Diffusion

This question is about cells.

Figure 1 shows an animal cell seen through a microscope.

What is part X in Figure 1 ?

Tick () one box.

Name one structure found in the nucleus.

Name one cell part that is found in a plant cell but is not found in an animal cell.

Root hair cells are found in plants.

Which substance do root hair cells absorb from the soil?

Tick () one box.

A sperm cell is a specialised cell.

What is the function of a sperm cell?

Draw one line from each specialised cell to the type of organism where the specialised cell is found.

The cell membrane controls which substances move into and out of cells.

Which two processes move substances into and out of cells?

Tick () two boxes.

Table 1 shows substances that are exchanged between the blood and muscle cells.

Complete Table 1 to show the direction of movement of each substance.

Tick () one box in each row.

Plants and animals have adaptations that help them survive.

A stingray is an animal that lives in the sea. Seagrass is a plant that grows on the sea floor.

Figure 8 shows a stingray swimming above seagrass.

Draw one line from each adaptation of seagrass to how the adaptation helps the seagrass survive.

In the stingray, gas exchange takes place in the gills.

Name the organs where gas exchange takes place in humans.

Gills are adapted to maximise gas exchange.

Which two features of gills help to maximise gas exchange?

Tick () two boxes.

Stingrays rest on the sea floor.

Table 4 shows information about the metabolic rate of a stingray.

Calculate how many times greater the metabolic rate of the stingray is when swimming compared with when resting.

Give your answer to the nearest whole number.

When the metabolic rate of the stingray increases, the rate of aerobic respiration in the stingray increases.

Complete the word equation for aerobic respiration.

Choose answers from the box.

Explain why the rate of respiration in the stingray increases when the stingray starts to swim.

Some plants can use anaerobic respiration.

Which two substances are produced during anaerobic respiration in plants?

Tick () two boxes.

Diffusion is important for gas exchange.

Define the term ‘diffusion’.

Fish exchange gases through gills.

Oxygen from the water enters the blood of a fish through the gills.

Figure 8 shows part of a gill.

Explain how gills are adapted to maximise the exchange of oxygen between the water and the blood.

Some fish rest on the sea floor.

Explain why the metabolic rate of a fish is higher when swimming compared with when resting.

Cystic fibrosis (CF) is an inherited disorder caused by a faulty gene.

Where in a cell would the CF gene be found?

CF affects many organs in the body.

The main organs affected are:

• the lungs

• the pancreas

• the small intestine.

Figure 2 shows organs of the human body.

Which letters in Figure 2 show the lungs, the pancreas and the small intestine?

Tick (✓) one box.

The pancreas produces several digestive enzymes.

CF reduces the amount of each enzyme that reaches the small intestine.

Explain why a person with CF has:

• difficulty digesting food

• difficulty gaining body mass.

Gas exchange happens in the alveoli in the lungs.

Describe three features of the alveoli that help maximise gas exchange.

CF reduces the amount of oxygen that can enter the blood from the alveoli.

Explain how a reduced amount of oxygen entering the blood will affect the human body.

Table 4 shows information about four jellyfish.

The jellyfish are listed in order of increasing size.

Calculate value X in Table 4.

Describe the relationship between the size of a jellyfish and its surface area to volume ratio.

Use Table 4.

The jellyfish in Table 4 take oxygen into their cells by diffusion.

Name one other substance that enters cells by diffusion.

Do not refer to oxygen in your answer.

Suggest two factors that affect the rate of diffusion of oxygen into a jellyfish.

Some organisms take in oxygen using a respiratory system.

In humans, gas exchange takes place in the lungs.

Name the organs where gas exchange takes place in fish.

Figure 8 shows parts of the human breathing system.

Explain how the human breathing system is adapted to maximise the rate of gas exchange.

Table 6 shows information about five different organisms.

Calculate value X in Table 6. Give your answer to the nearest whole number.

What is the relationship between the size of an organism and its surface area to volume ratio? Use Table 6.

Organism B exchanges gases with the environment directly through its skin. Organism D exchanges gases with the environment using its respiratory system.

Explain why organism D requires a respiratory system, but organism B does not require a respiratory system.

Table 6 is repeated below.

Table 7 shows information about organism D and organism E.

Organisms D and E both keep a constant body temperature (warm-blooded). Explain why the metabolic rate of organism D is greater than the metabolic rate of organism E. Use information from Table 6 and Table 7.

Organism D and organism E both have alveoli in the lungs and villi in the small intestine. Figure 8 shows some alveoli and some villi.

Describe how the alveoli and the villi are adapted to increase absorption.

This question is about cells.

Which diagram shows oxygen moving by diffusion? Tick (✓) one box.

Complete the sentences. Choose answers from the box.

Plant cells absorb substances from the soil.

Plant cells use active transport to absorb Active transport moves substances against the concentration gradient and

Figure 1 shows a specialised cell that absorbs substances from the soil.

Name the type of specialised cell in Figure 1.

Describe how the cell in Figure 1 is adapted to increase the absorption of substances from the soil.

A sperm cell is another specialised cell.

Figure 2 shows a sperm cell.

Draw one line from each feature to how the feature helps the sperm cell carry out its function. Feature of sperm cell How the feature helps

Figure 3 shows another specialised cell.

Name the type of cell in Figure 3. Describe one feature of the cell that helps it to carry out its function. Name of the cell Feature of the cell

Diffusion is an important process in animals and plants.

What is meant by the term diffusion?

Figure 11 shows part of a leaf.

Molecules of carbon dioxide diffuse from the air into the mesophyll cells. Which two changes will increase the rate at which carbon dioxide diffuses into the mesophyll cells? Tick (✓) two boxes.

Diffusion also happens in the human lungs. Figure 12 shows the human breathing system.

Explain how the human lungs are adapted for efficient exchange of gases by diffusion.

Figure 13 shows a root hair cell.

Name the process by which water molecules enter the root hair cell.

Nitrate ions need a different method of transport into the root hair cell. Explain how the nitrate ions in Figure 13 are transported into the root hair cell. Use information from Figure 13 in your answer.

Diffusion is an important process in animals and plants.

What is meant by the term diffusion?

Figure 2 shows part of a leaf.

Molecules of carbon dioxide diffuse from the air into the mesophyll cells. Which two changes will increase the rate at which carbon dioxide diffuses into the mesophyll cells? Tick (✓) two boxes.

Diffusion also happens in the human lungs. Figure 3 shows the human breathing system.

Explain how the human lungs are adapted for efficient exchange of gases by diffusion.

Figure 4 shows a root hair cell.

Name the process by which water molecules enter the root hair cell.

Nitrate ions need a different method of transport into the root hair cell. Explain how the nitrate ions in Figure 4 are transported into the root hair cell. Use information from Figure 4 in your answer.

An animal called an axolotl lives in water.

Figure 3 shows an axolotl.

Oxygen enters the axolotl’s bloodstream through the gills by diffusion.

What is diffusion?

Tick (✓) one box.

Describe how one feature of the axolotl’s gills increases the rate of diffusion of oxygen.

Use information from Figure 3.

If a gill of an axolotl is removed, stem cells in the damaged area will divide and a new gill will grow.

Complete the sentence.

Choose the answer from the box.

When stem cells specialise to produce gill cells, this process is

known as.

Complete the sentence.

Choose the answer from the box.

To grow a new gill the stem cells divide by.

Which one of the following does not contain stem cells?

Tick (✓) one box.

Axolotls are small animals. Axolotls are used in stem cell research.

What are two advantages of using axolotls in stem cell research?

Tick (✓) two boxes.

Oxygen uptake in humans takes place in the lungs.

Figure 4 shows the human breathing system.

Where does oxygen enter the bloodstream?

Tick (✓) one box.

Name part E on Figure 4.

Which blood vessel carries blood to the lungs?

Tick (✓) one box.

People with diabetes have difficulty controlling their blood glucose concentration.

Which part of the blood transports glucose?

Tick (✓) one box.

Glucose is often found in the urine of people with diabetes.

Name a chemical used to test for glucose.

Describe a test that could be used to show that a person’s urine contains glucose.

The body cells of a person with untreated diabetes lose more water than the body cells of a person who does not have diabetes.

Explain how diabetes can cause the body cells to lose more water.

Glucose is absorbed into the blood in the small intestine by both diffusion and active transport.

Describe how the small intestine is adapted for efficient absorption.

A small animal called an axolotl lives in water. The axolotl has a double circulatory system.

Define the term double circulatory system.

Figure 7 shows the double circulatory system of the axolotl.

Figure 7

The following figure cannot be reproduced here due to third-party copyright restrictions.

The heart of the axolotl has only one ventricle.

Label the ventricle on Figure 7.

Explain why having only one ventricle makes the circulatory system less efficient than having two ventricles.

Figure 8 shows an axolotl.

Explain why an axolotl may die in water with a low concentration of oxygen.

If a gill of an axolotl is removed, a new gill will grow in its place.

Scientists hope to use information on how axolotls grow new gills to help with regenerating human tissue.

Name the type of cell that divides when a new gill grows.

Name one condition that could be treated using regenerated human tissue.

Suggest one reason why an axolotl is a suitable animal for research in the laboratory.

An axolotl may not be a suitable animal to study when researching regeneration in human tissue.

Suggest one reason why.

Earthworms are small animals that live in soil. Earthworms have no specialised gas exchange system and absorb oxygen through their skin.

What is the name of the process in which oxygen enters the skin cells?

Tick one box.

Table 3 shows information about four skin cells of an earthworm.

Which cell has the smallest difference in percentage of oxygen between the outside and the inside of the cell?

Tick one box.

Which cell will oxygen move into the fastest?

Tick one box.

Earthworms have a large surface area to volume ratio.

Suggest why a large surface area to volume ratio is an advantage to an earthworm.

The earthworm uses enzymes to digest dead plants.

Many plants contain fats or oils.

Which type of enzyme would digest fats?

Earthworms move through the soil.

This movement brings air into the soil.

Dead plants decay faster in soil containing earthworms compared with soil containing no earthworms.

Explain why.

When earthworms reproduce, a sperm cell from one earthworm fuses with an egg cell from a different earthworm.

Name the process when an egg cell and a sperm cell fuse.

Some types of worm reproduce by a process called fragmentation.

In fragmentation, the worm separates into two or more parts. Each part grows into a new worm.

What type of reproduction is fragmentation?