Food tests

Figure 1 shows a percentile chart for the height of boys from age 2 to age 16.

Which is the height of an 8-year-old boy on the 10th percentile?

The height of a 4-year-old boy was 94 cm.

Two years later, his height was 106 cm.

Using Figure 1, explain the conclusion that can be made about the growth of this child.

Fats are needed for energy.

Describe how a sample of food can be tested to show that it contains fat.

Which is produced when fats are digested?

State what calorimetry is used to measure.

As bananas ripen, they change colour and taste sweeter.

Figure 1 shows two bunches of bananas.

Unripe bananas contain more starch.

Describe the chemical test for starch.

As bananas ripen the starch is converted to glucose.

Describe how bananas can be tested for the presence of glucose.

A banana with green skin tested positive for starch and negative for glucose.

A banana with yellow skin tested positive for both starch and glucose.

Explain why there was glucose in the yellow banana.

Figure 7 shows the structure of a leaf.

Which layer has the highest number of chloroplasts per cell?

When iodine solution was put onto these cells, small parts of the cells became blue‑black.

Name the substance stored in the parts of the cells that turned blue‑black.

State how the guard cells control the amount of gas exchange that occurs through the stomata.

A scientist measured the thickness of the cuticle from the leaves of plants growing in soil that had a different percentage of water content.

The scientist measured six plants at each percentage of water content.

Figure 8 shows the results.

Calculate the mean thickness of cuticle for the plants growing in soil containing 15% water.

Give your answer to one decimal place.

Explain why the thickness of the cuticle is different when a plant is grown in soil with a higher water content.

State one other way that the leaves of plants are adapted to help plants grow in soil with low water content.

Figure 11 shows the structure of a kidney nephron.

Small soluble substances including glucose are forced out through small holes in the glomerulus into the Bowman’s capsule.

Which term describes this process?

Explain why red blood cells do not move from blood in the glomerulus into the Bowman’s capsule.

Describe what happens in the collecting duct to make the urine more concentrated.

State where urine is stored before it leaves the body.

*(d) Describe how you would use laboratory tests to show if a food contains glucose (a reducing sugar) and protein.

Include in your answer:

• how you would prepare the sample of food

• how you would use Benedict’s solution and Biuret solution

• the results you would expect.

1 (a) Banting and Best were the first scientists to use the hormone insulin for the treatment of diabetes. They extracted insulin from the body organs of animals.

(i) Which body organ produces insulin?

(ii) How does insulin travel to its target organ?

(b) Tasting urine was one of the first ways doctors tested for diabetes. If the urine tasted sweet, the patient may have diabetes. Describe the chemical test we now use to test for glucose in urine.

(c) A scientist wanted to compare the glucose concentration in two urine samples. State two variables that need to be controlled for the comparison to be valid.

5 Figure 9 shows a nephron from a kidney. Bowman’s capsule

(a) The pressure of the liquid in the Bowman’s capsule is 1.3 kPa. The pressure of the liquid in the glomerulus is 5.6 times greater than the pressure in the Bowman’s capsule.

(i) Calculate the pressure in the glomerulus. Give your answer to one decimal place.

(ii) The higher pressure in the glomerulus forces some parts of the blood into the Bowman’s capsule. Which row of the table shows the parts of the blood that move into the Bowman’s capsule?

(b) A scientist investigated the concentration of glucose in liquids from three different parts of the nephron.

(i) Describe how the equipment shown in Figure 10 can be used to see if these liquids contain different concentrations of glucose.

(ii) Figure 11 shows the concentration of glucose in the three different parts of the nephron.

Figure 11

Explain one conclusion that can be made from the data in Figure 11.

10 (a) When training, an athlete noticed some types of T‑shirts became wetter and heavier due to sweating. This athlete has three T‑shirts, each made of a different material. Devise a method this athlete could use to find the best T‑shirt for training.

(b) Athletes often eat a high protein diet.

(i) Which is the test and result for a food containing protein?

(ii) Digested protein is absorbed in the small intestine by diffusion. Figure 15 shows part of the small intestine.

(Source: © Science Photo Library C047/6177)

Figure 15

Using Figure 15 and Fick’s law, explain the effect of the villi on the rate of diffusion.

(iii) Digested protein enters the blood as amino acids. State which component of the blood transports amino acids.

(c) Explain how high levels of amino acids in the blood cause a high concentration of urea in urine.

1 (a) Animals and plants are made of cells. Figure 1 shows two types of cell from a human.

cheek cell sperm cell

Figure 1

(i) Which part of the cheek cell is labelled W?

(ii) Which labelled part of the sperm cell is also found in the cheek cell?

(b) Name the part of a plant cell that gives the cell support and protection.

(c) Some cells contain starch. Describe the chemical test for starch.

(d) Figure 2 shows the results of some food tests.

(i) Give the letter of the food sample that contains fat.

(ii) Give the letter of the food sample that contains reducing sugars and protein.

A student investigated fish food.

The student added some fish food to a blue liquid in a test tube.

The solution turned from blue to purple.

Use words from the box to complete the sentences.

The blue liquid was_........ solution.

The purple colour showed that the fish food contained_........ .

The blue solution may be harmful if swallowed.

Which procedure is a health and safety precaution needed for this investigation?

Fish eat fish food.

The fish food contains energy.

Some of this energy is used by the fish for growth.

Figure 6 shows this energy transfer.

Each square in Figure 6 represents 1 kJ of energy.

Calculate the percentage of energy from the fish food that has been used in the growth of fish.

Describe what happened to the fish food that was eaten but was not used in the growth of the fish.

Figure 21 shows the human urinary system.

Urine is made by removing water, urea and salts from the blood.

Use the letter X to label where urine is made.

Which substance is converted to urea in the liver?

A patient cannot remove enough urea from the blood when making urine.

Figure 22 shows a dialysis machine attached to the arm of this patient.

Their blood is pumped out of their arm, passed through the dialysis machine, and then put back into the patient.

Describe what happens to urea as the blood passes through the dialysis machine.

Two patients need to have dialysis treatment.

Patient A needs this treatment three times a week.

Patient B needs this treatment once a week.

Give one reason why patient B needs dialysis treatment less often than patient A.

Describe how to test for glucose in the dialysis fluid.

Urease is an enzyme that breaks down urea into smaller molecules.

Explain why urease will not break down starch into smaller molecules.

Figure 7 shows the human urinary system.

Urine is made by removing water, urea and salts from the blood.

Use the letter X to label where urine is made.

Which substance is converted to urea in the liver?

A patient cannot remove enough urea from the blood when making urine.

Figure 8 shows a dialysis machine attached to the arm of this patient.

Their blood is pumped out of their arm, passed through the dialysis machine, and then put back into the patient.

Describe what happens to urea as the blood passes through the dialysis machine.

Two patients need to have dialysis treatment.

Patient A needs this treatment three times a week.

Patient B needs this treatment once a week.

Give one reason why patient B needs dialysis treatment less often than patient A.

Describe how to test for glucose in the dialysis fluid.

Urease is an enzyme that breaks down urea into smaller molecules.

Explain why urease will not break down starch into smaller molecules.

Some foods contain starch.

Which chemical is used to test for starch?

Benedict’s solution is used to test for reducing sugars in food.

Figure 1 shows part of the method for this test.

Give two safety precautions needed when doing this test.

Give one reason for placing the test tube in boiling water.

Figure 2 shows some information about the results of the test for reducing sugar.

A student wanted to compare the amount of reducing sugar in three types of biscuit.

Give one variable the student should control.

Figure 3 shows the student’s results.

State two conclusions that can be made from the data in Figure 3.

Gregor Mendel used pea plants in plant breeding experiments. He discovered the basis of genetic inheritance.

He cross-bred tall pea plants with short pea plants.

All the offspring were tall, as shown in Figure 16.

Explain why the offspring are all tall.

In this investigation, the parent pea plants were grown in a warm, closed greenhouse.

Give two reasons why the parent pea plants were grown in a warm, closed greenhouse.

Pea plants produce different coloured peas.

The allele for yellow‑coloured peas (A) is dominant to the allele for green‑coloured peas (a).

Two heterozygous parent plants were used in a genetic cross.

Predict, using the Punnett square, the percentage probability that this cross will have offspring that produce green‑coloured peas.

Explain one advantage to pea plants of using sexual reproduction to produce offspring.

Peas contain small amounts of fat.

Describe a test to identify fat.

Gregor Mendel used pea plants in plant breeding experiments. He discovered the basis of genetic inheritance.

He cross-bred tall pea plants with short pea plants.

All the offspring were tall, as shown in Figure 4.

Explain why the offspring are all tall.

In this investigation, the parent pea plants were grown in a warm, closed greenhouse.

Give two reasons why the parent pea plants were grown in a warm, closed greenhouse.

Pea plants produce different coloured peas.

The allele for yellow‑coloured peas (A) is dominant to the allele for green‑coloured peas (a).

Two heterozygous parent plants were used in a genetic cross.

Predict, using the Punnett square, the percentage probability that this cross will have offspring that produce green‑coloured peas.

Explain one advantage to pea plants of using sexual reproduction to produce offspring.

Peas contain small amounts of fat.

Describe a test to identify fat.

Figure 24 shows the world human population from 1800 to 2015.

In 2015, 13% of the world human population were classified as malnourished.

Calculate, using Figure 24, how many people were classified as malnourished in 2015.

Protein is an important nutrient in meat.

Describe the laboratory test for protein.

Figure 25 shows the mass of meat eaten in the world from 1980 to 2010.

Calculate the rate of increase in the mass of meat eaten in the world from 2000 to 2010.

_........ millions of tonnes per year

Figure 26 shows an energy pyramid.

Explain why the area labelled cattle is smaller than the area labelled plants.

The World Health Organisation uses this definition of food security.

Explain how a large increase in the mass of meat eaten will decrease food security in the future.

Figure 7 shows the world human population from 1800 to 2015.

In 2015, 13% of the world human population were classified as malnourished.

Calculate, using Figure 7, how many people were classified as malnourished in 2015.

Protein is an important nutrient.

Describe the laboratory test for protein.

Figure 8 shows the mass of meat eaten in the world from 1980 to 2010.

Calculate the rate of increase in the mass of meat eaten in the world from 2000 to 2010.

_........ millions of tonnes per year

Figure 9 shows an energy pyramid.

Explain why the area labelled cattle is smaller than the area labelled plants.

The World Health Organisation uses this definition of food security.

Explain how a large increase in the mass of meat eaten will decrease food security in the future.

A person with kidney disease may need kidney dialysis treatment.

Figure 15 shows an experiment to show how a dialysis membrane works.

Describe the method that would be used to find out what is present in the solution in the beaker, after one hour.

Explain how this experiment represents a simple model of kidney dialysis treatment.

*(b) The nephrons in the kidney remove unwanted substances from the blood.

Figure 16 shows the structure of a nephron.

Explain how substances are exchanged between the blood entering the nephron and the filtrate leaving the collecting duct.

Include reference to named structures of the nephron in your answer.

Starch is a nutrient in food.

Starch is a source of energy.

Name the enzyme that breaks down starch.

Give one reason why the contents of both test tubes were blue-black at the beginning of the investigation.

Explain the results of this investigation after ten minutes.

*(c) The diagram shows equipment that can be used to measure the energy content of different foods.

Devise a method to compare the energy content of two foods using this equipment.

Include details of how to control the variables.

A student had solutions of four different foods labelled W, X, Y and Z.

Each solution was tested for starch and protein.

The colour of the solutions after the tests are shown in Figure 1.

Which solution contains starch but not protein?

Describe how a solution of food can be tested for reducing sugars.

Figure 2 shows a calorimeter.

Describe how this calorimeter can be used to find the energy content of 10 g of food.

The increasing human population is affecting farming and the habitats of animals.

Figure 12 shows the human population of the UK from 1960 to 2018.

Extend the line to estimate the human population of the UK in 2030 if this trend continues.

Food security means that a population has enough safe and healthy food.

Which of these would improve food security?

A scientist tested three samples of different foods.

Figure 13 shows the results.

Name the food group in sample E.

Name the food groups in sample F.

The emulsion test shows that food sample G contained fat. Describe how fat is digested in the body.

*(d) Figure 14 shows a field of a crop in one area of Africa.

The crop cannot be eaten by people.

The crop is used to produce biofuel.

(Source: © KAMBOU SIA/Stringer/Getty Images)

Figure 14

Describe the advantages and disadvantages of growing this crop to produce biofuel.

(a) A person had symptoms including difficulty passing urine, aching in the lower abdomen, constant thirst and fainting.

A sample of their urine was tested. The results are shown in Figure 8.

A doctor analysed the results and asked the person to have further tests for type 2 diabetes.

Give a reason why the doctor came to this conclusion.

Explain why the doctor also concluded that the person had a kidney infection.

Describe how a student could test a sample of urine for the presence of protein.

Describe the route taken by urine from the kidney until it leaves the body.

Urine contains urea.

State how urea is formed in the human body.

Figure 15 shows a method of producing plants.

Step 1. Cells taken from parent plant.

Step 2. Cells placed on agar growth medium.

Step 3. Cells develop into tiny plantlets.

Step 4. Plantlets grown in compost.

Figure 15

Some cells in each plantlet develop into root cells.

Name the process occurring as these cells develop into root cells.

Describe the advantages of producing plants by the method shown in Figure 15.

An autoclave is used to prepare the agar growth medium used in Step 2.

Explain why the agar growth medium is autoclaved.

One of the plantlets had different coloured leaves.

Give one reason why this plantlet had different coloured leaves.

Crop plants provide a source of energy in the form of carbohydrates such as starch and sugars.

Describe the test to identify starch.

The amount of energy in the sugars extracted from crop plants can be measured using the calorimeter shown in Figure 16.

Explain why the calorimeter has a lid.

State why it is important to stir the water in the calorimeter.

(a) Figure 8 shows a method of producing plants.

Step 1. Cells taken from parent plant.

Step 2. Cells placed on agar growth medium.

Step 3. Cells develop into tiny plantlets.

Step 4. Plantlets grown in compost.

Figure 8

Some cells in each plantlet develop into root cells.

Name the process occurring as these cells develop into root cells.

Describe the advantages of producing plants by the method shown in Figure 8.

An autoclave is used to prepare the agar growth medium used in Step 2.

Explain why the agar growth medium is autoclaved.

One of the plantlets had different coloured leaves.

Give one reason why this plantlet had different coloured leaves.

Crop plants provide a source of energy in the form of carbohydrates such as starch and sugars.

Describe the test to identify starch.

The amount of energy in the sugars extracted from crop plants can be measured using the calorimeter shown in Figure 9.

Explain why the calorimeter has a lid.

State why it is important to stir the water in the calorimeter.

(a) Figure 12 shows a cross section through a leaf.

What is the name of the part labelled R in Figure 12?

Figure 13 shows the mass of glucose produced in each layer of a leaf per hour.

Describe the difference in the mass of glucose produced per hour in the palisade mesophyll and the mass of glucose produced in the spongy mesophyll shown in Figure 13.

Figure 14 shows how light intensity changed during one day.

Use information in Figure 14 to explain why oxygen moved out of the leaf between 9 am and midday.

Glucose is produced in a leaf.

Glucose is a

Describe a test for glucose.

Figure 15 shows an enzyme and three substrates found in plant cells.

The enzyme will only break down one of these substrates.

State the name of this enzyme.