Oct/Nov 2018

Four kinds of cell found in the leaf of a green plant are shown below. 1 epidermal cells (guard cells not included) 2 guard cells 3 palisade mesophyll cells 4 spongy mesophyll cells Which of these cells contain chloroplasts?

Leaf structure

In a person with coeliac disease, the villi in the ileum are flattened. If someone with coeliac disease consumes the same amounts and kinds of food as a person without the disease, the concentrations of glucose and amino acids in the hepatic portal vein will be lower. Which row gives the correct explanation?

Absorption and assimilation

Which factor is least likely to increase the transpiration rate in a plant?

Transpiration and translocation

The illustration depicts a section of a tree trunk. A strip of bark, with the phloem included, has been taken away. The tree will eventually die because taking off the bark prevents the movement of

Transpiration and translocation

Which of these organs gets blood from both an artery and a vein?

Blood vessels

The diagram shows a cross-section of the human heart. Which indicates that blood is pumped out of the heart at different pressures on its way to the lungs and to the body?

Heart

The diagram illustrates chemicals being exchanged between some cells and a blood capillary. Which substances might P and Q be?

Circulatory system

By the breakdown of two molecules of glucose in anaerobic respiration, how many molecules of lactic acid will be produced?

Anaerobic respiration

Which process does not need energy released during respiration?

Diffusion and osmosis

Through what pathway does oxygen enter the blood?

Human gas exchange

Which organ eliminates most carbon dioxide from the human body?

Human gas exchange

Which of these statements about osmosis are correct?

Diffusion and osmosis

Which structures take part in controlling human body temperature?

Temperature control

What changes occur in the ciliary muscle, and what happens to the lens, when the eye focuses on a distant object?

Mammalian sense organs

Which statement concerning brain structure and function is not correct?

Mammalian nervous system

Which is not an example of a simple reflex action?

Mammalian nervous system

Which row indicates the type of joint and the kind of movement allowed at a joint in the forelimb?

Specialised cells, tissues and organs

The graph illustrates death rates from liver disease in two different countries. What might account for the gap between the two countries?

Disease

Which statement is true for all viruses but not for all bacteria and fungi?

Features of organisms

The graph illustrates how the rate at which the fungus Penicillium produces penicillin changes with temperature at two different oxygen concentrations. What conclusion can be drawn from the graph?

Effects of temperature and pH

Which organisms gain their energy only from dead organic matter?

Nutrient cycles

The diagram illustrates a section of a food web. Which pyramid of numbers is derived from this food web?

Energy flow

A seedling is placed in a solution containing potassium ions, with its roots immersed, and is then left for 48 hours. The table shows the relative concentrations of the potassium ions. At the beginning of the experiment: concentration of potassium ions in the solution = 20, in the root hair = 15. After 48 hours: concentration of potassium ions in the solution = 18, in the root hair = 35. By what process did the potassium ions enter the cell?

Active transport

Which human activity is likely to make the greatest contribution to global warming?

Effects of humans on ecosystems

Removing stagnant water is one way of controlling the malarial mosquito. Which stages in the mosquito life cycle are eliminated by this method?

Asexual and sexual reproduction

During the last few years, many major rivers in different regions of the world have become more acidic. What has led to this change?

Effects of humans on ecosystems

The diagram illustrates a cross-section of a flower. What are the names of the labelled structures?

Sexual reproduction in plants

Four dishes each contain some seeds under different conditions, as shown in the table. In which dish will the seeds germinate the fastest?

Sexual reproduction in plants

Which row identifies a disease together with the pathogen that causes it?

Disease

The graph illustrates the concentration of a hormone in the blood over one menstrual cycle. Which hormone’s concentration was measured?

Sexual reproduction in humans

What is DNA's main function?

DNA

Within the ABO blood group system, which genotype is homozygous dominant?

Inheritance

In a species of plant, the allele for yellow flowers is dominant over the allele for white flowers. From a cross between two plants heterozygous for flower colour, which offspring could be produced?

Inheritance

Enzyme action may be described by the lock and key hypothesis. Where is the active site located, and does the substrate function as the lock or the key?

Enzyme action

Which statement is the correct one?

Cell structure and function

Certain organisms inhabit the seabed, where there is almost no light. In order to synthesise glucose, they obtain energy from chemicals in the extremely hot water discharged by volcanoes. What is one distinguishing characteristic of these organisms?

Energy flow

Which graph illustrates how temperature affects the rate at which an aquatic plant releases oxygen when it is kept in strong light?

Photosynthesis

The diagram shows a transverse section of part of a leaf. In light conditions, and also in darkness, how does the oxygen content of the air at X compare with that of normal atmospheric air?

Photosynthesis

What is the colon’s main function?

Human digestive system

What foods can be consumed to help prevent scurvy, anaemia and rickets?

Diet

A cell is being examined with a microscope. Which feature shows that it is a plant cell?

Cell structure and function

A gland releases various enzymes into one section of the alimentary canal, where proteins and starch are digested. This section also receives alkaline secretions from a different gland and has muscles responsible for peristalsis. Which part of the alimentary canal is this?

Human digestive system

Which of the following is not a function of transpiration?

Transpiration and translocation

The diagram depicts a section of a tree trunk. A strip of bark, together with the phloem, has been taken away. In time, the tree will die because removing the bark prevents the movement of

Transpiration and translocation

Which one of these organs gets blood from both an artery and a vein?

Blood vessels

The diagram shows a cross-section of the human heart. Which feature indicates that blood leaves the heart at different pressures when it travels to the lungs and to the body?

Heart

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

Circulatory system

From the breakdown of two glucose molecules in aerobic respiration, how many carbon dioxide molecules will be formed?

Aerobic respiration

By what process does anaerobic respiration in muscle cells lead to a decrease in blood pH?

Anaerobic respiration

Which row shows the sequence of events that causes air to move into the lungs?

Human gas exchange

Why is it necessary for the lungs to remove carbon dioxide from the body?

Human gas exchange

Which of the following statements about diffusion are correct?

Diffusion and osmosis

Which structures are all involved in the regulation of human body temperature?

Temperature control

The diagrams show the eye from the front and the lens in cross-section. Which diagrams show the appearance of the pupil and the form of the lens when looking up at the night sky?

Mammalian sense organs

Which major role is carried out by the medulla in the brain?

Mammalian nervous system

Which of the following statements about insulin is correct?

Blood glucose control

The diagram illustrates the elbow joint in two different positions. What happens to the muscles in order to change the elbow joint into the position shown?

Specialised cells, tissues and organs

The graph illustrates how four different antibiotics affect the growth of a bacterial population. Which statement is correct?

Antibiotics

In the production of which materials is yeast used?

Anaerobic respiration

The following stages are part of yoghurt production: 1 liquid cooled rapidly; 2 liquid kept at $40-45\,^\circ\text{C}$ for 3 hours; 3 culture of bacteria added to liquid; 4 liquid pasteurised. In what sequence do these stages take place?

Biotechnology

Which organisms always derive their energy from dead organic matter?

Energy flow

The diagram illustrates a section of a food web. Which pyramid of numbers is built from this food web?

Energy flow

The diagram illustrates a root hair cell together with the surrounding soil particles. Osmosis takes place when areas of higher and lower water molecule concentration are separated by a partially permeable membrane. On the diagram, what are these areas?

Diffusion and osmosis

Which labelled arrow in the nitrogen cycle indicates nitrogen fixation?

Nutrient cycles

What kind of organism serves as the vector for the parasite that causes malaria?

Disease

Why are insecticides sometimes considered pollutants?

Effects of humans on ecosystems

State one benefit of sexual reproduction compared with asexual reproduction.

Asexual and sexual reproduction

State two male parts found in a flower.

Sexual reproduction in plants

Which row lists a disease and the pathogen responsible for it?

Disease

The table shows the mean dietary requirement for iron, in mg per day, for females and males of different ages. Why does a 20 year-old female need the greatest mean dietary requirement of iron?

Diet

What is the main role of DNA?

DNA

Within the ABO blood group system, which genotype is the homozygous dominant one?

Inheritance

The diagram illustrates a family in which some individuals have a disease caused by a recessive allele. Which two family members must be heterozygous for the gene?

Inheritance

What do enzymes mean?

Biological molecules

Which of the statements is correct?

Cell structure and function

A few organisms inhabit the bottom of the sea, where darkness is extreme. In order to synthesise glucose, they gain energy from chemicals in the extremely hot water discharged by volcanoes. What is one distinguishing feature of these organisms?

Energy flow

The experiment is arranged as shown. After 30 minutes, the volume of gas collected is measured. The experiment is carried out several more times. On each occasion, the light intensity is increased. Which graph shows the results?

Photosynthesis

The diagram shows a cross-section of part of a leaf. How does the oxygen content of the air at X compare with normal atmospheric air when the leaf is in the light and when it is in the dark?

Photosynthesis

Which smaller basic units are used to build glycogen and protein?

Biological molecules

Which route gives humans the greatest amount of fibre (roughage) in the diet?

Diet

The diagram presents the parts of a plant that are above the ground.

Asexual and sexual reproduction

The diagram shows a seed (Fig. 1) together with a plant that is developing from it (Fig. 2).

Sexual reproduction in plants

The diagram illustrates how the bones and muscles are arranged in the arm.

Specialised cells, tissues and organs

The diagram depicts the human thorax.

Human gas exchange

Fig. 1 illustrates cells from a plant tissue that were placed on a slide in distilled water and examined with a microscope. Fig. 2 illustrates cells from the same plant tissue after they had been placed on a slide in concentrated salt solution.

Diffusion and osmosis

The diagram indicates where a number of features are positioned beside a river that begins in the mountains and flows to the ocean.

Effects of humans on ecosystems

The diagram depicts a section of the alimentary canal together with the linked organs.

Human digestive system

Describe and explain how each of the following influences enzyme activity: pH; temperature.

Effects of temperature and pH

Describe and explain the way in which each of the following influences the rate of photosynthesis: light intensity; temperature.

Photosynthesis

Fig. 1 and Fig. 2 display transverse sections of two kinds of blood vessel.

Blood vessels

The diagram depicts the male reproductive organs in humans together with the related structures.

Genetic modification

The diagram presents a pollen grain with a pollen tube extending from it. Pollen grains taken from the same plant species were added to sucrose solutions of varied concentrations and left there for a set period. Once that period had passed, the pollen grains and tubes were viewed under a microscope. For each sucrose concentration, the observations recorded were: • how many pollen grains had germinated to form a pollen tube, • the length of every pollen tube. The table gives the findings from the investigation.

Sexual reproduction in plants

The graph illustrates how the concentration of dissolved carbon dioxide in pond water changes over 24 hours.

Photosynthesis

Describe what each of the following hormones does in the menstrual cycle: FSH progesterone

Sexual reproduction in humans

The graph illustrates how the percentage of carbon dioxide in the atmosphere has altered since 1700.

Effects of humans on ecosystems

Fig. 1 shows a leaf just after it has fallen from a growing plant. Fig. 2 shows a leaf from the same plant a few months after it dropped onto the soil beneath.

Nutrient cycles

Explain what is meant by each term below and give one example of each: discontinuous variation continuous variation

Variation

Explain what each of the following terms means and give one example of each in either a plant or an animal: diffusion active transport

Active transport