Oct/Nov 2024

Which structures are found in plant cells but not in animal cells?

Cell structure and function

The diagram illustrates how water moves through part of a leaf. Which processes are involved in water movement at these stages?

Transpiration and translocation

The diagram illustrates part of the human digestive system. Which parts make bile and store bile?

Human digestive system

As illustrated, five test-tubes are prepared with cooked egg white. Cooked egg white contains a protein. Protease solutions at different pH values are then placed into each tube. Which diagram represents the outcome of this experiment for a protease from the stomach?

Effects of temperature and pH

Which diagram illustrates the absorption of different food molecules into a villus?

Absorption and assimilation

The table illustrates the changes that happen in the thorax during breathing. Which changes happen during inspiration?

Human gas exchange

Scientists have reached the conclusion that the uptake of mineral ions in plants needs energy released by respiration. Which observation provides the strongest support for this conclusion?

Active transport

When passengers fly in an aircraft and remain seated without moving for extended periods, swelling can occur in their lower legs. Which statement accounts for this?

Blood vessels

The diagram depicts a blood cell viewed through a light microscope. Which type of blood cell is shown?

Blood

Which of the following statements about mosquitoes are correct?

Features of organisms

In many countries, the spread of HIV decreased between 1990 and 2010. Which measure helped to bring about this decrease?

Disease

The wobbegong, also called the carpet shark, is a shark species that spends its time lying on the seabed. There are twelve species of wobbegong. The biggest one is Orectolobus maculatus, the spotted wobbegong, which grows to about three metres long. What is the genus name of the biggest wobbegong?

Concept and use of a classification system

Which statement concerning the immune system is correct?

Immunity

Which disease can be treated effectively using antibiotics?

Antibiotics

The diagram illustrates a section of the human urinary system. What are the structures labelled X, Y and Z?

Urinary system

Nerve impulses in neurones may move: 1 out of the central nervous system 2 into the central nervous system 3 inside the central nervous system. In what direction do impulses travel in sensory neurones and in relay neurones?

Mammalian nervous system

The diameter of the eye pupil was measured at several different light intensities. What is the percentage decrease in pupil diameter (rounded to $1$ decimal place) when a person moves from complete darkness to a light intensity of $10\,000$ arbitrary units?

Mammalian sense organs

When a person is scared, which substance leads to a rise in blood sugar level?

Mammalian hormones

Raynaud’s syndrome is a condition that may be set off by stress. It makes the hands and feet respond as though they were exposed to extreme cold. What reaction will occur in the hands and feet of a person with Raynaud’s syndrome?

Blood vessels

Which flow diagram shows how auxin influences growth in negative gravitropism?

Coordination and response in plants

The diagram illustrates several stages in the asexual reproduction of a unicellular organism. Which row gives the relative quantities of DNA in cells V, W, X, Y and Z?

Nuclear division

Asexual reproduction is a process involving the cell cycle, during which the cell divides and is then followed by growth and DNA synthesis before it is ready to divide again. The diagram illustrates the stages in one full cell cycle. It takes $1.75$ hours for this cell cycle to be completed. Using the diagram, which activity in the cycle lasts $52.5$ minutes altogether?

Nuclear division

The bacterium Vibrio cholerae, which causes the disease cholera, acts on cells in the intestinal wall. It makes chloride ions move from the cells into the small intestine. Which process will then cause dangerously large amounts of watery diarrhoea to be produced?

Diffusion and osmosis

Which diagram shows the correct match between each type of flower and its features?

Sexual reproduction in plants

Through which sequence of organs must a sperm cell travel before it can fertilise an egg cell?

Sexual reproduction in humans

The diagram illustrates how the thickness of the uterus lining changes over a woman’s menstrual cycle. During which time is the woman most likely to be fertile?

Sexual reproduction in humans

State one example of discontinuous variation in humans.

Variation

Night-blindness is a genetic disorder in which a person’s vision is unusually poor under low light levels. The diagram illustrates how night-blindness is passed on through three generations of a family. Couple 4 and 5 are waiting for their second child, individual 7. What is the probability that individual 7 will be male and will also have night-blindness as his phenotype?

Inheritance

What is necessary for natural selection to happen?

Selection

The gene for human insulin production can be inserted into bacterial DNA so that insulin can be manufactured on an industrial scale. What is an advantage of using this type of insulin to treat a patient with diabetes?

Genetic modification

Which row shows the organisms in a food chain?

Energy flow

A group of students carried out an experiment to investigate the decay of leaves in garden soil. They placed leaves into bags with different mesh sizes, sealed the bags, and then buried them. Every month for 5 months, the bags were dug out and the overall percentage decrease in mass from the beginning of the experiment was worked out. The results are shown. What can the students conclude from these results?

Nutrient cycles

Animal populations are influenced by disease, the number of predators and the availability of food. Which row would result in the greatest increase in population size?

Ecosystems and biodiversity

Which movement of a substance in a plant needs the plant to supply energy?

Active transport

What human activity has done the most damage to tropical rainforests?

Effects of humans on ecosystems

Which of the following statements are correct?

Cell structure and function

Some students carried out an investigation into how temperature affects the breakdown of starch into maltose. They placed equal volumes of amylase and starch solution into several test-tubes. For 30 minutes, the test-tubes were kept at temperatures ranging from $10\,^{\circ}\text{C}$ to $60\,^{\circ}\text{C}$. After this, they measured the starch concentration in each test-tube. Which graph would be produced from these results?

Effects of temperature and pH

The graph compares the rate of photosynthesis in a plant in full sunlight at two different temperatures and with different carbon dioxide concentrations. At normal atmospheric concentrations of carbon dioxide, what factor limits the rate of photosynthesis?

Photosynthesis

The diagram shows a cross-section of a dicotyledonous leaf. Which cell is unable to photosynthesise?

Leaf structure

A leafy stem was cut from a plant and then put into a red dye solution for 18 hours. The diagram illustrates a transverse section of the stem after 18 hours. Which tissue will appear red?

Uptake and transport of water and ions

The diagram illustrates three different kinds of microscopic structure. What are these structures?

Specialised cells, tissues and organs

Four leafy shoots taken from the same plant were placed in beakers of coloured water and kept in rooms at different temperatures. In two of the rooms, electric fans were arranged to blow air over the stems. For each stem, the time for the coloured water to arrive at the leaves was recorded. In which stem will the coloured water reach the leaves the fastest?

Transpiration and translocation

Cubes of boiled egg white are put into test-tubes that contain $5\ \text{cm}^3$ of water. Boiled egg white has protein. As shown in the table, different additional substances are put into each test-tube. After the test-tubes have been left for eight hours, they are then checked for amino acids. Which test-tubes indicate that pepsin is an enzyme?

Enzyme action

The diagram shows a cross-section of a villus. What is the principal function of vessel X?

Absorption and assimilation

Which section of the human digestive system is a principal site for assimilation of amino acids?

Absorption and assimilation

As the volume of the thorax increases, the pressure inside the thorax decreases. This causes air to enter the body. By what process is the volume of the thorax increased so that air is inhaled?

Human gas exchange

The diagram illustrates the arrangement of apparatus used to investigate respiration in germinating seeds. The coloured oil drop travels through the capillary tube. What makes the coloured oil drop move?

Aerobic respiration

A ventricular septal defect is an opening in the septum separating the left ventricle and right ventricle of the heart. Which statement describes how blood flow through the heart is affected in a person with a ventricular septal defect?

Heart

Human blood is made up of plasma, red blood cells, white blood cells and platelets. Which row states the function of each of these components?

Blood

What is the usual method by which malaria is passed from one person to another?

Disease

Carbon monoxide is a poisonous gas that binds with haemoglobin to make carboxyhaemoglobin. Which blood function would be affected if a person breathed in carbon monoxide?

Blood

Scientific names of species are formed from two parts. What is the naming system called?

Concept and use of a classification system

What diseases can be cured using antibiotics?

Antibiotics

Vaccination is used to limit the spread of transmissible diseases. The MMR vaccine is administered to young children and gives immunity against a disease known as measles. The graph displays the percentage of a country’s population vaccinated with the MMR vaccine and the number of measles cases over time. Which statement is supported by the data?

Immunity

The diagram illustrates the excretory system. Which row correctly names the labelled structures?

Urinary system

Following an accident in a factory, a tiny fragment of metal entered an engineer’s spinal cord and cut through the tissue at X. The diagram presents a transverse section of the spinal cord in the neck at the site of the injury. A nervous pathway is also illustrated. Which consequence of the accident is possible?

Mammalian nervous system

The diagram shows a cross-section of the eye. Which two structures are used to focus light rays on the retina?

Mammalian sense organs

The diagram illustrates several of the endocrine glands in a human female. Which row pairs the glands with the correct hormones?

Mammalian hormones

When the body temperature is too high, which process makes the body temperature go back to normal?

Temperature control

Some seedlings were kept in a warm, damp and dark setting. The growing shoot tips were removed and then placed back onto one side of each shoot, as shown. The shoots were then allowed to continue growing. Which growth pattern was observed in the shoots?

Coordination and response in plants

Which of the following statements about meiosis are correct?

Nuclear division

State one feature of asexual reproduction in plants.

Asexual and sexual reproduction

The diagram indicates the water potentials, given in units of $\text{kPa}$, for a group of plant cells. A more negative value means a lower water potential. Which sequence of arrows represents the net movement of water from cell X?

Diffusion and osmosis

The seeds of certain plants usually do not germinate until they have remained in the soil for several months. Seeds were taken from a plant of this kind. Some students wanted to investigate whether a chemical in the testa was stopping germination. The seeds were split into three groups, as outlined. Only the seeds in group 2 germinated. What would be the most sensible next step in this experiment?

Sexual reproduction in plants

The diagram illustrates how the thickness of the uterus lining changes over one menstrual cycle. At what point would progesterone and LH levels be at their highest?

Sexual reproduction in humans

Within the umbilical cord, the blood travelling from the fetus to the placenta along the umbilical artery has

Blood

DNA is split into sections called

DNA

A husband and wife have three children. The first two children are both girls; one has blood group A and the other has blood group O. The children's father has blood group B. What is the probability that the third child will be a boy with blood group B?

Inheritance

What results might farmers hope to achieve by using artificial selection?

Selection

Single-cell protein may be made by culturing a fungus in a fermenter. Why does the fermenter need a cooling unit?

Effects of temperature and pH

The diagram presents the pyramid of energy for this food chain: grass $\rightarrow$ grasshopper $\rightarrow$ bluebird. A pyramid of energy indicates the total amount of energy contained in the biomass of organisms at each trophic level in the food chain per year. To one decimal place, what percentage of energy is passed from the producer to the herbivore?

Energy flow

Which statements concerning the carbon cycle are correct?

Nutrient cycles

Aphids are tiny insects that obtain nutrients from plants by drawing fluids out of plant cells. The number of aphids feeding on a bean plant rises very quickly. Which row shows a pair of factors that accounts for this rapid increase?

Asexual and sexual reproduction

Which statements concerning active transport are correct?

Active transport

A lake has been contaminated by sewage. How will the water in this lake differ from water that has not been polluted?

Effects of humans on ecosystems

Which biological molecule is composed of the chemical elements carbon, hydrogen, nitrogen and phosphorus?

Biological molecules

Catalase is an enzyme present in potato tissue. It speeds up the decomposition of hydrogen peroxide into water and oxygen. Five identical potato discs were placed into $15\text{ cm}^3$ of a $3\%$ hydrogen peroxide solution at a temperature of $20\degree\text{C}$. The time needed to produce $5\text{ cm}^3$ of oxygen was measured. The same method was then carried out at $30\degree\text{C}$, $40\degree\text{C}$, $50\degree\text{C}$, $60\degree\text{C}$ and $70\degree\text{C}$. Which graph would represent the findings of the investigation?

Effects of temperature and pH

The graphs illustrate factors that affect the rate of photosynthesis. At which points on the graphs might the rate of photosynthesis be limited by the concentration of carbon dioxide?

Photosynthesis

The diagram shows a cross-section of a leaf. What is the primary function of the region labelled X?

Leaf structure

Root hair cells absorb water and ions from the soil. Which row correctly shows the way that water and ions enter root hair cells?

Uptake and transport of water and ions

Fig. 1.1 presents an experiment designed to measure how much water a small plant loses over 24 hours.

Transpiration and translocation

Maltase is an enzyme located in the intestines of vertebrates, humans included.

Enzyme action

Fig. 3.1 illustrates the central nervous system along with some other parts of a man’s body.

Mammalian nervous system

Carbon dioxide is excreted by living organisms.

Excretion

The castor oil plant is a flowering plant that produces seeds. Each seed has an extra structure called an oil body, which contains oil.

Sexual reproduction in plants

Lake Victoria in Africa is one of the largest freshwater lakes on Earth. It is a key ecosystem for people who live around the lake and catch fish there as part of their diet.

Effects of humans on ecosystems

Explain how long-term active immunity is produced in the human body after a pathogen has infected it.

Immunity

Use the dichotomous key in Fig. 1.1 to work out the five main vertebrate groups, A, B, C, D and E. Fill in Table 1.1.

Concept and use of a classification system

A virus is a kind of pathogen. Fig. 2.1 shows the outside structure of a virus.

Immunity

Choose words from the list to finish the paragraph.

Blood glucose control

Fig. 4.1 shows how the curved shape of the lens in a person's eye changes over time.

Mammalian sense organs

Fish are a significant component of many people’s balanced diet, and fishing provides an important source of jobs in some countries. For that reason, many people think fish should be regarded as a sustainable resource.

Conservation

In many countries, such as the United States of America (USA), farmers keep cows so that milk is produced. The milk is then sold for human consumption.

Genetic modification

Compare the processes listed below:

Coordination and response in plants

Yeast obtains energy for growth and reproduction by breaking down sugar (glucose) through anaerobic respiration: glucose → carbon dioxide + alcohol In human food, sugar is added to give a sweet taste. If the diet contains too much sugar, diseases can develop. Sugar substitutes are available and taste as sweet as sugar. A student chose to find out whether yeast could use a sugar substitute for respiration. Three test-tubes were arranged as shown in Table 1.1. Each test-tube was given a label so that it could be recognised. The level of the mixtures in each test-tube was marked with a water-resistant marker. This showed the starting level. When yeast respires, bubbles of gas are produced and trapped in the mixture, causing the level of the mixture to rise up the test-tube. The student used a large beaker as a water-bath to keep the temperature of the test-tubes constant in this investigation. The temperature of the water at the start was $35\,^{\circ}\text{C}$. The intention was to keep this temperature the same throughout the investigation by adding hot or cold water. The three test-tubes were placed in the water-bath, and a timer was started. At 5 minutes, 10 minutes and 15 minutes, the distances moved by the mixtures from the starting levels were measured and recorded. The temperature of the water-bath was also recorded. Fig. 1.1 shows the lower parts of the test-tubes at 5 minutes and the water-bath thermometer reading at 5 minutes. Fig. 1.2 shows the results for 10 and 15 minutes recorded in the student’s notebook.

Anaerobic respiration

In aerobic respiration, organisms take in oxygen and release carbon dioxide. A group of students used the apparatus in Fig. 2.1 to investigate how quickly germinating seeds respired. The carbon dioxide given off by the germinating seeds was removed by the soda lime. As oxygen was consumed, the gas volume inside the apparatus decreased, so the drop of coloured liquid travelled along the capillary tube towards the seeds. The students returned the drop of coloured liquid in the capillary tube to the start of the scale (0 mm) by opening the three-way tap and using the syringe to gently force air into the apparatus. The tap was then closed. This was the starting position of the drop of coloured liquid. Its position on the scale was noted during the next four minutes. The distance moved by the drop of coloured liquid shows the respiration rate of the seeds. The students’ results are given in Table 2.1.

Aerobic respiration

Fig. 3.1 illustrates the entire one-seeded fruit from a dandelion flower. One dandelion flowerhead may form as many as 200 of these one-seeded fruits. The mass of one fruit is $0.0005\,\text{g}$.

Sexual reproduction in plants

Carbohydrates occur in a range of plant organs as starch and as sugars, for example glucose and maltose. A student chose to check two different plant organs, a potato and an apple, for starch and sugar. The student did the starch test on pieces of potato and apple. Fig. 1.1 shows how the plant pieces looked before the test and after the test.

Biological molecules

Photosynthesis in green plants may be represented by the equation: carbon dioxide + water $\xrightarrow{\text{light and chlorophyll}}$ carbohydrate + oxygen A student used the apparatus shown in Fig. 2.1 to examine the rate of photosynthesis in an aquatic plant. After the student turned the lamp on, bubbles of oxygen were produced and drawn into the syringe. The student noted the volume of oxygen made in ten minutes. The syringe was then topped up with sodium hydrogencarbonate solution and the oxygen was collected for a further ten minutes. The student then chose to test how different colours of light affected the rate of photosynthesis. With the same plant left in the glass jar, a red transparent filter was wrapped around the glass jar so that the plant received only red light. The volume of oxygen made in ten minutes was measured. This measurement was then carried out again. Next, the red transparent filter was swapped for a green transparent filter and then for a blue transparent filter. For each filter, the volume of oxygen made in ten minutes was also measured twice. The measurements are shown in Table 2.1.

Photosynthesis

Fig. 3.1 contains photographs of a male and a female insect from the same species. Both insects are green.

Concept and use of a classification system