Oct/Nov 2015

The diagram illustrates a plant cell. The cell has been stained using iodine solution. After staining with iodine solution, what colours do the cell wall and the starch grain appear?

Cell structure and function

A population’s dental health can be assessed by calculating the average number of decayed, missing or filled teeth for each person. This is known as the DMFT. The graph presents the DMFT for four countries over the period from 1980 to 1995. Australia and the USA have fluoride added to their water, whereas Japan and Belgium do not. The statements below were made. Which statements are supported by the graph?

Disease

The diagram illustrates cross-sections of the root and stem from the same plant. Identify tissue T.

Specialised cells, tissues and organs

The diagrams illustrate a plant placed in a flask containing water. It is kept in light at $16\,^{\circ}\text{C}$ for six hours. What accounts for the change in mass after six hours?

Photosynthesis

Which organ is supplied with blood by two major vessels, and where does all of that blood leave through one major vessel?

Heart

In the human circulatory system, what leads to the movement of materials from the capillaries into tissue fluid?

Blood vessels

Which chamber of the heart would nicotine, absorbed into the blood in the lungs of a cigarette smoker, enter first?

Heart

What is the makeup of expired air?

Human gas exchange

What occurs when we exhale forcefully?

Human gas exchange

What changes happen as a person exercises?

Respiration

A person consumes a large volume of water. In what way does this change the water potentials of the liquids in the renal arteries, the renal veins and the ureters?

Urinary system

Which term refers to the diffusion of molecules?

Diffusion and osmosis

What responses occur when body temperature drops?

Temperature control

What symptoms does diabetes have?

Blood glucose control

Which row correctly shows how the neurones are linked in a reflex action?

Mammalian nervous system

Which functions are regulated by the hypothalamus?

Homeostasis

The diagram illustrates the principal muscles and bones in the arm. What occurs when muscle X contracts?

Specialised cells, tissues and organs

The graph illustrates the relative risk of lung cancer in relation to the number of years of smoking and the number of cigarettes smoked per day. The statements below were made. Which of these statements are supported by the data in the graph?

Disease

Milk can be processed in different ways to make foods. Which processes take place in both cheese and yoghurt production?

Biotechnology

An ocean has been contaminated by an oil spill. Which factor is least likely to increase the rate at which microorganisms break down the oil?

Nutrient cycles

The diagram illustrates a food chain. mahogany tree $\rightarrow$ caterpillar $\rightarrow$ songbird $\rightarrow$ hawk Which category of organism occurs in the greatest numbers in this food chain?

Energy flow

The diagram illustrates how the appearance of a leaf changes over time while it is lying on moist ground. Which kind of organism is most likely responsible for these changes?

Nutrient cycles

The diagram illustrates the concentration of magnesium ions in a healthy plant root hair cell and in the surrounding soil water. To keep the plant healthy, in which direction will the magnesium ions move?

Active transport

The diagram illustrates several stages in the nitrogen cycle. Which arrow shows the activity of nitrogen-fixing bacteria?

Nutrient cycles

Which malaria-control method is effective against both the adult and larval stages of the mosquito?

Disease

Which graph illustrates the changes that happen in a river after sewage pollution has entered it?

Effects of humans on ecosystems

The diagram illustrates peas developing on the plant. What are the structures that have been labelled?

Sexual reproduction in plants

What travels down a pollen tube after pollination?

Sexual reproduction in plants

The diagram illustrates a fetus developing inside the uterus. What function does X have?

Sexual reproduction in humans

Some indicators of syphilis are shown here. 1 fever 2 loss of appetite 3 skin ulcers that fail to heal 4 skin rash 5 tiny, painless sores 6 swelling of lymph nodes What are the initial signs of syphilis?

Disease

In horses, red hair is dominant over brown hair. A breeder mates a group of heterozygous red-haired horses. Approximately what percentage of the offspring would have red hair?

Inheritance

Which row shown in the table is the correct row?

Cell structure and function

Which of the following statements is correct?

Cell structure and function

What is the name of the enzyme that regulates a reaction in which both the enzyme and the substrate may denature at high temperatures?

Effects of temperature and pH

Bacteria may be genetically modified so that they manufacture human insulin by inserting a human insulin gene into the bacterial DNA. What benefit does this procedure have?

Genetic modification

Which section of a leaf contains cells, but has the smallest number of chloroplasts?

Leaf structure

What features of the mesophyll layer in a leaf help carbon dioxide diffuse rapidly into the cells?

Leaf structure

A student places seedlings in four separate test-tubes. Tube W has all the mineral ions required for healthy plant growth. The remaining three tubes contain water, all minerals except magnesium ions, and all minerals except nitrates. The diagram shows how these seedlings look after two weeks. What are the contents of tubes X, Y and Z?

Mineral nutrition

Which digestive processes occur in the mouth (buccal cavity)?

Human digestive system

Which factor would be least likely to lead to famine?

Effects of humans on ecosystems

Which diagram shows where the chloroplasts and the nucleus are located in a cell?

Cell structure and function

Which features help a villus to be well suited for taking up amino acids from the ileum?

Absorption and assimilation

Four samples of different tissues are taken from one plant. The water concentration in each of the four tissues is then measured. Which tissue is most likely to contain the greatest concentration of water?

Specialised cells, tissues and organs

The diagrams display a plant in a flask containing water. It is kept in the light at $16\,^{\circ}\text{C}$ for six hours. What explains the mass change after six hours?

Photosynthesis

The diagram illustrates chemicals moving between several cells and a blood capillary. What might chemicals P and Q be?

Human gas exchange

In the human circulatory system, what causes materials to move from the capillaries into the tissue fluid?

Blood vessels

The graph compares the death rates from coronary heart disease in two different countries. Which factor could not account for the difference between the two countries?

Disease

What do the diaphragm and the external intercostal muscles do during inhalation?

Human gas exchange

The pie charts illustrate the proportions of gases in samples of dried inspired air and dried expired air. Which segments correspond to which gases?

Human gas exchange

What alterations take place as a person exercises?

Homeostasis

The diagram shows the kidneys and the structures connected to them. What contents do the labelled structures contain?

Urinary system

By what process do plants take up nitrate ions using active transport?

Uptake and transport of water and ions

What responses occur when body temperature falls?

Temperature control

Which process ensures that conditions such as temperature and glucose concentration stay constant inside the body?

Homeostasis

What is one role of sensory neurones?

Mammalian nervous system

Which body processes does the hypothalamus regulate?

Temperature control

The diagram illustrates the principal muscles and bones in the arm. What occurs when muscle X contracts?

Specialised cells, tissues and organs

What are the causes, signs and symptoms, and treatment options for diabetes mellitus?

Blood glucose control

Foods may be produced by processing milk in different ways. Which processes take place in both cheese and yoghurt production?

Biotechnology

An ocean has been contaminated by an oil spill. What would be least likely to increase the rate at which microorganisms break down the oil?

Effects of humans on ecosystems

The diagram presents the label on a bottle of gin. What is likely to occur over the next few hours after someone drinks a large quantity of gin?

Urinary system

The diagram illustrates how the appearance of a leaf changes over time while it is lying on damp ground. Which type of organism is most likely responsible for these changes?

Nutrient cycles

The diagram illustrates the net movement of water by osmosis between four neighbouring cells. Which cell has the greatest water potential?

Diffusion and osmosis

The diagram illustrates several stages in the nitrogen cycle. Which arrow shows the action of nitrogen-fixing bacteria?

Nutrient cycles

Which malaria control method is effective against both the adult mosquito and its larval stage?

Disease

The diagram displays a food web. For which pair of animals is the largest amount of energy available?

Energy flow

Some consequences of deforestation are given below. 1 reduced uptake of carbon dioxide from the atmosphere 2 desertification 3 carbon released from soil and rotting wood through the action of microorganisms 4 dry soil 5 flooding, landslides and soil erosion Which of these consequences help to cause climate change?

Effects of humans on ecosystems

What is transported through a pollen tube following pollination?

Sexual reproduction in plants

The diagram illustrates a broad bean seed. A section has been removed to reveal its internal structure. Which structures together form the complete embryo?

Sexual reproduction in plants

Human gametes are not all the same. Which statement about male gametes is correct?

Sexual reproduction in humans

Which hormone’s main function is to keep the uterus lining intact after ovulation?

Mammalian hormones

Which row in the table is the correct one?

Features of organisms

The diagram illustrates how the allele, $E$, for polydactyly (having extra fingers) is inherited; this allele is dominant over the normal allele, $e$. What genotypes do persons M and N have?

Inheritance

The diagram shows an enzyme together with four molecules, A, B, C and D. Which of these molecules is the substrate for this enzyme?

Enzyme action

Bacteria can be genetically engineered to make human insulin by inserting a human insulin gene into bacterial DNA. What is one advantage of carrying out this procedure?

Genetic modification

The diagram illustrates the upper layers of a leaf. Which structures are labelled X and Y?

Leaf structure

A variegated plant is destarched and then exposed to sunlight for several hours. A leaf is then removed and tested with iodine solution for starch. Which diagram shows the correct results?

Photosynthesis

A container is filled with lake water and set on an outdoor table in sunlight. Healthy plant seedlings are put into the container and left there for $3$ months. Distilled water is added when needed. At the end of each month, one typical mature leaf that has developed over the previous $30$ days is removed and sketched to the same scale. The diagram displays the three sketches that are produced. Why is the leaf from month $3$ smaller than the others?

Mineral nutrition

Which is a large molecule formed from amino acids?

Biological molecules

Every region of the alimentary canal has the pH that is most suitable for the enzymes digesting food there. What is the optimum pH for an enzyme that operates in the stomach?

Human digestive system

Fig. 1.1 presents a plant cell before it is placed in a concentrated salt solution and again after it has been placed in one.

Diffusion and osmosis

Fig. 2.1 gives a front-facing vertical section of a human heart, with chambers X and Y marked.

Circulatory system

Fig. 3.1 illustrates the distribution of blood groups within a country's population.

Variation

Fig. 4.1 illustrates how the thickness of the uterus lining and the concentration of progesterone in the blood vary during the menstrual cycle.

Sexual reproduction in humans

Fig. 5.1 shows a plant growing in soil that has been well watered.

Leaf structure

Explain why the majority of foods need digestion.

Human digestive system

A person shifts their gaze from a near object to one that is farther away. Describe how the named parts of the eye change to produce a focused image of the distant object.

Mammalian sense organs

Name the components present in human blood and explain how each one performs its function.

Blood

Define what is meant by excretion.

Urinary system

Fig. 1.1 shows a flower carpel with two pollen grains resting on its top.

Sexual reproduction in plants

Fig. 2.1 depicts a sloth. This mammal lives in the trees of South American rainforests. Sloths are described as having several features linked to feeding, movement, predators, and their associations with algae, moths, and mosquitoes.

Energy flow

Fig. 3.1 illustrates how blood pressure alters as blood passes through part of the circulatory system, starting in the right atrium, going to the lungs, and finishing in the pulmonary vein.

Circulatory system

Fig. 4.1 illustrates a transverse section of a plant leaf.

Leaf structure

Fig. 5.1 illustrates several human activities that have an impact on the environment.

Effects of humans on ecosystems

Describe the digestive processes occurring in the human mouth (buccal cavity).

Human digestive system

Explain how wilting develops in a plant.

Uptake and transport of water and ions

Describe the ways in which a bacterial cell is unlike a typical animal cell.

Nutrient cycles

Outline the processes of mitosis and meiosis, including where each takes place.

Asexual and sexual reproduction