May/June 2015

An enzyme is used to remove the cell wall from a plant cell. What would happen if this cell were then put into distilled water?

Diffusion and osmosis

Five tubes holding cooked egg-white are arranged as shown in the diagram. Protease solutions with different pH values are added to each tube. Which diagram represents the result of this experiment for a protease from the stomach?

Effects of temperature and pH

In which combination of conditions will a well-watered plant transpire most rapidly?

Transpiration and translocation

A plant was put into water that contained black dye. After 24 hours, the plant was taken out and slices were cut from the root and the stem. Which diagram shows the results?

Uptake and transport of water and ions

The diagram shows the heart and several major blood vessels. What could the blood pressures (in kPa) be for the vessels labelled on the diagram?

Blood vessels

The diagram illustrates how pressure in the aorta and the left ventricle changes over one full heartbeat. What causes the rise in pressure between points X and Y?

Heart

The diagram illustrates the liver and its blood supply. What is the name of blood vessel X, and which substance becomes more concentrated between vessel W and vessel X?

Blood vessels

In the equations below, the term shown in a box stands for energy or an energy-rich compound. Which equation gives the best representation of aerobic respiration?

Aerobic respiration

The diagram illustrates the rib cage and some of the muscles used in breathing, viewed from the side. What occurs when the intercostal muscles shown in the diagram contract?

Human gas exchange

The diagram illustrates part of an alveolus and a capillary in a lung. How do the carbon dioxide concentrations compare at X, Y and Z?

Human gas exchange

Through which body part are most nitrogen compounds removed from humans?

Urinary system

Which processes account for the absorption of ions from the soil by a plant and the absorption of glucose into the villi of a human?

Active transport

If the air temperature rises above body temperature, which of the following control mechanisms can help keep body temperature constant?

Temperature control

A motor neurone carries impulses away from

Mammalian nervous system

In what sequence does light travel through these structures in the eye?

Mammalian sense organs

Why does glucose appear in the urine of diabetics?

Blood glucose control

Which bones come together to make the shoulder joint?

Specialised cells, tissues and organs

Which statements about alcohol are correct?

Anaerobic respiration

During a practical lesson, a student notes the following features of some organisms: ‘They are round, unicellular organisms that can be seen using a light microscope. Their diameter is $0.01\,\text{mm}$. Cytoplasm is present and, after staining, a nucleus can be observed. There is a vacuole.’ What is being described?

Cell structure and function

Penicillium, a fungus, is cultured in fermenters to produce penicillin. The table gives the length of time needed for the fungus mycelium to double in size when different carbohydrates are used. Every other condition was kept the same. What conclusion can be drawn from the data?

Biotechnology

Which order shows how energy moves through an ecosystem?

Energy flow

The diagram illustrates a food web. What is most likely to happen to the owl population if foxes die out?

Energy flow

The diagram presents three plant cells, P, Q and R, with arrows indicating the direction in which water moves by osmosis. In which order should the cells be arranged for water potential, from highest to lowest?

Diffusion and osmosis

Which organisms convert ammonium compounds into nitrates?

Nutrient cycles

Transfer of the malarial parasite from mosquitoes to humans occurs when

Disease

The graph illustrates the concentration of dissolved oxygen at various points along a river. At which point is sewage discharged into the river?

Effects of humans on ecosystems

Which term describes the chromosome number in these human cells?

Nuclear division

A plant produces flowers in which the anthers ripen and drop away before the stigma has finished developing. What will this stop?

Sexual reproduction in plants

Which illnesses can be treated and cured using antibiotics?

Antibiotics

Which row correctly identifies an advantage of giving babies breast milk and an advantage of giving them bottle milk?

Diet

Which of these could be heterozygous?

Inheritance

A plant with red flowers is crossed with a plant with white flowers. Every offspring shows red flowers. What genotype do these offspring possess?

Inheritance

A person with Down’s syndrome is born with 47 chromosomes in each cell, rather than 46. What might have caused this?

Nuclear division

A dish is filled with agar jelly that contains starch. Four holes are cut into the jelly, and each hole is then filled as shown. After 30 minutes, which hole will be enclosed by the greatest starch-free area?

Enzyme action

The diagram illustrates a species changing so that it can survive in two different habitats. Which process causes these changes?

Selection

The diagram depicts a plant cell. In comparison with the rest of the cell, which row states the concentrations of oxygen and magnesium inside structure P during the daytime?

Photosynthesis

Some organisms inhabit the seabed, where the surroundings are extremely dark. To synthesise glucose, they obtain energy from chemicals in the superheated water released from volcanoes. What is a distinguishing characteristic of these organisms?

Energy flow

The diagram depicts cells in a transverse section of a leaf from a typical green plant. (No cell contents are shown.) Which cells normally contain chloroplasts?

Leaf structure

The element nitrogen is required to form

Biological molecules

Which process uses nutrients inside cells?

Absorption and assimilation

The diagram illustrates a plant cell. Which structure shows that it is a plant cell rather than an animal cell?

Cell structure and function

It is known that a food contains protein, but no reducing sugar. If this food is tested using biuret solution and Benedict’s solution, what colours would a student observe?

Biological molecules

In the diagrams, transverse sections of a plant stem and a plant root are shown. Which regions contain xylem vessels?

Specialised cells, tissues and organs

In an experiment to investigate transpiration, the leaves of four identical shoots are treated in the following ways: 1 upper surfaces coated with waterproof jelly, 2 lower surfaces coated with waterproof jelly, 3 both upper and lower surfaces coated with waterproof jelly, 4 left untreated. The graph shows the amount of water lost by the four shoots. Which line represents the result for shoot 4?

Transpiration and translocation

The diagram shows the heart and several major blood vessels. What could the blood pressures be (in $\text{kPa}$) for the vessels labelled on the diagram?

Blood vessels

The diagram shows how pressure changes in the aorta and the left ventricle during one full heart beat. What causes the rise in pressure between points X and Y?

Heart

The diagram illustrates the liver together with its blood supply. What is the name of blood vessel X, and which substance has a greater concentration in vessel X than in vessel W?

Blood vessels

Which word equation represents anaerobic respiration in yeast?

Anaerobic respiration

The table indicates how exercise affects the rate and depth of breathing. What is the increase in the volume of air exchanged per minute after exercise, compared with when at rest?

Human gas exchange

The diagram illustrates part of an alveolus together with a capillary in a lung. What are the relative concentrations of carbon dioxide at X, Y and Z?

Human gas exchange

The diagram shows a kidney machine. Which two substances are also found in the dialysis fluid as it enters the machine?

Urinary system

What processes are involved in a plant taking up ions from the soil and in glucose being taken up into the villi of a human?

Active transport

The diagram illustrates some of the structures found in human skin. Which labels name the structures Y and Z when the conditions are hot?

Temperature control

What characteristics do all neurones have?

Specialised cells, tissues and organs

An antelope is feeding beneath a tree. It hears men calling far away. Which changes occur in the antelope’s eyes as it lifts its head to see the men?

Mammalian sense organs

A patient reports unexplained weight loss, intense thirst and a frequent urge to urinate to the doctor. A test reveals a high level of glucose in the urine. Which condition does the doctor diagnose?

Blood glucose control

The diagram shows part of the elbow joint. Explain why the muscles labelled X and Y are said to be antagonistic.

Mammalian nervous system

The diagrams illustrate the alveoli structure in the lungs of a healthy person and in the lungs of a smoker who has emphysema. What is the effect of emphysema?

Human gas exchange

A student investigated four different microorganisms. She recorded whether each microorganism contained a nucleus, chloroplasts and cytoplasm. She then prepared the table below to help identify them. Which organisms are Q, R and S?

Concept and use of a classification system

The diagram illustrates several stages in cheese making. During which stage in cheese making are bacteria introduced?

Biotechnology

Certain kinds of bacteria produce carbohydrates from carbon dioxide and water by using energy from sunlight. Which of the following best describes these bacteria?

Photosynthesis

The diagram illustrates a food web. Which statement about this food web is correct?

Energy flow

The diagram depicts three plant cells named P, Q and R. The arrows indicate the direction in which water moves by osmosis. What is the correct sequence of water potential in the cells, from highest to lowest?

Diffusion and osmosis

In what way do nitrogen-fixing bacteria increase soil fertility?

Nutrient cycles

The malarial parasite can be transmitted from mosquitoes to humans when

Disease

Which row identifies a cause and an effect of eutrophication?

Effects of humans on ecosystems

Immediately after the pollen tube has entered which structure does a male gamete leave the pollen tube?

Sexual reproduction in plants

What is always necessary for seeds to start germinating?

Sexual reproduction in plants

Which illnesses can be cured using antibiotics?

Antibiotics

The diagram illustrates some cells in the life cycle of an animal. Which processes are taking place at X, Y and Z?

Nuclear division

Which of these could be heterozygous?

Inheritance

As time passes, one bird species evolves a beak that is more sharply pointed. This pointed beak shape makes it easier for the birds to catch small insects that could be concealed in cracks among the rocks. What is a reason for the change in the shape of the birds’ beaks?

Selection

An individual with Down’s syndrome has 47 chromosomes in each cell at birth, rather than 46. What might have caused this?

Nuclear division

A dish contains agar jelly mixed with starch. Four holes are made in the jelly, and each hole is filled as shown. After $30$ minutes, which hole will be surrounded by the largest area free of starch?

Enzyme action

Bacteria can be genetically engineered to make human insulin. Prior to the development of this technique, the only insulin available came from cattle or pigs. It was extracted from animal pancreases. Which statements about the two methods are correct?

Genetic modification

The diagram shows a plant cell. In comparison with the other parts of the cell, which row describes the concentrations of oxygen and magnesium inside structure P during the daytime?

Photosynthesis

A plant has leaves that are green in the middle but white at the margins. The plant is destarched and then one of its leaves is partly covered on both sides with black paper, as shown. It is then left in bright light for 48 hours. After that, the leaf is tested for starch. Which diagram shows the colours obtained?

Photosynthesis

The diagram shows cells in a cross-section of a leaf from a typical green plant. (No cell contents are shown.) Which cells normally contain chloroplasts?

Leaf structure

Give one example of assimilation.

Absorption and assimilation

What are the simple units from which glycogen is synthesised?

Biological molecules

Fig. 1.1 presents a vertical cut through the skin under two contrasting environmental conditions, A and B.

Temperature control

Table 2.1 displays the amount of blood delivered to different body parts at rest and while doing strenuous exercise.

Circulatory system

Fig. 3.1 presents a fetus developing inside a mother’s uterus. The fluid marked C has cells from the fetus in it. A long, hollow needle may be used to draw some of the fluid into a syringe. DNA taken from the cells in this fluid can then be examined to determine the fetus’s sex and to identify mutations.

Biotechnology

Fig. 4.1 illustrates some of the organs in a person that may be harmed by drug use.

Disease

Fig. 5.1 illustrates several interactions occurring within an aquatic ecosystem.

Nutrient cycles

Fig. 6.1 illustrates a structure that occurs in a section of the alimentary canal.

Absorption and assimilation

Describe the importance of the distribution of chloroplasts in the process of photosynthesis in a dicotyledonous leaf.

Leaf structure

Describe the external features of one named example of a fruit or seed dispersed by wind. State why this dispersal method is important to the plant.

Sexual reproduction in plants

Describe and explain the effect on the rate of transpiration of an increase in each of the following factors around a plant: • temperature • light intensity • humidity.

Transpiration and translocation

Fig. 1.1 illustrates how temperature influences the rate at which yeast cells in a nutrient solution give off bubbles of a gas.

Anaerobic respiration

Fig. 2.1 presents a plant known as the ghost plant together with an enlarged drawing of its flower. It is referred to as a ghost plant because it is usually completely white in colour. The cells of the ghost plant do not contain chloroplasts.

Sexual reproduction in plants

Fig. 3.1 illustrates the blood supply reaching the cells in the liver.

Blood glucose control

A is used for the dominant allele that lets a person detect the scent of a particular flower. The recessive allele, which prevents the flower scent from being smelt, is written as a.

Inheritance

Table 5.1 gives the mean daily water intake and the mean daily water loss for one person.

Excretion

For a named fruit or seed, describe the adaptations that make animal dispersal possible.

Sexual reproduction in plants

Describe how active transport takes place.

Diffusion and osmosis

Outline the function of microorganisms in yoghurt production.

Biotechnology

Syphilis and HIV are both transmitted through sexual contact.

Disease