pancreas

Small intestine (Ileum)

Sucrose

Glucose

Glucose + galactose

Produced where? Enzyme? Poly/disaccharide

Monosaccharide

Salivary amylase

Pancreas

Small intestine (Ileum)

Sucrose

Glucose

Glucose + galactose