Digestion

The endocrine system produces hormones.

The pituitary gland is part of the endocrine system.

Where is the pituitary gland?

Tick (✓) one box.

In the head

In the heart

In the liver

Oestrogen is a hormone.

Which organ in the female reproductive system produces oestrogen?

Tick (✓) one box.

Kidney

Ovary

Stomach

Some chemicals in the environment affect the body in a similar way to hormones.

A scientist investigated the effect of feeding chemical X to rats.

Table 1 shows the results.

The scientist calculated the mean thickness of the uterus lining.

First, the scientist added together the measurements for all the rats in a group.

For the control group, the total was 4500 micrometres.

Calculate how many rats were in the control group.

Use Table 1.

Complete the sentence.

Choose the answer from the box.

The mean thickness of the uterus lining in the two groups in Table 1 was compared.

In rats fed chemical X, the mean thickness of the uterus lining

Some food packaging contains chemical Y.

Chemical Y decreases antibody production in humans.

Food packaging in landfill can release chemical Y into streams, rivers and lakes.

Which are two reasons why food packaging containing chemical Y is a problem?

Tick (✓) two boxes.

Chemical Y could become a fossil fuel.

Chemical Y could contaminate drinking water.

Chemical Y could get into food.

Chemical Y does not dissolve in water.

Chemical Y will be broken down quickly.

Which risk increases when a person produces fewer antibodies?

Tick (✓) one box.

Developing Type 1 diabetes

Getting lung cancer due to mutations

Not being able to recover from infections

If a pathogen enters the body, white blood cells can engulf and digest the pathogen.

What is the name of the process where white blood cells engulf and digest a pathogen?

The pathogen is digested by white blood cells.

Which of the following digests large molecules into smaller molecules?

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Carbohydrates

Enzymes

Lipids

Doctors sometimes advise people with kidney disease to eat a diet that is low in protein.

How does a diet that is low in protein help people with kidney disease?

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Fewer amino acids will break down to form urea.

More urea will be produced and excreted in urine.

Protease will be needed to digest the protein into amino acids.

Table 2 shows information about two types of bread.

Compare the mass of each nutrient in wholemeal bread with the mass of each nutrient in low-protein bread.

Use Table 2.

Lipids

One slice of low-protein bread has a mass of 40 g.

Calculate the mass of carbohydrate in the slice of bread.

Use Table 2.

A person eats some bread.

Describe how carbohydrates and lipids from the bread are broken down and used in cells.

You should include:

the enzymes involved

the molecules formed

how the molecules are used in cells.

Funnel-web spiders produce a poison to kill prey.

The poison enters the prey when the spider bites the prey.

The poison contains a protein.

Animals produce protease enzymes.

Explain why protease enzymes do not protect animals that are bitten by funnel-web spiders.

The protein from the poison may be used in a new drug.

The protein allows heart muscle tissue to function in low concentrations of oxygen.

Explain how coronary heart disease can decrease the concentration of oxygen in heart muscle tissue.

The new drug may be useful when transporting a donor heart to a patient for a heart transplant.

Suggest why.

The species of funnel-web spider that produces the poison comes from a small, remote area.

Evaluate the use of the poison from the funnel-web spider as a drug.

Starch molecules are broken down into glucose molecules in the small intestine (gut).

The glucose molecules are absorbed across the wall of the small intestine into the blood.

Figure 9 shows part of the wall of the small intestine.

Give two ways that the small intestine is adapted for the absorption of glucose into the blood.

Use Figure 9.

Figure 10 shows:

the breakdown of starch molecules

the movement of glucose molecules across the wall of the small intestine.

Give one reason why starch molecules cannot be absorbed into the blood.

Use Figure 10.

A student investigated the breakdown of starch with an enzyme and without an enzyme.

Figure 11 shows the apparatus.

This is the method used.

1. Add 5 cm³ of starch and enzyme mixture to a test tube.

2. Place the test tube into a water bath at 37 °C.

3. Remove one drop of the mixture every 60 seconds and test for starch using iodine solution.

4. Repeat step 3 until the starch is broken down or until 20 minutes is reached.

5. Repeat steps 1 to 4 another three times.

6. Repeat steps 1 to 5 using 5 cm³ of starch solution with no enzyme.

What colour will the iodine solution change to when starch is present?

Tick (✓) one box.

Black

Orange

Red

White

What is the dependent variable in this investigation?

Tick (✓) one box.

Temperature of the water bath

Time taken for starch to break down

Volume of the sample tested

Table 2 shows the results for the starch and enzyme mixture.

One of the results in Table 2 is anomalous.

Which result is anomalous?

Tick (✓) one box.

300 s
420 s 60 s
360 s

What should the student do with the anomalous result?

The student removed one drop of the mixture every 60 seconds and tested the drop for starch.

How could the student improve the method?

Tick (✓) one box.

Test for starch every 30 seconds

Test for starch every 3 minutes

Test for starch every 10 minutes

Another student repeated the investigation.

Table 3 shows the results.

Give one conclusion that can be made from the results.

The small intestine (gut) is adapted to digest and absorb food molecules.

Digested food molecules pass across the wall of the small intestine into the blood.

Figure 5 shows part of the wall of the small intestine.

A student used partially permeable tubing to make a model of a human small intestine.

Figure 6 shows the apparatus used.

This is the method used.

1. Add starch and enzyme solution to the tubing.

2. Take a sample of the mixture from inside the tubing and a sample of the water from the test tube. Test each sample:

using the iodine test

using the Benedict’s test.

3. Place the test tube into a water bath at 37 °C.

4. Repeat step 2 after 30 minutes.

What type of enzyme breaks down starch?

The water bath was kept at 37 °C.

Explain why 37 °C was the most suitable temperature for the investigation.

Table 3 shows the results.

Explain the results for test 3.

Explain the results for test 4.

Students investigated the effect of different concentrations of salt solution on the mass of pieces of potato.

This is the method used.

1. Cut three pieces of potato, each with a mass of 2.00 g.

2. Place the pieces of potato into a salt solution with a concentration of 0.2 mol/dm³

3. After 30 minutes, measure the mass of each piece of potato.

4. Calculate the change in mass.

5. Repeat steps 1 to 4 for five other concentrations of salt solution.

Table 3 shows the results.

Give two control variables the students should have used in the investigation.

Do not refer to mass or time in your answer.

Calculate value X in Table 3.

Figure 14 shows a potato cell.

Explain why the mass of the pieces of potato increased in the 0.2 mol/dm³ salt solution.

You should refer to the cell parts labelled in Figure 14.

The image in Figure 14 was made using an electron microscope and not a light microscope.

Give one piece of evidence to support this.

Starch is digested in the gut.

Why is digestion of starch needed?

Tick (✓) one box.

Starch is a carbohydrate.

Starch molecules are insoluble.

Starch molecules are small.

Describe the process of starch digestion.

Students investigated the effect of different concentrations of salt solution on the mass of pieces of potato.

This is the method used.

1. Cut three pieces of potato, each with a mass of 2.00 g.

2. Place the pieces of potato into a salt solution with a concentration of 0.2 mol/dm³

3. After 30 minutes, measure the mass of each piece of potato.

4. Calculate the change in mass.

5. Repeat steps 1 to 4 for five other concentrations of salt solution.

Table 1 shows the results.

Give two control variables the students should have used in the investigation.

Do not refer to mass or time in your answer.

Calculate value X in Table 1.

Figure 2 shows a potato cell.

Explain why the mass of the pieces of potato increased in the 0.2 mol/dm³ salt solution.

You should refer to the cell parts labelled in Figure 2.

The image in Figure 2 was made using an electron microscope and not a light microscope.

Give one piece of evidence to support this.

Starch is digested in the gut.

Why is digestion of starch needed?

Tick (✓) one box.

Starch is a carbohydrate.

Starch molecules are insoluble.

Starch molecules are small.

Describe the process of starch digestion.

Proteins are an important part of the human diet.

Proteins are large food molecules that must be broken down in the digestive system.

Which enzyme breaks down proteins?

Tick (✓) one box.

Carbohydrase

Lipase

Protease

Proteins are digested into amino acids.

The body breaks down unwanted amino acids.

Which organ breaks down unwanted amino acids?

Tick (✓) one box.

Brain Liver Lung

What is produced by the breakdown of unwanted amino acids?

Tick (✓) one box.

Fat Starch Urea

Mycoprotein is a protein made from a fungus.

Table 3 shows information about mycoprotein sausages and meat sausages.

Give three differences between the nutrient content of mycoprotein sausages and meat sausages.

A student tested the mycoprotein sausage and the meat sausage for protein.

What is used to test for protein?

Tick (✓) one box.

Biuret reagent

Iodine solution

pH indicator solution

What colour is the positive result for the test for protein?

Tick (✓) one box.

Black

Lilac

Red

White

The student investigated the sugar content of the mycoprotein sausage and the meat sausage.

Figure 8 shows some of the apparatus used.

Describe a method to compare the amount of sugar in the two types of sausage.

Use the apparatus in Figure 8 in your answer.

Fat, protein and carbohydrate are important parts of the human diet.

Table 3 shows information for cow’s milk and three plant-based milks.

The different types of milk in Table 3 can be bought in bottles.

Suggest why the nutritional information is given as ‘grams per 100 grams’ of milk instead of ‘grams per bottle’.

Suggest which milk in Table 3 has the greatest energy content.

Give one reason for your answer.

A student added iodine solution to each milk.

Explain why only the oat milk and the soy milk turned blue-black.

Use Table 3.

A student tested samples of the different milks for sugar.

This is the method used.

1. Add 1.0 cm³ of the milk sample to a test tube.

2. Add 1.0 cm³ of water and 2.0 cm³ of Benedict’s solution.

3. Place the test tube in a water bath at 80 °C.

4. Record the colour of the mixture at the end of the test.

5. Repeat steps 1 to 4 for the other milk samples.

The volume of each mixture in the test tube and the temperature of the water bath were control variables.

Give one other variable that should have been a control variable.

Do not refer to volume or temperature in your answer.

What was the dependent variable in the investigation?

To improve the method the student set up a control test tube.

What should the student add to the control test tube?

The fat in milk is broken down in the digestive system.

Describe the breakdown of fat in the digestive system.

Explain why the fat in milk needs to be broken down before it can be used in the body.

Protein in milk is broken down into amino acids.

Describe how unwanted amino acids are processed and removed from the body.

Sewers are often blocked by ‘fatbergs’.

Fatbergs are made of very large lumps of fat and other solids.

The fat and solids come from waste being washed down drains and flushed down toilets.

Figure 11 shows a person holding a small fatberg.

The chemical composition of fatbergs can be tested.

Describe how a sample from a fatberg could be tested for fat and for protein.

Positive result for fat

Positive result for protein

Some fats in fatbergs come from undigested food in faeces.

Most fat that humans eat is digested.

Give the two products of fat digestion.

It may be possible to use fatbergs as a fuel in power stations.

Burning 1.0 kg of fatbergs transfers 40 MJ of energy.

A power station could burn 1250 kg of fatbergs each hour.

Calculate the energy output from the power station in 1 year.

1 year = 8760 hours

Energy output in 1 year = MJ

Evaluate burning fatbergs in power stations compared with burning coal in power stations.

Sewers are often blocked by ‘fatbergs’.

Fatbergs are made of very large lumps of fat and other solids.

The fat and solids come from waste being washed down drains and flushed down toilets.

Figure 2 shows a person holding a small fatberg.

The chemical composition of fatbergs can be tested.

Describe how a sample from a fatberg could be tested for fat and for protein.

Positive result for fat

Positive result for protein

Some fats in fatbergs come from undigested food in faeces.

Most fat that humans eat is digested.

Give the two products of fat digestion.

It may be possible to use fatbergs as a fuel in power stations.

Burning 1.0 kg of fatbergs transfers 40 MJ of energy.

A power station could burn 1250 kg of fatbergs each hour.

Calculate the energy output from the power station in 1 year.

1 year = 8760 hours

Evaluate burning fatbergs in power stations compared with burning coal in power stations.